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LBitmapBase::SetPaintGamma

#include "ltwrappr.h"

L_INT LBitmapBase::SetPaintGamma(uValue)

Sets the current gamma correction value for the class objects bitmap. This value is used by painting operations and can be retrieved using the LBitmapBase::GetPaintGamma function.

Parameters

L_UINT uValue

Unsigned integer that represents the gamma value. It can be any number greater than 0. The default value is 100.

Because this is an unsigned integer, it is 100 times the actual gamma value. For example, use 235 to set a gamma value of 2.35.

Returns

Value	Meaning
SUCCESS	The function was successful.
< 1	An error occurred. Refer to Return Codes.

Comments

This is the local paint gamma for the class object and is used when painting the bitmap.

Setting the gamma correction that is used for painting lets you adjust the displayed brightness of all images without changing the bitmap data.

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.

Required DLLs and Libraries

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

Platforms

Win32, x64.

Example

L_INT LBitmapBase__SetPaintGammaExample() 
{ 
   L_INT nRet; 
   LBitmapBase MyBitmap; 
 
   nRet =MyBitmap.Load(MAKE_IMAGE_PATH(TEXT("image1.cmp")),24); 
   if(nRet !=SUCCESS) 
      return nRet; 
   MyBitmap.SetPaintGamma(150); 
    
   return SUCCESS; 
}