L_GetBitmapAlpha

#include "l_bitmap.h"

L_LTKRN_API L_INT L_GetBitmapAlpha(pBitmap, pAlpha, uStructSize)

Creates a grayscale bitmap from the source bitmap's alpha channel data.

Parameters

pBITMAPHANDLE pBitmap

Points to the source bitmap handle.

pBITMAPHANDLE pAlpha

Points to the destination bitmap handle to hold the alpha channel data.

L_UINT uStructSize

Size in bytes, of the structure pointed to by pAlpha, for versioning. Use sizeof(BITMAPHANDLE).

Returns

Value Meaning
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

Platforms

Win32, x64, Linux.

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