slint/internal/backends/qt/qt_window.rs

// Copyright © SixtyFPS GmbH <info@slint.dev>
// SPDX-License-Identifier: GPL-3.0-only OR LicenseRef-Slint-Royalty-free-2.0 OR LicenseRef-Slint-Software-3.0

// cSpell: ignore frameless qbrush qpointf qreal qwidgetsize svgz

use cpp::*;
use i_slint_core::graphics::rendering_metrics_collector::{
    RenderingMetrics, RenderingMetricsCollector,
};
use i_slint_core::graphics::{
    euclid, Brush, Color, FontRequest, IntRect, Point, Rgba8Pixel, SharedImageBuffer,
    SharedPixelBuffer,
};
use i_slint_core::input::{KeyEvent, KeyEventType, MouseEvent};
use i_slint_core::item_rendering::{
    CachedRenderingData, ItemCache, ItemRenderer, RenderBorderRectangle, RenderImage,
    RenderRectangle, RenderText,
};
use i_slint_core::item_tree::ParentItemTraversalMode;
use i_slint_core::item_tree::{ItemTreeRc, ItemTreeRef};
use i_slint_core::items::{
    self, ColorScheme, FillRule, ImageRendering, ItemRc, ItemRef, Layer, LineCap, MouseCursor,
    Opacity, PointerEventButton, RenderingResult, TextOverflow, TextStrokeStyle, TextWrap,
};
use i_slint_core::layout::Orientation;
use i_slint_core::lengths::{
    LogicalBorderRadius, LogicalLength, LogicalPoint, LogicalRect, LogicalSize, LogicalVector,
    PhysicalPx, ScaleFactor,
};
use i_slint_core::platform::{PlatformError, WindowEvent};
use i_slint_core::window::{WindowAdapter, WindowAdapterInternal, WindowInner};
use i_slint_core::{ImageInner, Property, SharedString};
use items::{TextHorizontalAlignment, TextVerticalAlignment};

use std::cell::RefCell;
use std::pin::Pin;
use std::ptr::NonNull;
use std::rc::{Rc, Weak};

use crate::key_generated;
use i_slint_core::renderer::Renderer;
use std::cell::OnceCell;

cpp! {{
    #include <QtWidgets/QtWidgets>
    #include <QtWidgets/QGraphicsScene>
    #include <QtWidgets/QGraphicsBlurEffect>
    #include <QtWidgets/QGraphicsPixmapItem>
    #include <QtGui/QAccessible>
    #include <QtGui/QPainter>
    #include <QtGui/QPaintEngine>
    #include <QtGui/QPainterPath>
    #include <QtGui/QWindow>
    #include <QtGui/QResizeEvent>
    #include <QtGui/QTextLayout>
    #include <QtGui/QImageReader>
    #include <QtGui/QCursor>
    #include <QtCore/QBasicTimer>
    #include <QtCore/QTimer>
    #include <QtCore/QPointer>
    #include <QtCore/QBuffer>
    #include <QtCore/QEvent>
    #include <QtCore/QFileInfo>

    #include <memory>

    void ensure_initialized(bool from_qt_backend);

    using QPainterPtr = std::unique_ptr<QPainter>;

    struct TimerHandler : QObject {
        QBasicTimer timer;
        static TimerHandler& instance() {
            static TimerHandler instance;
            return instance;
        }

        void timerEvent(QTimerEvent *event) override {
            if (event->timerId() != timer.timerId()) {
                QObject::timerEvent(event);
                return;
            }
            timer.stop();
            rust!(Slint_timerEvent [] { timer_event() });
        }

    };

    struct SlintWidget : QWidget {
        void *rust_window = nullptr;
        bool isMouseButtonDown = false;
        QRect ime_position;
        QString ime_text;
        int ime_cursor = 0;
        int ime_anchor = 0;

        SlintWidget() {
            setMouseTracking(true);
            setFocusPolicy(Qt::StrongFocus);
            setAttribute(Qt::WA_TranslucentBackground);
            // WA_TranslucentBackground sets WA_NoSystemBackground, but we actually need WA_NoSystemBackground
            // to draw the window background which is set on the palette.
            // (But the window background might not be opaque)
            setAttribute(Qt::WA_NoSystemBackground, false);
        }

        void paintEvent(QPaintEvent *) override {
            if (!rust_window)
                return;
            auto painter = std::unique_ptr<QPainter>(new QPainter(this));
            painter->setClipRect(rect());
            painter->setRenderHints(QPainter::Antialiasing | QPainter::SmoothPixmapTransform);
            QPainterPtr *painter_ptr = &painter;
            rust!(Slint_paintEvent [rust_window: &QtWindow as "void*", painter_ptr: &mut QPainterPtr as "QPainterPtr*"] {
                rust_window.paint_event(std::mem::take(painter_ptr))
            });
        }

        void resizeEvent(QResizeEvent *) override {
            if (!rust_window)
                return;

            // On windows, the size in the event is not reliable during
            // fullscreen changes. Querying the widget itself seems to work
            // better, see: https://stackoverflow.com/questions/52157587/why-qresizeevent-qwidgetsize-gives-different-when-fullscreen
            QSize size = this->size();
            rust!(Slint_resizeEvent [rust_window: &QtWindow as "void*", size: qttypes::QSize as "QSize"] {
                rust_window.resize_event(size)
            });
        }

        /// If this window is a PopupWindow and the mouse event is outside of the popup, then adjust the event to map to the parent window
        /// Returns the position and the rust_window to which we need to deliver the event
        std::tuple<QPoint, void*> adjust_mouse_event_to_popup_parent(QMouseEvent *event) {
            auto pos = event->pos();
            if (auto p = dynamic_cast<const SlintWidget*>(parent()); p && !rect().contains(pos)) {
    #if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
                QPoint eventPos = event->globalPosition().toPoint();
    #else
                QPoint eventPos = event->globalPos();
    #endif
                while (auto pp = dynamic_cast<const SlintWidget*>(p->parent())) {
                    if (p->rect().contains(p->mapFromGlobal(eventPos)))
                        break;
                    p = pp;
                }
                return { p->mapFromGlobal(eventPos), p->rust_window };
            } else {
                return { pos, rust_window };
            }
        }

        void mousePressEvent(QMouseEvent *event) override {
            isMouseButtonDown = true;
            auto [pos, rust_window] = adjust_mouse_event_to_popup_parent(event);
            if (!rust_window)
                return;
            int button = event->button();
            rust!(Slint_mousePressEvent [rust_window: &QtWindow as "void*", pos: qttypes::QPoint as "QPoint", button: u32 as "int" ] {
                let position = LogicalPoint::new(pos.x as _, pos.y as _);
                let button = from_qt_button(button);
                rust_window.mouse_event(MouseEvent::Pressed{ position, button, click_count: 0 })
            });
        }
        void mouseReleaseEvent(QMouseEvent *event) override {
            auto [pos, rust_window] = adjust_mouse_event_to_popup_parent(event);
            if (!rust_window)
                return;

            // HACK: Qt on windows is a bit special when clicking on the window
            //       close button and when the resulting close event is ignored.
            //       In that case a release event that was not preceded by
            //       a press event is sent on Windows.
            //       This confuses Slint, so eat this event.
            //
            //       One example is a popup is shown in the close event that
            //       then ignores the close request to ask the user what to
            //       do. The stray release event will then close the popup
            //       straight away
            //
            //       However, we must still forward the event to the right popup menu
            //       that's why we compare rust_window with this->rust_window
            if (!isMouseButtonDown && rust_window == this->rust_window) {
                return;
            }
            isMouseButtonDown = event->button() != Qt::NoButton;

            int button = event->button();
            rust!(Slint_mouseReleaseEvent [rust_window: &QtWindow as "void*", pos: qttypes::QPoint as "QPoint", button: u32 as "int" ] {
                let position = LogicalPoint::new(pos.x as _, pos.y as _);
                let button = from_qt_button(button);
                rust_window.mouse_event(MouseEvent::Released{ position, button, click_count: 0 })
            });
        }
        void mouseMoveEvent(QMouseEvent *event) override {
            auto [pos, rust_window] = adjust_mouse_event_to_popup_parent(event);
            if (!rust_window)
                return;
            rust!(Slint_mouseMoveEvent [rust_window: &QtWindow as "void*", pos: qttypes::QPoint as "QPoint"] {
                let position = LogicalPoint::new(pos.x as _, pos.y as _);
                rust_window.mouse_event(MouseEvent::Moved{position})
            });
        }
        void wheelEvent(QWheelEvent *event) override {
            if (!rust_window)
                return;
            QPointF pos = event->position();
            QPoint delta = event->pixelDelta();
            if (delta.isNull()) {
                delta = event->angleDelta();
            }
            rust!(Slint_mouseWheelEvent [rust_window: &QtWindow as "void*", pos: qttypes::QPointF as "QPointF", delta: qttypes::QPoint as "QPoint"] {
                let position = LogicalPoint::new(pos.x as _, pos.y as _);
                rust_window.mouse_event(MouseEvent::Wheel{position, delta_x: delta.x as _, delta_y: delta.y as _})
            });
        }
        void leaveEvent(QEvent *) override {
            if (!rust_window)
                return;
            rust!(Slint_mouseLeaveEvent [rust_window: &QtWindow as "void*"] {
                rust_window.mouse_event(MouseEvent::Exit)
            });
        }

        void keyPressEvent(QKeyEvent *event) override {
            if (!rust_window)
                return;
            QString text =  event->text();
            int key = event->key();
            bool repeat = event->isAutoRepeat();
            rust!(Slint_keyPress [rust_window: &QtWindow as "void*", key: i32 as "int", text: qttypes::QString as "QString", repeat: bool as "bool"] {
                rust_window.key_event(key, text.clone(), false, repeat);
            });
        }
        void keyReleaseEvent(QKeyEvent *event) override {
            if (!rust_window)
                return;
            // Qt sends repeated releases together with presses for auto-repeat events, but Slint only sends presses in that case.
            // This matches the behavior of at least winit, Web and Android.
            if (event->isAutoRepeat())
                return;

            QString text =  event->text();
            int key = event->key();
            rust!(Slint_keyRelease [rust_window: &QtWindow as "void*", key: i32 as "int", text: qttypes::QString as "QString"] {
                rust_window.key_event(key, text.clone(), true, false);
            });
        }

        void changeEvent(QEvent *event) override {
            if (!rust_window)
                return QWidget::changeEvent(event);

            if (event->type() == QEvent::ActivationChange) {
                bool active = isActiveWindow();
                rust!(Slint_updateWindowActivation [rust_window: &QtWindow as "void*", active: bool as "bool"] {
                    rust_window.window.dispatch_event(WindowEvent::WindowActiveChanged(active));
                });
            } else if (event->type() == QEvent::PaletteChange || event->type() == QEvent::StyleChange) {
                bool dark_color_scheme = qApp->palette().color(QPalette::Window).valueF() < 0.5;
                rust!(Slint_updateWindowDarkColorScheme [rust_window: &QtWindow as "void*", dark_color_scheme: bool as "bool"] {
                    if let Some(ds) = rust_window.color_scheme.get() {
                        ds.as_ref().set(if dark_color_scheme {
                            ColorScheme::Dark
                        } else {
                            ColorScheme::Light
                        });
                    }
                });
            }

            // Entering fullscreen, maximizing or minimizing the window will
            // trigger a change event. We need to update the internal window
            // state to match the actual window state.
            if (event->type() == QEvent::WindowStateChange)
            {
                rust!(Slint_syncWindowState [rust_window: &QtWindow as "void*"]{
                    rust_window.window_state_event();
                });
            }


            QWidget::changeEvent(event);
        }

        void closeEvent(QCloseEvent *event) override {
            if (!rust_window)
                return;
            rust!(Slint_requestClose [rust_window: &QtWindow as "void*"] {
                rust_window.window.dispatch_event(WindowEvent::CloseRequested);
            });
            event->ignore();
        }

        QSize sizeHint() const override {
            if (!rust_window)
                return {};
            auto preferred_size = rust!(Slint_sizeHint [rust_window: &QtWindow as "void*"] -> qttypes::QSize as "QSize" {
                let component_rc = WindowInner::from_pub(&rust_window.window).component();
                let component = ItemTreeRc::borrow_pin(&component_rc);
                let layout_info_h = component.as_ref().layout_info(Orientation::Horizontal);
                let layout_info_v = component.as_ref().layout_info(Orientation::Vertical);
                qttypes::QSize {
                    width: layout_info_h.preferred_bounded() as _,
                    height: layout_info_v.preferred_bounded() as _,
                }
            });
            if (!preferred_size.isEmpty()) {
                return preferred_size;
            } else {
                return QWidget::sizeHint();
            }
        }

        QVariant inputMethodQuery(Qt::InputMethodQuery query) const override {
            switch (query) {
            case Qt::ImCursorRectangle: return ime_position;
            case Qt::ImCursorPosition: return ime_cursor;
            case Qt::ImSurroundingText: return ime_text;
            case Qt::ImCurrentSelection: return ime_text.mid(qMin(ime_cursor, ime_anchor), qAbs(ime_cursor - ime_anchor));
            case Qt::ImAnchorPosition: return ime_anchor;
            case Qt::ImTextBeforeCursor: return ime_text.left(ime_cursor);
            case Qt::ImTextAfterCursor: return ime_text.right(ime_cursor);
            default: break;
            }
            return QWidget::inputMethodQuery(query);
        }

        void inputMethodEvent(QInputMethodEvent *event) override {
            if (!rust_window)
                return;
            QString commit_string = event->commitString();
            QString preedit_string = event->preeditString();
            int replacement_start = event->replacementStart();
            QStringView ime_text(this->ime_text);
            replacement_start = replacement_start < 0 ?
                -ime_text.mid(ime_cursor,-replacement_start).toUtf8().size() :
                ime_text.mid(ime_cursor,replacement_start).toUtf8().size();
            int replacement_length = qMax(0, event->replacementLength());
            ime_text.mid(ime_cursor + replacement_start, replacement_length).toUtf8().size();
            int preedit_cursor = -1;
            for (const QInputMethodEvent::Attribute &attribute: event->attributes()) {
                if (attribute.type == QInputMethodEvent::Cursor) {
                    if (attribute.length > 0) {
                        preedit_cursor = QStringView(preedit_string).left(attribute.start).toUtf8().size();
                    }
                }
            }
            event->accept();
            rust!(Slint_inputMethodEvent [rust_window: &QtWindow as "void*", commit_string: qttypes::QString as "QString",
                preedit_string: qttypes::QString as "QString", replacement_start: i32 as "int", replacement_length: i32 as "int",
                preedit_cursor: i32 as "int"] {
                    let runtime_window = WindowInner::from_pub(&rust_window.window);

                    let event = KeyEvent {
                        event_type: KeyEventType::UpdateComposition,
                        text: i_slint_core::format!("{}", commit_string),
                        preedit_text: i_slint_core::format!("{}", preedit_string),
                        preedit_selection: (preedit_cursor >= 0).then_some(preedit_cursor..preedit_cursor),
                        replacement_range: (!commit_string.is_empty() || !preedit_string.is_empty() || preedit_cursor >= 0)
                            .then_some(replacement_start..replacement_start+replacement_length),
                        ..Default::default()
                    };
                    runtime_window.process_key_input(event);
                });
        }
    };

    // Helper function used for the TextInput layouting
    //
    // if line_for_y_pos > 0, then the function will return the line at this y position
    static int do_text_layout(QTextLayout &layout, int flags, const QRectF &rect, int line_for_y_pos = -1) {
        QTextOption options;
        options.setWrapMode((flags & Qt::TextWordWrap) ? QTextOption::WordWrap : ((flags & Qt::TextWrapAnywhere) ? QTextOption::WrapAnywhere : QTextOption::NoWrap));
        if (flags & Qt::AlignHCenter)
            options.setAlignment(Qt::AlignCenter);
        else if (flags & Qt::AlignLeft)
            options.setAlignment(Qt::AlignLeft);
        else if (flags & Qt::AlignRight)
            options.setAlignment(Qt::AlignRight);
        options.setFlags(QTextOption::IncludeTrailingSpaces);
        layout.setTextOption(options);
        layout.setCacheEnabled(true);
        QFontMetrics fm(layout.font());
        int leading = fm.leading();
        qreal height = 0;
        layout.beginLayout();
        int count = 0;
        while(1) {
            auto line = layout.createLine();
            if (!line.isValid())
                break;
            line.setLineWidth(rect.width());
            height += leading;
            line.setPosition(QPointF(0, height));
            height += line.height();
            if (line_for_y_pos >= 0 && height > line_for_y_pos) {
                return count;
            }
            count++;
        }
        layout.endLayout();
        if (flags & Qt::AlignVCenter) {
            layout.setPosition(QPointF(0, (rect.height() - height) / 2.));
        } else if (flags & Qt::AlignBottom) {
            layout.setPosition(QPointF(0, rect.height() - height));
        }
        return -1;
    }

    QPainterPath to_painter_path(const QRectF &rect, qreal top_left_radius, qreal top_right_radius, qreal bottom_right_radius, qreal bottom_left_radius) {
        QPainterPath path;
        if (qFuzzyCompare(top_left_radius, top_right_radius) && qFuzzyCompare(top_left_radius, bottom_right_radius) && qFuzzyCompare(top_left_radius, bottom_left_radius)) {
            path.addRoundedRect(rect, top_left_radius, top_left_radius);
        } else {
            QSizeF half = rect.size() / 2.0;

            qreal tl_rx = qMin(top_left_radius, half.width());
            qreal tl_ry = qMin(top_left_radius, half.height());
            QRectF top_left(rect.left(), rect.top(), 2 * tl_rx, 2 * tl_ry);

            qreal tr_rx = qMin(top_right_radius, half.width());
            qreal tr_ry = qMin(top_right_radius, half.height());
            QRectF top_right(rect.right() - 2 * tr_rx, rect.top(), 2 * tr_rx, 2 * tr_ry);

            qreal br_rx = qMin(bottom_right_radius, half.width());
            qreal br_ry = qMin(bottom_right_radius, half.height());
            QRectF bottom_right(rect.right() - 2 * br_rx, rect.bottom() - 2 * br_ry, 2 * br_rx, 2 * br_ry);

            qreal bl_rx = qMin(bottom_left_radius, half.width());
            qreal bl_ry = qMin(bottom_left_radius, half.height());
            QRectF bottom_left(rect.left(), rect.bottom() - 2 * bl_ry, 2 * bl_rx, 2 * bl_ry);

            if (top_left.isNull()) {
                path.moveTo(rect.topLeft());
            } else {
                path.arcMoveTo(top_left, 180);
                path.arcTo(top_left, 180, -90);
            }
            if (top_right.isNull()) {
                path.lineTo(rect.topRight());
            } else {
                path.arcTo(top_right, 90, -90);
            }
            if (bottom_right.isNull()) {
                path.lineTo(rect.bottomRight());
            } else {
                path.arcTo(bottom_right, 0, -90);
            }
            if (bottom_left.isNull()) {
                path.lineTo(rect.bottomLeft());
            } else {
                path.arcTo(bottom_left, -90, -90);
            }
            path.closeSubpath();
        }
        return path;
    };
}}

cpp_class!(
    /// Wrapper around a pointer to a QPainter.
    // We can't use [`qttypes::QPainter`] because it is not sound <https://github.com/woboq/qmetaobject-rs/issues/267>
    pub unsafe struct QPainterPtr as "QPainterPtr"
);
impl QPainterPtr {
    pub fn restore(&mut self) {
        cpp!(unsafe [self as "QPainterPtr*"] {
            (*self)->restore();
        });
    }

    pub fn save(&mut self) {
        cpp!(unsafe [self as "QPainterPtr*"] {
            (*self)->save();
        });
    }
}

cpp_class! {pub unsafe struct QPainterPath as "QPainterPath"}

impl QPainterPath {
    /*
    pub fn reserve(&mut self, size: usize) {
        cpp! { unsafe [self as "QPainterPath*", size as "long long"] {
            self->reserve(size);
        }}
    }*/

    pub fn move_to(&mut self, to: qttypes::QPointF) {
        cpp! { unsafe [self as "QPainterPath*", to as "QPointF"] {
            self->moveTo(to);
        }}
    }
    pub fn line_to(&mut self, to: qttypes::QPointF) {
        cpp! { unsafe [self as "QPainterPath*", to as "QPointF"] {
            self->lineTo(to);
        }}
    }
    pub fn quad_to(&mut self, ctrl: qttypes::QPointF, to: qttypes::QPointF) {
        cpp! { unsafe [self as "QPainterPath*", ctrl as "QPointF", to as "QPointF"] {
            self->quadTo(ctrl, to);
        }}
    }
    pub fn cubic_to(
        &mut self,
        ctrl1: qttypes::QPointF,
        ctrl2: qttypes::QPointF,
        to: qttypes::QPointF,
    ) {
        cpp! { unsafe [self as "QPainterPath*", ctrl1 as "QPointF", ctrl2 as "QPointF", to as "QPointF"] {
            self->cubicTo(ctrl1, ctrl2, to);
        }}
    }

    pub fn close(&mut self) {
        cpp! { unsafe [self as "QPainterPath*"] {
            self->closeSubpath();
        }}
    }

    pub fn set_fill_rule(&mut self, rule: key_generated::Qt_FillRule) {
        cpp! { unsafe [self as "QPainterPath*", rule as "Qt::FillRule" ] {
            self->setFillRule(rule);
        }}
    }
}

fn into_qbrush(
    brush: i_slint_core::Brush,
    width: qttypes::qreal,
    height: qttypes::qreal,
) -> qttypes::QBrush {
    /// Mangle the position to work around the fact that Qt merge stop at equal position
    fn mangle_position(position: f32, idx: usize, count: usize) -> f32 {
        // Add or subtract a small amount to make sure each stop is different but still in [0..1].
        // It is possible that we swap stops that are both really really close to 0.54321+ε,
        // but that is really unlikely
        if position < 0.54321 + 67.8 * f32::EPSILON {
            position + f32::EPSILON * idx as f32
        } else {
            position - f32::EPSILON * (count - idx - 1) as f32
        }
    }
    match brush {
        i_slint_core::Brush::SolidColor(color) => {
            let color: u32 = color.as_argb_encoded();
            cpp!(unsafe [color as "QRgb"] -> qttypes::QBrush as "QBrush" {
                return QBrush(QColor::fromRgba(color));
            })
        }
        i_slint_core::Brush::LinearGradient(g) => {
            let (start, end) = i_slint_core::graphics::line_for_angle(
                g.angle(),
                [width as f32, height as f32].into(),
            );
            let p1 = qttypes::QPointF { x: start.x as _, y: start.y as _ };
            let p2 = qttypes::QPointF { x: end.x as _, y: end.y as _ };
            cpp_class!(unsafe struct QLinearGradient as "QLinearGradient");
            let mut qlg = cpp! {
                unsafe [p1 as "QPointF", p2 as "QPointF"] -> QLinearGradient as "QLinearGradient" {
                    QLinearGradient qlg(p1, p2);
                    return qlg;
                }
            };
            let count = g.stops().count();
            for (idx, s) in g.stops().enumerate() {
                let pos: f32 = mangle_position(s.position, idx, count);
                let color: u32 = s.color.as_argb_encoded();
                cpp! {unsafe [mut qlg as "QLinearGradient", pos as "float", color as "QRgb"] {
                    qlg.setColorAt(pos, QColor::fromRgba(color));
                }};
            }
            cpp! {unsafe [qlg as "QLinearGradient"] -> qttypes::QBrush as "QBrush" {
                return QBrush(qlg);
            }}
        }
        i_slint_core::Brush::RadialGradient(g) => {
            cpp_class!(unsafe struct QRadialGradient as "QRadialGradient");
            let mut qrg = cpp! {
                unsafe [width as "qreal", height as "qreal"] -> QRadialGradient as "QRadialGradient" {
                    QRadialGradient qrg(width / 2, height / 2, sqrt(width * width + height * height) / 2);
                    return qrg;
                }
            };
            let count = g.stops().count();
            for (idx, s) in g.stops().enumerate() {
                let pos: f32 = mangle_position(s.position, idx, count);
                let color: u32 = s.color.as_argb_encoded();
                cpp! {unsafe [mut qrg as "QRadialGradient", pos as "float", color as "QRgb"] {
                    qrg.setColorAt(pos, QColor::fromRgba(color));
                }};
            }
            cpp! {unsafe [qrg as "QRadialGradient"] -> qttypes::QBrush as "QBrush" {
                return QBrush(qrg);
            }}
        }
        _ => qttypes::QBrush::default(),
    }
}

fn from_qt_button(qt_button: u32) -> PointerEventButton {
    match qt_button {
        // https://doc.qt.io/qt-6/qt.html#MouseButton-enum
        1 => PointerEventButton::Left,
        2 => PointerEventButton::Right,
        4 => PointerEventButton::Middle,
        8 => PointerEventButton::Back,
        16 => PointerEventButton::Forward,
        _ => PointerEventButton::Other,
    }
}

/// Given a position offset and an object of a given type that has x,y,width,height properties,
/// create a QRectF that fits it.
macro_rules! check_geometry {
    ($size:expr) => {{
        let size = $size;
        if size.width < 1. || size.height < 1. {
            return Default::default();
        };
        qttypes::QRectF { x: 0., y: 0., width: size.width as _, height: size.height as _ }
    }};
}

fn adjust_rect_and_border_for_inner_drawing(rect: &mut qttypes::QRectF, border_width: &mut f32) {
    // If the border width exceeds the width, just fill the rectangle.
    *border_width = border_width.min((rect.width as f32) / 2.);
    // adjust the size so that the border is drawn within the geometry
    rect.x += *border_width as f64 / 2.;
    rect.y += *border_width as f64 / 2.;
    rect.width -= *border_width as f64;
    rect.height -= *border_width as f64;
}

struct QtItemRenderer<'a> {
    painter: QPainterPtr,
    cache: &'a ItemCache<qttypes::QPixmap>,
    window: &'a i_slint_core::api::Window,
    metrics: RenderingMetrics,
}

impl ItemRenderer for QtItemRenderer<'_> {
    fn draw_rectangle(
        &mut self,
        rect_: Pin<&dyn RenderRectangle>,
        _: &ItemRc,
        size: LogicalSize,
        _cache: &CachedRenderingData,
    ) {
        let rect: qttypes::QRectF = check_geometry!(size);
        let brush: qttypes::QBrush = into_qbrush(rect_.background(), rect.width, rect.height);
        let painter: &mut QPainterPtr = &mut self.painter;
        cpp! { unsafe [painter as "QPainterPtr*", brush as "QBrush", rect as "QRectF"] {
            (*painter)->fillRect(rect, brush);
        }}
    }

    fn draw_border_rectangle(
        &mut self,
        rect: Pin<&dyn RenderBorderRectangle>,
        _: &ItemRc,
        size: LogicalSize,
        _: &CachedRenderingData,
    ) {
        Self::draw_rectangle_impl(
            &mut self.painter,
            check_geometry!(size),
            rect.background(),
            rect.border_color(),
            rect.border_width().get(),
            rect.border_radius(),
        );
    }

    fn draw_window_background(
        &mut self,
        _rect: Pin<&dyn RenderRectangle>,
        _self_rc: &ItemRc,
        _size: LogicalSize,
        _cache: &CachedRenderingData,
    ) {
        // Background is applied via WindowProperties::background()
    }

    fn draw_image(
        &mut self,
        image: Pin<&dyn RenderImage>,
        item_rc: &ItemRc,
        size: LogicalSize,
        _: &CachedRenderingData,
    ) {
        self.draw_image_impl(item_rc, size, image);
    }

    fn draw_text(
        &mut self,
        text: Pin<&dyn RenderText>,
        self_rc: &ItemRc,
        size: LogicalSize,
        _: &CachedRenderingData,
    ) {
        let rect: qttypes::QRectF = check_geometry!(size);
        let fill_brush: qttypes::QBrush = into_qbrush(text.color(), rect.width, rect.height);
        let mut string: qttypes::QString = text.text().as_str().into();
        let font: QFont = get_font(text.font_request(self_rc));
        let (horizontal_alignment, vertical_alignment) = text.alignment();
        let alignment = match horizontal_alignment {
            TextHorizontalAlignment::Left => key_generated::Qt_AlignmentFlag_AlignLeft,
            TextHorizontalAlignment::Center => key_generated::Qt_AlignmentFlag_AlignHCenter,
            TextHorizontalAlignment::Right => key_generated::Qt_AlignmentFlag_AlignRight,
        } | match vertical_alignment {
            TextVerticalAlignment::Top => key_generated::Qt_AlignmentFlag_AlignTop,
            TextVerticalAlignment::Center => key_generated::Qt_AlignmentFlag_AlignVCenter,
            TextVerticalAlignment::Bottom => key_generated::Qt_AlignmentFlag_AlignBottom,
        };
        let wrap = text.wrap() != TextWrap::NoWrap;
        let word_wrap = text.wrap() == TextWrap::WordWrap;
        let elide = text.overflow() == TextOverflow::Elide;
        let (stroke_brush, stroke_width, stroke_style) = text.stroke();
        let stroke_visible = !stroke_brush.is_transparent();
        let stroke_brush: qttypes::QBrush = into_qbrush(stroke_brush, rect.width, rect.height);
        let stroke_outside = stroke_style == TextStrokeStyle::Outside;
        let stroke_width = match stroke_style {
            TextStrokeStyle::Outside => stroke_width.get() * 2.0,
            TextStrokeStyle::Center => stroke_width.get(),
        };
        let painter: &mut QPainterPtr = &mut self.painter;
        cpp! { unsafe [painter as "QPainterPtr*", rect as "QRectF", fill_brush as "QBrush", stroke_brush as "QBrush", mut string as "QString", font as "QFont", elide as "bool", alignment as "Qt::Alignment", wrap as "bool", word_wrap as "bool", stroke_visible as "bool", stroke_outside as "bool", stroke_width as "float"] {
            QString elided;
            if (!elide) {
                elided = string;
            } else if (!wrap) {
                QFontMetrics fm(font);
                while (!string.isEmpty()) {
                    int pos = string.indexOf('\n');
                    if (pos < 0) {
                        elided += fm.elidedText(string, Qt::ElideRight, rect.width());
                        break;
                    }
                    QString line = string.left(pos);
                    elided += fm.elidedText(line, Qt::ElideRight, rect.width());
                    elided += '\n';
                    string = string.mid(pos + 1);
                }
            } else {
                // elide and word wrap: we need to add the ellipsis manually on the last line
                string.replace(QChar('\n'), QChar::LineSeparator);
                elided = string;
                QFontMetrics fm(font);
                QTextLayout layout(string, font);
                QTextOption options;
                if (word_wrap) {
                    options.setWrapMode(QTextOption::WordWrap);
                } else {
                    options.setWrapMode(QTextOption::WrapAnywhere);
                }
                layout.setTextOption(options);
                layout.setCacheEnabled(true);
                layout.beginLayout();
                int leading = fm.leading();
                qreal height = 0;
                int last_line_begin = 0, last_line_size = 0;
                while (true) {
                    auto line = layout.createLine();
                    if (!line.isValid()) {
                        last_line_begin = string.size();
                        break;
                    }
                    line.setLineWidth(rect.width());
                    height += leading + line.height();
                    if (height > rect.height()) {
                        break;
                    }
                    last_line_begin = line.textStart();
                    last_line_size = line.textLength();
                }
                if (last_line_begin < string.size()) {
                    elided = string.left(last_line_begin);
                    QString to_elide = QStringView(string).mid(last_line_begin, last_line_size).trimmed() % QStringView(QT_UNICODE_LITERAL("…"));
                    elided += fm.elidedText(to_elide, Qt::ElideRight, rect.width());
                }
            }

            if (!stroke_visible) {
                int flags = alignment;
                if (wrap) {
                    if (word_wrap) {
                        flags |= Qt::TextWordWrap;
                    } else {
                        flags |= Qt::TextWrapAnywhere;
                    }
                }

                (*painter)->setFont(font);
                (*painter)->setBrush(Qt::NoBrush);
                (*painter)->setPen(QPen(fill_brush, 0));
                (*painter)->drawText(rect, flags, elided);
            } else {
                QTextDocument document(elided);
                document.setDocumentMargin(0);
                document.setPageSize(rect.size());
                document.setDefaultFont(font);

                QTextOption options = document.defaultTextOption();
                options.setAlignment(alignment);
                if (wrap) {
                    if (word_wrap) {
                        options.setWrapMode(QTextOption::WordWrap);
                    } else {
                        options.setWrapMode(QTextOption::WrapAnywhere);
                    }
                }
                document.setDefaultTextOption(options);

                // Workaround for https://bugreports.qt.io/browse/QTBUG-13467
                float dy = 0;
                if (!(alignment & Qt::AlignTop)) {
                    QRectF bounding_rect;
                    for (QTextBlock it = document.begin(); it != document.end(); it = it.next()) {
                        bounding_rect = bounding_rect.united(document.documentLayout()->blockBoundingRect(it));
                    }
                    if (alignment & Qt::AlignVCenter) {
                        dy = (rect.height() - bounding_rect.height()) / 2.0;
                    } else if (alignment & Qt::AlignBottom) {
                        dy = (rect.height() - bounding_rect.height());
                    }
                }

                QTextCharFormat format;
                format.setFont(font);

                QPen stroke_pen(stroke_brush, stroke_width, Qt::SolidLine, Qt::FlatCap, Qt::MiterJoin);
                stroke_pen.setMiterLimit(10.0);
                if (stroke_width == 0.0) {
                    // Hairline stroke
                    if (stroke_outside)
                        stroke_pen.setWidthF(2.0);
                    else
                        stroke_pen.setWidthF(1.0);
                    stroke_pen.setCosmetic(true);
                }

                QTextCursor cursor(&document);
                cursor.select(QTextCursor::Document);

                (*painter)->save();
                (*painter)->translate(0, dy);

                if (stroke_outside) {
                    format.setForeground(Qt::NoBrush);
                    format.setTextOutline(stroke_pen);
                    cursor.mergeCharFormat(format);
                    document.drawContents((*painter).get(), rect);
                }

                format.setForeground(fill_brush);
                if (!stroke_outside) {
                    format.setTextOutline(stroke_pen);
                } else {
                    // Use a transparent pen instead of Qt::NoPen so the
                    // fill is aligned properly to the outside stroke
                    format.setTextOutline(QPen(QColor(Qt::transparent), stroke_width));
                }
                cursor.mergeCharFormat(format);
                document.drawContents((*painter).get(), rect);

                (*painter)->restore();
            }
        }}
    }

    fn draw_text_input(
        &mut self,
        text_input: Pin<&items::TextInput>,
        self_rc: &ItemRc,
        size: LogicalSize,
    ) {
        let rect: qttypes::QRectF = check_geometry!(size);
        let fill_brush: qttypes::QBrush = into_qbrush(text_input.color(), rect.width, rect.height);

        let font: QFont = get_font(text_input.font_request(self_rc));
        let flags = match text_input.horizontal_alignment() {
            TextHorizontalAlignment::Left => key_generated::Qt_AlignmentFlag_AlignLeft,
            TextHorizontalAlignment::Center => key_generated::Qt_AlignmentFlag_AlignHCenter,
            TextHorizontalAlignment::Right => key_generated::Qt_AlignmentFlag_AlignRight,
        } | match text_input.vertical_alignment() {
            TextVerticalAlignment::Top => key_generated::Qt_AlignmentFlag_AlignTop,
            TextVerticalAlignment::Center => key_generated::Qt_AlignmentFlag_AlignVCenter,
            TextVerticalAlignment::Bottom => key_generated::Qt_AlignmentFlag_AlignBottom,
        } | match text_input.wrap() {
            TextWrap::NoWrap => 0,
            TextWrap::WordWrap => key_generated::Qt_TextFlag_TextWordWrap,
            TextWrap::CharWrap => key_generated::Qt_TextFlag_TextWrapAnywhere,
        };

        let visual_representation = text_input.visual_representation(Some(qt_password_character));

        let text = &visual_representation.text;
        let mut string: qttypes::QString = text.as_str().into();

        // convert byte offsets to offsets in Qt UTF-16 encoded string, as that's
        // what QTextLayout expects.

        let (
            selection_start_as_offset,
            selection_end_as_offset,
            selection_foreground_color,
            selection_background_color,
            underline_selection,
        ): (usize, usize, u32, u32, bool) = if !visual_representation.preedit_range.is_empty() {
            (
                visual_representation.preedit_range.start,
                visual_representation.preedit_range.end,
                Color::default().as_argb_encoded(),
                Color::default().as_argb_encoded(),
                true,
            )
        } else {
            (
                visual_representation.selection_range.start,
                visual_representation.selection_range.end,
                text_input.selection_foreground_color().as_argb_encoded(),
                text_input.selection_background_color().as_argb_encoded(),
                false,
            )
        };

        let selection_start_position: i32 = if selection_start_as_offset > 0 {
            utf8_byte_offset_to_utf16_units(text.as_str(), selection_start_as_offset) as i32
        } else {
            0
        };
        let selection_end_position: i32 = if selection_end_as_offset > 0 {
            utf8_byte_offset_to_utf16_units(text.as_str(), selection_end_as_offset) as i32
        } else {
            0
        };

        let (text_cursor_width, cursor_position): (f32, i32) =
            if let Some(cursor_offset) = visual_representation.cursor_position {
                (
                    text_input.text_cursor_width().get(),
                    utf8_byte_offset_to_utf16_units(text.as_str(), cursor_offset) as i32,
                )
            } else {
                (0., 0)
            };

        let single_line: bool = text_input.single_line();

        let painter: &mut QPainterPtr = &mut self.painter;
        cpp! { unsafe [
                painter as "QPainterPtr*",
                rect as "QRectF",
                fill_brush as "QBrush",
                selection_foreground_color as "QRgb",
                selection_background_color as "QRgb",
                underline_selection as "bool",
                mut string as "QString",
                flags as "int",
                single_line as "bool",
                font as "QFont",
                selection_start_position as "int",
                selection_end_position as "int",
                cursor_position as "int",
                text_cursor_width as "float"] {
            if (!single_line) {
                string.replace(QChar('\n'), QChar::LineSeparator);
            }
            QTextLayout layout(string, font);
            do_text_layout(layout, flags, rect);
            (*painter)->setPen(QPen(fill_brush, 0));
            QVector<QTextLayout::FormatRange> selections;
            if (selection_end_position != selection_start_position) {
                QTextCharFormat fmt;
                if (qAlpha(selection_background_color) != 0) {
                    fmt.setBackground(QColor::fromRgba(selection_background_color));
                }
                if (qAlpha(selection_background_color) != 0) {
                    fmt.setForeground(QColor::fromRgba(selection_foreground_color));
                }
                if (underline_selection) {
                    fmt.setFontUnderline(true);
                }
                selections << QTextLayout::FormatRange{
                    std::min(selection_end_position, selection_start_position),
                    std::abs(selection_end_position - selection_start_position),
                    fmt
                };
            }
            layout.draw(painter->get(), rect.topLeft(), selections);
            if (text_cursor_width > 0) {
                layout.drawCursor(painter->get(), rect.topLeft(), cursor_position, text_cursor_width);
            }
        }}
    }

    fn draw_path(&mut self, path: Pin<&items::Path>, item_rc: &ItemRc, size: LogicalSize) {
        let (offset, path_events) = match path.fitted_path_events(item_rc) {
            Some(offset_and_events) => offset_and_events,
            None => return,
        };
        let rect: qttypes::QRectF = check_geometry!(size);
        let fill_brush: qttypes::QBrush = into_qbrush(path.fill(), rect.width, rect.height);
        let stroke_brush: qttypes::QBrush = into_qbrush(path.stroke(), rect.width, rect.height);
        let stroke_width: f32 = path.stroke_width().get();
        let stroke_pen_cap_style: i32 = match path.stroke_line_cap() {
            LineCap::Butt => 0x00,
            LineCap::Round => 0x20,
            LineCap::Square => 0x10,
        };
        let pos = qttypes::QPoint { x: offset.x as _, y: offset.y as _ };
        let mut painter_path = QPainterPath::default();

        painter_path.set_fill_rule(match path.fill_rule() {
            FillRule::Nonzero => key_generated::Qt_FillRule_WindingFill,
            FillRule::Evenodd => key_generated::Qt_FillRule_OddEvenFill,
        });

        for x in path_events.iter() {
            fn to_qpointf(p: Point) -> qttypes::QPointF {
                qttypes::QPointF { x: p.x as _, y: p.y as _ }
            }
            match x {
                lyon_path::Event::Begin { at } => {
                    painter_path.move_to(to_qpointf(at));
                }
                lyon_path::Event::Line { from: _, to } => {
                    painter_path.line_to(to_qpointf(to));
                }
                lyon_path::Event::Quadratic { from: _, ctrl, to } => {
                    painter_path.quad_to(to_qpointf(ctrl), to_qpointf(to));
                }

                lyon_path::Event::Cubic { from: _, ctrl1, ctrl2, to } => {
                    painter_path.cubic_to(to_qpointf(ctrl1), to_qpointf(ctrl2), to_qpointf(to));
                }
                lyon_path::Event::End { last: _, first: _, close } => {
                    // FIXME: are we supposed to do something with last and first?
                    if close {
                        painter_path.close()
                    }
                }
            }
        }

        let anti_alias: bool = path.anti_alias();

        let painter: &mut QPainterPtr = &mut self.painter;
        cpp! { unsafe [
                painter as "QPainterPtr*",
                pos as "QPoint",
                mut painter_path as "QPainterPath",
                fill_brush as "QBrush",
                stroke_brush as "QBrush",
                stroke_width as "float",
                stroke_pen_cap_style as "int",
                anti_alias as "bool"] {
            (*painter)->save();
            auto cleanup = qScopeGuard([&] { (*painter)->restore(); });
            (*painter)->translate(pos);
            (*painter)->setPen(stroke_width > 0 ? QPen(stroke_brush, stroke_width, Qt::SolidLine, Qt::PenCapStyle(stroke_pen_cap_style)) : Qt::NoPen);
            (*painter)->setBrush(fill_brush);
            (*painter)->setRenderHint(QPainter::Antialiasing, anti_alias);
            (*painter)->drawPath(painter_path);
        }}
    }

    fn draw_box_shadow(
        &mut self,
        box_shadow: Pin<&items::BoxShadow>,
        item_rc: &ItemRc,
        _size: LogicalSize,
    ) {
        let pixmap : qttypes::QPixmap = self.cache.get_or_update_cache_entry( item_rc, || {
                let shadow_rect = check_geometry!(item_rc.geometry().size);

                let source_size = qttypes::QSize {
                    width: shadow_rect.width.ceil() as _,
                    height: shadow_rect.height.ceil() as _,
                };

                let mut source_image =
                    qttypes::QImage::new(source_size, qttypes::ImageFormat::ARGB32_Premultiplied);
                source_image.fill(qttypes::QColor::from_rgba_f(0., 0., 0., 0.));

                let img = &mut source_image;
                let mut painter_ = cpp!(unsafe [img as "QImage*"] -> QPainterPtr as "QPainterPtr" {
                    return std::make_unique<QPainter>(img);
                });

                Self::draw_rectangle_impl(
                    &mut painter_,
                    qttypes::QRectF { x: 0., y: 0., width: shadow_rect.width, height: shadow_rect.height },
                    Brush::SolidColor(box_shadow.color()),
                    Brush::default(),
                    0.,
                    LogicalBorderRadius::new_uniform(box_shadow.border_radius().get()),
                );

                drop(painter_);

                let blur_radius = box_shadow.blur().get();

                if blur_radius > 0. {
                    cpp! {
                    unsafe[img as "QImage*", blur_radius as "float"] -> qttypes::QPixmap as "QPixmap" {
                        class PublicGraphicsBlurEffect : public QGraphicsBlurEffect {
                        public:
                            // Make public what's protected
                            using QGraphicsBlurEffect::draw;
                        };

                        // Need a scene for the effect source private to draw()
                        QGraphicsScene scene;

                        auto pixmap_item = scene.addPixmap(QPixmap::fromImage(*img));

                        auto blur_effect = new PublicGraphicsBlurEffect;
                        blur_effect->setBlurRadius(blur_radius);
                        blur_effect->setBlurHints(QGraphicsBlurEffect::QualityHint);

                        // takes ownership of the effect and registers the item with
                        // the effect as source.
                        pixmap_item->setGraphicsEffect(blur_effect);

                        QImage blurred_scene(img->width() + 2 * blur_radius, img->height() + 2 * blur_radius, QImage::Format_ARGB32_Premultiplied);
                        blurred_scene.fill(Qt::transparent);

                        QPainter p(&blurred_scene);
                        p.translate(blur_radius, blur_radius);
                        blur_effect->draw(&p);
                        p.end();

                        return QPixmap::fromImage(blurred_scene);
                    }}
                } else {
                    cpp! { unsafe[img as "QImage*"] -> qttypes::QPixmap as "QPixmap" {
                        return QPixmap::fromImage(*img);
                    }}
                }
            });

        let blur_radius = box_shadow.blur();

        let shadow_offset = qttypes::QPointF {
            x: (box_shadow.offset_x() - blur_radius).get() as f64,
            y: (box_shadow.offset_y() - blur_radius).get() as f64,
        };

        let painter: &mut QPainterPtr = &mut self.painter;
        cpp! { unsafe [
                painter as "QPainterPtr*",
                shadow_offset as "QPointF",
                pixmap as "QPixmap"
            ] {
            (*painter)->drawPixmap(shadow_offset, pixmap);
        }}
    }

    fn visit_opacity(
        &mut self,
        opacity_item: Pin<&Opacity>,
        item_rc: &ItemRc,
        _size: LogicalSize,
    ) -> RenderingResult {
        let opacity = opacity_item.opacity();
        if Opacity::need_layer(item_rc, opacity) {
            self.render_and_blend_layer(opacity, item_rc)
        } else {
            self.apply_opacity(opacity);
            self.cache.release(item_rc);
            RenderingResult::ContinueRenderingChildren
        }
    }

    fn visit_layer(
        &mut self,
        layer_item: Pin<&Layer>,
        self_rc: &ItemRc,
        _size: LogicalSize,
    ) -> RenderingResult {
        if layer_item.cache_rendering_hint() {
            self.render_and_blend_layer(1.0, self_rc)
        } else {
            RenderingResult::ContinueRenderingChildren
        }
    }

    fn combine_clip(
        &mut self,
        rect: LogicalRect,
        radius: LogicalBorderRadius,
        border_width: LogicalLength,
    ) -> bool {
        let mut border_width: f32 = border_width.get();
        let mut clip_rect = qttypes::QRectF {
            x: rect.min_x() as _,
            y: rect.min_y() as _,
            width: rect.width() as _,
            height: rect.height() as _,
        };
        adjust_rect_and_border_for_inner_drawing(&mut clip_rect, &mut border_width);
        let painter: &mut QPainterPtr = &mut self.painter;
        let top_left_radius = radius.top_left;
        let top_right_radius = radius.top_right;
        let bottom_left_radius = radius.bottom_left;
        let bottom_right_radius = radius.bottom_right;
        cpp! { unsafe [
                painter as "QPainterPtr*",
                clip_rect as "QRectF",
                top_left_radius as "float",
                top_right_radius as "float",
                bottom_right_radius as "float",
                bottom_left_radius as "float"] -> bool as "bool" {
            if (top_left_radius <= 0 && top_right_radius <= 0 && bottom_right_radius <= 0 && bottom_left_radius <= 0) {
                (*painter)->setClipRect(clip_rect, Qt::IntersectClip);
            } else {
                QPainterPath path = to_painter_path(clip_rect, top_left_radius, top_right_radius, bottom_right_radius, bottom_left_radius);
                (*painter)->setClipPath(path, Qt::IntersectClip);
            }
            return !(*painter)->clipBoundingRect().isEmpty();
        }}
    }

    fn get_current_clip(&self) -> LogicalRect {
        let painter: &QPainterPtr = &self.painter;
        let res = cpp! { unsafe [painter as "const QPainterPtr*" ] -> qttypes::QRectF as "QRectF" {
            return (*painter)->clipBoundingRect();
        }};
        LogicalRect::new(
            LogicalPoint::new(res.x as _, res.y as _),
            LogicalSize::new(res.width as _, res.height as _),
        )
    }

    fn save_state(&mut self) {
        self.painter.save()
    }

    fn restore_state(&mut self) {
        self.painter.restore()
    }

    fn scale_factor(&self) -> f32 {
        1.
        /* cpp! { unsafe [painter as "QPainterPtr*"] -> f32 as "float" {
            return (*painter)->paintEngine()->paintDevice()->devicePixelRatioF();
        }} */
    }

    fn draw_cached_pixmap(
        &mut self,
        _item_rc: &ItemRc,
        update_fn: &dyn Fn(&mut dyn FnMut(u32, u32, &[u8])),
    ) {
        update_fn(&mut |width: u32, height: u32, data: &[u8]| {
            let data = data.as_ptr();
            let painter: &mut QPainterPtr = &mut self.painter;
            cpp! { unsafe [painter as "QPainterPtr*",  width as "int", height as "int", data as "const unsigned char *"] {
                QImage img(data, width, height, width * 4, QImage::Format_RGBA8888_Premultiplied);
                (*painter)->drawImage(QPoint(), img);
            }}
        })
    }

    fn draw_string(&mut self, string: &str, color: Color) {
        let fill_brush: qttypes::QBrush = into_qbrush(color.into(), 1., 1.);
        let mut string: qttypes::QString = string.into();
        let font: QFont = get_font(Default::default());
        let painter: &mut QPainterPtr = &mut self.painter;
        cpp! { unsafe [painter as "QPainterPtr*", fill_brush as "QBrush", mut string as "QString", font as "QFont"] {
            (*painter)->setFont(font);
            (*painter)->setPen(QPen(fill_brush, 0));
            (*painter)->setBrush(Qt::NoBrush);
            (*painter)->drawText(0, QFontMetrics((*painter)->font()).ascent(), string);
        }}
    }

    fn draw_image_direct(&mut self, _image: i_slint_core::graphics::Image) {
        todo!()
    }

    fn window(&self) -> &i_slint_core::window::WindowInner {
        i_slint_core::window::WindowInner::from_pub(self.window)
    }

    fn as_any(&mut self) -> Option<&mut dyn std::any::Any> {
        Some(&mut self.painter)
    }

    fn translate(&mut self, distance: LogicalVector) {
        let x: f32 = distance.x;
        let y: f32 = distance.y;
        let painter: &mut QPainterPtr = &mut self.painter;
        cpp! { unsafe [painter as "QPainterPtr*", x as "float", y as "float"] {
            (*painter)->translate(x, y);
        }}
    }

    fn rotate(&mut self, angle_in_degrees: f32) {
        let painter: &mut QPainterPtr = &mut self.painter;
        cpp! { unsafe [painter as "QPainterPtr*", angle_in_degrees as "float"] {
            (*painter)->rotate(angle_in_degrees);
        }}
    }

    fn apply_opacity(&mut self, opacity: f32) {
        let painter: &mut QPainterPtr = &mut self.painter;
        cpp! { unsafe [painter as "QPainterPtr*", opacity as "float"] {
            (*painter)->setOpacity((*painter)->opacity() * opacity);
        }}
    }

    fn metrics(&self) -> RenderingMetrics {
        self.metrics.clone()
    }
}

fn shared_image_buffer_to_pixmap(buffer: &SharedImageBuffer) -> Option<qttypes::QPixmap> {
    let (format, bytes_per_line, buffer_ptr) = match buffer {
        SharedImageBuffer::RGBA8(img) => {
            (qttypes::ImageFormat::RGBA8888, img.width() * 4, img.as_bytes().as_ptr())
        }
        SharedImageBuffer::RGBA8Premultiplied(img) => {
            (qttypes::ImageFormat::RGBA8888_Premultiplied, img.width() * 4, img.as_bytes().as_ptr())
        }
        SharedImageBuffer::RGB8(img) => {
            (qttypes::ImageFormat::RGB888, img.width() * 3, img.as_bytes().as_ptr())
        }
    };
    let width: i32 = buffer.width() as _;
    let height: i32 = buffer.height() as _;
    let pixmap = cpp! { unsafe [format as "QImage::Format", width as "int", height as "int", bytes_per_line as "uint32_t", buffer_ptr as "const uchar *"] -> qttypes::QPixmap as "QPixmap" {
        QImage img(buffer_ptr, width, height, bytes_per_line, format);
        return QPixmap::fromImage(img);
    } };
    Some(pixmap)
}

pub(crate) fn image_to_pixmap(
    image: &ImageInner,
    source_size: Option<euclid::Size2D<u32, PhysicalPx>>,
) -> Option<qttypes::QPixmap> {
    shared_image_buffer_to_pixmap(&image.render_to_buffer(source_size)?)
}

impl QtItemRenderer<'_> {
    fn draw_image_impl(
        &mut self,
        item_rc: &ItemRc,
        size: LogicalSize,
        image: Pin<&dyn i_slint_core::item_rendering::RenderImage>,
    ) {
        let dest_rect: qttypes::QRectF = check_geometry!(size);

        let source_rect = image.source_clip();

        let pixmap: qttypes::QPixmap = self.cache.get_or_update_cache_entry(item_rc, || {
            let source = image.source();
            let origin = source.size();
            let source: &ImageInner = (&source).into();

            // Query target_width/height here again to ensure that changes will invalidate the item rendering cache.
            let scale_factor = ScaleFactor::new(self.scale_factor());
            let t = (image.target_size() * scale_factor).cast();

            let source_size = if source.is_svg() {
                let has_source_clipping = source_rect.map_or(false, |rect| {
                    rect.origin.x != 0
                        || rect.origin.y != 0
                        || !rect.size.width != t.width
                        || !rect.size.height != t.height
                });
                if has_source_clipping {
                    // Source size & clipping is not implemented yet
                    None
                } else {
                    Some(
                        i_slint_core::graphics::fit(
                            image.image_fit(),
                            t.cast(),
                            IntRect::from_size(origin.cast()),
                            scale_factor,
                            Default::default(), // We only care about the size, so alignments don't matter
                            image.tiling(),
                        )
                        .size
                        .cast(),
                    )
                }
            } else {
                None
            };

            image_to_pixmap(source, source_size).map_or_else(
                Default::default,
                |mut pixmap: qttypes::QPixmap| {
                    let colorize = image.colorize();
                    if !colorize.is_transparent() {
                        let brush: qttypes::QBrush =
                            into_qbrush(colorize, dest_rect.width, dest_rect.height);
                        cpp!(unsafe [mut pixmap as "QPixmap", brush as "QBrush"] {
                            QPainter p(&pixmap);
                            p.setCompositionMode(QPainter::CompositionMode_SourceIn);
                            p.fillRect(QRect(QPoint(), pixmap.size()), brush);
                        });
                    }
                    pixmap
                },
            )
        });

        let image_size = pixmap.size();
        let source_rect = source_rect
            .unwrap_or_else(|| euclid::rect(0, 0, image_size.width as _, image_size.height as _));
        let scale_factor = ScaleFactor::new(self.scale_factor());

        let fit = if let &i_slint_core::ImageInner::NineSlice(ref nine) = (&image.source()).into() {
            i_slint_core::graphics::fit9slice(
                nine.0.size(),
                nine.1,
                size * scale_factor,
                scale_factor,
                image.alignment(),
                image.tiling(),
            )
            .collect::<Vec<_>>()
        } else {
            vec![i_slint_core::graphics::fit(
                image.image_fit(),
                size * scale_factor,
                source_rect,
                scale_factor,
                image.alignment(),
                image.tiling(),
            )]
        };

        for fit in fit {
            let dest_rect = qttypes::QRectF {
                x: fit.offset.x as _,
                y: fit.offset.y as _,
                width: fit.size.width as _,
                height: fit.size.height as _,
            };
            let source_rect = qttypes::QRectF {
                x: fit.clip_rect.origin.x as _,
                y: fit.clip_rect.origin.y as _,
                width: fit.clip_rect.size.width as _,
                height: fit.clip_rect.size.height as _,
            };

            let painter: &mut QPainterPtr = &mut self.painter;
            let smooth: bool = image.rendering() == ImageRendering::Smooth;
            if let Some(offset) = fit.tiled {
                let scale_x: f32 = fit.source_to_target_x;
                let scale_y: f32 = fit.source_to_target_y;
                let offset = qttypes::QPoint { x: offset.x as _, y: offset.y as _ };
                cpp! { unsafe [
                    painter as "QPainterPtr*", pixmap as "QPixmap", source_rect as "QRectF",
                    dest_rect as "QRectF", smooth as "bool", scale_x as "float", scale_y as "float",
                    offset as "QPoint"
                    ] {
                        (*painter)->save();
                        (*painter)->setRenderHint(QPainter::SmoothPixmapTransform, smooth);
                        auto transform = QTransform::fromScale(1 / scale_x, 1 / scale_y);
                        auto scaled_destination = (dest_rect * transform).boundingRect();
                        QPixmap source_pixmap = pixmap.copy(source_rect.toRect());
                        (*painter)->scale(scale_x, scale_y);
                        (*painter)->drawTiledPixmap(scaled_destination, source_pixmap, offset);
                        (*painter)->restore();
                    }
                };
            } else {
                cpp! { unsafe [
                        painter as "QPainterPtr*",
                        pixmap as "QPixmap",
                        source_rect as "QRectF",
                        dest_rect as "QRectF",
                        smooth as "bool"] {
                    (*painter)->save();
                    (*painter)->setRenderHint(QPainter::SmoothPixmapTransform, smooth);
                    (*painter)->drawPixmap(dest_rect, pixmap, source_rect);
                    (*painter)->restore();
                }};
            }
        }
    }

    fn draw_rectangle_impl(
        painter: &mut QPainterPtr,
        mut rect: qttypes::QRectF,
        brush: Brush,
        border_color: Brush,
        mut border_width: f32,
        border_radius: LogicalBorderRadius,
    ) {
        if border_color.is_transparent() {
            border_width = 0.;
        };
        let brush: qttypes::QBrush = into_qbrush(brush, rect.width, rect.height);
        let border_color: qttypes::QBrush = into_qbrush(border_color, rect.width, rect.height);
        let top_left_radius = border_radius.top_left;
        let top_right_radius = border_radius.top_right;
        let bottom_left_radius = border_radius.bottom_left;
        let bottom_right_radius = border_radius.bottom_right;
        border_width = border_width.min(rect.height.min(rect.width) as f32 / 2.);
        cpp! { unsafe [
                painter as "QPainterPtr*",
                brush as "QBrush",
                border_color as "QBrush",
                border_width as "float",
                top_left_radius as "float",
                top_right_radius as "float",
                bottom_left_radius as "float",
                bottom_right_radius as "float",
                mut rect as "QRectF"] {
            (*painter)->setBrush(brush);
            QPen pen = border_width > 0 ? QPen(border_color, border_width, Qt::SolidLine, Qt::FlatCap, Qt::MiterJoin) : Qt::NoPen;
            if (top_left_radius <= 0 && top_right_radius <= 0 && bottom_left_radius <= 0 && bottom_right_radius <= 0) {
                if (!border_color.isOpaque() && border_width > 1) {
                    // In case of transparent pen, we want the background to cover the whole rectangle, which Qt doesn't do.
                    // So first draw the background, then draw the pen over it
                    (*painter)->setPen(Qt::NoPen);
                    (*painter)->drawRect(rect);
                    (*painter)->setBrush(QBrush());
                }
                rect.adjust(border_width / 2, border_width / 2, -border_width / 2, -border_width / 2);
                (*painter)->setPen(pen);
                (*painter)->drawRect(rect);
            } else {
                if (!border_color.isOpaque() && border_width > 1) {
                    // See adjustment below
                    float tl_r = qFuzzyIsNull(top_left_radius) ? top_left_radius : qMax(border_width/2, top_left_radius);
                    float tr_r = qFuzzyIsNull(top_right_radius) ? top_right_radius : qMax(border_width/2, top_right_radius);
                    float br_r = qFuzzyIsNull(bottom_right_radius) ? bottom_right_radius : qMax(border_width/2, bottom_right_radius);
                    float bl_r = qFuzzyIsNull(bottom_left_radius) ? bottom_left_radius : qMax(border_width/2, bottom_left_radius);
                    // In case of transparent pen, we want the background to cover the whole rectangle, which Qt doesn't do.
                    // So first draw the background, then draw the pen over it
                    (*painter)->setPen(Qt::NoPen);
                    (*painter)->drawPath(to_painter_path(rect, tl_r, tr_r, br_r, bl_r));
                    (*painter)->setBrush(QBrush());
                }
                // Qt's border radius is in the middle of the border. But we want it to be the radius of the rectangle itself.
                // This is incorrect if border_radius < border_width/2,  but this can't be fixed. Better to have a radius a bit too big than no radius at all
                float tl_r = qMax(0.0f, top_left_radius - border_width / 2);
                float tr_r = qMax(0.0f, top_right_radius - border_width / 2);
                float br_r = qMax(0.0f, bottom_right_radius - border_width / 2);
                float bl_r = qMax(0.0f, bottom_left_radius - border_width / 2);
                rect.adjust(border_width / 2, border_width / 2, -border_width / 2, -border_width / 2);
                (*painter)->setPen(pen);
                (*painter)->drawPath(to_painter_path(rect, tl_r, tr_r, br_r, bl_r));
            }
        }}
    }

    fn render_layer(
        &mut self,
        item_rc: &ItemRc,
        layer_size_fn: &dyn Fn() -> LogicalSize,
    ) -> qttypes::QPixmap {
        self.cache.get_or_update_cache_entry(item_rc,  || {
            let painter: &mut QPainterPtr = &mut self.painter;
            let dpr = cpp! { unsafe [painter as "QPainterPtr*"] -> f32 as "float" {
                return (*painter)->paintEngine()->paintDevice()->devicePixelRatioF();
            }};

            let layer_size = layer_size_fn();
            let layer_size = qttypes::QSize {
                width: (layer_size.width * dpr) as _,
                height: (layer_size.height * dpr) as _,
            };

            let mut layer_image = qttypes::QImage::new(layer_size, qttypes::ImageFormat::ARGB32_Premultiplied);
            layer_image.fill(qttypes::QColor::from_rgba_f(0., 0., 0., 0.));

            *self.metrics.layers_created.as_mut().unwrap() += 1;

            let img_ref: &mut qttypes::QImage = &mut layer_image;
            let mut layer_painter = cpp!(unsafe [img_ref as "QImage*", dpr as "float"] -> QPainterPtr as "QPainterPtr" {
                img_ref->setDevicePixelRatio(dpr);
                auto painter = std::make_unique<QPainter>(img_ref);
                painter->setClipRect(0, 0, img_ref->width(), img_ref->height());
                painter->setRenderHints(QPainter::Antialiasing | QPainter::SmoothPixmapTransform);
                return painter;
            });

            std::mem::swap(&mut self.painter, &mut layer_painter);

            let window_adapter = self.window().window_adapter();

            i_slint_core::item_rendering::render_item_children(
                self,
                &item_rc.item_tree(),
                item_rc.index() as isize, &window_adapter
            );

            std::mem::swap(&mut self.painter, &mut layer_painter);
            drop(layer_painter);

            qttypes::QPixmap::from(layer_image)
        })
    }

    fn render_and_blend_layer(&mut self, alpha_tint: f32, self_rc: &ItemRc) -> RenderingResult {
        let current_clip = self.get_current_clip();
        let mut layer_image = self.render_layer(self_rc, &|| {
            // We don't need to include the size of the opacity item itself, since it has no content.
            let children_rect = i_slint_core::properties::evaluate_no_tracking(|| {
                self_rc.geometry().union(
                    &i_slint_core::item_rendering::item_children_bounding_rect(
                        &self_rc.item_tree(),
                        self_rc.index() as isize,
                        &current_clip,
                    ),
                )
            });
            children_rect.size
        });
        self.save_state();
        self.apply_opacity(alpha_tint);
        {
            let painter: &mut QPainterPtr = &mut self.painter;
            let layer_image_ref: &mut qttypes::QPixmap = &mut layer_image;
            cpp! { unsafe [
                    painter as "QPainterPtr*",
                    layer_image_ref as "QPixmap*"
                ] {
                (*painter)->drawPixmap(0, 0, *layer_image_ref);
            }}
        }
        self.restore_state();
        RenderingResult::ContinueRenderingWithoutChildren
    }
}

cpp! {{
    struct QWidgetDeleteLater
    {
        void operator()(QWidget *widget_ptr)
        {
            if (widget_ptr->parent()) {
                // if the widget is a popup, use deleteLater (#4129)
                widget_ptr->hide();
                widget_ptr->deleteLater();
            } else {
                // Otherwise, use normal delete as it would otherwise cause crash at exit (#7570)
                delete widget_ptr;
            }
        }
    };
}}

cpp_class!(pub(crate) unsafe struct QWidgetPtr as "std::unique_ptr<QWidget, QWidgetDeleteLater>");

pub struct QtWindow {
    widget_ptr: QWidgetPtr,
    pub(crate) window: i_slint_core::api::Window,
    self_weak: Weak<Self>,

    rendering_metrics_collector: RefCell<Option<Rc<RenderingMetricsCollector>>>,

    cache: ItemCache<qttypes::QPixmap>,

    tree_structure_changed: RefCell<bool>,

    color_scheme: OnceCell<Pin<Box<Property<ColorScheme>>>>,
}

impl Drop for QtWindow {
    fn drop(&mut self) {
        let widget_ptr = self.widget_ptr();
        cpp! {unsafe [widget_ptr as "SlintWidget*"]  {
            // widget_ptr uses deleteLater to destroy the SlintWidget, we must prevent events to still call us
            widget_ptr->rust_window = nullptr;
        }};
    }
}

impl QtWindow {
    pub fn new() -> Rc<Self> {
        let rc = Rc::new_cyclic(|self_weak| {
            let window_ptr = self_weak.clone().into_raw();
            let widget_ptr = cpp! {unsafe [window_ptr as "void*"] -> QWidgetPtr as "std::unique_ptr<QWidget, QWidgetDeleteLater>" {
                ensure_initialized(true);
                auto widget = std::unique_ptr<SlintWidget, QWidgetDeleteLater>(new SlintWidget, QWidgetDeleteLater());

                auto accessibility = new Slint_accessible_window(widget.get(), window_ptr);
                QAccessible::registerAccessibleInterface(accessibility);

                return widget;
            }};

            QtWindow {
                widget_ptr,
                window: i_slint_core::api::Window::new(self_weak.clone() as _),
                self_weak: self_weak.clone(),
                rendering_metrics_collector: Default::default(),
                cache: Default::default(),
                tree_structure_changed: RefCell::new(false),
                color_scheme: Default::default(),
            }
        });
        let widget_ptr = rc.widget_ptr();
        let rust_window = Rc::as_ptr(&rc);
        cpp! {unsafe [widget_ptr as "SlintWidget*", rust_window as "void*"]  {
            widget_ptr->rust_window = rust_window;
        }};
        ALL_WINDOWS.with(|aw| aw.borrow_mut().push(rc.self_weak.clone()));
        rc
    }

    /// Return the QWidget*
    pub fn widget_ptr(&self) -> NonNull<()> {
        unsafe { std::mem::transmute_copy::<QWidgetPtr, NonNull<_>>(&self.widget_ptr) }
    }

    fn paint_event(&self, painter: QPainterPtr) {
        let runtime_window = WindowInner::from_pub(&self.window);
        let window_adapter = runtime_window.window_adapter();
        runtime_window.draw_contents(|components| {
            i_slint_core::animations::update_animations();
            let mut renderer = QtItemRenderer {
                painter,
                cache: &self.cache,
                window: &self.window,
                metrics: RenderingMetrics { layers_created: Some(0) },
            };

            for (component, origin) in components {
                i_slint_core::item_rendering::render_component_items(
                    component,
                    &mut renderer,
                    *origin,
                    &window_adapter,
                );
            }

            if let Some(collector) = &*self.rendering_metrics_collector.borrow() {
                collector.measure_frame_rendered(&mut renderer);
            }

            if self.window.has_active_animations() {
                self.request_redraw();
            }
        });

        // Update the accessibility tree (if the component tree has changed)
        if self.tree_structure_changed.replace(false) {
            let widget_ptr = self.widget_ptr();
            cpp! { unsafe [widget_ptr as "QWidget*"] {
                auto accessible = dynamic_cast<Slint_accessible_window*>(QAccessible::queryAccessibleInterface(widget_ptr));
                if (accessible->isUsed()) { accessible->updateAccessibilityTree(); }
            }};
        }

        timer_event();
    }

    fn resize_event(&self, size: qttypes::QSize) {
        self.window().dispatch_event(WindowEvent::Resized {
            size: i_slint_core::api::LogicalSize::new(size.width as _, size.height as _),
        });
    }

    fn mouse_event(&self, event: MouseEvent) {
        WindowInner::from_pub(&self.window).process_mouse_input(event);
        timer_event();
    }

    fn key_event(&self, key: i32, text: qttypes::QString, released: bool, repeat: bool) {
        i_slint_core::animations::update_animations();
        let text: String = text.into();

        let text = qt_key_to_string(key as key_generated::Qt_Key, text);

        let event = if released {
            WindowEvent::KeyReleased { text }
        } else if repeat {
            WindowEvent::KeyPressRepeated { text }
        } else {
            WindowEvent::KeyPressed { text }
        };
        self.window.dispatch_event(event);

        timer_event();
    }

    fn window_state_event(&self) {
        let widget_ptr = self.widget_ptr();

        // This function is called from the changeEvent slot which triggers whenever
        // one of these properties changes. To prevent recursive call issues (e.g.,
        // set_fullscreen -> update_window_properties -> changeEvent ->
        // window_state_event -> set_fullscreen), we avoid resetting the internal state
        // when it already matches the Qt state.

        let minimized = cpp! { unsafe [widget_ptr as "QWidget*"] -> bool as "bool" {
            return widget_ptr->isMinimized();
        }};

        if minimized != self.window().is_minimized() {
            self.window().set_minimized(minimized);
        }

        let maximized = cpp! { unsafe [widget_ptr as "QWidget*"] -> bool as "bool" {
            return widget_ptr->isMaximized();
        }};

        if maximized != self.window().is_maximized() {
            self.window().set_maximized(maximized);
        }

        let fullscreen = cpp! { unsafe [widget_ptr as "QWidget*"] -> bool as "bool" {
            return widget_ptr->isFullScreen();
        }};

        if fullscreen != self.window().is_fullscreen() {
            self.window().set_fullscreen(fullscreen);
        }
    }
}

impl WindowAdapter for QtWindow {
    fn window(&self) -> &i_slint_core::api::Window {
        &self.window
    }

    fn renderer(&self) -> &dyn Renderer {
        self
    }

    fn set_visible(&self, visible: bool) -> Result<(), PlatformError> {
        if let Some(xdg_app_id) = WindowInner::from_pub(&self.window)
            .xdg_app_id()
            .map(|s| qttypes::QString::from(s.as_str()))
        {
            cpp! {unsafe [xdg_app_id as "QString"] {
                QGuiApplication::setDesktopFileName(xdg_app_id);
            }};
        }

        if visible {
            let widget_ptr = self.widget_ptr();
            cpp! {unsafe [widget_ptr as "QWidget*"] {
                widget_ptr->show();
            }};
            let qt_platform_name = cpp! {unsafe [] -> qttypes::QString as "QString" {
                return QGuiApplication::platformName();
            }};
            *self.rendering_metrics_collector.borrow_mut() = RenderingMetricsCollector::new(
                &format!("Qt backend (platform {})", qt_platform_name),
            );
            Ok(())
        } else {
            self.rendering_metrics_collector.take();
            let widget_ptr = self.widget_ptr();
            cpp! {unsafe [widget_ptr as "QWidget*"] {

                bool wasVisible = widget_ptr->isVisible();

                widget_ptr->hide();
                if (wasVisible) {
                    // Since we don't call close(), try to compute whether this was the last window and that
                    // we must end the application
                    auto windows = QGuiApplication::topLevelWindows();
                    bool visible_windows_left = std::any_of(windows.begin(), windows.end(), [](auto window) {
                        return window->isVisible() || window->transientParent();
                    });
                    g_lastWindowClosed = !visible_windows_left;
                }
            }};

            Ok(())
        }
    }

    fn position(&self) -> Option<i_slint_core::api::PhysicalPosition> {
        let widget_ptr = self.widget_ptr();
        let qp = cpp! {unsafe [widget_ptr as "QWidget*"] -> qttypes::QPoint as "QPoint" {
            return widget_ptr->pos();
        }};
        // Qt returns logical coordinates, so scale those!
        i_slint_core::api::LogicalPosition::new(qp.x as _, qp.y as _)
            .to_physical(self.window().scale_factor())
            .into()
    }

    fn set_position(&self, position: i_slint_core::api::WindowPosition) {
        let physical_position = position.to_physical(self.window().scale_factor());
        let widget_ptr = self.widget_ptr();
        let pos = qttypes::QPoint { x: physical_position.x as _, y: physical_position.y as _ };
        cpp! {unsafe [widget_ptr as "QWidget*", pos as "QPoint"] {
            widget_ptr->move(pos);
        }};
    }

    fn set_size(&self, size: i_slint_core::api::WindowSize) {
        let logical_size = size.to_logical(self.window().scale_factor());
        let widget_ptr = self.widget_ptr();
        let sz: qttypes::QSize = into_qsize(logical_size);

        // Qt uses logical units!
        cpp! {unsafe [widget_ptr as "QWidget*", sz as "QSize"] {
            widget_ptr->resize(sz);
        }};

        self.resize_event(sz);
    }

    fn size(&self) -> i_slint_core::api::PhysicalSize {
        let widget_ptr = self.widget_ptr();
        let s = cpp! {unsafe [widget_ptr as "QWidget*"] -> qttypes::QSize as "QSize" {
            return widget_ptr->size();
        }};
        i_slint_core::api::PhysicalSize::new(s.width as _, s.height as _)
    }

    fn request_redraw(&self) {
        let widget_ptr = self.widget_ptr();
        cpp! {unsafe [widget_ptr as "QWidget*"] {
            // If embedded as a QWidget, just use regular QWidget::update(), but if we're a top-level,
            // then use requestUpdate() to achieve frame-throttling.
            if (widget_ptr->parentWidget()) {
                widget_ptr->update();
            } else if (auto w = widget_ptr->window()->windowHandle()) {
                w->requestUpdate();
            }
        }}
    }

    /// Apply windows property such as title to the QWidget*
    fn update_window_properties(&self, properties: i_slint_core::window::WindowProperties<'_>) {
        let widget_ptr = self.widget_ptr();
        let title: qttypes::QString = properties.title().as_str().into();
        let Some(window_item) = WindowInner::from_pub(&self.window).window_item() else { return };
        let window_item = window_item.as_pin_ref();
        let no_frame = window_item.no_frame();
        let always_on_top = window_item.always_on_top();
        let mut size = qttypes::QSize {
            width: window_item.width().get().ceil() as _,
            height: window_item.height().get().ceil() as _,
        };

        if size.width == 0 || size.height == 0 {
            let existing_size = cpp!(unsafe [widget_ptr as "QWidget*"] -> qttypes::QSize as "QSize" {
                return widget_ptr->size();
            });
            if size.width == 0 {
                window_item.width.set(LogicalLength::new(existing_size.width as _));
                size.width = existing_size.width;
            }
            if size.height == 0 {
                window_item.height.set(LogicalLength::new(existing_size.height as _));
                size.height = existing_size.height;
            }
        }

        let background =
            into_qbrush(properties.background(), size.width.into(), size.height.into());

        match (&window_item.icon()).into() {
            &ImageInner::None => (),
            r => {
                if let Some(pixmap) = image_to_pixmap(r, None) {
                    cpp! {unsafe [widget_ptr as "QWidget*", pixmap as "QPixmap"] {
                        widget_ptr->setWindowIcon(QIcon(pixmap));
                    }};
                }
            }
        };

        let fullscreen: bool = properties.is_fullscreen();
        let minimized: bool = properties.is_minimized();
        let maximized: bool = properties.is_maximized();

        cpp! {unsafe [widget_ptr as "QWidget*",  title as "QString", size as "QSize", background as "QBrush", no_frame as "bool", always_on_top as "bool",
                      fullscreen as "bool", minimized as "bool", maximized as "bool"] {

            if (size != widget_ptr->size()) {
                widget_ptr->resize(size.expandedTo({1, 1}));
            }

            widget_ptr->setWindowFlag(Qt::FramelessWindowHint, no_frame);
            widget_ptr->setWindowFlag(Qt::WindowStaysOnTopHint, always_on_top);

                        {
                // Depending on the request, we either set or clear the bits.
                // See also: https://doc.qt.io/qt-6/qt.html#WindowState-enum
                auto state = widget_ptr->windowState();

                if (fullscreen != widget_ptr->isFullScreen()) {
                    state = state ^ Qt::WindowFullScreen;
                }
                if (minimized != widget_ptr->isMinimized()) {
                    state = state ^ Qt::WindowMinimized;
                }
                if (maximized != widget_ptr->isMaximized()) {
                    state = state ^ Qt::WindowMaximized;
                }

                widget_ptr->setWindowState(state);
            }

            widget_ptr->setWindowTitle(title);
            auto pal = widget_ptr->palette();

            #if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
            // If the background color is the same as what NativeStyleMetrics supplied from QGuiApplication::palette().color(QPalette::Window),
            // then the setColor (implicitly setBrush) call will not detach the palette. However it will set the resolveMask, which due to the
            // lack of a detach changes QGuiApplicationPrivate::app_pal's resolve mask and thus breaks future theme based palette changes.
            // Therefore we force a detach.
            // https://bugreports.qt.io/browse/QTBUG-98762
            {
                pal.setResolveMask(~pal.resolveMask());
                pal.setResolveMask(~pal.resolveMask());
            }
            #endif
            pal.setBrush(QPalette::Window, background);
            widget_ptr->setPalette(pal);
        }};

        let constraints = properties.layout_constraints();

        let min_size: qttypes::QSize = constraints.min.map_or_else(
            || qttypes::QSize { width: 0, height: 0 }, // (0x0) means unset min size for QWidget
            into_qsize,
        );

        const WIDGET_SIZE_MAX: u32 = 16_777_215;

        let max_size: qttypes::QSize = constraints.max.map_or_else(
            || qttypes::QSize { width: WIDGET_SIZE_MAX, height: WIDGET_SIZE_MAX },
            into_qsize,
        );

        cpp! {unsafe [widget_ptr as "QWidget*",  min_size as "QSize", max_size as "QSize"] {
            widget_ptr->setMinimumSize(min_size);
            widget_ptr->setMaximumSize(max_size);
        }};
    }

    fn internal(&self, _: i_slint_core::InternalToken) -> Option<&dyn WindowAdapterInternal> {
        Some(self)
    }
}

fn into_qsize(logical_size: i_slint_core::api::LogicalSize) -> qttypes::QSize {
    qttypes::QSize {
        width: logical_size.width.round() as _,
        height: logical_size.height.round() as _,
    }
}

impl WindowAdapterInternal for QtWindow {
    fn register_item_tree(&self) {
        self.tree_structure_changed.replace(true);
    }

    fn unregister_item_tree(
        &self,
        _component: ItemTreeRef,
        _: &mut dyn Iterator<Item = Pin<ItemRef<'_>>>,
    ) {
        self.tree_structure_changed.replace(true);
    }

    fn create_popup(&self, geometry: LogicalRect) -> Option<Rc<dyn WindowAdapter>> {
        let popup_window = QtWindow::new();

        let size = qttypes::QSize { width: geometry.width() as _, height: geometry.height() as _ };

        let popup_ptr = popup_window.widget_ptr();
        let pos = qttypes::QPoint { x: geometry.origin.x as _, y: geometry.origin.y as _ };
        let widget_ptr = self.widget_ptr();
        cpp! {unsafe [widget_ptr as "QWidget*", popup_ptr as "QWidget*", pos as "QPoint", size as "QSize"] {
            popup_ptr->setParent(widget_ptr, Qt::Popup);
            popup_ptr->setGeometry(QRect(pos + widget_ptr->mapToGlobal(QPoint(0,0)), size));
            popup_ptr->show();
        }};
        Some(popup_window as _)
    }

    fn set_mouse_cursor(&self, cursor: MouseCursor) {
        let widget_ptr = self.widget_ptr();
        //unidirectional resize cursors are replaced with bidirectional ones
        let cursor_shape = match cursor {
            MouseCursor::Default => key_generated::Qt_CursorShape_ArrowCursor,
            MouseCursor::None => key_generated::Qt_CursorShape_BlankCursor,
            MouseCursor::Help => key_generated::Qt_CursorShape_WhatsThisCursor,
            MouseCursor::Pointer => key_generated::Qt_CursorShape_PointingHandCursor,
            MouseCursor::Progress => key_generated::Qt_CursorShape_BusyCursor,
            MouseCursor::Wait => key_generated::Qt_CursorShape_WaitCursor,
            MouseCursor::Crosshair => key_generated::Qt_CursorShape_CrossCursor,
            MouseCursor::Text => key_generated::Qt_CursorShape_IBeamCursor,
            MouseCursor::Alias => key_generated::Qt_CursorShape_DragLinkCursor,
            MouseCursor::Copy => key_generated::Qt_CursorShape_DragCopyCursor,
            MouseCursor::Move => key_generated::Qt_CursorShape_DragMoveCursor,
            MouseCursor::NoDrop => key_generated::Qt_CursorShape_ForbiddenCursor,
            MouseCursor::NotAllowed => key_generated::Qt_CursorShape_ForbiddenCursor,
            MouseCursor::Grab => key_generated::Qt_CursorShape_OpenHandCursor,
            MouseCursor::Grabbing => key_generated::Qt_CursorShape_ClosedHandCursor,
            MouseCursor::ColResize => key_generated::Qt_CursorShape_SplitHCursor,
            MouseCursor::RowResize => key_generated::Qt_CursorShape_SplitVCursor,
            MouseCursor::NResize => key_generated::Qt_CursorShape_SizeVerCursor,
            MouseCursor::EResize => key_generated::Qt_CursorShape_SizeHorCursor,
            MouseCursor::SResize => key_generated::Qt_CursorShape_SizeVerCursor,
            MouseCursor::WResize => key_generated::Qt_CursorShape_SizeHorCursor,
            MouseCursor::NeResize => key_generated::Qt_CursorShape_SizeBDiagCursor,
            MouseCursor::NwResize => key_generated::Qt_CursorShape_SizeFDiagCursor,
            MouseCursor::SeResize => key_generated::Qt_CursorShape_SizeFDiagCursor,
            MouseCursor::SwResize => key_generated::Qt_CursorShape_SizeBDiagCursor,
            MouseCursor::EwResize => key_generated::Qt_CursorShape_SizeHorCursor,
            MouseCursor::NsResize => key_generated::Qt_CursorShape_SizeVerCursor,
            MouseCursor::NeswResize => key_generated::Qt_CursorShape_SizeBDiagCursor,
            MouseCursor::NwseResize => key_generated::Qt_CursorShape_SizeFDiagCursor,
        };
        cpp! {unsafe [widget_ptr as "QWidget*", cursor_shape as "Qt::CursorShape"] {
            widget_ptr->setCursor(QCursor{cursor_shape});
        }};
    }

    fn input_method_request(&self, request: i_slint_core::window::InputMethodRequest) {
        let widget_ptr = self.widget_ptr();
        let props = match request {
            i_slint_core::window::InputMethodRequest::Enable(props) => {
                cpp! {unsafe [widget_ptr as "QWidget*"] {
                    widget_ptr->setAttribute(Qt::WA_InputMethodEnabled, true);
                }};
                props
            }
            i_slint_core::window::InputMethodRequest::Disable => {
                cpp! {unsafe [widget_ptr as "SlintWidget*"] {
                    widget_ptr->ime_text = "";
                    widget_ptr->ime_cursor = 0;
                    widget_ptr->ime_anchor = 0;
                    widget_ptr->setAttribute(Qt::WA_InputMethodEnabled, false);
                }};
                return;
            }
            i_slint_core::window::InputMethodRequest::Update(props) => props,
            _ => return,
        };

        let rect = qttypes::QRectF {
            x: props.cursor_rect_origin.x as _,
            y: props.cursor_rect_origin.y as _,
            width: props.cursor_rect_size.width as _,
            height: props.cursor_rect_size.height as _,
        };
        let cursor: i32 = props.text[..props.cursor_position].encode_utf16().count() as _;
        let anchor: i32 =
            props.anchor_position.map_or(cursor, |a| props.text[..a].encode_utf16().count() as _);
        let text: qttypes::QString = props.text.as_str().into();
        cpp! {unsafe [widget_ptr as "SlintWidget*", rect as "QRectF", cursor as "int", anchor as "int", text as "QString"]  {
            widget_ptr->ime_position = rect.toRect();
            widget_ptr->ime_text = text;
            widget_ptr->ime_cursor = cursor;
            widget_ptr->ime_anchor = anchor;
            QGuiApplication::inputMethod()->update(Qt::ImQueryInput);
        }};
    }

    fn as_any(&self) -> &dyn std::any::Any {
        self
    }

    fn handle_focus_change(&self, _old: Option<ItemRc>, new: Option<ItemRc>) {
        let widget_ptr = self.widget_ptr();
        if let Some(ai) = accessible_item(new) {
            let item = &ai;
            cpp! {unsafe [widget_ptr as "QWidget*", item as "void*"] {
                auto accessible = QAccessible::queryAccessibleInterface(widget_ptr);
                if (auto slint_accessible = dynamic_cast<Slint_accessible*>(accessible)) {
                    slint_accessible->clearFocus();
                    slint_accessible->focusItem(item);
                }
            }};
        }
    }

    fn color_scheme(&self) -> ColorScheme {
        let ds = self.color_scheme.get_or_init(|| {
            Box::pin(Property::new(
                if cpp! {unsafe [] -> bool as "bool" {
                    return qApp->palette().color(QPalette::Window).valueF() < 0.5;
                }} {
                    ColorScheme::Dark
                } else {
                    ColorScheme::Light
                },
            ))
        });
        ds.as_ref().get()
    }

    fn bring_to_front(&self) -> Result<(), i_slint_core::platform::PlatformError> {
        let widget_ptr = self.widget_ptr();
        cpp! {unsafe [widget_ptr as "QWidget*"] {
            widget_ptr->raise();
            widget_ptr->activateWindow();
        }};
        Ok(())
    }
}

impl i_slint_core::renderer::RendererSealed for QtWindow {
    fn text_size(
        &self,
        font_request: FontRequest,
        text: &str,
        max_width: Option<LogicalLength>,
        _scale_factor: ScaleFactor,
        text_wrap: TextWrap,
    ) -> LogicalSize {
        get_font(font_request).font_metrics().text_size(
            text,
            max_width.map(|logical_width| logical_width.get()),
            text_wrap,
        )
    }

    fn font_metrics(
        &self,
        font_request: i_slint_core::graphics::FontRequest,
        _scale_factor: ScaleFactor,
    ) -> i_slint_core::items::FontMetrics {
        let qt_font_metrics = get_font(font_request).font_metrics();
        i_slint_core::items::FontMetrics {
            ascent: qt_font_metrics.ascent(),
            descent: -qt_font_metrics.descent(),
            x_height: qt_font_metrics.x_height(),
            cap_height: qt_font_metrics.cap_height(),
        }
    }

    fn text_input_byte_offset_for_position(
        &self,
        text_input: Pin<&i_slint_core::items::TextInput>,
        pos: LogicalPoint,
        font_request: FontRequest,
        _scale_factor: ScaleFactor,
    ) -> usize {
        if pos.y < 0. {
            return 0;
        }
        let size = LogicalSize::new(text_input.width().get(), text_input.height().get());
        let rect: qttypes::QRectF = check_geometry!(size);
        let pos = qttypes::QPointF { x: pos.x as _, y: pos.y as _ };
        let font: QFont = get_font(font_request);

        let visual_representation = text_input.visual_representation(Some(qt_password_character));

        let string = qttypes::QString::from(visual_representation.text.as_str());

        let flags = match text_input.horizontal_alignment() {
            TextHorizontalAlignment::Left => key_generated::Qt_AlignmentFlag_AlignLeft,
            TextHorizontalAlignment::Center => key_generated::Qt_AlignmentFlag_AlignHCenter,
            TextHorizontalAlignment::Right => key_generated::Qt_AlignmentFlag_AlignRight,
        } | match text_input.vertical_alignment() {
            TextVerticalAlignment::Top => key_generated::Qt_AlignmentFlag_AlignTop,
            TextVerticalAlignment::Center => key_generated::Qt_AlignmentFlag_AlignVCenter,
            TextVerticalAlignment::Bottom => key_generated::Qt_AlignmentFlag_AlignBottom,
        } | match text_input.wrap() {
            TextWrap::NoWrap => 0,
            TextWrap::WordWrap => key_generated::Qt_TextFlag_TextWordWrap,
            TextWrap::CharWrap => key_generated::Qt_TextFlag_TextWrapAnywhere,
        };
        let single_line: bool = text_input.single_line();
        let byte_offset = cpp! { unsafe [font as "QFont", string as "QString", pos as "QPointF", flags as "int",
                rect as "QRectF", single_line as "bool"] -> usize as "size_t" {
            // we need to do the \n replacement in a copy because the original need to be kept to know the utf8 offset
            auto copy = string;
            if (!single_line) {
                copy.replace(QChar('\n'), QChar::LineSeparator);
            }
            QTextLayout layout(copy, font);
            auto line = do_text_layout(layout, flags, rect, pos.y());
            if (line < 0 || layout.lineCount() <= line)
                return string.toUtf8().size();
            QTextLine textLine = layout.lineAt(line);
            int cur;
            if (pos.x() > textLine.naturalTextWidth()) {
                cur = textLine.textStart() + textLine.textLength();
                // cur is one past the last character of the line (eg, the \n or space).
                // Go one back to get back on this line.
                // Unless we were at the end of the text, in which case there was no \n
                if (cur > textLine.textStart() && (cur < string.size() || string[cur-1] == '\n'))
                    cur--;
            } else {
                cur = textLine.xToCursor(pos.x());
            }
            if (cur < string.size() && string[cur].isLowSurrogate())
                cur++;
            // convert to an utf8 pos;
            return QStringView(string).left(cur).toUtf8().size();
        }};
        visual_representation.map_byte_offset_from_byte_offset_in_visual_text(byte_offset)
    }

    fn text_input_cursor_rect_for_byte_offset(
        &self,
        text_input: Pin<&i_slint_core::items::TextInput>,
        byte_offset: usize,
        font_request: FontRequest,
        _scale_factor: ScaleFactor,
    ) -> LogicalRect {
        let size = LogicalSize::new(text_input.width().get(), text_input.height().get());
        let rect: qttypes::QRectF = check_geometry!(size);
        let font: QFont = get_font(font_request);
        let text = text_input.text();
        let mut string = qttypes::QString::from(text.as_str());
        let offset: u32 = utf8_byte_offset_to_utf16_units(text.as_str(), byte_offset) as _;
        let flags = match text_input.horizontal_alignment() {
            TextHorizontalAlignment::Left => key_generated::Qt_AlignmentFlag_AlignLeft,
            TextHorizontalAlignment::Center => key_generated::Qt_AlignmentFlag_AlignHCenter,
            TextHorizontalAlignment::Right => key_generated::Qt_AlignmentFlag_AlignRight,
        } | match text_input.vertical_alignment() {
            TextVerticalAlignment::Top => key_generated::Qt_AlignmentFlag_AlignTop,
            TextVerticalAlignment::Center => key_generated::Qt_AlignmentFlag_AlignVCenter,
            TextVerticalAlignment::Bottom => key_generated::Qt_AlignmentFlag_AlignBottom,
        } | match text_input.wrap() {
            TextWrap::NoWrap => 0,
            TextWrap::WordWrap => key_generated::Qt_TextFlag_TextWordWrap,
            TextWrap::CharWrap => key_generated::Qt_TextFlag_TextWrapAnywhere,
        };
        let single_line: bool = text_input.single_line();
        let r = cpp! { unsafe [font as "QFont", mut string as "QString", offset as "int", flags as "int", rect as "QRectF", single_line as "bool"]
                -> qttypes::QRectF as "QRectF" {
            if (!single_line) {
                string.replace(QChar('\n'), QChar::LineSeparator);
            }
            QTextLayout layout(string, font);
            do_text_layout(layout, flags, rect);

            QTextLine textLine = layout.lineForTextPosition(offset);
            if (!textLine.isValid())
                return QRectF();
            return QRectF(textLine.x() + textLine.cursorToX(offset), layout.position().y() + textLine.y(), 1.0, textLine.height());
        }};

        LogicalRect::new(
            LogicalPoint::new(r.x as _, r.y as _),
            LogicalSize::new(r.width as _, r.height as _),
        )
    }

    fn register_font_from_memory(
        &self,
        data: &'static [u8],
    ) -> Result<(), Box<dyn std::error::Error>> {
        let data = qttypes::QByteArray::from(data);
        cpp! {unsafe [data as "QByteArray"] {
            ensure_initialized(true);
            QFontDatabase::addApplicationFontFromData(data);
        } }
        Ok(())
    }

    fn register_font_from_path(
        &self,
        path: &std::path::Path,
    ) -> Result<(), Box<dyn std::error::Error>> {
        let encoded_path: qttypes::QByteArray = path.to_string_lossy().as_bytes().into();
        cpp! {unsafe [encoded_path as "QByteArray"] {
            ensure_initialized(true);

            QString requested_path = QFileInfo(QFile::decodeName(encoded_path)).canonicalFilePath();
            static QSet<QString> loaded_app_fonts;
            // QFontDatabase::addApplicationFont unconditionally reads the provided file from disk,
            // while we want to do this only once to avoid things like the live-review going crazy.
            if (!loaded_app_fonts.contains(requested_path)) {
                loaded_app_fonts.insert(requested_path);
                QFontDatabase::addApplicationFont(requested_path);
            }
        } }
        Ok(())
    }

    fn default_font_size(&self) -> LogicalLength {
        let default_font_size = cpp!(unsafe[] -> i32 as "int" {
            return QFontInfo(qApp->font()).pixelSize();
        });
        // Ideally this would return the value from another property with a binding that's updated
        // as a FontChange event is received. This is relevant for the case of using the Qt backend
        // with a non-native style.
        LogicalLength::new(default_font_size as f32)
    }

    fn free_graphics_resources(
        &self,
        component: ItemTreeRef,
        _items: &mut dyn Iterator<Item = Pin<i_slint_core::items::ItemRef<'_>>>,
    ) -> Result<(), i_slint_core::platform::PlatformError> {
        // Invalidate caches:
        self.cache.component_destroyed(component);
        Ok(())
    }

    fn set_window_adapter(&self, _window_adapter: &Rc<dyn WindowAdapter>) {
        // No-op because QtWindow is also the WindowAdapter
    }

    fn take_snapshot(&self) -> Result<SharedPixelBuffer<Rgba8Pixel>, PlatformError> {
        let widget_ptr = self.widget_ptr();

        let size = cpp! {unsafe [widget_ptr as "QWidget*"] -> qttypes::QSize as "QSize" {
            return widget_ptr->size();
        }};

        let rgba8_data = cpp! {unsafe [widget_ptr as "QWidget*"] -> qttypes::QByteArray as "QByteArray" {
            QPixmap pixmap = widget_ptr->grab();
            QImage image = pixmap.toImage();
            image.convertTo(QImage::Format_ARGB32);
            return QByteArray(reinterpret_cast<const char *>(image.constBits()), image.sizeInBytes());
        }};

        let buffer = i_slint_core::graphics::SharedPixelBuffer::<i_slint_core::graphics::Rgba8Pixel>::clone_from_slice(
            rgba8_data.to_slice(),
            size.width,
            size.height,
        );
        Ok(buffer)
    }
}

fn accessible_item(item: Option<ItemRc>) -> Option<ItemRc> {
    let mut current = item;
    while let Some(c) = current {
        if c.is_accessible() {
            return Some(c);
        } else {
            current = c.parent_item(ParentItemTraversalMode::StopAtPopups);
        }
    }
    None
}

fn get_font(request: FontRequest) -> QFont {
    let family: qttypes::QString = request.family.unwrap_or_default().as_str().into();
    let pixel_size: f32 = request.pixel_size.map_or(0., |logical_size| logical_size.get());
    let weight: i32 = request.weight.unwrap_or(0);
    let letter_spacing: f32 =
        request.letter_spacing.map_or(0., |logical_spacing| logical_spacing.get());
    let italic: bool = request.italic;
    cpp!(unsafe [family as "QString", pixel_size as "float", weight as "int", letter_spacing as "float", italic as "bool"] -> QFont as "QFont" {
        QFont f;
        if (!family.isEmpty())
            f.setFamily(family);
        if (pixel_size > 0)
            f.setPixelSize(pixel_size);
        if (weight > 0) {
    #if QT_VERSION < QT_VERSION_CHECK(6, 0, 0)
            f.setWeight(qMin((weight-100)/8, 99));
    #else
            f.setWeight(QFont::Weight(weight));
    #endif
        }
        f.setLetterSpacing(QFont::AbsoluteSpacing, letter_spacing);
        f.setItalic(italic);
        // Mark all font properties as resolved, to avoid inheriting font properties
        // from the widget hierarchy. Later we call QPainter::setFont, which would
        // merge in unset properties (such as bold, etc.) that it retrieved from
        // the widget the painter is associated with.
    #if QT_VERSION < QT_VERSION_CHECK(6, 0, 0)
        f.resolve(QFont::AllPropertiesResolved);
    #else
        f.setResolveMask(QFont::AllPropertiesResolved);
    #endif
        return f;
    })
}

cpp_class! {pub unsafe struct QFontMetricsF as "QFontMetricsF"}

impl QFontMetricsF {
    fn text_size(&self, text: &str, max_width: Option<f32>, text_wrap: TextWrap) -> LogicalSize {
        let string = qttypes::QString::from(text);
        let char_wrap = text_wrap == TextWrap::CharWrap;
        let mut r = qttypes::QRectF::default();
        if let Some(max) = max_width {
            r.height = f32::MAX as _;
            r.width = max as _;
        }
        let size = cpp! { unsafe [self as "const QFontMetricsF*", string as "QString", r as "QRectF", char_wrap as "bool"]
                -> qttypes::QSizeF as "QSizeF" {
            return self->boundingRect(r, r.isEmpty() ? 0 : ((char_wrap) ? Qt::TextWrapAnywhere : Qt::TextWordWrap) , string).size();
        }};
        LogicalSize::new(size.width as _, size.height as _)
    }

    fn ascent(&self) -> f32 {
        cpp! { unsafe [self as "const QFontMetricsF*"]
                -> f32 as "float" {
            return self->ascent();
        }}
    }

    fn descent(&self) -> f32 {
        cpp! { unsafe [self as "const QFontMetricsF*"]
                -> f32 as "float" {
            return self->descent();
        }}
    }

    fn cap_height(&self) -> f32 {
        cpp! { unsafe [self as "const QFontMetricsF*"]
                -> f32 as "float" {
            return self->capHeight();
        }}
    }

    fn x_height(&self) -> f32 {
        cpp! { unsafe [self as "const QFontMetricsF*"]
                -> f32 as "float" {
            return self->xHeight();
        }}
    }
}

cpp_class! {pub unsafe struct QFont as "QFont"}

impl QFont {
    fn font_metrics(&self) -> QFontMetricsF {
        cpp! { unsafe [self as "const QFont *"] -> QFontMetricsF as "QFontMetricsF" {
            return QFontMetricsF(*self);
        }}
    }
}

thread_local! {
    // FIXME: currently the window are never removed
    static ALL_WINDOWS: RefCell<Vec<Weak<QtWindow>>> = Default::default();
}

/// Called by C++'s TimerHandler::timerEvent, or every time a timer might have been started
pub(crate) fn timer_event() {
    i_slint_core::platform::update_timers_and_animations();
    restart_timer();
}

pub(crate) fn restart_timer() {
    let timeout = i_slint_core::timers::TimerList::next_timeout().map(|instant| {
        let now = std::time::Instant::now();
        let instant: std::time::Instant = instant.into();
        if instant > now {
            instant.duration_since(now).as_millis() as i32
        } else {
            0
        }
    });
    if let Some(timeout) = timeout {
        cpp! { unsafe [timeout as "int"] {
            ensure_initialized(true);
            TimerHandler::instance().timer.start(timeout, &TimerHandler::instance());
        }}
    }
}

mod key_codes {
    macro_rules! define_qt_key_to_string_fn {
        ($($char:literal # $name:ident # $($qt:ident)|* # $($winit:ident $(($_pos:ident))?)|* # $($_xkb:ident)|*;)*) => {
            use crate::key_generated;
            pub fn qt_key_to_string(key: key_generated::Qt_Key) -> Option<i_slint_core::SharedString> {

                let char = match(key) {
                    $($(key_generated::$qt => $char,)*)*
                    _ => return None,
                };
                Some(char.into())
            }
        };
    }

    i_slint_common::for_each_special_keys!(define_qt_key_to_string_fn);
}

fn qt_key_to_string(key: key_generated::Qt_Key, event_text: String) -> SharedString {
    // First try to see if we received one of the non-ascii keys that we have
    // a special representation for. If that fails, try to use the provided
    // text. If that's empty, then try to see if the provided key has an ascii
    // representation. The last step is needed because modifiers may result in
    // the text to be empty otherwise, for example Ctrl+C.
    if let Some(special_key_code) = key_codes::qt_key_to_string(key) {
        return special_key_code;
    };

    // On Windows, X11 and Wayland, Ctrl+C for example sends a terminal control character,
    // which we choose not to supply to the application. Instead we fall through to translating
    // the supplied key code.
    if !event_text.is_empty() && !event_text.chars().any(|ch| ch.is_control()) {
        return event_text.into();
    }

    match key {
        key_generated::Qt_Key_Key_Space => " ",
        key_generated::Qt_Key_Key_Exclam => "!",
        key_generated::Qt_Key_Key_QuoteDbl => "\"",
        key_generated::Qt_Key_Key_NumberSign => "#",
        key_generated::Qt_Key_Key_Dollar => "$",
        key_generated::Qt_Key_Key_Percent => "%",
        key_generated::Qt_Key_Key_Ampersand => "&",
        key_generated::Qt_Key_Key_Apostrophe => "'",
        key_generated::Qt_Key_Key_ParenLeft => "(",
        key_generated::Qt_Key_Key_ParenRight => ")",
        key_generated::Qt_Key_Key_Asterisk => "*",
        key_generated::Qt_Key_Key_Plus => "+",
        key_generated::Qt_Key_Key_Comma => ",",
        key_generated::Qt_Key_Key_Minus => "-",
        key_generated::Qt_Key_Key_Period => ".",
        key_generated::Qt_Key_Key_Slash => "/",
        key_generated::Qt_Key_Key_0 => "0",
        key_generated::Qt_Key_Key_1 => "1",
        key_generated::Qt_Key_Key_2 => "2",
        key_generated::Qt_Key_Key_3 => "3",
        key_generated::Qt_Key_Key_4 => "4",
        key_generated::Qt_Key_Key_5 => "5",
        key_generated::Qt_Key_Key_6 => "6",
        key_generated::Qt_Key_Key_7 => "7",
        key_generated::Qt_Key_Key_8 => "8",
        key_generated::Qt_Key_Key_9 => "9",
        key_generated::Qt_Key_Key_Colon => ":",
        key_generated::Qt_Key_Key_Semicolon => ";",
        key_generated::Qt_Key_Key_Less => "<",
        key_generated::Qt_Key_Key_Equal => "=",
        key_generated::Qt_Key_Key_Greater => ">",
        key_generated::Qt_Key_Key_Question => "?",
        key_generated::Qt_Key_Key_At => "@",
        key_generated::Qt_Key_Key_A => "a",
        key_generated::Qt_Key_Key_B => "b",
        key_generated::Qt_Key_Key_C => "c",
        key_generated::Qt_Key_Key_D => "d",
        key_generated::Qt_Key_Key_E => "e",
        key_generated::Qt_Key_Key_F => "f",
        key_generated::Qt_Key_Key_G => "g",
        key_generated::Qt_Key_Key_H => "h",
        key_generated::Qt_Key_Key_I => "i",
        key_generated::Qt_Key_Key_J => "j",
        key_generated::Qt_Key_Key_K => "k",
        key_generated::Qt_Key_Key_L => "l",
        key_generated::Qt_Key_Key_M => "m",
        key_generated::Qt_Key_Key_N => "n",
        key_generated::Qt_Key_Key_O => "o",
        key_generated::Qt_Key_Key_P => "p",
        key_generated::Qt_Key_Key_Q => "q",
        key_generated::Qt_Key_Key_R => "r",
        key_generated::Qt_Key_Key_S => "s",
        key_generated::Qt_Key_Key_T => "t",
        key_generated::Qt_Key_Key_U => "u",
        key_generated::Qt_Key_Key_V => "v",
        key_generated::Qt_Key_Key_W => "w",
        key_generated::Qt_Key_Key_X => "x",
        key_generated::Qt_Key_Key_Y => "y",
        key_generated::Qt_Key_Key_Z => "z",
        key_generated::Qt_Key_Key_BracketLeft => "[",
        key_generated::Qt_Key_Key_Backslash => "\\",
        key_generated::Qt_Key_Key_BracketRight => "]",
        key_generated::Qt_Key_Key_AsciiCircum => "^",
        key_generated::Qt_Key_Key_Underscore => "_",
        key_generated::Qt_Key_Key_QuoteLeft => "`",
        key_generated::Qt_Key_Key_BraceLeft => "{",
        key_generated::Qt_Key_Key_Bar => "|",
        key_generated::Qt_Key_Key_BraceRight => "}",
        key_generated::Qt_Key_Key_AsciiTilde => "~",
        _ => "",
    }
    .into()
}

pub(crate) mod ffi {
    use std::ffi::c_void;

    use super::QtWindow;

    #[no_mangle]
    pub extern "C" fn slint_qt_get_widget(
        window_adapter: &i_slint_core::window::WindowAdapterRc,
    ) -> *mut c_void {
        window_adapter
            .internal(i_slint_core::InternalToken)
            .and_then(|wa| <dyn std::any::Any>::downcast_ref(wa.as_any()))
            .map_or(std::ptr::null_mut(), |win: &QtWindow| {
                win.widget_ptr().cast::<c_void>().as_ptr()
            })
    }
}

fn utf8_byte_offset_to_utf16_units(str: &str, byte_offset: usize) -> usize {
    let mut current_offset = 0;
    let mut utf16_units = 0;
    for ch in str.chars() {
        if current_offset >= byte_offset {
            break;
        }
        current_offset += ch.len_utf8();
        utf16_units += ch.len_utf16();
    }
    utf16_units
}

#[test]
fn test_utf8_byte_offset_to_utf16_units() {
    assert_eq!(utf8_byte_offset_to_utf16_units("Hello", 2), 2);

    {
        let test_str = "a🚀🍌";
        assert_eq!(test_str.encode_utf16().count(), 5);

        let banana_offset = test_str.char_indices().nth(2).unwrap().0;

        assert_eq!(
            utf8_byte_offset_to_utf16_units(test_str, banana_offset),
            // 'a' encodes as one utf-16 unit, the rocket ship requires two units
            3
        );
    }
}

fn qt_password_character() -> char {
    char::from_u32(cpp! { unsafe [] -> i32 as "int" {
        return qApp->style()->styleHint(QStyle::SH_LineEdit_PasswordCharacter, nullptr, nullptr);
    }} as u32)
    .unwrap_or('●')
}