L_AlphaBlendBitmap
#include "l_bitmap.h"
L_INT EXT_FUNCTION L_AlphaBlendBitmap(pBitmapDst, nXDst, nYDst, nWidth, nHeight, pBitmapSrc, nXSrc, nYSrc, nOpacity)
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pBITMAPHANDLE pBitmapDst; |
/* pointer to a bitmap handle */ |
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L_INT nXDst; |
/* x coordinate */ |
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L_INT nYDst; |
/* y coordinate */ |
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L_INT nWidth; |
/* width */ |
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L_INT nHeight; |
/* height */ |
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pBITMAPHANDLE pBitmapSrc; |
/* pointer to a bitmap handle */ |
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L_INT nXSrc; |
/* x coordinate */ |
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L_INT nYSrc; |
/* y coordinate */ |
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L_INT nOpacity; |
/* opacity value */ |
Combines image data from two bitmaps, using the specified opacity value.
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Parameter |
Description |
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pBitmapDst |
Pointer to the bitmap handle that references the destination bitmap. The function will update this bitmap. |
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nXDst |
The X coordinate of the origin of the destination rectangle. |
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nYDst |
The Y coordinate of the origin of the destination rectangle. |
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nWidth |
Width of the area to be combined, in pixels. This width applies to both the source and the destination areas. |
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nHeight |
Height of the area to be combined, in pixels. This height applies to both the source and the destination areas. |
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pBitmapSrc |
Pointer to the bitmap handle that references the source bitmap. |
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nXSrc |
The X coordinate of the origin of the source rectangle. |
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nYSrc |
The Y coordinate of the origin of the source rectangle. |
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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
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SUCCESS |
The function was successful. |
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< 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 L_SetStatusCallback.
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.
Required DLLs and Libraries
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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. |
Platforms
Windows 95 / 98 / Me, Windows 2000 / XP.
See Also
Example
BITMAPHANDLE BitmapDst; /* Bitmap handle to hold the loaded image */
BITMAPHANDLE BitmapSrc; /* source bitmap */
L_INT XDst; /* Column offset of the destination */
L_INT XSize; /* Pixel width of the rectangle to combine */
L_INT YDst; /* Row offset of the destination */
L_INT YSize; /* Pixel height of the rectangle to combine */
L_INT XSrc; /* Column offset of the source */
L_INT YSrc; /* Column offset of the source */
/* Load both bitmaps, at 24 bits per pixel */
L_LoadBitmap (TEXT("IMAGE1.CMP"), &BitmapDst, sizeof(BITMAPHANDLE), 24, ORDER_BGR, NULL, NULL);
L_LoadBitmap (TEXT("IMAGE2.BMP"), &BitmapSrc, sizeof(BITMAPHANDLE), 24, ORDER_BGR, NULL, NULL);
/* Specify a position in the top left part of the displayed image */
XDst = BITMAPWIDTH(&BitmapDst) / 8;
YDst = BITMAPHEIGHT(&BitmapDst) / 8;
/* Use the full size of the source bitmap */
YSize = BITMAPHEIGHT(&BitmapSrc);
XSize = BITMAPWIDTH(&BitmapSrc);
XSrc = 0;
YSrc = 0;
/* Combine BitmapSrc with BitmapDst, with half opacity */
L_AlphaBlendBitmap (&BitmapDst, XDst, YDst, XSize, YSize,
& BitmapSrc, XSrc, YSrc, 128);
/* Free the temporary bitmap */
L_FreeBitmap(&BitmapSrc);