On Fri, Jul 15, 2011 at 8:11 AM, Henri Sivonen <hsivonen@iki.fi> wrote: > On Thu, 2011-07-14 at 13:40 -0700, Jonas Sicking wrote: >> We can and should improve the >> SVG DOM to attract more people, but I suspect there will always be a >> group of people that choose to use canvas anyway due to better >> performance or other reasons. > > Do you have examples of people choosing <canvas> over SVG for perf > reasons? Are the perf reasons data-based or merely assumed? Are the perf > reasons the kind of quality of implementation issues that can be > considered to be transient and addressed over the next couple of years? > > In theory, SVG should be able to outperform <canvas> for painting, > because the browser engine gets to control how often to repaint, what > parts to repaint and can avoid intermediate bitmaps when the path > stroking and filling can be performed nearer hardware and there are > guaranteed not to be readbacks because the browser knows there aren't > filters in use. There's discussions at these two pages: http://andreasgal.com/2011/06/15/pdf-js/ http://blog.mozilla.com/cjones/2011/06/15/overview-of-pdf-js-guts/ It doesn't contain numbers, but it sounds like they have measured. I'm sure that if you ask you can get details. > So in theory, if SVG has performance issues, they should be attributable > to the DOM. If a sub-DOM is used for accessibility in the <canvas> case, > then the <canvas> case has a DOM, too. Rendering a über complicated checkbox could require hundreds of DOM objects in the SVG DOM used to render it. But only a single DOM element in the sub-DOM representing the <input type=checkbox>. So I would expect severely different performance. / JonasReceived on Friday, 15 July 2011 22:19:22 UTC
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