25647 2014-05-09 21:47:57 +0000 ImageBitmap: Have a way to turn an ImageBitmap into a renderable <img> or <canvas> efficiently 2016-04-21 14:37:18 +0000 1 1 1 Unclassified WHATWG HTML unspecified Other other RESOLVED FIXED P3 enhancement Needs Impl Interest 1 ian junov d ian junov mike contributor oldest_to_newest 105598 0 ian 2014-05-09 21:47:57 +0000 On Tue, 17 Dec 2013, David Flanagan wrote: > > Once a large image is decoded and downsampled into a smaller > ImageBitmap, the only thing that we can do with that ImageBitmap is to > copy it into a Canvas, either for display to the end user (as an > alternative to an <img>) or for re-encoding with Canvas.toBlob() (when > creating thumbnails for large images). The motivation for this > downsampling feature is memory use. But having to copy an ImageBitmap > into a canvas in order to use it immediately doubles the amount of > memory required. So for this reason, I also want to propose that > ImageBitmap have a transferToCanvas() method akin to the > transferToImageBitmap() and transferToImage() methods proposed at > http://wiki.whatwg.org/wiki/WorkerCanvas. transferToCanvas would > transfer the image data into a new Canvas object and would neuter the > ImageBitmap so that it could no longer be used. 125808 1 junov 2016-04-11 20:20:55 +0000 WIP: https://github.com/whatwg/html/pull/1028 125811 2 d 2016-04-11 21:14:20 +0000 Note that https://github.com/whatwg/html/pull/1028 covers the transfer-to-canvas case. That is probably enough for most situations. https://www.w3.org/Bugs/Public/show_bug.cgi?id=23502 talks a bit about the img case, although that API is more likely to be copying than transferring.