Hi Sergey,

Do these changes look good? Please give your feedback.

Regards,
Pankaj Bansal

-----Original Message-----
From: Pankaj Bansal 
Sent: Wednesday, November 8, 2017 8:09 PM
To: Sergey Bylokhov; awt-dev@openjdk.java.net; 2d-...@openjdk.java.net; Philip 
Race
Subject: RE: <AWT Dev> [10] Review Request: JDK-8159142 : Visible artifacts in 
sun/java2d/SunGraphics2D/DrawImageBilinear.java

+ 2d-dev, Phil.

Regards,
Pankaj Bansal

-----Original Message-----
From: Pankaj Bansal
Sent: Friday, November 3, 2017 3:11 PM
To: Sergey Bylokhov; awt-dev@openjdk.java.net
Subject: RE: <AWT Dev> [10] Review Request: JDK-8159142 : Visible artifacts in 
sun/java2d/SunGraphics2D/DrawImageBilinear.java

Hi Sergey,


XRSurfaceData, GLXSurfaceData:        On linux, only integer scale  is 
supported. If we give non-integer, the the uiScale is truncated to integer and 
used. So the ceil or round does not matter. In both XRSurfaceData and 
GLXSurfaceData, ceil function or direct multiplication is used arbitrarily at 
different places. So, we can make changes for making things more consistent, 
but it is not necessary as of now. 
PS: There are artifacts in same test case on Linux and there is a separate bug 
https://bugs.openjdk.java.net/browse/JDK-8189957. But these don't seem to be 
result of this precision error. I will look into this bug later.

WGLSurfaceData:     In openGL, ceil function is used in WGLSurfaceData, so it 
will create WGLOffScreenSurfaceData and in turn create native resource. Then in 
DrawImage class, the clipRound is used, and these sizes are sent to native 
size. Then in OGLBlitTextureToSurface function inside OGLBlitLoops file, the 
texture coordinates are calculated by dividing the sizes sent from Java side by 
the native resource size. So the texture coordinates are wrong. For instance, 
in DrawImageBilinear, the size is 5x5 and uiScale is 2.5, so the native 
resource is of size, 13x13. But the dimensions sent to native are 12x12, so the 
textures are (0,0) and (12/13, 12/13). So artifacts in final image. 

D3DSurfaceData:     In D3D, everything is similar to OpenGL, but in 
D3DBlitTextureToSurface function inside D3DBlitLoops file,  the calculated 
texture coordinates are sent to D3DDrawTextureWithHint and then data is copied 
from texture to surface. Here if the native resource size and dimensions sent 
from Java are not same, the data is copied in parts. This is somehow handling 
the wrong texture coordinates. So this test does not produce any artifacts in 
D3D pipeline. But it can in some other case. So this needs to be fixed.

GDIWindowSurfacedata: Here the volatile image creates a BufImageSurfaceData as 
backing resource using the ceil function and while copying from 
BugImageSurfaceData to a GDIWindowSurface, the 
Java_sun_java2d_loops_TransformHelper_Transform in native side is able to 
handle the difference in sizes. So the artifacts are not visible. But I think 
this should be fixed. So should make changes to getBackupImage function in 
SunVolatileImage to use clipRound instead of ceil. 

BufImageSurfaceData : It uses the image raster size to create the native 
resource.  The raster size is already scaled according to the uiScale. So no 
need to change this.

So in a nutshell,
I feel we may not change the code in XRSurfaceData, GLXSurfaceData as linux 
only support integer scaling. We can do it later if required.
We should change code for D3DSurfaceData, GDIWindowSurfacedata and 
WGLSurfacedata as it may cause artifacts. I have updated the webrev for the 
same. Please review.

Webrev:
http://cr.openjdk.java.net/~pbansal/8159142/webrev.01/


Regards,
Pankaj Bansal


-----Original Message-----
From: Sergey Bylokhov
Sent: Wednesday, November 1, 2017 11:46 PM
To: Pankaj Bansal; awt-dev@openjdk.java.net
Subject: Re: <AWT Dev> [10] Review Request: JDK-8159142 : Visible artifacts in 
sun/java2d/SunGraphics2D/DrawImageBilinear.java

Hi, Pankaj.
D3DSurfaceData, XRSurfaceData and probably other SurfaceData use simple 
multiplication or ceil(). Should we update them also? and the test to catch the 
errors there as well.

On 30/10/2017 03:39, Pankaj Bansal wrote:
> Hi All,
> 
> Please review the fix for JDK 10.
> 
> Bug:
> 
> https://bugs.openjdk.java.net/browse/JDK-8159142
> 
> Webrev:
> 
> http://cr.openjdk.java.net/~pbansal/8159142/webrev.00/
> 
> Issue:
> 
> The test runs with D3D and OpenGL both. The issue is with the OpenGL 
> run as there aee some visual artifacts in image when the HiDPI scale 
> is set to non-integer value like 2.5.
> 
> Fix:
> 
> The issue is due to precision error. In WGLSurfaceData.java, the width 
> and height is calculated by multiplying the width and height with scale.
> But the ceil function was being used instead of round. It should be 
> using round as at most of the places, the round function is being used.
> 
> Also changed the test to run at uiScale of 2.5 to catch any further errors.
> 
> Regards,
> 
> Pankaj Bansal
> 


--
Best regards, Sergey.

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