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Creates a grayscale bitmap from the source bitmap's alpha channel data.
#include "l_bitmap.h"
L_LTKRN_API L_INT L_GetBitmapAlpha(pBitmap, pAlpha, uStructSize)
Points to the source bitmap handle.
Points to the destination bitmap handle to hold the alpha channel data.
Size in bytes, of the structure pointed to by pAlpha, for versioning. Use sizeof(BITMAPHANDLE).
| Value | Meaning |
|---|---|
| SUCCESS | The function was successful. |
| < 1 | An error occurred. Refer to Return Codes. |
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.
Win32, x64, Linux.
For an example, refer to L_SetBitmapAlpha.
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