Bug 41190 – Canvas: Don't paint with empty radial gradients

• Component: WebCore Misc.
• Status: RESOLVED FIXED

[Andreas Kling]

CanvasRenderingContext2D shouldn't paint anything with radial gradients that have x0==x1, y0==y1 and r0==r1.
Similar logic is already in place for linear gradients.

This would fix canvas/philip/tests/2d.gradient.radial.equal.html on Qt.

The test is not skipped on mac, so I suppose there's something further down the stack that prevents painting with these gradients.

[Andreas Kling]

Created attachment 59723 [details]
Proposed patch

[Andreas Kling]

Tossing in a spec link for good measure:
http://www.whatwg.org/specs/web-apps/current-work/#dom-context-2d-createradialgradient

"If x0 = x1 and y0 = y1 and r0 = r1, then the radial gradient must paint nothing."

[Andreas Kling]

Created attachment 60275 [details]
Proposed patch v2

Style nit - s/1/true/

[Darin Adler]

Comment on attachment 60275 [details]
Proposed patch v2

> -        bool isZeroSize() const { return m_p0.x() == m_p1.x() && m_p0.y() == m_p1.y(); }
> +        bool isZeroSize() const { return m_p0.x() == m_p1.x() && m_p0.y() == m_p1.y() && (m_radial ? m_r0 == m_r1 : true); }

I think it would read better as:

    (!m_radial || m_r0 == m_r1)

[Andreas Kling]

Created attachment 60280 [details]
Proposed patch v3 (Darinized)

That looks nicer indeed.

[Tor Arne Vestbø]

Comment on attachment 60280 [details]
Proposed patch v3 (Darinized)

Thanks Andreas!

[WebKit Commit Bot]

Comment on attachment 60280 [details]
Proposed patch v3 (Darinized)

Clearing flags on attachment: 60280

Committed r62350: <http://trac.webkit.org/changeset/62350>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.