dotnet / dotnet/winforms

Win11 24H2 .NET bug rendering text to image using GDI+

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#12,910 15 comments 0 reactions 1 assignee Claimed by @JeremyKuhne View on GitHub
area-System.Drawing external-OS-issue
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Description

### Description

Previous to 24H2, running the same code to generate an image with text produced an identical image every time that passed a pixel-by-pixel comparison test. As of 24H2 the same images generated twice fail pixel-by-pixel comparison.

This is a .NET issue. The tests pass when I use .NET Framework 4.8.

Note: I reported this bug to Windows 11 feedback before realizing this is a .NET issue (https://aka.ms/AAuckmw).

### Reproduction Steps

Repo with code to reproduce the bug: https://github.com/tracktownsoftware/Win11-24H2-ImageTextBug
Press the "Compare Images" button.

### Expected behavior

Expected behavior:
- The code generates identical images every time.
- Pixel-by-pixel comparison passes (before Windows 11 version 24H2)

### Actual behavior

Actual behavior:
The same images are generated twice but fail pixel-by-pixel comparison. This started with the release of Windows 11 version 24H2.

Note: On a computer with 24H2 I changed the test app to use .NET Framework 4.8. The comparison tests passed, showing this to be a .NET issue.

### Regression?

Yes this is a regression. If you run the repo test app with a Win11 version before 24H2 then it works.

### Known Workarounds

Don't upgrade to Windows 11 to 24H2

### Configuration

_No response_

### Other information

_No response_

Contributor guide

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Assessment

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