Convert CMYK data block to 4:4:4 YCCK MCU
FwStatus | fwiCMYKToYCCK444LS_MCU_8u16s_C4P4R | ( | const Fw8u * pSrcCMYK, int srcStep, Fw16s * pDstMCU[4] ); |
pDstMCU[4] | Array of pointers to destination MCU image blocks. | |
pSrcCMYK | Pointer to source image ROI for CMYK image format. | |
srcStep | Source buffer step size (width of the buffer in bytes). |
This function steps through an 8X8 data block in a source buffer, converts the source data from the CMYK color model to the YCCK color space with 4:4:4 chroma sub-sampling, level-shifts the unsigned values to signed values, creates a minimum coded unit, and writes the data to a destination buffer.
The following formulas are used to convert cyan, magenta, and yellow values to red, green, and blue values.
R = 255 -C G = 255 -M B = 255 -Y
The following formulas are used to convert red, green, and blue values to luminance and chrominance values.
Y = 0.299*R + 0.587*G + 0.114*B Cb = -0.16874*R - 0.33126*G + 0.5*B + 128 Cr = 0.5*R - 0.41869*G - 0.08131*B + 128
The black (K) channel value remains the same during conversion.