Struct Canvas 

pub struct Canvas { /* private fields */ }

Available on crate feature winio only.

A simple drawing canvas.

Implementations

impl Canvas

pub fn context(&mut self) -> Result<DrawingContext<'_>, Error>

Create the DrawingContext of the current canvas.

Examples found in repository

examples/test/widgets.rs (line 290)

    fn render(&mut self, _sender: &ComponentSender<Self>) -> Result<(), Self::Error> {
        let csize = self.window.size()?;
        {
            let mut cred_panel = layout! {
                Grid::from_str("auto,1*,auto", "1*,auto,auto,1*").unwrap(),
                self.ulabel => { column: 0, row: 1, valign: VAlign::Center },
                self.uentry => { column: 1, row: 1, margin: Margin::new_all_same(4.0) },
                self.plabel => { column: 0, row: 2, valign: VAlign::Center },
                self.pentry => { column: 1, row: 2, margin: Margin::new_all_same(4.0) },
                self.pcheck => { column: 2, row: 2 },
            };

            let mut rgroup_panel = Grid::from_str("auto", "1*,auto,auto,auto,1*").unwrap();
            for (i, rb) in self.radio_group.iter_mut().enumerate() {
                rgroup_panel.push(rb).row(i + 1).finish();
            }

            let mut buttons_panel = layout! {
                StackPanel::new(Orient::Vertical),
                self.push_button => { margin: Margin::new_all_same(4.0) },
                self.pop_button  => { margin: Margin::new_all_same(4.0) },
                self.show_button => { margin: Margin::new_all_same(4.0) },
            };

            let mut root_panel = layout! {
                Grid::from_str("1*,1*,1*", "1*,auto,1*").unwrap(),
                cred_panel    => { column: 1, row: 0 },
                rgroup_panel  => { column: 2, row: 0, halign: HAlign::Center },
                self.canvas   => { column: 0, row: 1, row_span: 2 },
                self.combo    => { column: 1, row: 1, halign: HAlign::Center },
                self.progress => { column: 2, row: 1 },
                self.mltext   => { column: 1, row: 2, margin: Margin::new_all_same(8.0) },
                buttons_panel => { column: 2, row: 2 },
            };

            root_panel.set_size(csize);
        }

        let size = self.canvas.size()?;
        let is_dark = ColorTheme::current()? == ColorTheme::Dark;
        let back_color = if is_dark {
            Color::new(255, 255, 255, 255)
        } else {
            Color::new(0, 0, 0, 255)
        };
        let brush = SolidColorBrush::new(back_color);
        let pen = BrushPen::new(&brush, 1.0);
        let mut ctx = self.canvas.context()?;
        let cx = size.width / 2.0;
        let cy = size.height / 2.0;
        let r = cx.min(cy) - 2.0;
        ctx.draw_pie(
            &pen,
            Rect::new(Point::new(cx - r, cy - r), Size::new(r * 2.0, r * 2.0)),
            std::f64::consts::PI,
            std::f64::consts::PI * 2.0,
        );

        let brush2 = LinearGradientBrush::new(
            [
                GradientStop::new(Color::new(0x87, 0xCE, 0xEB, 0xFF), 0.0),
                GradientStop::new(back_color, 1.0),
            ],
            RelativePoint::zero(),
            RelativePoint::new(0.0, 1.0),
        );
        let pen2 = BrushPen::new(&brush2, 1.0);
        ctx.draw_round_rect(
            &pen2,
            Rect::new(
                Point::new(cx - r - 1.0, cy - r - 1.0),
                Size::new(r * 2.0 + 2.0, r * 1.618 + 2.0),
            ),
            Size::new(r / 10.0, r / 10.0),
        );
        let mut path = ctx.create_path_builder(Point::new(cx + r + 1.0 - r / 10.0, cy))?;
        path.add_arc(
            Point::new(cx, cy + r * 0.618 + 1.0),
            Size::new(r + 1.0 - r / 10.0, r * 0.382 / 2.0),
            0.0,
            std::f64::consts::PI,
            true,
        );
        path.add_line(Point::new(cx - r - 1.0 + r / 10.0, cy));
        let path = path.build(false)?;
        ctx.draw_path(&pen, &path);
        let brush3 = RadialGradientBrush::new(
            [
                GradientStop::new(Color::new(0xF5, 0xF5, 0xF5, 0xFF), 0.0),
                GradientStop::new(
                    Color::accent().unwrap_or(Color::new(0xFF, 0xC0, 0xCB, 0xFF)),
                    1.0,
                ),
            ],
            RelativePoint::new(0.5, 0.5),
            RelativePoint::new(0.2, 0.5),
            RelativeSize::new(0.5, 0.5),
        );
        let font = DrawingFontBuilder::new()
            .family("Arial")
            .size(r / 5.0)
            .halign(HAlign::Center)
            .valign(VAlign::Bottom)
            .build();
        ctx.draw_str(&brush3, font, Point::new(cx, cy), "Hello world!");
        Ok(())
    }

Trait Implementations

impl AsWidget for Canvas

fn as_widget(&self) -> BorrowedWidget<'_>

Get the widget handle.

impl Component for Canvas

type Error = Error

The error type.

type Event = CanvasEvent

The output event type to the parent.

type Init<'a> = BorrowedContainer<'a>

Initial parameter type.

type Message = CanvasMessage

The input message type to update.

async fn init( init: <Canvas as Component>::Init<'_>, _sender: &ComponentSender<Canvas>, ) -> Result<Canvas, Error>

Create the initial component.

async fn start(&mut self, sender: &ComponentSender<Canvas>) -> !

Start the event listening.

async fn update( &mut self, message: Self::Message, sender: &ComponentSender<Self>, ) -> Result<bool, Self::Error>

Respond to the message. Return true if need render.

fn render(&mut self, sender: &ComponentSender<Self>) -> Result<(), Self::Error>

Render the widgets.

async fn update_children(&mut self) -> Result<bool, Self::Error>

Update the children components. Return true if any child needs render.

fn render_children(&mut self) -> Result<(), Self::Error>

Render the children components. It will be called if any child or self needs render.

impl Debug for Canvas

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl Enable for Canvas

fn is_enabled(&self) -> Result<bool, Error>

If the widget is enabled.

fn set_enabled(&mut self, v: bool) -> Result<(), Error>

Set if the widget is enabled.

fn enable(&mut self) -> Result<(), Self::Error>

Enable the widget.

fn disable(&mut self) -> Result<(), Self::Error>

Disable the widget.

impl Failable for Canvas

type Error = Error

The error type associated.

impl Layoutable for Canvas

fn loc(&self) -> Result<Point2D<f64, LogicalSpace>, Error>

The left top location.

fn set_loc(&mut self, p: Point2D<f64, LogicalSpace>) -> Result<(), Error>

Move the location.

fn size(&self) -> Result<Size2D<f64, LogicalSpace>, Error>

The size.

fn set_size(&mut self, v: Size2D<f64, LogicalSpace>) -> Result<(), Error>

Resize.

fn rect(&self) -> Result<Rect<f64, LogicalSpace>, Self::Error>

The bounding rectangle.

fn set_rect(&mut self, r: Rect<f64, LogicalSpace>) -> Result<(), Self::Error>

Set the location and size.

fn preferred_size(&self) -> Result<Size2D<f64, LogicalSpace>, Self::Error>

The preferred size.

fn min_size(&self) -> Result<Size2D<f64, LogicalSpace>, Self::Error>

Min acceptable size.

impl ToolTip for Canvas

fn tooltip(&self) -> Result<String, Error>

Get the tooltip text of the widget.

fn set_tooltip(&mut self, s: impl AsRef<str>) -> Result<(), Error>

Set the tooltip text of the widget.

impl Visible for Canvas

fn is_visible(&self) -> Result<bool, Error>

If the widget is visible.

fn set_visible(&mut self, v: bool) -> Result<(), Error>

Set the visibility.

fn show(&mut self) -> Result<(), Self::Error>

Show the widget.

fn hide(&mut self) -> Result<(), Self::Error>

Hide the widget.