Issue 12711 in skia: Path op leaves crescent-shaped artifacts

[tdenn… via monorail]

Updates:
Labels: Area-PathOps
Summary: Path op leaves crescent-shaped artifacts

Comment #1 on issue 12711 by tdenn...@google.com: Path op leaves crescent-shaped artifacts
https://bugs.chromium.org/p/skia/issues/detail?id=12711#c1

Quoting via Google translate (I am also editing the title to make it easier to search):

> 1 Use skia library to draw multiple paths;
> 2 Use the skia library to calculate the difference between the current path and the target path (erasing operation);
> 3 Use OP function operation;
> 4 Occasionally, crescent-shaped marks remain after erasing (such as the attached figure);
> 5 Operating frequency (draw and write multiple times, quickly erase 500+ times and reproduce once)

It sounds like #1-4 is a path ops issue. @benmingchen2021 can you please try to write a program to reproduce the issue you're seeing, using fiddle.skia.org?

#5 was not clear to me. What is the issue you're seeing?

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[johns… via monorail]

Updates:
Status: Accepted

Comment #2 on issue 12711 by johns...@google.com: Path op leaves crescent-shaped artifacts
https://bugs.chromium.org/p/skia/issues/detail?id=12711#c2

(No comment was entered for this change.)

[johns… via monorail]

Comment #3 on issue 12711 by johns...@google.com: Path op leaves crescent-shaped artifacts
https://bugs.chromium.org/p/skia/issues/detail?id=12711#c3

Just a wild guess, but is the bug trying to say that "drawing and then immediately erasing a path will leave behind some pixel artifacts at the edges"?

If that's the concern, then that's probably the effects of antialiasing. Unfortunately, if you draw a black antialiased stroke on a white background, then draw the same path again in white, the end result won't be a white background. The antialiased edge will partially remain. There's no simple fix (other than "disable antialiasing")

[micha… via monorail]

Updates:
Status: Unconfirmed

Comment #4 on issue 12711 by michae...@google.com: Path op leaves crescent-shaped artifacts
https://bugs.chromium.org/p/skia/issues/detail?id=12711#c4

Waiting on info from reporter.

[johns… via monorail]

Updates:
Status: Obsolete

Comment #5 on issue 12711 by johns...@google.com: Path op leaves crescent-shaped artifacts
https://bugs.chromium.org/p/skia/issues/detail?id=12711#c5

Closing for lack of activity.

benming...@gmail.com : if you are still affected by this issue, please file a new bug and include a fiddle demonstrating the issue. (See https://fiddle.skia.org/ )

Thank you!