379321 - spreadmethod="reflect" or "repeat" with linear gradient in <object> doesn't work?

Status: RESOLVED FIXED

(Core :: SVG, defect)

Description

[Jesse Ruderman]

http://www.w3.org/Graphics/SVG/Test/20061213/htmlObjectHarness/full-pservers-grad-14-b.html

All of the examples on the left look the same (pad).  But if I right-click and select "Show only this frame", it looks right.  So maybe being in an <object> is somehow screwing it up?

Comment 1

[Jesse Ruderman]

This might be Mac-specific, or even a bug in the cairo quartz backend.

Comment 2

[Robert Longson [:longsonr]]

(In reply to comment #1)
> This might be Mac-specific, or even a bug in the cairo quartz backend.
> 

It does seem to work properly on Windows XP.

Comment 3

[Jonathan Watt [:jwatt]]

CC'ing Brian in case he knows anything about this.

Comment 4

[Brian Ewins]

Yes, its a cairo bug. Looking at our tests I see the extend_pad test is marked XFAIL, and the extend_reflect test case isn't even being run (IIRC its an intermittent X11-crasher). So theres known bugs in there.

In any case, fixing extend_* and making the quartz surface fully supported is on the roadmap for 1.6 - supposedly in July - which is supposed to target anything still needing done for firefox 3.

Comment 5

[Brian Ewins]

Attachment: implements extend-reflect for quartz

Previously cairo quartz only implemented extend-repeat, which makes it even odder that you only see extend-pad here! I've started implementing the others - this adds extend-reflect. I've checked it out using cairo's tests and it works fine, but some other fallback must be kicking in to cause this rendering in minefield, which is unchanged. Also, its only affecting the linear gradients? Weird.

So, this patch isn't really helping (yet), but will be part of getting this all to work. I'll dig on.

Comment 6

[Brian Ewins]

Attachment: make gradient+extend-r* unsupported in cairo-quartz

The 'correct' linear gradient rendering happens when the test in _cairo_quartz_cairo_gradient_pattern_to_quartz for an identity pattern matrix fails. 
The radial gradient doesn't even get this far before dropping to the fallback implementation, so it works too;
Finally, the incorrect rendering happens because the quartz implementation doesn't actually support extend for gradients - gradients are implemented directly on top of CGShadingRef, when we have extend-reflect or extend-repeat we need to create a CGPattern first.

There is an easy workaround and a harder fix; the workaround is just to check for unsupported options at the same point in _cairo_quartz_cairo_gradient_pattern_to_quartz, and return NULL. That's this patch, which fixes the bug in my minefield.

The fix is to implement gradients properly (doh! :) ). Marking previous patch as superseded, you won't need it for this to work. I'll shepherd this or a proper fix into cairo trunk for 1.6.

Comment 7

[Jonathan Watt [:jwatt]]

Is this still broken?

Comment 8

[Brian Ewins]

Working now, fixed by 383960 landing.

Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.5; en-US; rv:1.9b2pre) Gecko/2007113023 Minefield/3.0b2pre

Comment 9

[Alecazam]

This isn't fixed on the mozilla url describing the feature.  
https://developer.mozilla.org/en-US/docs/Web/SVG/Tutorial/Gradients

But it does appear to work here:
http://www.w3.org/Graphics/SVG/Test/20061213/htmlObjectHarness/full-pservers-grad-14-b.html

Comment 10

[Alecazam]

Here's the reduced test case of failure.  Looks different with focus fx/fy values.
  Chrome looks correct, and Safari ignores spreadMethod.  Tested on OSX.

<svg width="220" height="220" version="1.1" xmlns="http://www.w3.org/2000/svg">
  <defs>
      <!-- repeat case not correct in FF either, doesn't match Chrome with fx,fy  -->
      <radialGradient id="GradientReflect"
            cx="0.5" cy="0.5" r="0.4" fx="0.75" fy="0.75"
            spreadMethod="reflect">
        <stop offset="0%" stop-color="red"/>
        <stop offset="100%" stop-color="blue"/>
      </radialGradient>
  </defs>
  <rect x="120" y="120" rx="15" ry="15" width="100" height="100" fill="url(#GradientReflect)"/>
  <text x="125" y="140" fill="white" font-family="sans-serif" font-size="12pt">Reflect</text>
</svg>

Comment 11

[Robert Longson [:longsonr]]

Please create a new bug Alecazam, commenting on an old fixed bug won't go anywhere.