Add a qt_viewer example that uses QWidget

CMakeLists.txt

@@ -18,4 +18,5 @@ add_subdirectory(examples/printerdemo/cpp_interpreted/)
 add_subdirectory(examples/todo/cpp/)
 add_subdirectory(examples/gallery/)
 add_subdirectory(examples/memory/)
+add_subdirectory(examples/qt_viewer/)
 

api/sixtyfps-cpp/include/sixtyfps_interpreter.h

@@ -15,6 +15,12 @@ LICENSE END */
 
 #include <optional>
 
+#define SIXTYFPS_QT_INTEGRATION // In the future, should be defined by cmake only if this is enabled
+#ifdef SIXTYFPS_QT_INTEGRATION
+class QWidget;
+#endif
+
+
 namespace sixtyfps::cbindgen_private {
 //  This has to stay opaque, but VRc don't compile if it is just forward declared
 struct ErasedComponentBox : vtable::Dyn
@@ -501,6 +507,17 @@ public:
         cbindgen_private::sixtyfps_run_event_loop();
         hide();
     }
+#ifdef SIXTYFPS_QT_INTEGRATION
+    /// Return a QWidget for this instance.
+    /// This function is only available if the qt graphical backend was compiled in, and
+    /// it may return nullptr if the Qt backend is not used at runtime.
+    QWidget *qwidget() const {
+        cbindgen_private::ComponentWindowOpaque win;
+        cbindgen_private::sixtyfps_interpreter_component_instance_window(inner(), &win);
+        return reinterpret_cast<QWidget *>(cbindgen_private::sixtyfps_qt_get_widget(
+            reinterpret_cast<cbindgen_private::ComponentWindow *>(&win)));
+    }
+#endif
 
     bool set_property(std::string_view name, const Value &value) const
     {

examples/qt_viewer/CMakeLists.txt

@@ -0,0 +1,24 @@
+# LICENSE BEGIN
+# This file is part of the SixtyFPS Project -- https://sixtyfps.io
+# Copyright (c) 2020 Olivier Goffart <olivier.goffart@sixtyfps.io>
+# Copyright (c) 2020 Simon Hausmann <simon.hausmann@sixtyfps.io>
+#
+# SPDX-License-Identifier: GPL-3.0-only
+# This file is also available under commercial licensing terms.
+# Please contact info@sixtyfps.io for more information.
+# LICENSE END
+cmake_minimum_required(VERSION 3.14)
+project(qt_viewer LANGUAGES CXX)
+
+if (NOT TARGET SixtyFPS::SixtyFPS)
+    find_package(SixtyFPS REQUIRED)
+endif()
+
+find_package(Qt5 COMPONENTS Core Widgets)
+
+if (Qt5Widgets_FOUND)
+    set(CMAKE_AUTOUIC ON)
+    add_executable(qt_viewer qt_viewer.cpp)
+    target_link_libraries(qt_viewer PRIVATE SixtyFPS::SixtyFPS Qt5::Core Qt5::Widgets)
+endif(Qt5Widgets_FOUND)
+

examples/qt_viewer/README.md

@@ -0,0 +1,7 @@
+# qt_viewer
+
+This is an example that shows how to embed a dynamically loaded .60 into a Qt (QWidgets) application
+
+The trick is that it uses the C++ `sixtyfps::interpreter::ComponentInstance::qwidget` and embed
+that widget in a Qt application.
+

examples/qt_viewer/interface.ui

@@ -0,0 +1,78 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<ui version="4.0">
+ <class>Interface</class>
+ <widget class="QWidget" name="Interface">
+  <property name="geometry">
+   <rect>
+    <x>0</x>
+    <y>0</y>
+    <width>512</width>
+    <height>524</height>
+   </rect>
+  </property>
+  <property name="windowTitle">
+   <string>Form</string>
+  </property>
+  <layout class="QGridLayout" name="gridLayout">
+   <item row="0" column="0">
+    <widget class="QPushButton" name="load_button">
+     <property name="text">
+      <string>Load</string>
+     </property>
+    </widget>
+   </item>
+   <item row="0" column="1" rowspan="7">
+    <widget class="QFrame" name="my_content">
+     <property name="frameShape">
+      <enum>QFrame::StyledPanel</enum>
+     </property>
+     <property name="frameShadow">
+      <enum>QFrame::Raised</enum>
+     </property>
+    </widget>
+   </item>
+   <item row="1" column="0">
+    <widget class="QLabel" name="label">
+     <property name="text">
+      <string>Property name</string>
+     </property>
+    </widget>
+   </item>
+   <item row="2" column="0">
+    <widget class="QLineEdit" name="prop_name"/>
+   </item>
+   <item row="3" column="0">
+    <widget class="QLabel" name="label_2">
+     <property name="text">
+      <string>Value</string>
+     </property>
+    </widget>
+   </item>
+   <item row="4" column="0">
+    <widget class="QLineEdit" name="prop_value"/>
+   </item>
+   <item row="5" column="0">
+    <widget class="QPushButton" name="set_button">
+     <property name="text">
+      <string>Set</string>
+     </property>
+    </widget>
+   </item>
+   <item row="6" column="0">
+    <spacer name="verticalSpacer">
+     <property name="orientation">
+      <enum>Qt::Vertical</enum>
+     </property>
+     <property name="sizeHint" stdset="0">
+      <size>
+       <width>20</width>
+       <height>233</height>
+      </size>
+     </property>
+    </spacer>
+   </item>
+  </layout>
+ </widget>
+ <resources/>
+ <connections/>
+</ui>

examples/qt_viewer/qt_viewer.cpp

@@ -0,0 +1,73 @@
+/* LICENSE BEGIN
+    This file is part of the SixtyFPS Project -- https://sixtyfps.io
+    Copyright (c) 2020 Olivier Goffart <olivier.goffart@sixtyfps.io>
+    Copyright (c) 2020 Simon Hausmann <simon.hausmann@sixtyfps.io>
+
+    SPDX-License-Identifier: GPL-3.0-only
+    This file is also available under commercial licensing terms.
+    Please contact info@sixtyfps.io for more information.
+LICENSE END */
+
+#include <QtWidgets/QtWidgets>
+#include <sixtyfps_interpreter.h>
+
+#include "ui_interface.h"
+
+
+struct LoadedFile {
+    sixtyfps::ComponentHandle<sixtyfps::interpreter::ComponentInstance> instance;
+    QWidget *widget;
+};
+
+void show_diagnostics(QWidget *root, const sixtyfps::SharedVector< sixtyfps::interpreter::Diagnostic > &diags) {
+    QString text;
+
+    for (auto diagnostic : diags) {
+        text += (diagnostic.level == sixtyfps::interpreter::DiagnosticLevel::Warning
+                              ? QApplication::translate("qt_viewer", "warning: %1\n")
+                              : QApplication::translate("qt_viewer", "error: %1\n")
+                 ).arg(QString::fromUtf8(diagnostic.message.data()));
+
+        text += QApplication::translate("qt_viewer", "location: %1").arg(QString::fromUtf8(diagnostic.source_file.data()));
+        if (diagnostic.line > 0)
+            text += ":" + QString::number(diagnostic.line);
+        if (diagnostic.column > 0)
+            text += ":" + QString::number(diagnostic.column);
+        text += "\n";
+    }
+
+    QMessageBox::critical(root, QApplication::translate("qt_viewer", "Compilation error"), text, QMessageBox::StandardButton::Ok);
+}
+
+int main(int argc, char **argv) {
+    QApplication app(argc, argv);
+    std::unique_ptr<LoadedFile> loaded_file;
+
+    QWidget main;
+    Ui::Interface ui;
+    ui.setupUi(&main);
+    QHBoxLayout layout(ui.my_content);
+
+    QObject::connect(ui.load_button, &QPushButton::clicked, [&] {
+        QString fileName = QFileDialog::getOpenFileName(
+            &main, QApplication::translate("qt_viewer", "Open SixtyFPS File"), {},
+            QApplication::translate("qt_viewer", "SixtyFPS File (*.60)"));
+        if (fileName.isEmpty())
+            return;
+        loaded_file.reset();
+        sixtyfps::interpreter::ComponentCompiler compiler;
+        auto def = compiler.build_from_path(fileName.toUtf8().data());
+        if (!def) {
+            show_diagnostics(&main, compiler.diagnostics());
+            return;
+        }
+        auto instance = def->create();
+        QWidget *wid = instance->qwidget();
+        wid->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);
+        layout.addWidget(wid);
+        loaded_file = std::make_unique<LoadedFile>(LoadedFile{ instance, wid });
+    });
+    main.show();
+    return app.exec();
+}
+

sixtyfps_runtime/corelib/window.rs

@@ -65,6 +65,9 @@ pub trait PlatformWindow {
         &self,
         source: Pin<&crate::properties::Property<ImageReference>>,
     ) -> crate::graphics::Size;
+
+    /// Return self as any so the backend can upcast
+    fn as_any(&self) -> &dyn core::any::Any;
 }
 
 /// Structure that represent a Window in the runtime

sixtyfps_runtime/interpreter/ffi.rs

@@ -420,6 +420,23 @@ pub extern "C" fn sixtyfps_interpreter_component_instance_show(
     }
 }
 
+/// Return a window for the component
+///
+/// The out pointer must be uninitialized and must be destroyed with
+/// sixtyfps_component_window_drop after usage
+#[no_mangle]
+pub unsafe extern "C" fn sixtyfps_interpreter_component_instance_window(
+    inst: &ErasedComponentBox,
+    out: *mut sixtyfps_corelib::window::ffi::ComponentWindowOpaque,
+) {
+    use sixtyfps_corelib::window::ComponentWindow;
+    assert_eq!(
+        core::mem::size_of::<ComponentWindow>(),
+        core::mem::size_of::<sixtyfps_corelib::window::ffi::ComponentWindowOpaque>()
+    );
+    core::ptr::write(out as *mut ComponentWindow, inst.window())
+}
+
 /// Instantiate an instance from a definition.
 ///
 /// The `out` must be uninitialized and is going to be initialized after the call

sixtyfps_runtime/rendering_backends/gl/graphics_window.rs

@@ -502,6 +502,10 @@ impl PlatformWindow for GraphicsWindow {
             }
         }
     }
+
+    fn as_any(&self) -> &dyn std::any::Any {
+        self
+    }
 }
 
 struct MappedWindow {

sixtyfps_runtime/rendering_backends/qt/lib.rs

@@ -39,7 +39,8 @@ pub fn use_modules() -> usize {
     }
     #[cfg(not(no_qt))]
     {
-        (&widgets::NativeButtonVTable) as *const _ as usize
+        qt_window::ffi::sixtyfps_qt_get_widget as usize
+            + (&widgets::NativeButtonVTable) as *const _ as usize
     }
 }
 

sixtyfps_runtime/rendering_backends/qt/qt_window.rs

@@ -1010,6 +1010,10 @@ impl PlatformWindow for QtWindow {
             })
             .unwrap_or_default()
     }
+
+    fn as_any(&self) -> &dyn std::any::Any {
+        self
+    }
 }
 
 fn get_font(request: FontRequest) -> QFont {
@@ -1199,3 +1203,19 @@ fn qt_key_to_string(key: key_generated::Qt_Key, event_text: String) -> SharedStr
     }
     .into()
 }
+
+pub(crate) mod ffi {
+    use std::any::Any;
+    use std::ffi::c_void;
+
+    use super::QtWindow;
+
+    #[no_mangle]
+    pub extern "C" fn sixtyfps_qt_get_widget(
+        window: &sixtyfps_corelib::window::ComponentWindow,
+    ) -> *mut c_void {
+        Any::downcast_ref(window.0.as_any()).map_or(std::ptr::null_mut(), |win: &QtWindow| {
+            win.widget_ptr().cast::<c_void>().as_ptr()
+        })
+    }
+}

sixtyfps_runtime/rendering_backends/qt/widgets.rs

@@ -130,6 +130,9 @@ cpp! {{
     void ensure_initialized()
     {
         static auto app [[maybe_unused]]  = []{
+            if (qApp) {
+                return qApp;
+            }
             QCoreApplication::setAttribute(Qt::AA_PluginApplication, true);
             static int argc  = 1;
             static char argv[] = "sixtyfps";