Screenshots come up blank when brightness dimmed

[fxerkan]

Before opening the issue, have you...?

• Searched for existing issues
• Looked through the wiki
• Updated MonitorControl to the latest version (if applicable)

Describe the bug

Hi,
I'm using Macbook Air 2020 M1 chipset with 2 Extended Displays (Dell S2721QS & Dell P2719H) via a Dock station (plugable displaylink) so that there is no brightness adjustment option.

Because of that I installed MotionControl 4.2.0 app to control the extended displays brightness at software level dimming and hardware level not available at my monitors.

When I set the brightness level %100 there is no issue, I can take screenshots with any of these applications at any displays.

• Apple's own screenshot functionality ( cmd+shift+ 4 or 5 )
• Parallels Toolbox Screen Capture
• Lightshot screenshot ( cmd+shift+s )

But, when I decreased the brightness under the %100 like %90, %80, %70.. and try to take a screenshot at any extended display - all the screenshots seems blank or black only color.

If i set the brightness again at %100 everything works as expected.

Steps to reproduce

1. use an extended display which does not support hardware dimming
2. decrease the brightness %90 or %75
3. try to take a screenshot at the extended display with one of these tools (Apple's own screenshot functionality , Parallels Toolbox Screen Capture, Lightshot screenshot
4. check the saved screenshot is blank/black

Expected behavior

saved screenshot should be like this, not blank or black only

Anything else?

Issue %90 brightness-Apples Screenshot as you can see its a blank image

%90 brightness-Parallels Toolbox Capture Screen

%90 brightness-Lightshot

Environment Information (please complete the following information)

- macOS version: Sonoma 14.0 (23A344)
- Mac model: MacBook Air M1 2020
- MonitorControl version: 4.2.0 Build 7048
- Monitor(s): Dell S2721QS and Dell P2719H
- Apple Silicon/M1 (yes or no): yes

[waydabber]

This happens if only software dimming is applied and gamma table manipulation is disabled in the app or is unavailable for the display due to some incompatibility. In this case a black overlay is used with changing transparency as a last resort - the screenshot app captures this black overlay.

[forthrin]

+1

The screenshot is actually much darker (here) than the dimmed screen. Can this be resolved, or is it WONTFIX because of sandboxing / the way the macOS video pipeline works?