Eyes Above The Waves

In the last week or two I've been spending most of my time working on cairo-gtk2 trunk builds, trying to get them back into shape. Vlad did some wonderful, long-needed work to move all double-buffering and window translucency management out of the view manager into into platform-specific windowing code, in a very elegant way, but he only updated Windows, so GTK2 needed to catch up there. When I fixed that, I encountered a serious cairo issue --- it was creating 24-bit temporary pixmaps for the offscreen buffer, which was killing performance on my 16-bit display setup --- and it took a while to diagnose and fix (in cairo).

But the biggest chunk of work has been reenabling GTK2 native themes in cairo builds, without which Firefox looks completely naff. This isn't easy since we want to be able to render GTK2 themes to any cairo context (e.g., a PDF context, or a screen context with some rotation applied) but GTK2 themes expect to be rendering to an X pixmap or window. We can hack around this by having the theme render to an offscreen pixmap and then extracting the data, but that's painful and slow especially when the theme paints with transparency or translucency. It's important that the common case of painting the theme to an X window with no scaling or rotation remain as efficient as it is today. Well, it's done :-).

One bonus of this work is that we can finally enable GTK2 themes for HTML content. We never did so before because we never wrote the code to handle rendering to a non-X printing context (i.e. render to temporary pixmaps and send them as images to the printer). Now that we've solved this problem in a general way, we will (when my patches land) turn on GTK2 themes for HTML. The screenshot below is using the "Industrial" theme. The Cancel button is being hovered.