Intel 82854 GMCH - Manual (Page 35)

Intel® Digital Set Top Box Display Driver 35
User’s Guide for Microsoft* Windows* CE 5.0
7.1.1.6 ICEGD_ESCAPE_SET_FB_GAMMA_RAMP
Input Data Structure Output Data Structure Notes
esc_color_params_t N/A
esc_color_params flag options:
Mandatory:
GAMMA_FLAG (0x1)
Not Applicable:
BRIGHTNESS_FLAG (0x2)
CONTRAST_FLAG (0x4)
SATURATION_FLAG (0x8)
OVL_COLOR_FLAG (0x10)
Description
This escape code is used to set frame buffer gamma correction ramp. Legal values are from 1-500, 1 - default, 500 –
brightest.
Input Data Structure Definition
Same data structure as ICEGD_ESCAPE_SET_OVL_COLOR_PARAMS, but for this escape code, you need only
set the GAMMA_FLAG.
Example
esc_color_params_t color;
memset(&color, 0, sizeof(esc_color_params_t));
//set flag to gamma
color.flag = GAMMA_FLAG;
color.gamma = 0;
for(int i=1;i<10;i++){
//change gamma value gradually, and the legal value is between 1 and 500
color.gamma=i*50;
ExtEscape(
Hdc,
ICEGD_ESCAPE_SET_FB_GAMMA_RAMP,
sizeof(esc_color_params_t),
(LPCSTR)&color,
0,
NULL);
//Check error status returned by ExtEscape
// …
// Wait a while for HW to complete the operation of changing the gamma value
Sleep(500);
}