script::dom::canvas::canvas_context

Trait CanvasContext

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pub(crate) trait CanvasContext {
    type ID;

    // Required methods
    fn context_id(&self) -> Self::ID;
    fn canvas(
        &self,
    ) -> Option<HTMLCanvasElementOrOffscreenCanvas<DomTypeHolder>>;
    fn resize(&self);
    fn reset_bitmap(&self);
    fn get_image_data(&self) -> Option<Snapshot>;
    fn mark_as_dirty(&self);
    fn image_key(&self) -> Option<ImageKey>;

    // Provided methods
    fn origin_is_clean(&self) -> bool { ... }
    fn size(&self) -> Size2D<u32> { ... }
    fn update_rendering(&self, _canvas_epoch: Epoch) -> bool { ... }
    fn onscreen(&self) -> bool { ... }
}

Required Associated Types§

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type ID

Required Methods§

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fn context_id(&self) -> Self::ID

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fn canvas(&self) -> Option<HTMLCanvasElementOrOffscreenCanvas<DomTypeHolder>>

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fn resize(&self)

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fn reset_bitmap(&self)

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fn get_image_data(&self) -> Option<Snapshot>

Returns none if area of canvas is zero.

In case of other errors it returns cleared snapshot

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fn mark_as_dirty(&self)

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fn image_key(&self) -> Option<ImageKey>

The WebRender ImageKey of this CanvasContext if any.

Provided Methods§

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fn origin_is_clean(&self) -> bool

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fn size(&self) -> Size2D<u32>

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fn update_rendering(&self, _canvas_epoch: Epoch) -> bool

Request that the CanvasContext update the rendering of its contents, returning true if new image was produced.

Note: If this function returns true, script will wait for all images to be updated before updating the rendering again. Be sure that image updates are always sent even in the failure case by sending transparent black image or return false in the case of failure.

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fn onscreen(&self) -> bool

Implementors§