- From: Philip Taylor <philip@zaynar.demon.co.uk>
- Date: Sun, 05 Aug 2007 18:35:45 +0100
- To: Ben Boyle <benjamins.boyle@gmail.com>
- CC: HTML WG <public-html@w3.org>
Ben Boyle wrote: > [quoting from the spec] The canvas must initially be fully transparent black. I think that sentence should be modified to say "The canvas bitmap must initially be fully transparent black.", so it's clear that it applies to the bitmap rather than to the element itself. > 1. "transparent black" ? Transparent I understand. Why black? "Transparent black" means rgba(0, 0, 0, 0). A colour like rgba(255, 0, 255, 0) would be fully transparent too (but not black). Normally all fully transparent colours act indistinguishably, but you can call CanvasRenderingContext2D's getImageData() to see the difference between [0, 0, 0, 0] and [255, 0, 255, 0], so the distinction matters a bit here, and specifying "transparent black" ensures everyone implements the same. > This would be adjustable through CSS? You can't change the canvas bitmap with CSS. If you do <canvas style="background:red"> then the canvas is still initially a transparent black bitmap, though it's rendered on top of a red square (which is rendered on top of whatever's behind the canvas element). (I don't know whether the rendering is actually specified anywhere, but it's consistent with how <img> works.) -- Philip Taylor philip@zaynar.demon.co.uk
Received on Sunday, 5 August 2007 17:35:56 UTC