LBitmapBase::AlphaBlend

#include "ltwrappr.h"

virtual L_INT LBitmapBase::AlphaBlend (nXDst, nYDst, nWidth, nHeight, pBitmapSrc, nXSrc, nYSrc, nOpacity)

L_INT nXDst;	/* x coordinate */
L_INT nYDst;	/* y coordinate */
L_INT nWidth;	/* width */
L_INT nHeight;	/* height */
LBitmapBase *pBitmapSrc;	/* pointer to an LBitmapBase object */
L_INT nXSrc;	/* x coordinate */
L_INT nYSrc;	/* y coordinate */
L_INT nOpacity;	/* opacity value */

Combines image data of both the class object's bitmap and the specified bitmap, using the specified opacity value. The class object's bitmap is considered as the destination bitmap and it will be updated with the result of the operation. The specified bitmap is considered as the source bitmap.

Parameter	Description
nXDst	The X coordinate of the origin of the destination rectangle.
nYDst	The Y coordinate of the origin of the destination rectangle.
nWidth	Width of the area to be combined, in pixels. This width applies to both the source and the destination areas.
nHeight	Height of the area to be combined, in pixels. This height applies to both the source and the destination areas.
pBitmapSrc	Pointer to the LBitmapBase that contains the source bitmap.
nXSrc	The X coordinate of the origin of the source rectangle.
nYSrc	The Y coordinate of the origin of the source rectangle.
nOpacity	Opacity value used when combining the areas from the source and destination bitmaps. The valid range is from 0 - 65535 for 64-bit, 48-bit and 16-bit grayscale images and from 0 - 4095 for 12-bit grayscale images. Otherwise, it is from 0 to 255.

Returns

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

Comments

The opacity determines how much the destination bitmap will show through the source bitmap. For example, if the opacity is 255 (completely opaque) then the source image will appear and the destination image will not show through the source image at all. If the opacity is 128 (half opacity), then the pixels for that area will consist of 50 percent from the source image and 50 percent from the destination image.

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 signed data images. It returns the error code ERROR_SIGNED_DATA_NOT_SUPPORTED if a signed data image is passed to this function.

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

LTDIS
LTFIL
LTIMGEFX

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::BricksTexture, LBitmap::Canvas, LBitmap::DisplaceMap, LBitmap::Fragment, LBitmap::Vignette, LBitmapBase::Underlay, LBitmapBase::Combine, LBitmapBase::FeatherAlphaBlend, LBitmapBase::CreateFadedMask
Topics:	Raster Image Functions: Combining Images
	Processing an Image
	Raster Image Functions: Processing an Image

Example

L_INT LBitmapBase__AlphaBlendExample(LBitmapBase & Bitmap, L_TCHAR * szFile1, 
                                                         L_TCHAR * szFile2)
{
   L_INT nRet;
   LBitmapBase BitmapSrc;
   nRet =Bitmap.Load(szFile1);
   if(nRet !=SUCCESS)
      return nRet;
   nRet =BitmapSrc.Load(szFile2);
   if(nRet !=SUCCESS)
      return nRet;
   nRet =BitmapSrc.Size(2 * Bitmap.GetWidth() / 3,
                        2 * Bitmap.GetHeight() / 3,
                        SIZE_RESAMPLE);
   if(nRet !=SUCCESS)
      return nRet;
   nRet =Bitmap.AlphaBlend(Bitmap.GetWidth() / 6,
                     Bitmap.GetHeight() / 6,
                     BitmapSrc.GetWidth(),
                     BitmapSrc.GetHeight(),
                     &BitmapSrc,
                     0,
                     0,
                     150);
   if(nRet !=SUCCESS)
      return nRet;
   return SUCCESS;
}