Hi! First off, thanks for building Backdropper — it's a genuinely handy tool, and the live preview in the settings app looks great. 😊 I ran into one issue while using it and did a bit of digging, so I figured I'd share what I found in case it's useful. No urgency at all!
What I'm seeing
On Windows 11 (v0.9.4), thumbnails for some transparent PNGs show up with a black background instead of my configured checkerboard. The artwork itself decodes perfectly — it's only the transparent areas that come out black.
What seems to trigger it
After comparing a bunch of files, the common thread is an embedded ICC color profile (iCCP chunk). Files that render black all contain iCCP (+cHRM); otherwise they're ordinary 8-bit RGBA, non-interlaced (IHDR pHYs iCCP cHRM IDAT IEND). PNGs without a profile — including the app's own preview demo images — render the checkerboard just as expected. I saw the same black result in both a OneDrive folder and a plain local folder, so it doesn't seem cache- or OneDrive-related. My (totally amateur) guess is that the color-management path might be skipping the composite-over-background step and falling back to a black matte.
Environment / settings (in case it helps)
- Backdropper v0.9.4 (Windows x64), Windows 11 Pro build 26100
Mode=checker, CheckerColorA=#FFFFFF, CheckerColorB=#A7A7A7, CheckerSize=8
Thanks again for the tool — happy to test a build or provide sample files if that would help. 🙌
Hi! First off, thanks for building Backdropper — it's a genuinely handy tool, and the live preview in the settings app looks great. 😊 I ran into one issue while using it and did a bit of digging, so I figured I'd share what I found in case it's useful. No urgency at all!
What I'm seeing
On Windows 11 (v0.9.4), thumbnails for some transparent PNGs show up with a black background instead of my configured checkerboard. The artwork itself decodes perfectly — it's only the transparent areas that come out black.
What seems to trigger it
After comparing a bunch of files, the common thread is an embedded ICC color profile (
iCCPchunk). Files that render black all containiCCP(+cHRM); otherwise they're ordinary 8-bit RGBA, non-interlaced (IHDR pHYs iCCP cHRM IDAT IEND). PNGs without a profile — including the app's own preview demo images — render the checkerboard just as expected. I saw the same black result in both a OneDrive folder and a plain local folder, so it doesn't seem cache- or OneDrive-related. My (totally amateur) guess is that the color-management path might be skipping the composite-over-background step and falling back to a black matte.Environment / settings (in case it helps)
Mode=checker,CheckerColorA=#FFFFFF,CheckerColorB=#A7A7A7,CheckerSize=8Thanks again for the tool — happy to test a build or provide sample files if that would help. 🙌