1// Copyright © SixtyFPS GmbH <info@slint.dev>
2// SPDX-License-Identifier: MIT
3
4#pragma once
5
6#include <slint-interpreter.h>
7
8#include <optional>
9#include <string_view>
10#include <vector>
11#include <unordered_set>
12
13struct PropertyDeclaration
14{
15 std::string name;
16 std::string type_name;
17};
18
19/**
20 The Widget base class is a wrapper around slint::interpreter::ComponentInstance that allows
21 conveniently reading and writing properties of an element of which the properties have been
22 forwarded via two-way bindings.
23
24 When an instance of a Widget sub-class is added to the DashboardBuilder, the value of
25 type_name() is used to create an element declaration in the generated .slint code ("SomeElement {
26 ... }"), the element is given an automatically generated name and all properties returned by the
27 properties() function are forwarded. For example two instances of a "Clock" element become this
28 in .slint:
29
30 export component MainWindow inherits Window {
31 ...
32 widget_1 := Clock {
33 }
34 widget_2 := Clock {
35 }
36
37 in-out property <string> widget_1__time <=> widget_1.time;
38 in-out property <string> widget_2__time <=> widget_2.time;
39 }
40
41 The DashboardBuilder calls connect_ui() to inform the instance about the "widget_1__" and
42 "widget_2__" prefix and passes a reference to the MainWindow as ComponentInstance. Subsequently
43 calls to set_property("time", some_value) translate to setting "widget_1__time" or
44 "widget_2__time", depending on the Widget instance.
45 */
46class Widget
47{
48public:
49 virtual ~Widget() { }
50 virtual std::string type_name() const = 0;
51 virtual std::vector<PropertyDeclaration> properties() const = 0;
52
53 void set_property(std::string_view name, const slint::interpreter::Value &value);
54
55 std::optional<slint::interpreter::Value> property(std::string_view name) const;
56
57 void connect_ui(const slint::ComponentHandle<slint::interpreter::ComponentInstance> &ui,
58 std::string_view properties_prefix);
59
60 std::pair<std::string, std::vector<PropertyDeclaration>>
61 generate_forwarding_two_way_property_bindings(std::string_view widget_name) const;
62
63private:
64 std::string qualified_property_name(std::string_view name) const;
65
66 std::optional<slint::ComponentHandle<slint::interpreter::ComponentInstance>> m_ui;
67 std::string m_properties_prefix;
68};
69
70using WidgetPtr = std::shared_ptr<Widget>;
71
72struct WidgetLocation
73{
74 int row = 0;
75 int column = 0;
76 std::optional<int> row_span;
77 std::optional<int> col_span;
78
79 std::string location_bindings() const;
80};
81
82/**
83 The DashboardBuilder is dynamically builds the .slint code that represents the IOT-Dashboard demo
84 and allows placing widgets into the top-bar or the main grid. All the properties of the added
85 widgets are forwarded and their name prefix is registered with the individual widget instances.
86*/
87struct DashboardBuilder
88{
89 void add_grid_widget(WidgetPtr widget, const WidgetLocation &location);
90 void add_top_bar_widget(WidgetPtr widget);
91
92 std::optional<slint::ComponentHandle<slint::interpreter::ComponentInstance>>
93 build(slint::interpreter::ComponentCompiler &compiler) const;
94
95private:
96 int register_widget(WidgetPtr widget);
97
98 std::unordered_set<std::string> widgets_used = { "TopBar", "MenuBar" };
99 std::vector<int> top_bar_widgets;
100 std::vector<std::pair<int, WidgetLocation>> grid_widgets;
101
102 std::vector<std::pair<std::string, WidgetPtr>> widgets;
103};
104

source code of slint/examples/iot-dashboard/dashboard.h