slint/examples/iot-dashboard/dashboard.h
2023-07-27 15:42:11 +02:00

103 lines
3.4 KiB
C++

// Copyright © SixtyFPS GmbH <info@slint.dev>
// SPDX-License-Identifier: MIT
#pragma once
#include <slint-interpreter.h>
#include <optional>
#include <string_view>
#include <vector>
#include <unordered_set>
struct PropertyDeclaration
{
std::string name;
std::string type_name;
};
/**
The Widget base class is a wrapper around slint::interpreter::ComponentInstance that allows
conveniently reading and writing properties of an element of which the properties have been
forwarded via two-way bindings.
When an instance of a Widget sub-class is added to the DashboardBuilder, the value of
type_name() is used to create an element declaration in the generated .slint code ("SomeElement {
... }"), the element is given an automatically generated name and all properties returned by the
properties() function are forwarded. For example two instances of a "Clock" element become this
in .slint:
export component MainWindow inherits Window {
...
widget_1 := Clock {
}
widget_2 := Clock {
}
in-out property <string> widget_1__time <=> widget_1.time;
in-out property <string> widget_2__time <=> widget_2.time;
}
The DashboardBuilder calls connect_ui() to inform the instance about the "widget_1__" and
"widget_2__" prefix and passes a reference to the MainWindow as ComponentInstance. Subsequently
calls to set_property("time", some_value) translate to setting "widget_1__time" or
"widget_2__time", depending on the Widget instance.
*/
class Widget
{
public:
virtual ~Widget() { }
virtual std::string type_name() const = 0;
virtual std::vector<PropertyDeclaration> properties() const = 0;
void set_property(std::string_view name, const slint::interpreter::Value &value);
std::optional<slint::interpreter::Value> property(std::string_view name) const;
void connect_ui(const slint::ComponentHandle<slint::interpreter::ComponentInstance> &ui,
std::string_view properties_prefix);
std::pair<std::string, std::vector<PropertyDeclaration>>
generate_forwarding_two_way_property_bindings(std::string_view widget_name) const;
private:
std::string qualified_property_name(std::string_view name) const;
std::optional<slint::ComponentHandle<slint::interpreter::ComponentInstance>> m_ui;
std::string m_properties_prefix;
};
using WidgetPtr = std::shared_ptr<Widget>;
struct WidgetLocation
{
int row = 0;
int column = 0;
std::optional<int> row_span;
std::optional<int> col_span;
std::string location_bindings() const;
};
/**
The DashboardBuilder is dynamically builds the .slint code that represents the IOT-Dashboard demo
and allows placing widgets into the top-bar or the main grid. All the properties of the added
widgets are forwarded and their name prefix is registered with the individual widget instances.
*/
struct DashboardBuilder
{
void add_grid_widget(WidgetPtr widget, const WidgetLocation &location);
void add_top_bar_widget(WidgetPtr widget);
std::optional<slint::ComponentHandle<slint::interpreter::ComponentInstance>>
build(slint::interpreter::ComponentCompiler &compiler) const;
private:
int register_widget(WidgetPtr widget);
std::unordered_set<std::string> widgets_used = { "TopBar", "MenuBar" };
std::vector<int> top_bar_widgets;
std::vector<std::pair<int, WidgetLocation>> grid_widgets;
std::vector<std::pair<std::string, WidgetPtr>> widgets;
};