[Webkit-unassigned] [Bug 155288] Compositing layer is too large when inner element has a blur that is within bounds

[bugzilla-daemon at webkit.org]

https://bugs.webkit.org/show_bug.cgi?id=155288

Simon Fraser (smfr) <simon.fraser at apple.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Depends on|                            |81239

--- Comment #1 from Simon Fraser (smfr) <simon.fraser at apple.com> ---
For the first square:
renderer().style().filterOutsets().expandRect(unionBounds);
is adding 28px on each side for the 10px blur. This comes from outsetSizeForBlur() which has this comment:
    // We take the half kernel size and multiply it with three, because we run box blur three times.

The kernel size is 19x19, which is computed by:
    unsigned size = std::max<unsigned>(2, static_cast<unsigned>(floorf(value * gaussianKernelFactor() + 0.5f)));
where gaussianKernelFactor() returns 1.87997127

This is emulating the suggested approximation the SVG spec <https://www.w3.org/TR/SVG/filters.html#feGaussianBlurElement>

-- 
You are receiving this mail because:
You are the assignee for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.webkit.org/pipermail/webkit-unassigned/attachments/20160310/6755eaf1/attachment-0001.html>