- From: T.V Raman <raman@google.com>
- Date: Tue, 9 Feb 2010 12:10:08 -0800
- To: robert@ocallahan.org
- Cc: mjs@apple.com, david.bolter@gmail.com, public-html@w3.org
note that the image-map usecase would cover a significant portion of uses of canvas for UI that today remain out of reach when implemented via canvas. Robert O'Callahan writes: > On Tue, Feb 9, 2010 at 1:25 PM, Maciej Stachowiak <mjs@apple.com> wrote: > > > I am concerned however about overlaying the canvas with 0.01 opacity divs. > > I expect this will have a negative impact on canvas rendering performance, > > especially if there are significant animations. Because even though 0.01 > > opacity likely won't draw anything visible, the browser still has to render > > and composite the content on top of the canvas. > > > > In the future we can probably expect most browsers to use graphics hardware > in a way that makes the compositing cheap/free. However, opacity:epsilon > does seem rather ugly. Wouldn't opacity:0 work here? In Gecko at least that > would optimize away almost all rendering (while still catching events). > > I am also wondering how this technique can be extended to control target > > areas that are not rectangles. > > > > I'm wondering that too. I wonder if it would make sense to add some kind of > canvas API that lets you associate an element with the current path. Mmm, > sounds like image maps :-). > > Rob > -- > "He was pierced for our transgressions, he was crushed for our iniquities; > the punishment that brought us peace was upon him, and by his wounds we are > healed. We all, like sheep, have gone astray, each of us has turned to his > own way; and the LORD has laid on him the iniquity of us all." [Isaiah > 53:5-6]
Received on Tuesday, 9 February 2010 20:11:04 UTC