On Tue, Nov 24, 2015 at 7:05 PM, Robert O'Callahan <rob...@ocallahan.org> wrote: >> >> It still seems like, where possible, we should switch from passing >> around an nsRenderingContext or a gfxContext to passing around a >> DrawTarget. (Presumably starting from leaf functions and moving >> up.) > > Yes.
I spent some time trying to do this, and it's harder than you might think. A lot of the leaf functions are using gfxContext in complicated ways. I'm trying with the small number that don't seem too bad but even they are challenging to me (as a newbie to this stuff). I suspect a lot of the easy cases have already been converted. One interesting thing I found is that a *lot* of the functions that take an nsRenderingContext or gfxContext do so because they end up passing it into text run code -- gfxTextRun uses a gfxContext, via gfxTextRunFactory::Parameters::mContext. However, only a few things from the gfxContext are used by the text run code: - gfxContext::mDT is only used in gfxGDIFont::GetGlyphWidth(). - gfxContext::GetCairo() is called in numerous places. This function is weird, and Matt Woodrow suggested it could probably be split into two parts. It seems like its usage usually boils down to using the "reference" Cairo context (gfxContext::mRefCairo) for font scaling. - gfxContext::GetRoundOffsetsToPixels() is called in a couple of places. It calls CurrentMatrix().HasNonTranslation(). - gfxFont::CalcXScale() is called from PostShapingFixup(). It calls gfxContext::UserToDevice() which uses gfxContext::mTransform. I think that's it. It feels like it should be possible to simplify this, but I can't quite work out how. Nick _______________________________________________ dev-platform mailing list dev-platform@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-platform
