pub struct PaintCtx<'a, 'b, 'c> {
pub render_ctx: &'a mut CairoRenderContext<'c>,
/* private fields */
}Expand description
A context passed to paint methods of widgets.
In addition to the API below, PaintCtx derefs to an implementation of
the RenderContext trait, which defines the basic available drawing
commands.
Fields§
§render_ctx: &'a mut CairoRenderContext<'c>The render context for actually painting.
Implementations§
§impl PaintCtx<'_, '_, '_>
impl PaintCtx<'_, '_, '_>
pub fn window(&self) -> &WindowHandle
pub fn window(&self) -> &WindowHandle
Returns a reference to the current WindowHandle.
pub fn scale(&self) -> Scale
pub fn scale(&self) -> Scale
The current window’s Scale.
The returned Scale is a copy and thus its information will be stale after
the platform changes the window’s scale. This means you can only rely on it
until the next Event::WindowScale event happens.
§impl PaintCtx<'_, '_, '_>
impl PaintCtx<'_, '_, '_>
pub fn size(&self) -> Size
pub fn size(&self) -> Size
The layout size.
This is the layout size as ultimately determined by the parent container, on the previous layout pass.
Generally it will be the same as the size returned by the child widget’s
layout method.
pub fn window_origin(&self) -> Point
pub fn window_origin(&self) -> Point
The origin of the widget in window coordinates, relative to the top left corner of the content area.
pub fn to_window(&self, widget_point: Point) -> Point
pub fn to_window(&self, widget_point: Point) -> Point
Convert a point from the widget’s coordinate space to the window’s.
The returned point is relative to the content area; it excludes window chrome.
pub fn to_screen(&self, widget_point: Point) -> Point
pub fn to_screen(&self, widget_point: Point) -> Point
Convert a point from the widget’s coordinate space to the screen’s.
See the Screen module
pub fn is_hot(&self) -> bool
pub fn is_hot(&self) -> bool
Query the “hot” state of the widget.
See WidgetPod::is_hot for additional information.
pub fn is_active(&self) -> bool
pub fn is_active(&self) -> bool
Query the “active” state of the widget.
See WidgetPod::is_active for additional information.
pub fn is_focused(&self) -> bool
pub fn is_focused(&self) -> bool
The focus status of a widget.
Returns true if this specific widget is focused.
To check if any descendants are focused use has_focus.
Focus means that the widget receives keyboard events.
A widget can request focus using the request_focus method.
It’s also possible to register for automatic focus via register_for_focus.
If a widget gains or loses focus it will get a LifeCycle::FocusChanged event.
Only one widget at a time is focused. However due to the way events are routed, all ancestors of that widget will also receive keyboard events.
pub fn has_focus(&self) -> bool
pub fn has_focus(&self) -> bool
The (tree) focus status of a widget.
Returns true if either this specific widget or any one of its descendants is focused.
To check if only this specific widget is focused use is_focused,
pub fn is_disabled(&self) -> bool
pub fn is_disabled(&self) -> bool
The disabled state of a widget.
Returns true if this widget or any of its ancestors is explicitly disabled.
To make this widget explicitly disabled use set_disabled.
Disabled means that this widget should not change the state of the application. What
that means is not entirely clear but in any it should not change its data. Therefore
others can use this as a safety mechanism to prevent the application from entering an
illegal state.
For an example the decrease button of a counter of type usize should be disabled if the
value is 0.
§impl PaintCtx<'_, '_, '_>
impl PaintCtx<'_, '_, '_>
pub fn depth(&self) -> u32
pub fn depth(&self) -> u32
The depth in the tree of the currently painting widget.
This may be used in combination with paint_with_z_index in order
to correctly order painting operations.
The depth here may not be exact; it is only guaranteed that a child will
have a greater depth than its parent.
pub fn with_child_ctx(
&mut self,
region: impl Into<Region>,
f: impl FnOnce(&mut PaintCtx<'_, '_, '_>)
)
pub fn with_child_ctx( &mut self, region: impl Into<Region>, f: impl FnOnce(&mut PaintCtx<'_, '_, '_>) )
Creates a temporary PaintCtx with a new visible region, and calls
the provided function with that PaintCtx.
This is used by containers to ensure that their children have the correct visible region given their layout.
pub fn with_save(&mut self, f: impl FnOnce(&mut PaintCtx<'_, '_, '_>))
pub fn with_save(&mut self, f: impl FnOnce(&mut PaintCtx<'_, '_, '_>))
Saves the current context, executes the closures, and restores the context.
This is useful if you would like to transform or clip or otherwise modify the drawing context but do not want that modification to effect other widgets.
Examples
fn paint(&mut self, ctx: &mut PaintCtx, _data: &T, env: &Env) {
let clip_rect = ctx.size().to_rect().inset(5.0);
ctx.with_save(|ctx| {
ctx.clip(clip_rect);
ctx.stroke(clip_rect, &env.get(theme::PRIMARY_DARK), 5.0);
});
}pub fn paint_with_z_index(
&mut self,
z_index: u32,
paint_func: impl FnOnce(&mut PaintCtx<'_, '_, '_>) + 'static
)
pub fn paint_with_z_index( &mut self, z_index: u32, paint_func: impl FnOnce(&mut PaintCtx<'_, '_, '_>) + 'static )
Allows to specify order for paint operations.
Larger z_index indicate that an operation will be executed later.