CPU surfaces antialiasing size limit

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Joe

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May 25, 2023, 4:16:26 PM5/25/23
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Hello!

I just discovered that antialiasing gets disabled on CPU surfaces with size > ~8000px and found the confirmation on this old thread.

More precisely, the content inside the limit is still antialiased, but what's outside the limit is not antialiased.

So I wanted to ask: As of today, is the only workaround still manually tiling the the surface? or is there some new API that allows to bypass the limit?

Thank you

Brian Osman

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May 25, 2023, 4:24:02 PM5/25/23
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Yes, manually tiling is still the only workaround.

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Joe

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May 25, 2023, 4:56:24 PM5/25/23
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Got it, thanks Brian.

Mike Reed

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May 25, 2023, 5:30:51 PM5/25/23
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Interesting. I just created a raster surface 11,000 wide, and drew antialiased circles at both ends -- and they both came out antialiased. What is your test case that shows this not working?

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Mike Reed

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May 25, 2023, 5:32:24 PM5/25/23
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huge.png

bungeman

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May 25, 2023, 11:29:55 PM5/25/23
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Yes, I was fairly sure this was fixed shortly after that conversation with https://skia-review.googlesource.com/c/skia/+/112723 (and follow ups).

craste...@gmail.com

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May 26, 2023, 12:17:33 AM5/26/23
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SkDraw?
I had not heard of this beast before. He looks like an SkCanvas?
What is he about?

Joe

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May 26, 2023, 2:58:10 AM5/26/23
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hey there, after playing with this, I think I have narrowed down the issue.

I created a surface large 2000 x 10000, and the antialiasing seems to get disabled after y > ~8000 when drawing using clipPath (clipPath + drawPaint).
When drawing using drawPath, the issue seems to disappear.


antialias-issue.png

Mike Reed

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May 26, 2023, 8:53:26 AM5/26/23
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Good catch! I never thought about AA clips and the size limit.

On May 26, 2023, at 2:58 AM, Joe <giuseppe...@gmail.com> wrote:

hey there, after playing with this, I think I have narrowed down the issue.

I created a surface large 2000 x 10000, and the antialiasing seems to get disabled after y > ~8000 when drawing using clipPath (clipPath + drawPaint).
When drawing using drawPath, the issue seems to disappear.


Brian Osman

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May 26, 2023, 9:05:39 AM5/26/23
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Ah, yes. Sorry - I remembered seeing the comment in the code recently about AA turned off after 8k, but I forgot that it was in the clipping (not drawing) code.

To view this discussion on the web visit https://groups.google.com/d/msgid/skia-discuss/CA7D3064-F167-4797-93FD-3833CF013BBB%40reedtribe.org.
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