IG_dspl_gamma_correction

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 for C and C++.

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.