Why does GetDeviceGammaRamp always return false

Question

Why does GetDeviceGammaRamp always return false

z l 20

I want to get the gamma value of the monitor, my code is below, but bget keeps FALSE, how can I tell where the problem is?

WORD gArray[3][256]; 	HDC hdc = GetDC(NULL); // 得到屏幕DC   	
int client_width = GetDeviceCaps(hdc, HORZRES); // 宽   	
BOOL bget = GetDeviceGammaRamp(hdc, gArray);   // 得到当前Gamma  	
ReleaseDC(NULL, hdc); // 释放DC

David Lowndes 2,640 Reputation points MVP

2023-07-11T10:14:43.51+00:00

Does your device support downloadable gamma ramps in hardware? See the remarks section of the APIs documentation - including the major note not to use this API.

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David Lowndes 2,640 Reputation points MVP

2023-07-11T10:14:43.51+00:00

Does your device support downloadable gamma ramps in hardware? See the remarks section of the APIs documentation - including the major note not to use this API.

Answer 1

Castorix31 90,686

I want to get the gamma value of the monitor

You can use GetVCPFeatureAndVCPFeatureReply with VCP code = 0x72 for Gamma (details : https://milek7.pl/ddcbacklight/mccs.pdf)

(works on my monitor, Philips 247ELH)

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Why does GetDeviceGammaRamp always return false

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