[OpenJDK 2D-Dev] [9] Review Request: 8039774 [OGL] Image painting is broken if 'sun.java2d.accthreshold' is set to 0

[Jim Graham]

The fix looks good - approved.

It might be worth noting in the comment that the returned image will be 
a single use image and so acceleration caching wouldn't help and just 
add overhead compared to rendering it directly from the sw surface.  Or 
add a single-line comment on the new call to set the priority to 0.

Either way, approved regardless of comment changes...

			...jim

On 4/10/14 4:45 AM, Sergey Bylokhov wrote:
> Hello.
> Please review the fix for jdk 9.
> The bug occurs, when we try to call drawImageBg with scale and
> 'sun.java2d.accthreshold' is set to 0.
>
> The bug exists in the DrawImage.renderImageXform(). This method is
> called, when all our attempts to scale the image fails, and we create a
> buffered image, and use it as intermediate buffer.
> Note that the buffered image has predefined image type
> (TYPE_INT_RGB/TYPE_INT_ARGB), because we know that for these types we
> have necessary tranform helpers.
> So if "sun.java2d.accthreshold" set to 0 the next code [1] is broken,
> because dstData.getSourceSurfaceData() returns cached version of the
> surface, which is unexpected.
>
> [1]:
>              srcData = dstData.getSourceSurfaceData(img,
> SunGraphics2D.TRANSFORM_GENERIC,
>                                                     sg.imageComp,
>                                                     null);
>              srcType = srcData.getSurfaceType();
>              helper = TransformHelper.getFromCache(srcType);
>
> !!!!! helper is null here.
>
> I can reproduce the problem on OGL, and sure that it will be reproduced
> on d3d as well.
>
> BTW: we have to do something with this code path because DrawImageBg()
> in this scenario 10000 slower than DrawImage().
>
> Bug: https://bugs.openjdk.java.net/browse/JDK-8039774
> Webrev can be found at: http://cr.openjdk.java.net/~serb/8039774/webrev.00
>