ImageGear Professional for Unix
IG_dspl_gamma_correction_set
ImageGear Professional v18.2 > API Reference Guide > Core Component API Reference > Core Component Functions Reference > Display Functions > IG_dspl_gamma_correction_set

This function takes contrast (dblContrast), brightness (dblBrightness) and gamma (dblGamma) parameters and calculates look-up tables accordingly and sets them into the corresponding options.

Declaration:

 
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AT_ERRCOUNT  ACCUAPI  IG_dspl_gamma_correction_set(
        [IN] HIGEAR hIGear,
        [IN] DWORD dwGrpID,
        [IN] AT_MODE nFlags,
        [IN] DOUBLE dblContrast,
        [IN] DOUBLE dblBrightness,
        [IN] DOUBLE dblGamma
);

Arguments:

Name Type Description
hIGear HIGEAR ImageGear handle of image.
dwGrpID DWORD Identifier of group in which to set look-up tables.
nFlags AT_MODE

Specify which look-up tables to set. Possible values are 0 or a combination of these flags:

  • IG_DSPL_R_CHANNEL - if this flag is set then the RedLut option is to be set.
  • IG_DSPL_G_CHANNEL - if this flag is set then the GreenLut option is to be set.
  • IG_DSPL_B_CHANNEL - if this flag is set then the BlueLut option is to be set.
  • The constant IG_DSPL_ALL_CHANNELS is defined for convenience and can be used to set all three options.
 
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#define IG_DSPL_ALL_CHANNELS
(IG_DSPL_R_CHANNEL|IG_DSPL_G_CHANNEL|I
G_DSPL_B_CHANNEL)
dblContrast DOUBLE Contrast value to use in calculations. You can use any value.
dblBrightness DOUBLE Brightness value to use in calculations. Must be in the range from -255.0 to +255.0.
dblGamma DOUBLE Gamma value to use in calculations. Must be greater than 0.0; however the most useful values are in the range from 1.8 to 2.2.

Return Value:

Returns the number of ImageGear errors that occurred during this function call.

Supported Raster Image Formats:

All pixel formats supported by ImageGear Professional.

Example:

 
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HIGEAR           hIGear;    /* HIGEAR handle of image  */ 
DWORD           nGrpID;    /* display group identifier */
 ...
IG_dspl_gamma_correction_set( hIGear, nGrpID, IG_DSPL_ALL_CHANNELS, 2.0, 120.0, 2.0 );
 ...

Remarks:

All look-up tables specified in the nFlagsparameter are initialized with the same value based on the dblContrast, dblBrightness, and dblGamma values.

 

 

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