Available in LEADTOOLS Imaging Pro, Vector, Document, and Medical Imaging toolkits. |
#include "l_bitmap.h"
L_LTKRN_API L_INT L_GetBitmapAlpha(pBitmap, pAlpha, uStructSize)
pBITMAPHANDLE pBitmap; |
/* points to the source bitmap handle */ |
pBITMAPHANDLE pAlpha; |
/* points to the destination bitmap handle */ |
L_UINT uStructSize; |
/* size in bytes, of the structure pointed to by pAlpha */ |
Creates a grayscale bitmap from the source bitmap's alpha channel data.
Parameter |
Description |
pBitmap |
Points to the source bitmap handle. |
pAlpha |
Points to the destination bitmap handle to hold the alpha channel data. |
uStructSize |
Size in bytes, of the structure pointed to by pAlpha, for versioning. Use sizeof(BITMAPHANDLE). |
Returns
SUCCESS |
The function was successful. |
< 1 |
An error occurred. Refer to Return Codes. |
Comments
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.
Only 16-, 32-, and 64-bit images can have an alpha channel. If the source bitmap has another color resolution, the result is an image filled with zeros.
Typically, the alpha channel contains a mask that is used for transparency, as shown in the example for L_SetBitmapAlpha.
Required DLLs and Libraries
LTKRN 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.
See Also
Functions: |
L_SetBitmapAlpha, L_CreateMaskFromBitmapRgn, L_SetBitmapRgnFromMask, L_BitmapHasMeaningfulAlpha |
Topics: |
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Example
For an example, refer to L_SetBitmapAlpha.