SVG performance with the fallback path with WebRender is very bad. This
patch avoids fallback by always producing a rasterized surface we store
in SurfaceCache, but also clamping the size consistently to a configured
maximum. This will cause us to upscale rasterized SVGs which is
undesirable visually but is a lower risk change that we can uplift to
beta than fixing the underlying performance issue.
Differential Revision: https://phabricator.services.mozilla.com/D27159
If FLAG_HIGH_QUALITY_SCALING is used, we should use
SurfaceCache::LookupBestMatch just like how it is done in RasterImage.
This may provide an alternative size at which we should rasterize the
SVG instead of the requested size. Since SurfaceCache imposes a maximum
size for which it will permit rasterized SVGs, we should also bypass the
cache entirely if we are well above that and simply draw directly to the
draw target in such cases.
With WebRender, it is somewhat more complicated. We will now return
NOT_SUPPORTED if the size is too big, and this should trigger fallback
to blob images. This should only produce drawing commands for the
relevant region and save us the high cost of rasterized a very large
surface on the main thread, which at the same time, looking as crisp as
a user would expect.
If FLAG_HIGH_QUALITY_SCALING is used, we should use
SurfaceCache::LookupBestMatch just like how it is done in RasterImage.
This may provide an alternative size at which we should rasterize the
SVG instead of the requested size. Since SurfaceCache imposes a maximum
size for which it will permit rasterized SVGs, we should also bypass the
cache entirely if we are well above that and simply draw directly to the
draw target in such cases.
With WebRender, it is somewhat more complicated. We will now return
NOT_SUPPORTED if the size is too big, and this should trigger fallback
to blob images. This should only produce drawing commands for the
relevant region and save us the high cost of rasterized a very large
surface on the main thread, which at the same time, looking as crisp as
a user would expect.
This was done automatically replacing:
s/mozilla::Move/std::move/
s/ Move(/ std::move(/
s/(Move(/(std::move(/
Removing the 'using mozilla::Move;' lines.
And then with a few manual fixups, see the bug for the split series..
MozReview-Commit-ID: Jxze3adipUh
Andrew Osmond
Sylvestre Ledru
Andreea Pavel
Emilio Cobos Álvarez
Seth Fowler
Timothy Nikkel
Carsten "Tomcat" Book