Bug 87915 – [chromium] Fix min/max bounds error in CCMathUtil.cpp

• Status: RESOLVED
• Resolution: FIXED
• Component: Layout and Rendering

[Shawn Singh]

To compute bounds of vertices in CCMathUtil.cpp, there were two places where min/max values were assigned to initial opposite max/min values.

There was a mistake in this code however, because numeric_limits<float>::min() is actually zero, not -flt_max.  The desired correct behavior is to use -flt_max.

Patch coming in a moment:
  - moves some code around so that unit testing is nice and clean
  - fixes the numeric_limits mistake in two places (computeEnclosingRectForVertices and computeEnclosingClippedRect)
  - adds two unit tests to cover the change.

[Shawn Singh]

Created attachment 144967 [details]
Patch

[James Robinson]

Comment on attachment 144967 [details]
Patch

numeric_limits<float>::min() is actually something like the least positive representable number (can't remember if it's a denormal or not).  Pretty much never what you want.

Looks good, do we expect any impact on pages?

[Shawn Singh]

Comment on attachment 144967 [details]
Patch

(In reply to comment #2)
> (From update of attachment 144967 [details])
> numeric_limits<float>::min() is actually something like the least positive representable number (can't remember if it's a denormal or not).  Pretty much never what you want.
> 
> Looks good, do we expect any impact on pages?

Thanks for the review

I wouldn't be surprised if a few rare uncommon pages broke because of this, but I have not actually encountered them.  On pages that have been already working, there would not be any performance benefit or any other change.

[WebKit Review Bot]

Comment on attachment 144967 [details]
Patch

Clearing flags on attachment: 144967

Committed r119058: <http://trac.webkit.org/changeset/119058>

[WebKit Review Bot]

All reviewed patches have been landed.  Closing bug.