#include "ltwrappr.h"

L_INT LBitmap::GammaCorrectExt(uGamma, uFlags)

L_UINT uGamma;

gamma value

L_UINT uFlags;


Adjusts the intensity of colors in a bitmap by changing the gamma constant that is used to map the intensity values. Either of two different color spaces can be specified.

Parameter Description
uGamma Any value greater than 0 that represents the gamma value. This value is divided internally by 100.
uFlags Flag that indicates which color space to use. Possible values are:
  Value Meaning
  RGB_SPACE [0x0001] Adjust the intensity of the pixel colors across the RGB color space.
  YUV_SPACE [0x0002] Adjust the intensity of the pixel colors across the YUV color space.



The function was successful.

< 1

An error occurred. Refer to Return Codes.


This function is like the LBitmap::GammaCorrect function, but has been extended to allow the specification of the color space to be used.

Intensity values ideally follow a logarithmic progression, because the eye perceives changes in intensity as being equal when the ratio of change is equal. For example, we would see a change from 0.1 to 0.2 as being equal to a change from 0.2 to 0.4.

Gamma is a standard constant that is used to calculate the progression. For most CRTs the gamma constant is in the range of 2.2 to 2.5.

To update a status bar or detect a user interrupt during execution of this function, refer to LBase::EnableStatusCallback.

This function supports 12 and 16-bit grayscale and 48 and 64-bit color images. Support for 12 and 16-bit grayscale and 48 and 64-bit color images is available only in the Document/Medical toolkits.

This function does not support 32-bit grayscale images. It returns the error code ERROR_GRAY32_UNSUPPORTED if a 32-bit grayscale image is passed to this function.

Required DLLs and Libraries


For a listing of the exact DLLs and Libraries needed, based on the toolkit version, refer to Files To Be Included With Your Application.


Win32, x64.

See Also


LBitmap::GammaCorrect, LBitmap::ChangeIntensity, LBitmap::ChangeContrast, LBitmap::HistoContrast, LBitmap::StretchIntensity, LBitmap::RemapIntensity, LBitmap::Invert, LBitmap::ChangeHue, LBitmap::ChangeSaturation, LBitmap::HistoEqualize, LBitmapBase::Fill, LBitmapBase::GetPixelColor, LBitmapBase::PutPixelColor, LBitmap::GetHistogram, LDialogColor::DoModalGammaAdjustment, LBitmap::WindowLevel, LBitmap::WindowLevelExt, LBitmap::ChannelMix, LBitmap::Deinterlace, LBitmap::Desaturate, LBitmap::EdgeDetectStatistical, LBitmap::LightControl, LBitmap::SmoothEdges, LBitmap::LocalHistoEqualize, LBitmap::AddWeighted, LBitmap::ColorMerge, LBitmap::ColorSeparate, LBuffer::ConvertColorSpace, LBitmap::Multiply, LBitmap::AutoColorLevel, LBitmap::ColorLevel, LBitmap::Correlation, LBitmap::GrayScaleToDuotone, LBitmap::GrayScaleToMultitone, LBitmapRgn::HolesRemovalRgn, LBitmap::SelectiveColor, LBitmap::Skeleton, LBitmap::ChangeHueSatInt, LBitmap::ColorReplace, LBitmap::ColorThreshold, LBitmap::MathFunction, LBitmap::Segment, LBitmap::AdaptiveContrast, LBitmap::ApplyMathLogic, LBitmap::ColorIntensityBalance, LBitmap::ColorizeGray, LBitmap::ContBrightInt, LBitmap::DigitalSubtract, LBitmap::DynamicBinary, LBitmap::EdgeDetectEffect, LBitmap::FunctionalLight, LBitmap::MultiScaleEnhancement, LBitmap::SelectData, LBitmap::ShiftData, LBitmap::Skeleton2, LBitmap::EdgeDetectStatistical2


Raster Image Functions: Modifying Intensity Values


Changing Brightness and Contrast


Raster Image Functions: Doing Color Space Conversions


Raster Image Functions: Changing Brightness and Contrast


L_INT LBitmap__GammaCorrectExtExample() 
   L_INT nRet; 
   LBitmap LeadBitmap; 
   nRet =LeadBitmap.Load(MAKE_IMAGE_PATH(TEXT("sample5.cmp")), 0,ORDER_BGR); 
   if(nRet !=SUCCESS) 
      return nRet; 
   nRet =LeadBitmap.GammaCorrectExt (250, YUV_SPACE); 
   if(nRet !=SUCCESS) 
      return nRet; 
   return SUCCESS; 
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