cc [ flag... ] file... –lmlib [ library... ] #include <mlib.h> mlib_status mlib_ImageMulAlpha_Inp(mlib_image *srcdst, mlib_s32 cmask);
The mlib_ImageMulAlpha_Inp() function multiplies color channels by the alpha channel on a pixel by pixel basis, in place.
For the MLIB_BYTE image, it uses the following equation:
srcdst[x][y][c] = srcdst[x][y][c] * srcdst[x][y][a] * 2**(-8)
For the MLIB_SHORT image, it uses the following equation:
srcdst[x][y][c] = srcdst[x][y][c] * srcdst[x][y][a] * 2**(-15)
For the MLIB_USHORT image, it uses the following equation:
srcdst[x][y][c] = srcdst[x][y][c] * srcdst[x][y][a] * 2**(-16)
For the MLIB_INT image, it uses the following equation:
srcdst[x][y][c] = srcdst[x][y][c] * srcdst[x][y][a] * 2**(-31)
where c and a are the indices for the color channels and the alpha channel, respectively, so c != a.
The function takes the following arguments:
Pointer to source and destination image.
Channel mask to indicate the alpha channel. Each bit of the mask represents a channel in the image. The channel corresponding to the 1 bit of cmask is the alpha channel.
The function returns MLIB_SUCCESS if successful. Otherwise it returns MLIB_FAILURE.
See attributes(5) for descriptions of the following attributes:
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mlib_ImageMulAlpha(3MLIB), mlib_ImageMulAlpha_Fp(3MLIB), mlib_ImageMulAlpha_Fp_Inp(3MLIB), attributes(5)