diff --git a/examples/README.md b/examples/README.md index 5aea51eb..5d880d71 100644 --- a/examples/README.md +++ b/examples/README.md @@ -69,7 +69,7 @@ cargo run --package styling ## Extras A bunch of simpler examples exist: -- [`bezier_tool`](bezier_tool), a Paint-like tool for drawing Bézier curves using [`lyon`]. +- [`bezier_tool`](bezier_tool), a Paint-like tool for drawing Bézier curves using the `Canvas` widget. - [`clock`](clock), an application that uses the `Canvas` widget to draw a clock and its hands to display the current time. - [`counter`](counter), the classic counter example explained in the [`README`](../README.md). - [`custom_widget`](custom_widget), a demonstration of how to build a custom widget that draws a circle. diff --git a/examples/bezier_tool/Cargo.toml b/examples/bezier_tool/Cargo.toml index b13a0aa5..a88975a7 100644 --- a/examples/bezier_tool/Cargo.toml +++ b/examples/bezier_tool/Cargo.toml @@ -6,7 +6,4 @@ edition = "2018" publish = false [dependencies] -iced = { path = "../.." } -iced_native = { path = "../../native" } -iced_wgpu = { path = "../../wgpu" } -lyon = "0.15" +iced = { path = "../..", features = ["canvas"] } diff --git a/examples/bezier_tool/README.md b/examples/bezier_tool/README.md index 933f2120..ebbb12cc 100644 --- a/examples/bezier_tool/README.md +++ b/examples/bezier_tool/README.md @@ -1,6 +1,6 @@ ## Bézier tool -A Paint-like tool for drawing Bézier curves using [`lyon`]. +A Paint-like tool for drawing Bézier curves using the `Canvas` widget. The __[`main`]__ file contains all the code of the example. @@ -16,4 +16,3 @@ cargo run --package bezier_tool ``` [`main`]: src/main.rs -[`lyon`]: https://github.com/nical/lyon diff --git a/examples/bezier_tool/src/main.rs b/examples/bezier_tool/src/main.rs index 8012ea0a..a00a1005 100644 --- a/examples/bezier_tool/src/main.rs +++ b/examples/bezier_tool/src/main.rs @@ -1,290 +1,4 @@ -//! This example showcases a simple native custom widget that renders arbitrary -//! path with `lyon`. -mod bezier { - // 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::{ - input, layout, Clipboard, Color, Element, Event, Font, Hasher, - HorizontalAlignment, Layout, Length, MouseCursor, Point, Rectangle, - Size, Vector, VerticalAlignment, Widget, - }; - use iced_wgpu::{ - triangle::{Mesh2D, Vertex2D}, - Defaults, Primitive, Renderer, - }; - use lyon::tessellation::{ - basic_shapes, BuffersBuilder, StrokeAttributes, StrokeOptions, - StrokeTessellator, VertexBuffers, - }; - - pub struct Bezier<'a, Message> { - state: &'a mut State, - curves: &'a [Curve], - // [from, to, ctrl] - on_click: Box Message>, - } - - #[derive(Debug, Clone, Copy)] - pub struct Curve { - from: Point, - to: Point, - control: Point, - } - - #[derive(Default)] - pub struct State { - pending: Option, - } - - enum Pending { - One { from: Point }, - Two { from: Point, to: Point }, - } - - impl<'a, Message> Bezier<'a, Message> { - pub fn new( - state: &'a mut State, - curves: &'a [Curve], - on_click: F, - ) -> Self - where - F: 'static + Fn(Curve) -> Message, - { - Self { - state, - curves, - on_click: Box::new(on_click), - } - } - } - - impl<'a, Message> Widget for Bezier<'a, Message> { - fn width(&self) -> Length { - Length::Fill - } - - fn height(&self) -> Length { - Length::Fill - } - - fn layout( - &self, - _renderer: &Renderer, - limits: &layout::Limits, - ) -> layout::Node { - let size = limits - .height(Length::Fill) - .width(Length::Fill) - .resolve(Size::ZERO); - layout::Node::new(size) - } - - fn draw( - &self, - _renderer: &mut Renderer, - defaults: &Defaults, - layout: Layout<'_>, - cursor_position: Point, - ) -> (Primitive, MouseCursor) { - let mut buffer: VertexBuffers = VertexBuffers::new(); - let mut path_builder = lyon::path::Path::builder(); - - let bounds = layout.bounds(); - - // Draw rectangle border with lyon. - basic_shapes::stroke_rectangle( - &lyon::math::Rect::new( - lyon::math::Point::new(0.5, 0.5), - lyon::math::Size::new( - bounds.width - 1.0, - bounds.height - 1.0, - ), - ), - &StrokeOptions::default().with_line_width(1.0), - &mut BuffersBuilder::new( - &mut buffer, - |pos: lyon::math::Point, _: StrokeAttributes| Vertex2D { - position: pos.to_array(), - color: [0.0, 0.0, 0.0, 1.0], - }, - ), - ) - .unwrap(); - - for curve in self.curves { - path_builder.move_to(lyon::math::Point::new( - curve.from.x, - curve.from.y, - )); - - path_builder.quadratic_bezier_to( - lyon::math::Point::new(curve.control.x, curve.control.y), - lyon::math::Point::new(curve.to.x, curve.to.y), - ); - } - - match self.state.pending { - None => {} - Some(Pending::One { from }) => { - path_builder - .move_to(lyon::math::Point::new(from.x, from.y)); - path_builder.line_to(lyon::math::Point::new( - cursor_position.x - bounds.x, - cursor_position.y - bounds.y, - )); - } - Some(Pending::Two { from, to }) => { - path_builder - .move_to(lyon::math::Point::new(from.x, from.y)); - path_builder.quadratic_bezier_to( - lyon::math::Point::new( - cursor_position.x - bounds.x, - cursor_position.y - bounds.y, - ), - lyon::math::Point::new(to.x, to.y), - ); - } - } - - let mut tessellator = StrokeTessellator::new(); - - // Draw strokes with lyon. - tessellator - .tessellate( - &path_builder.build(), - &StrokeOptions::default().with_line_width(3.0), - &mut BuffersBuilder::new( - &mut buffer, - |pos: lyon::math::Point, _: StrokeAttributes| { - Vertex2D { - position: pos.to_array(), - color: [0.0, 0.0, 0.0, 1.0], - } - }, - ), - ) - .unwrap(); - - let mesh = Primitive::Translate { - translation: Vector::new(bounds.x, bounds.y), - content: Box::new(Primitive::Mesh2D { - buffers: Mesh2D { - vertices: buffer.vertices, - indices: buffer.indices, - }, - }), - }; - - ( - Primitive::Clip { - bounds, - offset: Vector::new(0, 0), - content: Box::new( - if self.curves.is_empty() - && self.state.pending.is_none() - { - let instructions = Primitive::Text { - bounds: Rectangle { - x: bounds.center_x(), - y: bounds.center_y(), - ..bounds - }, - color: Color { - a: defaults.text.color.a * 0.7, - ..defaults.text.color - }, - content: String::from( - "Click to create bezier curves!", - ), - font: Font::Default, - size: 30.0, - horizontal_alignment: - HorizontalAlignment::Center, - vertical_alignment: VerticalAlignment::Center, - }; - - Primitive::Group { - primitives: vec![mesh, instructions], - } - } else { - mesh - }, - ), - }, - MouseCursor::OutOfBounds, - ) - } - - fn hash_layout(&self, _state: &mut Hasher) {} - - fn on_event( - &mut self, - event: Event, - layout: Layout<'_>, - cursor_position: Point, - messages: &mut Vec, - _renderer: &Renderer, - _clipboard: Option<&dyn Clipboard>, - ) { - let bounds = layout.bounds(); - - if bounds.contains(cursor_position) { - match event { - Event::Mouse(input::mouse::Event::Input { - state: input::ButtonState::Pressed, - .. - }) => { - let new_point = Point::new( - cursor_position.x - bounds.x, - cursor_position.y - bounds.y, - ); - - match self.state.pending { - None => { - self.state.pending = - Some(Pending::One { from: new_point }); - } - Some(Pending::One { from }) => { - self.state.pending = Some(Pending::Two { - from, - to: new_point, - }); - } - Some(Pending::Two { from, to }) => { - self.state.pending = None; - - messages.push((self.on_click)(Curve { - from, - to, - control: new_point, - })); - } - } - } - _ => {} - } - } - } - } - - impl<'a, Message> Into> for Bezier<'a, Message> - where - Message: 'static, - { - fn into(self) -> Element<'a, Message, Renderer> { - Element::new(self) - } - } -} - -use bezier::Bezier; +//! This example showcases an interactive `Canvas` for drawing Bézier curves. use iced::{ button, Align, Button, Column, Container, Element, Length, Sandbox, Settings, Text, @@ -325,6 +39,7 @@ impl Sandbox for Example { match message { Message::AddCurve(curve) => { self.curves.push(curve); + self.bezier.request_redraw(); } Message::Clear => { self.bezier = bezier::State::default(); @@ -343,11 +58,7 @@ impl Sandbox for Example { .width(Length::Shrink) .size(50), ) - .push(Bezier::new( - &mut self.bezier, - self.curves.as_slice(), - Message::AddCurve, - )) + .push(self.bezier.view(&self.curves).map(Message::AddCurve)) .push( Button::new(&mut self.button_state, Text::new("Clear")) .padding(8) @@ -362,3 +73,147 @@ impl Sandbox for Example { .into() } } + +mod bezier { + use iced::{ + canvas::{ + self, Canvas, Drawable, Event, Frame, Geometry, Path, Stroke, + }, + mouse, ButtonState, Element, Length, Point, Size, + }; + + #[derive(Default)] + pub struct State { + pending: Option, + cursor_position: Point, + cache: canvas::Cache, + } + + impl State { + pub fn view<'a>( + &'a mut self, + curves: &'a [Curve], + ) -> Element<'a, Curve> { + Canvas::new(Bezier { + state: self, + curves, + }) + .width(Length::Fill) + .height(Length::Fill) + .into() + } + + pub fn request_redraw(&mut self) { + self.cache.clear() + } + } + + struct Bezier<'a> { + state: &'a mut State, + curves: &'a [Curve], + } + + impl<'a> canvas::State for Bezier<'a> { + fn update(&mut self, event: Event, _bounds: Size) -> Option { + match event { + Event::Mouse(mouse_event) => match mouse_event { + mouse::Event::CursorMoved { x, y } => { + self.state.cursor_position = Point::new(x, y); + + None + } + mouse::Event::Input { + button: mouse::Button::Left, + state: ButtonState::Pressed, + } => match self.state.pending { + None => { + self.state.pending = Some(Pending::One { + from: self.state.cursor_position, + }); + None + } + Some(Pending::One { from }) => { + self.state.pending = Some(Pending::Two { + from, + to: self.state.cursor_position, + }); + + None + } + Some(Pending::Two { from, to }) => { + self.state.pending = None; + + Some(Curve { + from, + to, + control: self.state.cursor_position, + }) + } + }, + _ => None, + }, + } + } + + fn draw(&self, bounds: Size) -> Vec { + let curves = self.state.cache.draw(bounds, &self.curves); + + if let Some(pending) = &self.state.pending { + let pending_curve = + pending.draw(bounds, self.state.cursor_position); + + vec![curves, pending_curve] + } else { + vec![curves] + } + } + } + + #[derive(Debug, Clone, Copy)] + pub struct Curve { + from: Point, + to: Point, + control: Point, + } + + impl Drawable for Curve { + fn draw(&self, frame: &mut Frame) { + let curve = Path::new(|p| { + p.move_to(self.from); + p.quadratic_curve_to(self.control, self.to); + }); + + frame.stroke(&curve, Stroke::default().with_width(2.0)); + } + } + + #[derive(Debug, Clone, Copy)] + enum Pending { + One { from: Point }, + Two { from: Point, to: Point }, + } + + impl Pending { + fn draw(&self, bounds: Size, cursor_position: Point) -> Geometry { + let mut frame = Frame::new(bounds); + + match *self { + Pending::One { from } => { + let line = Path::line(from, cursor_position); + frame.stroke(&line, Stroke::default().with_width(2.0)); + } + Pending::Two { from, to } => { + let curve = Curve { + from, + to, + control: cursor_position, + }; + + curve.draw(&mut frame); + } + }; + + frame.into_geometry() + } + } +}