fyrox_ui/canvas.rs
1// Copyright (c) 2019-present Dmitry Stepanov and Fyrox Engine contributors.
2//
3// Permission is hereby granted, free of charge, to any person obtaining a copy
4// of this software and associated documentation files (the "Software"), to deal
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20
21//! Canvas widget allows its children to have an arbitrary position on an imaginable infinite plane, it also
22//! gives the children constraints of infinite size, which forces them to take all the desired size. See
23//! [`Canvas`] docs for more info and usage examples.
24
25#![warn(missing_docs)]
26
27use crate::{
28 core::{
29 algebra::Vector2, math::Rect, pool::Handle, reflect::prelude::*, type_traits::prelude::*,
30 visitor::prelude::*,
31 },
32 message::UiMessage,
33 widget::{Widget, WidgetBuilder},
34 BuildContext, Control, UiNode, UserInterface,
35};
36use fyrox_graph::constructor::{ConstructorProvider, GraphNodeConstructor};
37
38/// Canvas widget allows its children to have an arbitrary position on an imaginable infinite plane, it also
39/// gives the children constraints of infinite size, which forces them to take all the desired size. This widget
40/// could be used when you need to have an ability to put widgets at arbitrary positions. Canvas widget is the
41/// root widget of the widget hierarchy used in `fyrox-ui`.
42///
43/// ## Examples
44///
45/// An instance of [`Canvas`] widget can be created using [`CanvasBuilder`] with a set of children widgets provided
46/// to [`WidgetBuilder`]:
47///
48/// ```rust
49/// # use fyrox_ui::{
50/// # button::ButtonBuilder, canvas::CanvasBuilder, core::pool::Handle, text::TextBuilder,
51/// # widget::WidgetBuilder, BuildContext, UiNode,
52/// # };
53/// # use fyrox_ui::canvas::Canvas;
54/// #
55/// fn create_canvas(ctx: &mut BuildContext) -> Handle<Canvas> {
56/// CanvasBuilder::new(
57/// WidgetBuilder::new()
58/// .with_child(
59/// ButtonBuilder::new(WidgetBuilder::new())
60/// .with_text("Click me!")
61/// .build(ctx),
62/// )
63/// .with_child(
64/// TextBuilder::new(WidgetBuilder::new())
65/// .with_text("Some text")
66/// .build(ctx),
67/// ),
68/// )
69/// .build(ctx)
70/// }
71/// ```
72#[derive(Default, Clone, Visit, Reflect, Debug, TypeUuidProvider, ComponentProvider)]
73#[type_uuid(id = "6b843a36-53da-467b-b85e-2380fe891ca1")]
74#[reflect(derived_type = "UiNode")]
75pub struct Canvas {
76 /// Base widget of the canvas.
77 pub widget: Widget,
78}
79
80impl ConstructorProvider<UiNode, UserInterface> for Canvas {
81 fn constructor() -> GraphNodeConstructor<UiNode, UserInterface> {
82 GraphNodeConstructor::new::<Self>()
83 .with_variant("Canvas", |ui| {
84 CanvasBuilder::new(WidgetBuilder::new().with_name("Canvas"))
85 .build(&mut ui.build_ctx())
86 .to_base()
87 .into()
88 })
89 .with_group("Layout")
90 }
91}
92
93crate::define_widget_deref!(Canvas);
94
95impl Control for Canvas {
96 fn measure_override(&self, ui: &UserInterface, _available_size: Vector2<f32>) -> Vector2<f32> {
97 let size_for_child = Vector2::new(f32::INFINITY, f32::INFINITY);
98
99 for child_handle in self.widget.children() {
100 ui.measure_node(*child_handle, size_for_child);
101 }
102
103 Vector2::default()
104 }
105
106 fn arrange_override(&self, ui: &UserInterface, final_size: Vector2<f32>) -> Vector2<f32> {
107 for &child_handle in self.widget.children() {
108 let child = ui.nodes.borrow(child_handle);
109 ui.arrange_node(
110 child_handle,
111 &Rect::new(
112 child.desired_local_position().x,
113 child.desired_local_position().y,
114 child.desired_size().x,
115 child.desired_size().y,
116 ),
117 );
118 }
119
120 final_size
121 }
122
123 fn handle_routed_message(&mut self, ui: &mut UserInterface, message: &mut UiMessage) {
124 self.widget.handle_routed_message(ui, message);
125 }
126}
127
128/// Canvas builder creates new [`Canvas`] widget instances and adds them to the user interface.
129pub struct CanvasBuilder {
130 widget_builder: WidgetBuilder,
131}
132
133impl CanvasBuilder {
134 /// Creates new builder instance.
135 pub fn new(widget_builder: WidgetBuilder) -> Self {
136 Self { widget_builder }
137 }
138
139 /// Finishes canvas widget building and adds the instance to the user interface and returns its handle.
140 pub fn build(self, ctx: &mut BuildContext) -> Handle<Canvas> {
141 let canvas = Canvas {
142 widget: self.widget_builder.build(ctx),
143 };
144 ctx.add(canvas)
145 }
146}
147
148#[cfg(test)]
149mod test {
150 use crate::canvas::CanvasBuilder;
151 use crate::{test::test_widget_deletion, widget::WidgetBuilder};
152
153 #[test]
154 fn test_deletion() {
155 test_widget_deletion(|ctx| CanvasBuilder::new(WidgetBuilder::new()).build(ctx));
156 }
157}