Contains the different color components (channels).

Values:

IG_COLOR_COMP_ALL	All components.
IG_COLOR_COMP_R	R component of RGB image.
IG_COLOR_COMP_G	G component of RGB image.
IG_COLOR_COMP_B	B component of RGB image.
IG_COLOR_COMP_RGB	R, G and B components of RGB image.
IG_COLOR_COMP_I	Used when the ave of RGB is to be used.
IG_COLOR_COMP_C	C component of CMYK image.
IG_COLOR_COMP_M	M component of CMYK image.
IG_COLOR_COMP_Y	Y component of CMYK image.
IG_COLOR_COMP_K	K component of CMYK image.
IG_COLOR_COMP_CMYK	C, M, Y and K components of CMYK image.
IG_COLOR_COMP_YUV_Y	Y component of YUV image.
IG_COLOR_COMP_YUV_U	U component of YUV image.
IG_COLOR_COMP_YUV_V	V component of YUV image.
IG_COLOR_COMP_YUV	Y, U and V components of YUV image.
IG_COLOR_COMP_LAB_L
IG_COLOR_COMP_LAB_A
IG_COLOR_COMP_LAB_B
IG_COLOR_COMP_LAB
IG_COLOR_COMP_IHS_I
IG_COLOR_COMP_IHS_H
IG_COLOR_COMP_IHS_S
IG_COLOR_COMP_IHS
IG_COLOR_COMP_HLS_H
IG_COLOR_COMP_HLS_L
IG_COLOR_COMP_HLS_S
IG_COLOR_COMP_HLS
IG_COLOR_COMP_HSL_H
IG_COLOR_COMP_HSL_S
IG_COLOR_COMP_HSL_L
IG_COLOR_COMP_HSL