LBitmap::HistoContrast

#include "ltwrappr.h"

virtual L_INT LBitmap::HistoContrast(nChange)

L_INT nChange;

/* amount of contrast change */

Increases or decreases the contrast of the image in the class object's bitmap, using a histogram to determine the median brightness.

Parameter	Description
nChange	Amount of contrast change. Valid values are -1000 to +1000.

Returns

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

Comments

This function finds the median brightness of the image; then brightens the pixels with values above the median and darkens the pixels with values below the median. This is more sophisticated (but slower) than the LBitmap::ChangeContrast function, which uses the middle possible value (128) rather than finding the actual median.

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.

Required DLLs and Libraries

LTDIS
LTFIL
LTIMG

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

See Also

Functions:	LBitmap::AdjustTint, LBitmap::GammaCorrectExt, LBitmap::ChangeHue, LBitmap::ChangeSaturation, LBitmap::Invert, LBitmap::StretchIntensity, LBitmap::RemapIntensity, LBitmap::GetHistogram, LBitmap::ChangeContrast, LBitmap::ChangeIntensity, LBitmap::HistoEqualize, LBitmap::GammaCorrect, LBitmap::WindowLevel, LBitmapBase::Fill, LBitmapBase::GetPixelColor, LBitmapBase::PutPixelColor, Class Members
Topics:	Raster Image Functions: Modifying Intensity Values
	Changing Brightness and Contrast
	Raster Image Functions: Working with Color Halftones, Halftones, and Grayscale Images
	Raster Image Functions: Changing Brightness and Contrast

Example

LBitmap LeadBitmap;
LeadBitmap.Load(TEXT("image1.cmp"), 0,ORDER_BGR);
LeadBitmap.HistoContrast(250);