Should vector skins/costumes always be rendered with a resolution greater than their screen-space dimensions?

[adroitwhiz]

Expected Behavior

Vector skins/costumes should appear sharp at all scales.

Actual Behavior

Vector skins are internally represented by a series of textures at various resolutions. These textures are allowed to appear on-screen at up to 1.5x their resolution, meaning that at worst, 1 "texture pixel" will be magnified to 1.5 "screen pixels". This results in vector sprites often appearing blurry:

This blurriness is particularly bad for things like text, which results in issues like #558.

This could be changed so that the textures must always be at a higher resolution than, or the same resolution as, their "screen-space" dimensions. This would consume more RAM, but the improvement in visual fidelity may well be worth it.

Keep in mind that until last October, vector costumes were rendered at least twice as large as they should have been on high-DPI devices like phones, so this shouldn't have an unprecedented RAM impact.

Steps to Reproduce

1. Create a new project
2. With the default cat sprite selected, click on the "change size by 10" block in the Blocks Palette while observing the cat sprite
3. Notice that as you continue clicking the block, the cat gets blurrier as it grows, eventually becoming crisp again if you click the block enough

Operating System and Browser

All

[kchadha]

@cwillisf @fsih @adroitwhiz, assigned this to you for discussion (and then documenting here)

[adroitwhiz]

The fix itself is quite easy to implement-- I already have it up in a branch:
https://adroitwhiz.github.io/scratch-gui/no-vector-blur/

The hard part is benchmarking across devices to make sure the increased RAM usage is acceptable (and figuring out what "acceptable" means).

[tutacat]

@adroitwhiz Have you also looked at why the vector sprites have odd cropping?
(e.g. a single straight won't display, and a single line sometimes gets chopped somewhere)

[apple502j]

@tutacat scratchfoundation/scratch-svg-renderer#85 (comment)

[adroitwhiz]

@tutacat If you're talking about #639 or #427, that'll be fixed by #594