COLOR(2) COLOR(2) NAME cmap2rgb, cmap2rgba, rgb2cmap - colors and color maps SYNOPSIS #include <u.h> #include <libc.h> #include <draw.h> int rgb2cmap(int red, int green, int blue) int cmap2rgb(int col) int cmap2rgba(int col) DESCRIPTION These routines convert between `true color' red/green/blue triples and the Plan 9 color map. See color(6) for a description of RGBV, the standard color map. Rgb2cmap takes a trio of color values, scaled from 0 (no intensity) to 255 (full intensity), and returns the index of the color in RGBV closest to that represented by those val- ues. Cmap2rgb decomposes the color of RGBV index col and returns a 24-bit integer with the low 8 bits representing the blue value, the next 8 representing green, and the next 8 repre- senting red. Cmap2rgba decomposes the color of RGBV index col and returns a 32-bit integer with the low 8 bits repre- senting an alpha value, defined to be 255, and the next 8 representing blue, then green, then red, as for cmap2rgba shifted up 8 bits. This 32-bit representation is the format used by draw(2) and memdraw(2) library routines that take colors as arguments. SOURCE /sys/src/libdraw SEE ALSO graphics(2), allocimage(2), draw(2), image(6), color(6) Page 1 Plan 9 (printed 9/8/24)