Build fails with transparent image for iOS icon

[Gys]

Describe the bug:

I tried to cross compile an app to ios.
I received this error:

/* com.apple.actool.errors */
[REDACTED PATH]/Images.xcassets: error: The stickers icon set or app icon set named "AppIcon" did not have any applicable content.
/* com.apple.actool.compilation-results */
/dev/null

: exit status 1

Searching for this error shows xcode expects the file Images.xcassets to exist and hold assets like icons. I understand Fyne creates these icons 'on the fly' so maybe my icon image was a problem. I changed it for another one and the error was resolved. The 'badlogo.png' is no problem if compiled to 'darwin' (on MacOS).

So the attached 'badlogo.png' is not usable for some reason. This was just a test logo for me, so I simple replaced it with another logo.

Maybe the docker image logs would have shown some more clear information or errors. Now it took some time before I realized the image file could be a problem. I have no idea though how to retrieve the logs or a more verbose output?

To Reproduce:

Steps to reproduce the behavior:
Download the 'badlogo.png' image file.
Create a simple app and compile with:
fyne-cross ios -icon badlogo.png -app-id my.test.app

(Using fyne package results in the same error)

Device and debug info (please complete the following information):

Device info

• OS: MacOS
• Version: Sonoma 14.5
• Go version: go1.21.5 darwin/amd64
• fyne-cross version: 1.5
• Fyne version: 2.4.5

badlogo.png.zip

[andydotxyz]

Perhaps you used transparency? That is not allowed by Apple's rules sadly - but will work on any other OS.

[Gys]

Aha, did not know that! Yes, the logo has transparency. It took me a while to realize the logo was the problem, especially because it indeed is no problem for Darwin and Windows. Maybe some code can be added to check for transparency? For example: https://stackoverflow.com/questions/68747745/check-if-png-image-is-all-transparent-in-golang

[andydotxyz]

Good plan, updating and re-opening to track