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| -rw-r--r-- | examples/geometry.rs | 209 |
1 files changed, 209 insertions, 0 deletions
diff --git a/examples/geometry.rs b/examples/geometry.rs new file mode 100644 index 00000000..ae6c9ca0 --- /dev/null +++ b/examples/geometry.rs @@ -0,0 +1,209 @@ +//! This example showcases a simple native custom widget that renders using +//! arbitrary low-level geometry. +mod rainbow { + // For now, to implement a custom native widget you will need to add + // `iced_native` and `iced_wgpu` to your dependencies. + // + // Then, you simply need to define your widget type and implement the + // `iced_native::Widget` trait with the `iced_wgpu::Renderer`. + // + // Of course, you can choose to make the implementation renderer-agnostic, + // if you wish to, by creating your own `Renderer` trait, which could be + // implemented by `iced_wgpu` and other renderers. + use iced_native::{ + layout, Element, Hasher, Layout, Length, MouseCursor, Point, Size, + Widget, + }; + use iced_wgpu::{ + triangle::{Mesh2D, Vertex2D}, + Primitive, Renderer, + }; + + pub struct Rainbow; + + impl Rainbow { + pub fn new() -> Self { + Self + } + } + + impl<Message> Widget<Message, Renderer> for Rainbow { + fn width(&self) -> Length { + Length::Fill + } + + fn height(&self) -> Length { + Length::Shrink + } + + fn layout( + &self, + _renderer: &Renderer, + limits: &layout::Limits, + ) -> layout::Node { + let size = limits.width(Length::Fill).resolve(Size::ZERO); + + layout::Node::new(Size::new(size.width, size.width)) + } + + fn hash_layout(&self, _state: &mut Hasher) {} + + fn draw( + &self, + _renderer: &mut Renderer, + layout: Layout<'_>, + cursor_position: Point, + ) -> (Primitive, MouseCursor) { + let b = layout.bounds(); + + // R O Y G B I V + let color_r = [1.0, 0.0, 0.0, 1.0]; + let color_o = [1.0, 0.5, 0.0, 1.0]; + let color_y = [1.0, 1.0, 0.0, 1.0]; + let color_g = [0.0, 1.0, 0.0, 1.0]; + let color_gb = [0.0, 1.0, 0.5, 1.0]; + let color_b = [0.0, 0.2, 1.0, 1.0]; + let color_i = [0.5, 0.0, 1.0, 1.0]; + let color_v = [0.75, 0.0, 0.5, 1.0]; + + let posn_center = { + if b.contains(cursor_position) { + [cursor_position.x, cursor_position.y] + } else { + [b.x + (b.width / 2.0), b.y + (b.height / 2.0)] + } + }; + + let posn_tl = [b.x, b.y]; + let posn_t = [b.x + (b.width / 2.0), b.y]; + let posn_tr = [b.x + b.width, b.y]; + let posn_r = [b.x + b.width, b.y + (b.height / 2.0)]; + let posn_br = [b.x + b.width, b.y + b.height]; + let posn_b = [b.x + (b.width / 2.0), b.y + b.height]; + let posn_bl = [b.x, b.y + b.height]; + let posn_l = [b.x, b.y + (b.height / 2.0)]; + + ( + Primitive::Mesh2D(std::sync::Arc::new(Mesh2D { + vertices: vec![ + Vertex2D { + position: posn_center, + color: [1.0, 1.0, 1.0, 1.0], + }, + Vertex2D { + position: posn_tl, + color: color_r, + }, + Vertex2D { + position: posn_t, + color: color_o, + }, + Vertex2D { + position: posn_tr, + color: color_y, + }, + Vertex2D { + position: posn_r, + color: color_g, + }, + Vertex2D { + position: posn_br, + color: color_gb, + }, + Vertex2D { + position: posn_b, + color: color_b, + }, + Vertex2D { + position: posn_bl, + color: color_i, + }, + Vertex2D { + position: posn_l, + color: color_v, + }, + ], + indices: vec![ + 0, 1, 2, // TL + 0, 2, 3, // T + 0, 3, 4, // TR + 0, 4, 5, // R + 0, 5, 6, // BR + 0, 6, 7, // B + 0, 7, 8, // BL + 0, 8, 1, // L + ], + })), + MouseCursor::OutOfBounds, + ) + } + } + + impl<'a, Message> Into<Element<'a, Message, Renderer>> for Rainbow { + fn into(self) -> Element<'a, Message, Renderer> { + Element::new(self) + } + } +} + +use iced::{ + scrollable, Align, Column, Container, Element, Length, Sandbox, Scrollable, + Settings, Text, +}; +use rainbow::Rainbow; + +pub fn main() { + Example::run(Settings::default()) +} + +struct Example { + scroll: scrollable::State, +} + +impl Sandbox for Example { + type Message = (); + + fn new() -> Self { + Example { + scroll: scrollable::State::new(), + } + } + + fn title(&self) -> String { + String::from("Custom 2D geometry - Iced") + } + + fn update(&mut self, _: ()) {} + + fn view(&mut self) -> Element<()> { + let content = Column::new() + .padding(20) + .spacing(20) + .max_width(500) + .align_items(Align::Start) + .push(Rainbow::new()) + .push(Text::new( + "In this example we draw a custom widget Rainbow, using \ + the Mesh2D primitive. This primitive supplies a list of \ + triangles, expressed as vertices and indices.", + )) + .push(Text::new( + "Move your cursor over it, and see the center vertex \ + follow you!", + )) + .push(Text::new( + "Every Vertex2D defines its own color. You could use the \ + Mesh2D primitive to render virtually any two-dimensional \ + geometry for your widget.", + )); + + let scrollable = Scrollable::new(&mut self.scroll) + .push(Container::new(content).width(Length::Fill).center_x()); + + Container::new(scrollable) + .width(Length::Fill) + .height(Length::Fill) + .center_y() + .into() + } +} |