text: /*
   * This file is part of the UCB release of Plan 9. It is subject to the license
   * terms in the LICENSE file found in the top-level directory of this
   * distribution and at http://akaros.cs.berkeley.edu/files/Plan9License. No
   * part of the UCB release of Plan 9, including this file, may be copied,
   * modified, propagated, or distributed except according to the terms contained
   * in the LICENSE file.
   */
  
  #include <u.h>
  #include <lib9.h>
  #include <draw.h>
  
  enum
  {
  	Max = 100
  };
  
  Point
  string(Image *dst, Point pt, Image *src, Point sp, Font *f, char *s)
  {
  	return _string(dst, pt, src, sp, f, s, nil, 1<<24, dst->clipr, nil, ZP, SoverD);
  }
  
  Point
  stringop(Image *dst, Point pt, Image *src, Point sp, Font *f, char *s,
  	 Drawop op)
  {
  	return _string(dst, pt, src, sp, f, s, nil, 1<<24, dst->clipr, nil, ZP, op);
  }
  
  Point
  stringn(Image *dst, Point pt, Image *src, Point sp, Font *f, char *s,
  	int len)
  {
  	return _string(dst, pt, src, sp, f, s, nil, len, dst->clipr, nil, ZP, SoverD);
  }
  
  Point
  stringnop(Image *dst, Point pt, Image *src, Point sp, Font *f, char *s,
  	  int len, Drawop op)
  {
  	return _string(dst, pt, src, sp, f, s, nil, len, dst->clipr, nil, ZP, op);
  }
  
  Point
  runestring(Image *dst, Point pt, Image *src, Point sp, Font *f, Rune *r)
  {
  	return _string(dst, pt, src, sp, f, nil, r, 1<<24, dst->clipr, nil, ZP, SoverD);
  }
  
  Point
  runestringop(Image *dst, Point pt, Image *src, Point sp, Font *f, Rune *r, Drawop op)
  {
  	return _string(dst, pt, src, sp, f, nil, r, 1<<24, dst->clipr, nil, ZP, op);
  }
  
  Point
  runestringn(Image *dst, Point pt, Image *src, Point sp, Font *f, Rune *r, int len)
  {
  	return _string(dst, pt, src, sp, f, nil, r, len, dst->clipr, nil, ZP, SoverD);
  }
  
  Point
  runestringnop(Image *dst, Point pt, Image *src, Point sp, Font *f, Rune *r, int len, Drawop op)
  {
  	return _string(dst, pt, src, sp, f, nil, r, len, dst->clipr, nil, ZP, op);
  }
  
  Point
  _string(Image *dst, Point pt, Image *src, Point sp, Font *f, char *s,
  	Rune *r, int len, Rectangle clipr, Image *bg, Point bgp,
  	Drawop op)
  {
  	int m, n, wid, max;
  	uint16_t cbuf[Max], *c, *ec;
  	uint8_t *b;
  	char *subfontname;
  	char **sptr;
  	Rune **rptr;
  	Font *def;
  	Subfont *sf;
  
  	if(s == nil){
  		s = "";
  		sptr = nil;
  	}else
  		sptr = &s;
  	if(r == nil){
  		r = (Rune*) L"";
  		rptr = nil;
  	}else
  		rptr = &r;
  	sf = nil;
  	while((*s || *r) && len > 0){
  		max = Max;
  		if(len < max)
  			max = len;
  		n = cachechars(f, sptr, rptr, cbuf, max, &wid, &subfontname);
  		if(n > 0){
  			_setdrawop(dst->display, op);
  
  			m = 47+2*n;
  			if(bg)
  				m += 4+2*4;
  			b = bufimage(dst->display, m);
  			if(b == 0){
  				fprint(2, "string: %r\n");
  				break;
  			}
  			if(bg)
  				b[0] = 'x';
  			else
  				b[0] = 's';
  			BPLONG(b+1, dst->id);
  			BPLONG(b+5, src->id);
  			BPLONG(b+9, f->cacheimage->id);
  			BPLONG(b+13, pt.x);
  			BPLONG(b+17, pt.y+f->ascent);
  			BPLONG(b+21, clipr.min.x);
  			BPLONG(b+25, clipr.min.y);
  			BPLONG(b+29, clipr.max.x);
  			BPLONG(b+33, clipr.max.y);
  			BPLONG(b+37, sp.x);
  			BPLONG(b+41, sp.y);
  			BPSHORT(b+45, n);
  			b += 47;
  			if(bg){
  				BPLONG(b, bg->id);
  				BPLONG(b+4, bgp.x);
  				BPLONG(b+8, bgp.y);
  				b += 12;
  			}
  			ec = &cbuf[n];
  			for(c=cbuf; c<ec; c++, b+=2)
  				BPSHORT(b, *c);
  			pt.x += wid;
  			bgp.x += wid;
  			agefont(f);
  			len -= n;
  		}
  		if(subfontname){
  			freesubfont(sf);
  			if((sf=_getsubfont(f->display, subfontname)) == 0){
  				def = f->display ? f->display->defaultfont : nil;
  				if(def && f!=def)
  					f = def;
  				else
  					break;
  			}
  			/* 
  			 * must not free sf until cachechars has found it in the cache
  			 * and picked up its own reference.
  			 */
  		}
  	}
  	return pt;
  }
  