[OpenJDK 2D-Dev] RFR: 8220150: macos10.14 Mojave returns anti-aliased glyphs instead of aliased B&W glyphs

[Sergey Bylokhov]

+1

On 4/4/20 10:59 pm, Philip Race wrote:
> Yeah. Faster.
> 
> -phil.
> 
> On 4/4/20, 9:57 PM, Sergey Bylokhov wrote:
>> Hi, Phil.
>>
>> Does the SolidTextRenderer have some benefits over AATextRenderer so we have to use it by default on 10.13 on jdk15?
>>
>> On 4/4/20 8:16 pm, Philip Race wrote:
>>> Bug: https://bugs.openjdk.java.net/browse/JDK-8220150
>>> Webrev : http://cr.openjdk.java.net/~prr/8220150/
>>>
>>> We are being returned grey glyphs when asking for B&W.
>>> The same is true for LCD, although they are a little different and not the main problem.
>>>
>>> The main problem is that when our software loops designed for B&W are handed greyscale
>>> glyphs, every byte encoded pixel that has a bit that is 1 is treated as 255.
>>> Once we are in those loops it is too late and the result is horrid blocky text.
>>>
>>> This hasn't been affecting too many people since the OpenGL pipeline treats
>>> the bytes as a mask so works for both B&W and greyscale.
>>>
>>> But if you are drawing to a BufferedImage  the problem is there.
>>> It can popup in a UI if the UI uses a s/w image as the backbuffer - in fact
>>> that is how this bug was reported.
>>>
>>> There isn't anything I can find that will make 10.14 generate B&W glyphs again -
>>> the workaround to change a system default is not viable for us, and it is a lot
>>> of work to use freetype in this case and that will almost certainly cause inconsistencies.
>>>
>>> There is no sure way to know that you are going to be handed AA instead of B&W.
>>> So the essence of the fix is that on 10.14 and later we use the AA rendering loops
>>> to draw B&W. They will properly blend even if somehow we were handled B&W glyphs.
>>> This is the change in SurfaceData.java.
>>>
>>> The other changes are a small optimisation, so that if B&W glyphs are requested we
>>> re-direct to greyscale. This prevents wastefully caching the AA glyphs twice - once
>>> as AA and once as (supposedly) B&W.
>>>
>>> -phil.
>>>
>>>
>>
>>


-- 
Best regards, Sergey.