[OpenJDK 2D-Dev] [9] Review Request: 8146042 Offscreen rendering is different from onscreen one

[Semyon Sadetsky]

On 1/15/2016 6:46 PM, Sergey Bylokhov wrote:
> On 15/01/16 17:29, Semyon Sadetsky wrote:
>> On 1/15/2016 4:30 PM, Sergey Bylokhov wrote:
>>> On 15/01/16 09:59, Semyon Sadetsky wrote:
>>>> Hi Phil & Sergey,
>>>>
>>>> I have integrated Intel GPU i5 and cannot test other hardware.
>>>> On Mac's retina display the screen capture doesn't return exact 
>>>> pixel to
>>>> pixel image but the scaled one. So Mac platform should be excluded 
>>>> from
>>>> testing:
>>>> http://cr.openjdk.java.net/~ssadetsky/8146042/webrev.01/
>>>
>>> In this cases non-retina hw will not be covered. If there are some
>>> issues in the Robot, then you can skip it and use VolatileImage as a
>>> destination for rendering.
>> But the issue is reproducible in on-screen painting on Windows platform.
>> It isn't necessary to spent extra efforts on the Mac workaround. The
>> test can be extended to the Mac platform later when Robot is fixed.
>
> I am sure that the problem is not in the robot itself, but in the fact 
> the test does not take into account that device scale is not necessary 
> =1 in which case it calculates incorrect expected coordinates. If this 
> is the case then the same issue will be on win/linux with HiDPI display.
Not sure. I have Linux with retina display. The problem with Mac is that 
lines are drawn with 1 pixel precision but screenshots are produced in 
low resolution and 1px width black line becomes a blured gray line on 
it. So is not possible to autotest with such inaccurate instrument.
Anyway, our target is Windows D3D, not Mac.
> Can you also provide an additional information/examples on which 
> coordinates we get an rounding error.
Please look on the left screenshot attached to the JIRA. Checkbox 
rectangles are wrong.
>
>>>
>>>>
>>>> --Semyon
>>>>
>>>> On 1/14/2016 9:23 PM, Phil Race wrote:
>>>>> This fudge factor was last adjusted in
>>>>> https://bugs.openjdk.java.net/browse/JDK-6597822
>>>>> way back before the D3D pipeline was released and the comments 
>>>>> seem to
>>>>> indicate that
>>>>> there was a fair amount of testing on different hardware.
>>>>>
>>>>> I don't know why this seems to be in un-specified hardware-dependent
>>>>> territory but
>>>>> it seems quite possible that this could just as easily introduce a
>>>>> different artifact
>>>>> on some other hardware.
>>>>>
>>>>> What exactly are you testing on ? And I think it needs to include at
>>>>> least one Nvidia
>>>>> and one AMD/ATI card.
>>>>>
>>>>> -phil.
>>>>>
>>>>> On 1/14/2016 10:09 AM, Semyon Sadetsky wrote:
>>>>>> Hello,
>>>>>>
>>>>>> Please review the fix for jdk9.
>>>>>>
>>>>>> bug: https://bugs.openjdk.java.net/browse/JDK-8146042
>>>>>> webrev: http://cr.openjdk.java.net/~ssadetsky/8146042/webrev.00/
>>>>>>
>>>>>> The root cause is incorrect coordinate rounding in D3D renderer. To
>>>>>> fix the issue one of fudge factors was adjusted.
>>>>>>
>>>>>> Another issue mentioning in the JIRA ticket is taken out as a
>>>>>> separate bug.
>>>>>>
>>>>>> --Semyon
>>>>>>
>>>>>
>>>>
>>>
>>>
>>
>
>