ref: fe5d1976a0b4376c955ca8423eb9005f5d035403
dir: /sys/src/libdraw/unloadimage.c/
#include <u.h> #include <libc.h> #include <draw.h> int unloadimage(Image *i, Rectangle r, uchar *data, int ndata) { int bpl, n, chunk, dx, dy; uchar *a, *start; Display *d; if(!rectinrect(r, i->r)){ werrstr("unloadimage: bad rectangle"); return -1; } bpl = bytesperline(r, i->depth); if(ndata < bpl*Dy(r)){ werrstr("unloadimage: buffer too small"); return -1; } start = data; d = i->display; chunk = d->bufsize; flushimage(d, 0); /* make sure subsequent flush is for us only */ while(r.min.y < r.max.y){ dx = Dx(r); dy = chunk/bpl; if(dy <= 0){ dy = 1; dx = ((chunk*dx)/bpl) & ~7; n = bytesperline(Rect(r.min.x, r.min.y, r.min.x+dx, r.min.y+dy), i->depth); if(unloadimage(i, Rect(r.min.x+dx, r.min.y, r.max.x, r.min.y+dy), data+n, bpl-n) < 0) return -1; } else { if(dy > Dy(r)) dy = Dy(r); n = bpl*dy; } a = bufimage(d, 1+4+4*4); if(a == nil){ werrstr("unloadimage: %r"); return -1; } a[0] = 'r'; BPLONG(a+1, i->id); BPLONG(a+5, r.min.x); BPLONG(a+9, r.min.y); BPLONG(a+13, r.min.x+dx); BPLONG(a+17, r.min.y+dy); if(flushimage(d, 0) < 0) return -1; if(read(d->fd, data, n) < 0) return -1; data += bpl*dy; r.min.y += dy; } return data - start; }