[webkit-reviews] review denied: [Bug 54587] Tiled backing store area is too big. : [Attachment 82723] Fix also webkit2 tile area calculation.

[bugzilla-daemon at webkit.org]

Kenneth Rohde Christiansen <kenneth at webkit.org> has denied Viatcheslav
Ostapenko <ostapenko.viatcheslav at nokia.com>'s request for review:
Bug 54587: Tiled backing store area is too big.
https://bugs.webkit.org/show_bug.cgi?id=54587

Attachment 82723: Fix also webkit2 tile area calculation.
https://bugs.webkit.org/attachment.cgi?id=82723&action=review

------- Additional Comments from Kenneth Rohde Christiansen
<kenneth at webkit.org>
View in context: https://bugs.webkit.org/attachment.cgi?id=82723&action=review

> Source/WebCore/ChangeLog:8
> +	   Tiled backing store area is too big.
> +	   Error in area calculcation causes size of backing store
> +	   up to 6 times bigger than viewport with default multipliers.
> +	   https://bugs.webkit.org/show_bug.cgi?id=54587

Why dont you explain how it is calculating wrong and why it wouldnt be better
to change the default multipliers?

> Source/WebCore/platform/graphics/TiledBackingStore.cpp:217
> -    keepRect.inflateX(visibleRect.width() * (m_keepAreaMultiplier.width() -
1.f));
> -    keepRect.inflateY(visibleRect.height() * (m_keepAreaMultiplier.height()
- 1.f));
> +    keepRect.inflateX(visibleRect.width() * (m_keepAreaMultiplier.width() -
1.f) / 2);
> +    keepRect.inflateY(visibleRect.height() * (m_keepAreaMultiplier.height()
- 1.f) / 2);

I dont understand why this is right. It is called a multiplier. So if we have
size 10, and a multiplier of two, we would expect a result of 20. ie 10 + 10 *
1 (10.inflate(10 * (2 - 1))