ref: 4195e1a54e54d76aad8352d62b774c07e2b8ec98
dir: /sys/src/libdraw/writecolmap.c/
#include <u.h> #include <libc.h> #include <draw.h> /* * This code (and the devdraw interface) will have to change * if we ever get bitmaps with ldepth > 3, because the * colormap will have to be written in chunks */ void writecolmap(Display *d, RGB *m) { int i, n, fd; char buf[64], *t; ulong r, g, b; sprint(buf, "/dev/draw/%d/colormap", d->dirno); fd = open(buf, OWRITE); if(fd < 0) drawerror(d, "writecolmap: open colormap failed"); t = malloc(8192); if (t == nil) drawerror(d, "writecolmap: no memory"); n = 0; for(i = 0; i < 256; i++) { r = m[i].red>>24; g = m[i].green>>24; b = m[i].blue>>24; n += sprint(t+n, "%d %lud %lud %lud\n", 255-i, r, g, b); } i = write(fd, t, n); free(t); close(fd); if(i != n) drawerror(d, "writecolmap: bad write"); }