In my bug 821210 patch to get reftests rendering in their native resolution, I've modified reftest.js to take a snapshot by doing: ctx.scale(2, 2); before the: ctx.drawWindow(window, 0, 0, 800, 600, ...flags...); call. That would draw the 800x600 CSS pixel window in the 1600x2000 canvas. Since bug 848482 landed, rather than getting the high resolution window snapshot, I get a scaled up view of an 800x600 rendering of the window (it looks like). Should that bug have affected whether drawWindow could give me a native resolution rendering of the window?

(In reply to Cameron McCormack (:heycam) from comment #0) > call. That would draw the 800x600 CSS pixel window in the 1600x2000 canvas. > > Since bug 848482 landed, rather than getting the high resolution window > snapshot, I get a scaled up view of an 800x600 rendering of the window (it > looks like). Should that bug have affected whether drawWindow could give me > a native resolution rendering of the window? s/800x600/800x1000/g

Yes, this is a bug. We want to detect that the destination surface has a scale transform, and move that onto our temporary surface. We also want to create our temporary surface at the scaled size.