598874 - Investigate putting (large-ish) content images in their own layers

Status: RESOLVED DUPLICATE of bug 650988

(Core :: Layout, defect)

Description

[Chris Jones [:cjones] inactive; ni?/f?/r? if you need me]

This would allow us to avoid scaling images in SW in content processes.  Instead, we would set scales on images' layers, then scale them with GL during compositing.  The potential benefit from this would be to save CPU cycles, use better interpolation with GL, and (possibly) reduce system memory usage.

There are many cases when this scheme would lose big time.  We'd need heuristics for when to do this.

This is strictly a losing proposition with SW compositing.

Comment 1

[Chris Jones [:cjones] inactive; ni?/f?/r? if you need me]

Um, don't know how that dependency snuck in.

Comment 2

[Robert O'Callahan (:roc) (email my personal email if necessary)]

For JPEG images, we could also decode to YCbCr format (i.e. skip the final YCbCr-to-RGB conversion in the imglib decoder), and do the final YCbCr conversion using the GPU at draw time. That would save half the memory since JPEG subsamples Cb/Cr. We already have all the layer-side support for this.