Double negate counts as a bitmap change

[rj-rl]

Severity Minor

Defect descirption Negating an image twice (without any other manipulations) will result in a 'save changes' prompt on closing the file

Steps to reproduce

• Open an image
• Select Colors > Negative twice (or any odd number of times for that matter)
• Close the file or quit the application

Expected result File (or application) closes quietly, no change is detected

Actual result User is prompted to save changes

Environment Windows 10, build 19042.1415, version 20H2 LazPaint 7.1.6 (64-bit)

https://user-images.githubusercontent.com/84194921/146585458-3fefb0f0-9697-4f31-a9eb-4d711c2f6acc.mp4

[circular17]

Yes, a negate (non linear) entails a loss of information, so in theory done twice is not exactly the identity. Though this could be identified as such.