Fix: Extract functions no longer throw an error if the frame is empty

[dev7355608]

The alternative is that we don't allow empty frames and throw an error ourselves if frame is empty that is perhaps more more helpful can the error messages generated by getImageData etc.

Pre-Merge Checklist

• Tests and/or benchmarks are included
• Lint process passed (npm run lint)
• Tests passed (npm run test)

[codesandbox-ci]

This pull request is automatically built and testable in CodeSandbox.

To see build info of the built libraries, click here or the icon next to each commit SHA.

Latest deployment of this branch, based on commit 5691829:

Sandbox	Source
pixijs/pixijs	Configuration

[GoodBoyDigital]

i like this! perhaps we set to 1, but also log a warning?

[dev7355608]

Not sure. If the render target resolution is low enough, something like extract.pixels(rt, new Rectangle(x, y, 1, 1)) to pick the the color of the pixel at (x, y) might spam an warning unnecessarily. At resolution above 1 if might return more than the 1 pixel we need. I was thinking maybe extract.pixels(rt, new Rectangle(x, y, 0, 0)) could be useful to just extract the one pixel at that point, but the rounding behavior doesn't work for that. Maybe we should use frame.ceil().

[bigtimebuddy]

What would be better is if we can assert the input before doing anything and throw a specific user-friendly error instead of defaulting to 1x1.

[dev7355608]

What would be better is if we can assert the input before doing anything and throw a specific user-friendly error instead of defaulting to 1x1.

Should we switch to frame.ceil() rounding though? I think it's more natural and cannot throw an error if extract.pixels(rt, new Rectangle(x, y, 1, 1)) is attempted on a low resolution texture.

[bigtimebuddy]

I think ceil would make sense, yes.

[dev7355608]

Maybe defaulting to 1x1 and no error is better after all considering generateTexture does the same if the extracted region is empty.

[dev7355608]

Reverted the throwing of an error: If generateTexture doesn't throw if empty, then it should be acceptable for the extraction methods to behave the same way.

Reverted the ceil rounding: If the extraction method ceil the frame, then generateTexture should probably ceil the width and height of the region too. Ceiling probably makes more sense in both cases, but I'll leave that for another PR.

[bigtimebuddy]

This has deviated a little from the original title of the PR. How would you rename this now?

[dev7355608]

Technically one of the others PR merged before this one already prevented the errors, but didn't mention it. Not sure how to describe the change in a single sentence:

CanvasExtract/Extract functions no longer throw an error if the frame is empty. If the width/height of the frame is less than 1 pixel, it is rounded up to 1 pixel just like the width/height of region parameter of generateTexture is.

[bigtimebuddy]

@dev7355608 could you resolve conflicts so I could merge this?