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Diffstat (limited to 'graphics/src/widget/canvas.rs')
| -rw-r--r-- | graphics/src/widget/canvas.rs | 236 |
1 files changed, 236 insertions, 0 deletions
diff --git a/graphics/src/widget/canvas.rs b/graphics/src/widget/canvas.rs new file mode 100644 index 00000000..d393a5c5 --- /dev/null +++ b/graphics/src/widget/canvas.rs @@ -0,0 +1,236 @@ +//! Draw 2D graphics for your users. +//! +//! A [`Canvas`] widget can be used to draw different kinds of 2D shapes in a +//! [`Frame`]. It can be used for animation, data visualization, game graphics, +//! and more! +//! +//! [`Canvas`]: struct.Canvas.html +//! [`Frame`]: struct.Frame.html +use crate::{Backend, Defaults, Primitive, Renderer}; +use iced_native::{ + layout, mouse, Clipboard, Element, Hasher, Layout, Length, Point, Size, + Vector, Widget, +}; +use std::hash::Hash; +use std::marker::PhantomData; + +pub mod path; + +mod cache; +mod cursor; +mod event; +mod fill; +mod frame; +mod geometry; +mod program; +mod stroke; +mod text; + +pub use cache::Cache; +pub use cursor::Cursor; +pub use event::Event; +pub use fill::Fill; +pub use frame::Frame; +pub use geometry::Geometry; +pub use path::Path; +pub use program::Program; +pub use stroke::{LineCap, LineJoin, Stroke}; +pub use text::Text; + +/// A widget capable of drawing 2D graphics. +/// +/// [`Canvas`]: struct.Canvas.html +/// +/// # Examples +/// The repository has a couple of [examples] showcasing how to use a +/// [`Canvas`]: +/// +/// - [`clock`], an application that uses the [`Canvas`] widget to draw a clock +/// and its hands to display the current time. +/// - [`game_of_life`], an interactive version of the Game of Life, invented by +/// John Conway. +/// - [`solar_system`], an animated solar system drawn using the [`Canvas`] widget +/// and showcasing how to compose different transforms. +/// +/// [examples]: https://github.com/hecrj/iced/tree/master/examples +/// [`clock`]: https://github.com/hecrj/iced/tree/master/examples/clock +/// [`game_of_life`]: https://github.com/hecrj/iced/tree/master/examples/game_of_life +/// [`solar_system`]: https://github.com/hecrj/iced/tree/master/examples/solar_system +/// +/// ## Drawing a simple circle +/// If you want to get a quick overview, here's how we can draw a simple circle: +/// +/// ```no_run +/// # mod iced { +/// # pub use iced_graphics::canvas; +/// # pub use iced_native::{Color, Rectangle}; +/// # } +/// use iced::canvas::{self, Canvas, Cursor, Fill, Frame, Geometry, Path, Program}; +/// use iced::{Color, Rectangle}; +/// +/// // First, we define the data we need for drawing +/// #[derive(Debug)] +/// struct Circle { +/// radius: f32, +/// } +/// +/// // Then, we implement the `Program` trait +/// impl Program<()> for Circle { +/// fn draw(&self, bounds: Rectangle, _cursor: Cursor) -> Vec<Geometry>{ +/// // We prepare a new `Frame` +/// let mut frame = Frame::new(bounds.size()); +/// +/// // We create a `Path` representing a simple circle +/// let circle = Path::circle(frame.center(), self.radius); +/// +/// // And fill it with some color +/// frame.fill(&circle, Fill::Color(Color::BLACK)); +/// +/// // Finally, we produce the geometry +/// vec![frame.into_geometry()] +/// } +/// } +/// +/// // Finally, we simply use our `Circle` to create the `Canvas`! +/// let canvas = Canvas::new(Circle { radius: 50.0 }); +/// ``` +#[derive(Debug)] +pub struct Canvas<Message, P: Program<Message>> { + width: Length, + height: Length, + program: P, + phantom: PhantomData<Message>, +} + +impl<Message, P: Program<Message>> Canvas<Message, P> { + const DEFAULT_SIZE: u16 = 100; + + /// Creates a new [`Canvas`]. + /// + /// [`Canvas`]: struct.Canvas.html + pub fn new(program: P) -> Self { + Canvas { + width: Length::Units(Self::DEFAULT_SIZE), + height: Length::Units(Self::DEFAULT_SIZE), + program, + phantom: PhantomData, + } + } + + /// Sets the width of the [`Canvas`]. + /// + /// [`Canvas`]: struct.Canvas.html + pub fn width(mut self, width: Length) -> Self { + self.width = width; + self + } + + /// Sets the height of the [`Canvas`]. + /// + /// [`Canvas`]: struct.Canvas.html + pub fn height(mut self, height: Length) -> Self { + self.height = height; + self + } +} + +impl<Message, P, B> Widget<Message, Renderer<B>> for Canvas<Message, P> +where + P: Program<Message>, + B: Backend, +{ + fn width(&self) -> Length { + self.width + } + + fn height(&self) -> Length { + self.height + } + + fn layout( + &self, + _renderer: &Renderer<B>, + limits: &layout::Limits, + ) -> layout::Node { + let limits = limits.width(self.width).height(self.height); + let size = limits.resolve(Size::ZERO); + + layout::Node::new(size) + } + + fn on_event( + &mut self, + event: iced_native::Event, + layout: Layout<'_>, + cursor_position: Point, + messages: &mut Vec<Message>, + _renderer: &Renderer<B>, + _clipboard: Option<&dyn Clipboard>, + ) { + let bounds = layout.bounds(); + + let canvas_event = match event { + iced_native::Event::Mouse(mouse_event) => { + Some(Event::Mouse(mouse_event)) + } + _ => None, + }; + + let cursor = Cursor::from_window_position(cursor_position); + + if let Some(canvas_event) = canvas_event { + if let Some(message) = + self.program.update(canvas_event, bounds, cursor) + { + messages.push(message); + } + } + } + + fn draw( + &self, + _renderer: &mut Renderer<B>, + _defaults: &Defaults, + layout: Layout<'_>, + cursor_position: Point, + ) -> (Primitive, mouse::Interaction) { + let bounds = layout.bounds(); + let translation = Vector::new(bounds.x, bounds.y); + let cursor = Cursor::from_window_position(cursor_position); + + ( + Primitive::Translate { + translation, + content: Box::new(Primitive::Group { + primitives: self + .program + .draw(bounds, cursor) + .into_iter() + .map(Geometry::into_primitive) + .collect(), + }), + }, + self.program.mouse_interaction(bounds, cursor), + ) + } + + fn hash_layout(&self, state: &mut Hasher) { + struct Marker; + std::any::TypeId::of::<Marker>().hash(state); + + self.width.hash(state); + self.height.hash(state); + } +} + +impl<'a, Message, P, B> From<Canvas<Message, P>> + for Element<'a, Message, Renderer<B>> +where + Message: 'static, + P: Program<Message> + 'a, + B: Backend, +{ + fn from(canvas: Canvas<Message, P>) -> Element<'a, Message, Renderer<B>> { + Element::new(canvas) + } +} |