Std.Ui.Canvas.render

fn

This is a callable function.

What it does

Render the display list into an opaque row-major RGBA framebuffer.

Rendered by bands and spans rather than by pixels. Rows between two

consecutive command edges are identical, so each band is composed once as

a list of spans and its bytes are repeated for the band's height; a command

blends into a span once, not into each pixel. The work follows the number of

edges, and the pixels are produced by whole-run copies. A program rendering

a 512 by 512 frame with a full-frame fill and a translucent 128 by 128 fill

runs in 0.10s at -O2, the same as one that renders nothing, against 4.35s

and 2.8 times the resident memory when each pixel is written into the buffer.

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