1 #include <u.h>
2 #include <libc.h>
3 #include <draw.h>
4 #include <memdraw.h>
5 
6 enum
7 {
8 	Arrow1 = 8,
9 	Arrow2 = 10,
10 	Arrow3 = 3
11 };
12 
13 /*
14 static
15 int
16 lmin(int a, int b)
17 {
18 	if(a < b)
19 		return a;
20 	return b;
21 }
22 */
23 
24 static
25 int
26 lmax(int a, int b)
27 {
28 	if(a > b)
29 		return a;
30 	return b;
31 }
32 
33 #ifdef NOTUSED
34 /*
35  * Rather than line clip, we run the Bresenham loop over the full line,
36  * and clip on each pixel.  This is more expensive but means that
37  * lines look the same regardless of how the windowing has tiled them.
38  * For speed, we check for clipping outside the loop and make the
39  * test easy when possible.
40  */
41 
42 static
43 void
44 horline1(Memimage *dst, Point p0, Point p1, int srcval, Rectangle clipr)
45 {
46 	int x, y, dy, deltay, deltax, maxx;
47 	int dd, easy, e, bpp, m, m0;
48 	uchar *d;
49 
50 	deltax = p1.x - p0.x;
51 	deltay = p1.y - p0.y;
52 	dd = dst->width*sizeof(u32int);
53 	dy = 1;
54 	if(deltay < 0){
55 		dd = -dd;
56 		deltay = -deltay;
57 		dy = -1;
58 	}
59 	maxx = lmin(p1.x, clipr.max.x-1);
60 	bpp = dst->depth;
61 	m0 = 0xFF^(0xFF>>bpp);
62 	m = m0 >> (p0.x&(7/dst->depth))*bpp;
63 	easy = ptinrect(p0, clipr) && ptinrect(p1, clipr);
64 	e = 2*deltay - deltax;
65 	y = p0.y;
66 	d = byteaddr(dst, p0);
67 	deltay *= 2;
68 	deltax = deltay - 2*deltax;
69 	for(x=p0.x; x<=maxx; x++){
70 		if(easy || (clipr.min.x<=x && clipr.min.y<=y && y<clipr.max.y))
71 			*d ^= (*d^srcval) & m;
72 		if(e > 0){
73 			y += dy;
74 			d += dd;
75 			e += deltax;
76 		}else
77 			e += deltay;
78 		d++;
79 		m >>= bpp;
80 		if(m == 0)
81 			m = m0;
82 	}
83 }
84 
85 static
86 void
87 verline1(Memimage *dst, Point p0, Point p1, int srcval, Rectangle clipr)
88 {
89 	int x, y, deltay, deltax, maxy;
90 	int easy, e, bpp, m, m0, dd;
91 	uchar *d;
92 
93 	deltax = p1.x - p0.x;
94 	deltay = p1.y - p0.y;
95 	dd = 1;
96 	if(deltax < 0){
97 		dd = -1;
98 		deltax = -deltax;
99 	}
100 	maxy = lmin(p1.y, clipr.max.y-1);
101 	bpp = dst->depth;
102 	m0 = 0xFF^(0xFF>>bpp);
103 	m = m0 >> (p0.x&(7/dst->depth))*bpp;
104 	easy = ptinrect(p0, clipr) && ptinrect(p1, clipr);
105 	e = 2*deltax - deltay;
106 	x = p0.x;
107 	d = byteaddr(dst, p0);
108 	deltax *= 2;
109 	deltay = deltax - 2*deltay;
110 	for(y=p0.y; y<=maxy; y++){
111 		if(easy || (clipr.min.y<=y && clipr.min.x<=x && x<clipr.max.x))
112 			*d ^= (*d^srcval) & m;
113 		if(e > 0){
114 			x += dd;
115 			d += dd;
116 			e += deltay;
117 		}else
118 			e += deltax;
119 		d += dst->width*sizeof(u32int);
120 		m >>= bpp;
121 		if(m == 0)
122 			m = m0;
123 	}
124 }
125 
126 static
127 void
128 horliner(Memimage *dst, Point p0, Point p1, Memimage *src, Point dsrc, Rectangle clipr)
129 {
130 	int x, y, sx, sy, deltay, deltax, minx, maxx;
131 	int bpp, m, m0;
132 	uchar *d, *s;
133 
134 	deltax = p1.x - p0.x;
135 	deltay = p1.y - p0.y;
136 	sx = drawreplxy(src->r.min.x, src->r.max.x, p0.x+dsrc.x);
137 	minx = lmax(p0.x, clipr.min.x);
138 	maxx = lmin(p1.x, clipr.max.x-1);
139 	bpp = dst->depth;
140 	m0 = 0xFF^(0xFF>>bpp);
141 	m = m0 >> (minx&(7/dst->depth))*bpp;
142 	for(x=minx; x<=maxx; x++){
143 		y = p0.y + (deltay*(x-p0.x)+deltax/2)/deltax;
144 		if(clipr.min.y<=y && y<clipr.max.y){
145 			d = byteaddr(dst, Pt(x, y));
146 			sy = drawreplxy(src->r.min.y, src->r.max.y, y+dsrc.y);
147 			s = byteaddr(src, Pt(sx, sy));
148 			*d ^= (*d^*s) & m;
149 		}
150 		if(++sx >= src->r.max.x)
151 			sx = src->r.min.x;
152 		m >>= bpp;
153 		if(m == 0)
154 			m = m0;
155 	}
156 }
157 
158 static
159 void
160 verliner(Memimage *dst, Point p0, Point p1, Memimage *src, Point dsrc, Rectangle clipr)
161 {
162 	int x, y, sx, sy, deltay, deltax, miny, maxy;
163 	int bpp, m, m0;
164 	uchar *d, *s;
165 
166 	deltax = p1.x - p0.x;
167 	deltay = p1.y - p0.y;
168 	sy = drawreplxy(src->r.min.y, src->r.max.y, p0.y+dsrc.y);
169 	miny = lmax(p0.y, clipr.min.y);
170 	maxy = lmin(p1.y, clipr.max.y-1);
171 	bpp = dst->depth;
172 	m0 = 0xFF^(0xFF>>bpp);
173 	for(y=miny; y<=maxy; y++){
174 		if(deltay == 0)	/* degenerate line */
175 			x = p0.x;
176 		else
177 			x = p0.x + (deltax*(y-p0.y)+deltay/2)/deltay;
178 		if(clipr.min.x<=x && x<clipr.max.x){
179 			m = m0 >> (x&(7/dst->depth))*bpp;
180 			d = byteaddr(dst, Pt(x, y));
181 			sx = drawreplxy(src->r.min.x, src->r.max.x, x+dsrc.x);
182 			s = byteaddr(src, Pt(sx, sy));
183 			*d ^= (*d^*s) & m;
184 		}
185 		if(++sy >= src->r.max.y)
186 			sy = src->r.min.y;
187 	}
188 }
189 
190 static
191 void
192 horline(Memimage *dst, Point p0, Point p1, Memimage *src, Point dsrc, Rectangle clipr)
193 {
194 	int x, y, deltay, deltax, minx, maxx;
195 	int bpp, m, m0;
196 	uchar *d, *s;
197 
198 	deltax = p1.x - p0.x;
199 	deltay = p1.y - p0.y;
200 	minx = lmax(p0.x, clipr.min.x);
201 	maxx = lmin(p1.x, clipr.max.x-1);
202 	bpp = dst->depth;
203 	m0 = 0xFF^(0xFF>>bpp);
204 	m = m0 >> (minx&(7/dst->depth))*bpp;
205 	for(x=minx; x<=maxx; x++){
206 		y = p0.y + (deltay*(x-p0.x)+deltay/2)/deltax;
207 		if(clipr.min.y<=y && y<clipr.max.y){
208 			d = byteaddr(dst, Pt(x, y));
209 			s = byteaddr(src, addpt(dsrc, Pt(x, y)));
210 			*d ^= (*d^*s) & m;
211 		}
212 		m >>= bpp;
213 		if(m == 0)
214 			m = m0;
215 	}
216 }
217 
218 static
219 void
220 verline(Memimage *dst, Point p0, Point p1, Memimage *src, Point dsrc, Rectangle clipr)
221 {
222 	int x, y, deltay, deltax, miny, maxy;
223 	int bpp, m, m0;
224 	uchar *d, *s;
225 
226 	deltax = p1.x - p0.x;
227 	deltay = p1.y - p0.y;
228 	miny = lmax(p0.y, clipr.min.y);
229 	maxy = lmin(p1.y, clipr.max.y-1);
230 	bpp = dst->depth;
231 	m0 = 0xFF^(0xFF>>bpp);
232 	for(y=miny; y<=maxy; y++){
233 		if(deltay == 0)	/* degenerate line */
234 			x = p0.x;
235 		else
236 			x = p0.x + deltax*(y-p0.y)/deltay;
237 		if(clipr.min.x<=x && x<clipr.max.x){
238 			m = m0 >> (x&(7/dst->depth))*bpp;
239 			d = byteaddr(dst, Pt(x, y));
240 			s = byteaddr(src, addpt(dsrc, Pt(x, y)));
241 			*d ^= (*d^*s) & m;
242 		}
243 	}
244 }
245 #endif /* NOTUSED */
246 
247 static Memimage*
248 membrush(int radius)
249 {
250 	static Memimage *brush;
251 	static int brushradius;
252 
253 	if(brush==nil || brushradius!=radius){
254 		freememimage(brush);
255 		brush = allocmemimage(Rect(0, 0, 2*radius+1, 2*radius+1), memopaque->chan);
256 		if(brush != nil){
257 			memfillcolor(brush, DTransparent);	/* zeros */
258 			memellipse(brush, Pt(radius, radius), radius, radius, -1, memopaque, Pt(radius, radius), S);
259 		}
260 		brushradius = radius;
261 	}
262 	return brush;
263 }
264 
265 static
266 void
267 discend(Point p, int radius, Memimage *dst, Memimage *src, Point dsrc, int op)
268 {
269 	Memimage *disc;
270 	Rectangle r;
271 
272 	disc = membrush(radius);
273 	if(disc != nil){
274 		r.min.x = p.x - radius;
275 		r.min.y = p.y - radius;
276 		r.max.x = p.x + radius+1;
277 		r.max.y = p.y + radius+1;
278 		memdraw(dst, r, src, addpt(r.min, dsrc), disc, Pt(0,0), op);
279 	}
280 }
281 
282 static
283 void
284 arrowend(Point tip, Point *pp, int end, int sin, int cos, int radius)
285 {
286 	int x1, x2, x3;
287 
288 	/* before rotation */
289 	if(end == Endarrow){
290 		x1 = Arrow1;
291 		x2 = Arrow2;
292 		x3 = Arrow3;
293 	}else{
294 		x1 = (end>>5) & 0x1FF;	/* distance along line from end of line to tip */
295 		x2 = (end>>14) & 0x1FF;	/* distance along line from barb to tip */
296 		x3 = (end>>23) & 0x1FF;	/* distance perpendicular from edge of line to barb */
297 	}
298 
299 	/* comments follow track of right-facing arrowhead */
300 	pp->x = tip.x+((2*radius+1)*sin/2-x1*cos);		/* upper side of shaft */
301 	pp->y = tip.y-((2*radius+1)*cos/2+x1*sin);
302 	pp++;
303 	pp->x = tip.x+((2*radius+2*x3+1)*sin/2-x2*cos);		/* upper barb */
304 	pp->y = tip.y-((2*radius+2*x3+1)*cos/2+x2*sin);
305 	pp++;
306 	pp->x = tip.x;
307 	pp->y = tip.y;
308 	pp++;
309 	pp->x = tip.x+(-(2*radius+2*x3+1)*sin/2-x2*cos);	/* lower barb */
310 	pp->y = tip.y-(-(2*radius+2*x3+1)*cos/2+x2*sin);
311 	pp++;
312 	pp->x = tip.x+(-(2*radius+1)*sin/2-x1*cos);		/* lower side of shaft */
313 	pp->y = tip.y+((2*radius+1)*cos/2-x1*sin);
314 }
315 
316 void
317 _memimageline(Memimage *dst, Point p0, Point p1, int end0, int end1, int radius, Memimage *src, Point sp, Rectangle clipr, int op)
318 {
319 	/*
320 	 * BUG: We should really really pick off purely horizontal and purely
321 	 * vertical lines and handle them separately with calls to memimagedraw
322 	 * on rectangles.
323 	 */
324 
325 	int hor;
326 	int sin, cos, dx, dy, t;
327 	Rectangle oclipr, r;
328 	Point q, pts[10], *pp, d;
329 
330 	if(radius < 0)
331 		return;
332 	if(rectclip(&clipr, dst->r) == 0)
333 		return;
334 	if(rectclip(&clipr, dst->clipr) == 0)
335 		return;
336 	d = subpt(sp, p0);
337 	if(rectclip(&clipr, rectsubpt(src->clipr, d)) == 0)
338 		return;
339 	if((src->flags&Frepl)==0 && rectclip(&clipr, rectsubpt(src->r, d))==0)
340 		return;
341 	/* this means that only verline() handles degenerate lines (p0==p1) */
342 	hor = (abs(p1.x-p0.x) > abs(p1.y-p0.y));
343 	/*
344 	 * Clipping is a little peculiar.  We can't use Sutherland-Cohen
345 	 * clipping because lines are wide.  But this is probably just fine:
346 	 * we do all math with the original p0 and p1, but clip when deciding
347 	 * what pixels to draw.  This means the layer code can call this routine,
348 	 * using clipr to define the region being written, and get the same set
349 	 * of pixels regardless of the dicing.
350 	 */
351 	if((hor && p0.x>p1.x) || (!hor && p0.y>p1.y)){
352 		q = p0;
353 		p0 = p1;
354 		p1 = q;
355 		t = end0;
356 		end0 = end1;
357 		end1 = t;
358 	}
359 
360 	if((p0.x == p1.x || p0.y == p1.y) && (end0&0x1F) == Endsquare && (end1&0x1F) == Endsquare){
361 		r.min = p0;
362 		r.max = p1;
363 		if(p0.x == p1.x){
364 			r.min.x -= radius;
365 			r.max.x += radius+1;
366 		}
367 		else{
368 			r.min.y -= radius;
369 			r.max.y += radius+1;
370 		}
371 		oclipr = dst->clipr;
372 		dst->clipr = clipr;
373 		memimagedraw(dst, r, src, sp, memopaque, sp, op);
374 		dst->clipr = oclipr;
375 		return;
376 	}
377 
378 /*    Hard: */
379 	/* draw thick line using polygon fill */
380 	icossin2(p1.x-p0.x, p1.y-p0.y, &cos, &sin);
381 	dx = (sin*(2*radius+1))/2;
382 	dy = (cos*(2*radius+1))/2;
383 	pp = pts;
384 	oclipr = dst->clipr;
385 	dst->clipr = clipr;
386 	q.x = ICOSSCALE*p0.x+ICOSSCALE/2-cos/2;
387 	q.y = ICOSSCALE*p0.y+ICOSSCALE/2-sin/2;
388 	switch(end0 & 0x1F){
389 	case Enddisc:
390 		discend(p0, radius, dst, src, d, op);
391 		/* fall through */
392 	case Endsquare:
393 	default:
394 		pp->x = q.x-dx;
395 		pp->y = q.y+dy;
396 		pp++;
397 		pp->x = q.x+dx;
398 		pp->y = q.y-dy;
399 		pp++;
400 		break;
401 	case Endarrow:
402 		arrowend(q, pp, end0, -sin, -cos, radius);
403 		_memfillpolysc(dst, pts, 5, ~0, src, addpt(pts[0], mulpt(d, ICOSSCALE)), 1, 10, 1, op);
404 		pp[1] = pp[4];
405 		pp += 2;
406 	}
407 	q.x = ICOSSCALE*p1.x+ICOSSCALE/2+cos/2;
408 	q.y = ICOSSCALE*p1.y+ICOSSCALE/2+sin/2;
409 	switch(end1 & 0x1F){
410 	case Enddisc:
411 		discend(p1, radius, dst, src, d, op);
412 		/* fall through */
413 	case Endsquare:
414 	default:
415 		pp->x = q.x+dx;
416 		pp->y = q.y-dy;
417 		pp++;
418 		pp->x = q.x-dx;
419 		pp->y = q.y+dy;
420 		pp++;
421 		break;
422 	case Endarrow:
423 		arrowend(q, pp, end1, sin, cos, radius);
424 		_memfillpolysc(dst, pp, 5, ~0, src, addpt(pts[0], mulpt(d, ICOSSCALE)), 1, 10, 1, op);
425 		pp[1] = pp[4];
426 		pp += 2;
427 	}
428 	_memfillpolysc(dst, pts, pp-pts, ~0, src, addpt(pts[0], mulpt(d, ICOSSCALE)), 0, 10, 1, op);
429 	dst->clipr = oclipr;
430 	return;
431 }
432 
433 void
434 memimageline(Memimage *dst, Point p0, Point p1, int end0, int end1, int radius, Memimage *src, Point sp, int op)
435 {
436 	_memimageline(dst, p0, p1, end0, end1, radius, src, sp, dst->clipr, op);
437 }
438 
439 /*
440  * Simple-minded conservative code to compute bounding box of line.
441  * Result is probably a little larger than it needs to be.
442  */
443 static
444 void
445 addbbox(Rectangle *r, Point p)
446 {
447 	if(r->min.x > p.x)
448 		r->min.x = p.x;
449 	if(r->min.y > p.y)
450 		r->min.y = p.y;
451 	if(r->max.x < p.x+1)
452 		r->max.x = p.x+1;
453 	if(r->max.y < p.y+1)
454 		r->max.y = p.y+1;
455 }
456 
457 int
458 memlineendsize(int end)
459 {
460 	int x3;
461 
462 	if((end&0x3F) != Endarrow)
463 		return 0;
464 	if(end == Endarrow)
465 		x3 = Arrow3;
466 	else
467 		x3 = (end>>23) & 0x1FF;
468 	return x3;
469 }
470 
471 Rectangle
472 memlinebbox(Point p0, Point p1, int end0, int end1, int radius)
473 {
474 	Rectangle r, r1;
475 	int extra;
476 
477 	r.min.x = 10000000;
478 	r.min.y = 10000000;
479 	r.max.x = -10000000;
480 	r.max.y = -10000000;
481 	extra = lmax(memlineendsize(end0), memlineendsize(end1));
482 	r1 = insetrect(canonrect(Rpt(p0, p1)), -(radius+extra));
483 	addbbox(&r, r1.min);
484 	addbbox(&r, r1.max);
485 	return r;
486 }