12.0 available (10.0.4 to follow)

I don't know what's going on with ESR 10.0.4 (there is no tagged build as of this writing), but 12 is signed off and has build tags, so we're shipping. I will build ESR 10 tomorrow regardless of whether there are build tags or not because we need to get basic testing by you, the basic testing basic audience, basically before we basically ship.

As promised, TenFourFox 12 contains a CoreGraphics backend to Azure, the 2D API Mozilla is developing to improve graphics performance. Azure right now is only used for canvas elements, but this is in more places than you'd think (for example, pdf.js, the JavaScript PDF reader, uses canvas and this backend is noticeably faster), so the improvement is more than you might suspect. The shipped backend with regular Firefox requires features of 10.5, but fortunately most of the features have undocumented private API versions in 10.4, particularly the compositing operators, so the port was relatively straightforward in that respect. It also relies on CGGradient, which is a CoreGraphics convenience interface to CGShading that was introduced in 10.5; we use Chad Weider's public domain CTGradient object instead to act as a gradient-style veneer over CGShading and then a custom Objective-C++ glue object to connect Mozilla's C++ interface to CTGradient's Objective-C interface. Finally, the regular Fx backend uses CGContextShowGlyphsAtPositions to display text, which is not in 10.4's CoreGraphics or private CoreText, so we just use a loop and good old CGContextShowGlyphsAtPoint (CGContextShowGlyphsWithAdvances is not suitable for a variety of reasons, not least being std::vector doesn't act quite right in 10.4). The only leftover bug on our part is a strange edge case with gradients where a terminal alpha-only stop can leave a strange dark fringe and I suspect this is actually a bug in CTGradient.

You will notice one particular difference between Cairo-based canvas and Azure CG canvas, depending on the fonts you have installed and their supported faces. If your Helvetica, say, lacks an italic, then if you ask for italic in that font you'll just get roman, whereas Cairo would try to simulate it. Strictly speaking I think CG has the correct behaviour here, and actually the CG backend works better with weird fonts in pdf.js as well that don't even display with Cairo.

Using CoreGraphics also introduces a modicum of hardware acceleration, which works on both 10.4 and 10.5. Stretching the canvas (such as in this GameBoy emulator when you press ESC) uses hardware to stretch it rather than software, and certain other CoreGraphics operations can also be accelerated by the graphics card. The proof is in the benchmarks. Not only compare TenFourFox 12 against 11, but try turning gfx.canvas.azure.enabled off and see what it does to your Peacekeeper scores. CoreGraphics accelerates these operations up to 60%. I can't wait for them to expand it to other components in the graphics stack, particularly SVG and HTML5 video blitting.

Other than that, 12 is a pretty blah release. There are some new CSS and DOM properties, but that's really it. Memory usage seems a bit worse due to a new font shape cache they are using, but this improves text-heavy pages, so it's hard to call it a bad tradeoff. The big changes in tab control and SPDY-by-default don't start appearing until Fx13.

In TenFourFox-specific news, this release improves XPCOM performance from JavaScript by simplifying the PowerPC assembly used for xptcall. It's a marginal win, but it's a win everywhere (issue 137). Java is also now disabled by default again, even if you have ignored my professional advice and turned on plugins, as reported by Chris (issue 141). This last fix will also occur in 10.0.4ESR stable, and the stable release will also have the blocklist disabled.

Release notes and architecture builds (watch for 10.0.4 probably tomorrow evening Pacific):

• G3
• G4/7400
• G4/7450
• G5