Struct RetainedRaster 

pub struct RetainedRaster { /* private fields */ }

What a host keeps between frames to rasterize them into one retained target: the damage scratch, the backdrop blur and, on a software adapter, the CPU canvas. The app’s own render worker draws with it, and so does the workspace’s render service for each surface it draws for an app, so both produce the same pixels from the same frame.

Implementations

impl RetainedRaster

pub fn new(on_cpu: bool) -> RetainedRaster

Scratch for one target; on_cpu rasterizes on the CPU and uploads the pixels (a software adapter, see crate::gpu::rasterizes_on_cpu).

pub fn on_cpu(&self) -> bool

Whether frames are rasterized on the CPU.

pub fn invalidate(&mut self)

The target was replaced (a resize): nothing retained is current.

pub fn rasterize( &mut self, _: (&Device, &Queue), renderer: Option<&mut Renderer>, target: RetainedTarget<'_>, frame: FrameContent<'_>, ) -> (Result<u64, String>, Option<BackdropStats>)

Bring target up to date with frame: its backdrops blurred and substituted, its scroll copies made, its damage (or all of it) repainted. Returns the pixels rasterized, and the backdrop pass’s statistics when the frame had backdrops.

renderer is None only while the host’s pipelines are still compiling: the frame is then rasterized on a raster made on_cpu, and one that would draw a backdrop is refused.

pub fn rasterize_damage_only( &mut self, gpu: (&Device, &Queue), renderer: &mut Renderer, target: RetainedTarget<'_>, frame: FrameContent<'_>, ) -> (Result<u64, String>, Option<BackdropStats>)

Self::rasterize for a frame whose scene holds only what its damage needs (crate::draw_cull): it is never repainted beyond its damage. Err with DAMAGE_ONLY_REFUSED when it would have to be (a whole frame, a backdrop, a copy that cannot be made, a damage too large to repaint alone); the target then still holds the last frame.