Struct SceneBuilder

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pub struct SceneBuilder { /* private fields */ }

Expand description

Builds a Scene containing the given visuals.

A Scene can then be rendered using crate::View::present.

To draw graphical operations onto a Scene, first create a Canvas, record into it, and add the resulting Picture with add_picture. Each push_* opens a compositing scope that pop closes; unbalanced scopes are a bug the builder asserts on.

Implementations§

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impl SceneBuilder

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pub fn new() -> SceneBuilder

Creates an empty SceneBuilder object.

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pub fn push_transform(&mut self, matrix4: &Matrix4)

Pushes a transform operation onto the operation stack.

The objects are transformed by the given matrix before rasterization.

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pub fn push_offset(&mut self, dx: f64, dy: f64)

Pushes an offset operation onto the operation stack.

This is equivalent to push_transform with a matrix with only translation.

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pub fn push_clip_rect(&mut self, rect: Rect, clip_behavior: Clip)

Pushes a rectangular clip operation onto the operation stack.

Rasterization outside the given rectangle is discarded.

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pub fn push_clip_rrect(&mut self, rrect: RRect, clip_behavior: Clip)

Pushes a rounded-rectangular clip operation onto the operation stack.

Rasterization outside the given rounded rectangle is discarded.

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pub fn push_clip_path(&mut self, path: &Arc<Path>, clip_behavior: Clip)

Pushes a path clip operation onto the operation stack.

Rasterization outside the given path is discarded.

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pub fn push_opacity(&mut self, alpha: i32, offset: Offset)

Pushes an opacity operation onto the operation stack.

The given alpha value is blended into the alpha value of the objects’ rasterization. An alpha value of 0 makes the objects entirely invisible. An alpha value of 255 has no effect (i.e., the objects retain the current opacity).

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pub fn push_backdrop_filter( &mut self, filter: &ImageFilter, blend_mode: BlendMode, backdrop_id: Option<u64>, )

Pushes a backdrop filter operation onto the operation stack.

The given filter is applied to the current contents of the scene as far back as the most recent save layer and rendered back to the scene using the indicated blend_mode prior to rasterizing the child layers.

Filters sharing a backdrop_id sample one backdrop, as Flutter’s BackdropKey groups them. valo’s backdrop is a blur: a colour filter in filter contributes nothing (see the host’s PORTING.md).

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pub fn pop(&mut self)

Ends the effect of the most recently pushed operation.

§Panics

In debug builds, if nothing is pushed.

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pub fn add_picture( &mut self, offset: Offset, picture: &Arc<Picture>, is_complex_hint: bool, will_change_hint: bool, )

Adds a Picture to the scene.

The picture is rasterized at the given offset. The hints are for a raster cache valo does not have; they are accepted so a layer can pass what Flutter passes.

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