ref: fe5d1976a0b4376c955ca8423eb9005f5d035403
dir: /sys/src/libdraw/bytesperline.c/
#include <u.h> #include <libc.h> #include <draw.h> static int unitsperline(Rectangle r, int d, int bitsperunit) { ulong l, t; if(d <= 0 || d > 32) /* being called wrong. d is image depth. */ abort(); if(r.min.x >= 0){ l = (r.max.x*d+bitsperunit-1)/bitsperunit; l -= (r.min.x*d)/bitsperunit; }else{ /* make positive before divide */ t = (-r.min.x*d+bitsperunit-1)/bitsperunit; l = t+(r.max.x*d+bitsperunit-1)/bitsperunit; } return l; } int wordsperline(Rectangle r, int d) { return unitsperline(r, d, 8*sizeof(ulong)); } int bytesperline(Rectangle r, int d) { return unitsperline(r, d, 8); }