Real WebGL, a real 2D canvas, and canvas text that matches the reference browser

Pages that ask for WebGL now get a real one, written for this engine: a compiler for the shading language, a rasteriser that fills triangles with the same coverage rules as the reference browser, and the whole WebGL 1 state machine and interface. The WebGL test page that showed an empty box now shows its spinning cube. It draws on the processor, so it works on every machine the same way.

2D canvases used to record every call and replay the whole list each time the page was drawn or read back, with text always drawn last and gradients and patterns as stand-ins. They now draw immediately into their own pixels using the reference browser's arithmetic: gradients, patterns, all 26 blend modes, clipping, both fill rules, dashes, joins, caps and hit tests, with text drawn in the order the page asked for it. Reading back a busy canvas went from seconds to milliseconds.

Canvas shadows and filters follow the standard's drawing model: the shape is filtered, then shadowed, then blended. Colour filters (grayscale, sepia, saturate, hue, brightness, contrast, invert, opacity) were measured against the reference browser and match its rounding exactly. And when a page redraws one sprite, only that rectangle is sent to the screen instead of the whole canvas.

Outlined text is now the letters' real outlines stroked with the line style (dashes and gradients included), not filled letters. A bold or italic font named only in script loads the real bold or italic, not a smeared one. Letter and word spacing, turning kerning off and small capitals all work, measureText reports how far the ink really reaches, and Hebrew and Arabic draw right to left with numbers kept in order and letters joined.

Pages can draw on a canvas that is not on the page, turn it into an image bitmap (cropped, flipped, resized sharp or smooth), hand a finished frame to the screen without a copy, and give a page canvas's drawing over to an offscreen one. Throwaway offscreen canvases are freed as soon as nothing uses them: a test makes 500 and requires none to stay.