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Diffstat (limited to 'chromium/docs/how_cc_works.md')
| -rw-r--r-- | chromium/docs/how_cc_works.md | 12 |
1 files changed, 6 insertions, 6 deletions
diff --git a/chromium/docs/how_cc_works.md b/chromium/docs/how_cc_works.md index 2b1f897ce58..fa3b84eb1cf 100644 --- a/chromium/docs/how_cc_works.md +++ b/chromium/docs/how_cc_works.md @@ -131,13 +131,13 @@ There are a number of heuristics to determine when and how to change rasterizati These arenβt perfect, but change them at your own peril. πππ -### PictureImageLayer +#### Directly composited images -A subclass of PictureLayer. -This is a special case for composited images in Blink. -If an image gets a composited layer but has no borders or padding (i.e. the painted content is exactly equal to the image) then some work can be saved here. -It "rasters" the image at fixed scales such that scaling this image is performant. -This is really a savings for software raster and in a gpu raster world such layers should never be created. +A specialized raster mode of PictureLayerImpl. +If a PictureLayer's DisplayItemList consists of a single drawImageRect DrawOp, we use different logic to determine what the raster scale of the image should end up being. +The layer is rastered at fixed scales such that scaling this image is performant. +The default raster scale is chosen such that the image will raster at its intrinsic side, then that scale is adjusted, based on how close it is to the ideal scale. +See PictureLayerImpl::ShouldAdjustRasterScale and RecalculateRasterScales for more details. ### TextureLayer |