Bug 6548 – <mask>, <marker>, <pattern> and <use> inside <defs> do not work

• Status: RESOLVED
• Resolution: FIXED
• Component: SVG

[Eric Seidel (no email)]

simple <mask> crashes Safari+SVG

Crashing test case attached.

[Eric Seidel (no email)]

Created attachment 5686 [details]
simple test case (should see only green!)

[Eric Seidel (no email)]

The problem here is that since <defs> does not create a renderer, all of its children will not create 
renderers, including the <mask>.  <mask> (wrongfully) assumes that it will create a renderer.  This is 
probably easiest to fix by making <pattern> and <mask> and <marker> all of their own separate render 
trees which are independent from the main tree.  I'm not sure how style resolution wil work in those cases.  
Another option is to "fix" the render tree (for at least defs) to allow it to skip over certain dom objects 
which do not need to create renderers.

[Eric Seidel (no email)]

Ok, we've landed a simple fix (r12109).

So this no longer crashes, but <mask> does not work in this situation.  This bug can now track that fix.

[Eric Seidel (no email)]

I'm pretty certain that <pattern> and <marker> also fail inside <defs> as well.

[Eric Seidel (no email)]

This is a fundemental issue in our <mask>, <marker>, <pattern> and <use> support.  The SVG spec officially recommends that content authors place these elements inside a <defs> element, however such content will fail in WebKit+SVG.  Bumping to p2 and adding SVGHitList keyword.

In order to implement this correctly, we would need to make these elements smart enough to manually create renderers and resolve style accross the <defs> boundery.  Another way to fix would be to make <defs> create a dummy renderer, but I think supporting disjoint style trees for these elements is a better fix than hacking <defs>.

[Eric Seidel (no email)]

Hyatt: how would you feel about us inserting a special dummy node into the render tree for <defs> which did not paint, but did hold style?  I think I might making a patch which does just that.

The other option (as I see it) is to make a separate render tree off to the side.

[Eric Seidel (no email)]

Created attachment 10000 [details]
simple test case (should see a 100x100 green block)

the use of <mask> was incorrect in the previous test case.

[Eric Seidel (no email)]

Created attachment 10036 [details]
the fix

Another fix from my long plane rides this weekend.

[Maciej Stachowiak]

Comment on attachment 10036 [details]
the fix

r=me