diff options
Diffstat (limited to 'wgpu/src/widget/canvas/program.rs')
| -rw-r--r-- | wgpu/src/widget/canvas/program.rs | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/wgpu/src/widget/canvas/program.rs b/wgpu/src/widget/canvas/program.rs index f8e54514..5b995bfa 100644 --- a/wgpu/src/widget/canvas/program.rs +++ b/wgpu/src/widget/canvas/program.rs @@ -1,7 +1,27 @@ use crate::canvas::{Cursor, Event, Geometry}; use iced_native::{MouseCursor, Rectangle}; +/// The state and logic of a [`Canvas`]. +/// +/// A [`Program`] can mutate internal state and produce messages for an +/// application. +/// +/// [`Canvas`]: struct.Canvas.html +/// [`Program`]: trait.Program.html pub trait Program<Message> { + /// Updates the state of the [`Program`]. + /// + /// When a [`Program`] is used in a [`Canvas`], the runtime will call this + /// method for each [`Event`]. + /// + /// This method can optionally return a `Message` to notify an application + /// of any meaningful interactions. + /// + /// By default, this method does and returns nothing. + /// + /// [`Program`]: trait.Program.html + /// [`Canvas`]: struct.Canvas.html + /// [`Event`]: enum.Event.html fn update( &mut self, _event: Event, @@ -11,8 +31,24 @@ pub trait Program<Message> { None } + /// Draws the state of the [`Program`], producing a bunch of [`Geometry`]. + /// + /// [`Geometry`] can be easily generated with a [`Frame`] or stored in a + /// [`Cache`]. + /// + /// [`Program`]: trait.Program.html + /// [`Geometry`]: struct.Geometry.html + /// [`Frame`]: struct.Frame.html + /// [`Cache`]: struct.Cache.html fn draw(&self, bounds: Rectangle, cursor: Cursor) -> Vec<Geometry>; + /// Returns the mouse cursor state of the [`Program`]. + /// + /// The mouse cursor returned will be in effect even if the cursor position + /// is out of bounds of the program's [`Canvas`]. + /// + /// [`Program`]: trait.Program.html + /// [`Canvas`]: struct.Canvas.html fn mouse_cursor(&self, _bounds: Rectangle, _cursor: Cursor) -> MouseCursor { MouseCursor::default() } |