- From: poot <cvsmail@w3.org>
- Date: Sat, 13 Jun 2009 03:45:19 +0900 (JST)
- To: public-html-diffs@w3.org
Mention that getImageData() might return different pixel data than you set, due to premultiplying. (whatwg r3230) http://dev.w3.org/cvsweb/html5/spec/Overview.html?r1=1.2378&r2=1.2379&f=h http://html5.org/tools/web-apps-tracker?from=3229&to=3230 =================================================================== RCS file: /sources/public/html5/spec/Overview.html,v retrieving revision 1.2378 retrieving revision 1.2379 diff -u -d -r1.2378 -r1.2379 --- Overview.html 12 Jun 2009 07:49:58 -0000 1.2378 +++ Overview.html 12 Jun 2009 18:44:54 -0000 1.2379 @@ -22606,6 +22606,12 @@ for all of the <code title="dom-context-2d-getImageData"><a href="#dom-context-2d-getimagedata">createImageData()</a></code>, <code title="dom-context-2d-getImageData"><a href="#dom-context-2d-getimagedata">getImageData()</a></code> and <code title="dom-context-2d-putImageData"><a href="#dom-context-2d-putimagedata">putImageData()</a></code> operations.</p> + <p class="note">Due to the lossy nature of converting to and from + premultiplied alpha color values, pixels that have just been set + using <code title="dom-context-2d-putImageData"><a href="#dom-context-2d-putimagedata">putImageData()</a></code> might be + returned to an equivalent <code title="dom-context-2d-getImageData"><a href="#dom-context-2d-getimagedata">getImageData()</a></code> as + different values.</p> + <p>The current path, <a href="#transformations" title="dom-context-2d-transformation">transformation matrix</a>, <a href="#shadows" title="shadows">shadow attributes</a>, <a href="#dom-context-2d-globalalpha" title="dom-context-2d-globalAlpha">global alpha</a>, the <a href="#clipping-region" title="clipping region">clipping region</a>, and <a href="#dom-context-2d-globalcompositeoperation" title="dom-context-2d-globalCompositeOperation">global composition operator</a> must not affect the <code title="dom-context-2d-getImageData"><a href="#dom-context-2d-getimagedata">getImageData()</a></code> and <code title="dom-context-2d-putImageData"><a href="#dom-context-2d-putimagedata">putImageData()</a></code>
Received on Friday, 12 June 2009 18:45:51 UTC