This was was cloned from bug 11739 as part of operation LATER convergence.
Originally filed: 2011-01-11 22:51:00 +0000

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 #0   contributor@whatwg.org                          2011-01-11 22:51:44 +0000 
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Specification: http://www.whatwg.org/specs/web-apps/current-work/multipage/the-canvas-element.html
Section: http://www.whatwg.org/specs/web-apps/current-work/complete.html#complex-shapes-(paths)

Comment:
I would like to see a clearPath or clearStroke functions similar to clearRect
but to clear lines, not just full rectangles

Posted from: 71.9.39.98
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 #1   Tab Atkins Jr.                                  2011-01-11 23:00:52 +0000 
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This can be achieved currently by making a path, calling clip(), *then* calling clearRect with a bounding rectangle specified.

That technique is fairly unintuitive, though.  A clear() method that clears out a path would be nice.
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 #2   Ian 'Hixie' Hickson                             2011-02-11 01:27:04 +0000 
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Status: Partially Accepted
Change Description: see diff given below
Rationale: That might make sense, but in a future version.
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 #3   Ian 'Hixie' Hickson                             2011-02-11 01:33:19 +0000 
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> Change Description: see diff given below

That should read "none yet", my apologies.
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 #5   Ian 'Hixie' Hickson                             2012-02-29 22:11:36 +0000 
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What's the use case for this, exactly? Having played with canvas quite a bit recently I've never found myself needing anything but clearRect() applied to the entire canvas...
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 #6   Tab Atkins Jr.                                  2012-02-29 22:16:00 +0000 
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I've used the technique I outlined in Comment #1 for a Worms-like game before.  When your gun hit, I did a clearRect() (clipped to a path) to remove pixels from the "level" canvas.
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 #7   Ian 'Hixie' Hickson                             2012-02-29 22:45:06 +0000 
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I guess that makes sense.

So basically this is just a shorthand for:

   .save();
   .clip();
   .setTranform(identity)
   .clearRect(entire canvas)
   .restore();

...?
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 #8   Tab Atkins Jr.                                  2012-02-29 22:46:39 +0000 
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Yup.
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 #9   Ian 'Hixie' Hickson                             2012-02-29 22:54:52 +0000 
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I'm going to punt on this for now, and review it at a later date to see how much demand there has been for it. So far it seems like it would be little more than a convenience method and I haven't heard much demand for it.
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