scratchfoundation / scratchfoundation/scratch-editor

Convex hull of bitmap costumes ignores the rightmost column and the bottom row of texels

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bug
Dominant language
JavaScript
Stars
281
Forks
276
Avg merge
7d 8h
Merged PRs (30d)
6

Description

Expected Behavior

Both of the costumes below produce the same highlight when the sprite thumbnail is clicked
Note that the highlight being 1 texel smaller than it should from all directions is a different bug, and it happens with more opaque costumes, too

Actual Behavior

One of the costumes has 0x0 highlight

Steps to Reproduce

Steps to reproduce the behavior:

  1. Go to 'https://scratch.mit.edu/projects/1204399333/'
  2. See inside
  3. Click the sprite thumbnail
  4. Switch to the other costume and click the thumbnail again
System Details

I've tested it on Windows 10, Chrome 138 but it probably happens on other systems, too

Screenshots
see above

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Reproduce the issue in project 1204399333 by switching costumes and clicking the sprite thumbnail. Trace the bitmap costume convex-hull and highlight path from that behavior; done means the rightmost column and bottom row of texels are included and both costumes produce the expected highlight.

Written by the indexing model from the issue text.

Assessment

Tech stack
javascript
Domain
frontend
Issue type
Bug
Difficulty
3/5
Estimated time
1-2 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
45/100

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