When saving a .kra or .ora file with transparent (alpha = 0) area at the boundary, the preview.png or Thumbnails/thumbnail.png inside the file is cropped to the minimum size such that no all-transparent rows and columns are present at the boundary. If the image is completely transparent, preview.png or Thumbnails/thumbnail.png is completely empty with 0 bytes. On the other hand, the mergedimage.png contains the full image uncropped. This is causing inconsistent behaviour when external software tries to optimize thumbnail extraction by using the preview.png or Thumbnails/thumbnail.png for sizes within 256x256px. Reproducible: Always
Git commit 18fea2e5f5a153961a5d08e2e41dc2645e2fc5f8 by Boudewijn Rempt. Committed on 01/11/2016 at 12:30. Pushed by rempt into branch 'krita/3.1'. M +9 -1 libs/ui/KisDocument.cpp http://commits.kde.org/krita/18fea2e5f5a153961a5d08e2e41dc2645e2fc5f8
Git commit c8ccd8b8c5c4062b0210905a5d1f12c5a1381683 by Boudewijn Rempt. Committed on 01/11/2016 at 12:49. Pushed by rempt into branch 'krita/3.1'. M +14 -12 libs/ui/KisDocument.cpp http://commits.kde.org/krita/c8ccd8b8c5c4062b0210905a5d1f12c5a1381683
Git commit 345919cdef1cf9dd7bf331e1477316969af45b89 by Boudewijn Rempt. Committed on 02/11/2016 at 09:51. Pushed by rempt into branch 'rempt/impex-refactoring'. M +9 -1 libs/ui/KisDocument.cpp http://commits.kde.org/krita/345919cdef1cf9dd7bf331e1477316969af45b89
I found that after the commits for this bug. the preview.png that gets generated is mostly horrizontal lines and noise the so the previews are corrupted or not correct. an example preview.png extracted from the kra saved from krita after these commits can be viewed here -> https://dl.dropboxusercontent.com/u/37777793/preview.png
Created attachment 102035 [details] preview.png which is corrupted
Still actual. I have a feeling that it is somehow related to the asynchronous saving of the image. But I didn't check for any details yet.
Asynchronous saving was implemented after this bug started happening.
Should be fixed now.