1 /*
2  * Some of the stuff in this file is not X-dependent and should be elsewhere.
3  */
4 #include <u.h>
5 #include "x11-inc.h"
6 #include <libc.h>
7 #include <draw.h>
8 #include <memdraw.h>
9 #include <keyboard.h>
10 #include <mouse.h>
11 #include <cursor.h>
12 #include "x11-memdraw.h"
13 
14 char *winsize;
15 static int parsewinsize(char*, Rectangle*, int*);
16 
17 static Memimage	*xattach(char*);
18 static void	plan9cmap(void);
19 static int	setupcmap(XWindow);
20 static int	xreplacescreenimage(void);
21 static XGC	xgc(XDrawable, int, int);
22 static Image	*getimage0(Display*, Image*);
23 
24 Xprivate _x;
25 
26 Display*
27 _initdisplay(void (*error)(Display*, char*), char *label)
28 {
29 	Display *d;
30 	Memimage *m;
31 
32 	/*
33 	 * This rfork(RFNOTEG) isn't exactly right,
34 	 * but we need some way to signal window 
35 	 * closes.  Right now we post a hangup
36 	 * note to the note group, which kills a whole
37 	 * lot more than just the current program
38 	 * if we don't do this.
39 	 */
40 	/*
41 	 * Actually, I don't know what I changed but
42 	 * this appears not to be necessary anymore.
43 	 * I'll regret this probably.
44 	rfork(RFNOTEG);
45 	*/
46 	memimageinit();
47 
48 	d = mallocz(sizeof(Display), 1);
49 	if(d == nil)
50 		return nil;
51 
52 	d->buf = malloc(16000+5);
53 	d->obuf = malloc(16000);
54 	if(d->buf == nil || d->obuf == nil){
55 		free(d->buf);
56 		free(d->obuf);
57 		free(d);
58 		return nil;
59 	}
60 	d->bufsize = 16000;
61 	d->obufsize = 16000;
62 	d->bufp = d->buf;
63 	d->obufp = d->obuf;
64 
65 	m = xattach(label);
66 	if(m == nil){
67 		free(d);
68 		return nil;
69 	}
70 
71 	d->error = error;
72 	_initdisplaymemimage(d, m);
73 	d->screenimage = getimage0(d, 0);
74 	return d;
75 }
76 
77 static Image*
78 getimage0(Display *d, Image *image)
79 {
80 	char info[12*12+1];
81 	uchar *a;
82 	int n;
83 	extern int _freeimage1(Image*);
84 
85 	/*
86 	 * If there's an old screen, it has id 0.  The 'J' request below
87 	 * will try to install the new screen as id 0, so the old one 
88 	 * must be freed first.
89 	 */
90 	if(image){
91 		_freeimage1(image);
92 		memset(image, 0, sizeof(Image));
93 	}
94 
95 	a = bufimage(d, 2);
96 	a[0] = 'J';
97 	a[1] = 'I';
98 	if(flushimage(d, 0) < 0){
99 		fprint(2, "cannot read screen info: %r\n");
100 		abort();
101 	}
102 
103 	n = _drawmsgread(d, info, sizeof info);
104 	if(n != 12*12){
105 		fprint(2, "short screen info\n");
106 		abort();
107 	}
108 
109 	if(image == nil){
110 		image = mallocz(sizeof(Image), 1);
111 		if(image == nil){
112 			fprint(2, "cannot allocate image: %r\n");
113 			abort();
114 		}
115 	}
116 
117 	image->display = d;
118 	image->id = 0;
119 	image->chan = strtochan(info+2*12);
120 	image->depth = chantodepth(image->chan);
121 	image->repl = atoi(info+3*12);
122 	image->r.min.x = atoi(info+4*12);
123 	image->r.min.y = atoi(info+5*12);
124 	image->r.max.x = atoi(info+6*12);
125 	image->r.max.y = atoi(info+7*12);
126 	image->clipr.min.x = atoi(info+8*12);
127 	image->clipr.min.y = atoi(info+9*12);
128 	image->clipr.max.x = atoi(info+10*12);
129 	image->clipr.max.y = atoi(info+11*12);
130 	return image;
131 }
132 
133 int
134 getwindow(Display *d, int ref)
135 {
136 	Image *i;
137 	Image *oi;
138 
139 	if(_x.destroyed)
140 		postnote(PNGROUP, getpgrp(), "hangup");
141 	if(xreplacescreenimage() == 0)
142 		return 0;
143 
144 	/*
145 	 * Libdraw promises not to change the value of "screen",
146 	 * so we have to reuse the image structure
147 	 * memory we already have.
148 	 */
149 	oi = d->screenimage;
150 	i = getimage0(d, oi);
151 	screen = d->screenimage = d->image = i;
152 	// fprint(2, "getwindow %p -> %p\n", oi, i);
153 	return 0;
154 }
155 
156 static int
157 xerror(XDisplay *d, XErrorEvent *e)
158 {
159 	char buf[200];
160 
161 	if(e->request_code == 42) /* XSetInputFocus */
162 		return 0;
163 	if(e->request_code == 18) /* XChangeProperty */
164 		return 0;
165 
166 	print("X error: error_code=%d, request_code=%d, minor=%d disp=%p\n",
167 		e->error_code, e->request_code, e->minor_code, d);
168 	XGetErrorText(d, e->error_code, buf, sizeof buf);
169 	print("%s\n", buf);
170 	return 0;
171 }
172 
173 static int
174 xioerror(XDisplay *d)
175 {
176 	//print("X I/O error\n");
177 	sysfatal("X I/O error\n");
178 	abort();
179 	return -1;
180 }
181 
182 
183 static Memimage*
184 xattach(char *label)
185 {
186 	char *argv[2], *disp;
187 	int i, havemin, height, mask, n, width, x, xrootid, y;
188 	Rectangle r;
189 	XClassHint classhint;
190 	XDrawable pmid;
191 	XPixmapFormatValues *pfmt;
192 	XScreen *xscreen;
193 	XSetWindowAttributes attr;
194 	XSizeHints normalhint;
195 	XTextProperty name;
196 	XVisualInfo xvi;
197 	XWindow xrootwin;
198 	XWindowAttributes wattr;
199 	XWMHints hint;
200 	Atom atoms[2];
201 
202 	/*
203 	if(XInitThreads() == 0){
204 		fprint(2, "XInitThreads failed\n");
205 		abort();
206 	}
207 	*/
208 
209 	/*
210 	 * Connect to X server.
211 	 */
212 	_x.display = XOpenDisplay(NULL);
213 	if(_x.display == nil){
214 		disp = getenv("DISPLAY");
215 		werrstr("XOpenDisplay %s: %r", disp ? disp : ":0");
216 		free(disp);
217 		return nil;
218 	}
219 	XSetErrorHandler(xerror);
220 	XSetIOErrorHandler(xioerror);
221 	xrootid = DefaultScreen(_x.display);
222 	xrootwin = DefaultRootWindow(_x.display);
223 
224 	/* 
225 	 * Figure out underlying screen format.
226 	 */
227 	if(XMatchVisualInfo(_x.display, xrootid, 16, TrueColor, &xvi)
228 	|| XMatchVisualInfo(_x.display, xrootid, 16, DirectColor, &xvi)){
229 		_x.vis = xvi.visual;
230 		_x.depth = 16;
231 	}
232 	else
233 	if(XMatchVisualInfo(_x.display, xrootid, 15, TrueColor, &xvi)
234 	|| XMatchVisualInfo(_x.display, xrootid, 15, DirectColor, &xvi)){
235 		_x.vis = xvi.visual;
236 		_x.depth = 15;
237 	}
238 	else
239 	if(XMatchVisualInfo(_x.display, xrootid, 24, TrueColor, &xvi)
240 	|| XMatchVisualInfo(_x.display, xrootid, 24, DirectColor, &xvi)){
241 		_x.vis = xvi.visual;
242 		_x.depth = 24;
243 	}
244 	else
245 	if(XMatchVisualInfo(_x.display, xrootid, 8, PseudoColor, &xvi)
246 	|| XMatchVisualInfo(_x.display, xrootid, 8, StaticColor, &xvi)){
247 		if(_x.depth > 8){
248 			werrstr("can't deal with colormapped depth %d screens",
249 				_x.depth);
250 			goto err0;
251 		}
252 		_x.vis = xvi.visual;
253 		_x.depth = 8;
254 	}
255 	else{
256 		_x.depth = DefaultDepth(_x.display, xrootid);
257 		if(_x.depth != 8){
258 			werrstr("can't understand depth %d screen", _x.depth);
259 			goto err0;
260 		}
261 		_x.vis = DefaultVisual(_x.display, xrootid);
262 	}
263 
264 	if(DefaultDepth(_x.display, xrootid) == _x.depth)
265 		_x.usetable = 1;
266 
267 	/*
268 	 * _x.depth is only the number of significant pixel bits,
269 	 * not the total number of pixel bits.  We need to walk the
270 	 * display list to find how many actual bits are used
271 	 * per pixel.
272 	 */
273 	_x.chan = 0;
274 	pfmt = XListPixmapFormats(_x.display, &n);
275 	for(i=0; i<n; i++){
276 		if(pfmt[i].depth == _x.depth){
277 			switch(pfmt[i].bits_per_pixel){
278 			case 1:	/* untested */
279 				_x.chan = GREY1;
280 				break;
281 			case 2:	/* untested */
282 				_x.chan = GREY2;
283 				break;
284 			case 4:	/* untested */
285 				_x.chan = GREY4;
286 				break;
287 			case 8:
288 				_x.chan = CMAP8;
289 				break;
290 			case 15:
291 				_x.chan = RGB15;
292 				break;
293 			case 16: /* how to tell RGB15? */
294 				_x.chan = RGB16;
295 				break;
296 			case 24: /* untested (impossible?) */
297 				_x.chan = RGB24;
298 				break;
299 			case 32:
300 				_x.chan = XRGB32;
301 				break;
302 			}
303 		}
304 	}
305 	if(_x.chan == 0){
306 		werrstr("could not determine screen pixel format");
307 		goto err0;
308 	}
309 
310 	/*
311 	 * Set up color map if necessary.
312 	 */
313 	xscreen = DefaultScreenOfDisplay(_x.display);
314 	_x.cmap = DefaultColormapOfScreen(xscreen);
315 	if(_x.vis->class != StaticColor){
316 		plan9cmap();
317 		setupcmap(xrootwin);
318 	}
319 
320 	/*
321 	 * We get to choose the initial rectangle size.
322 	 * This is arbitrary.  In theory we should read the
323 	 * command line and allow the traditional X options.
324 	 */
325 	mask = 0;
326 	x = 0;
327 	y = 0;
328 	if(winsize){
329 		if(parsewinsize(winsize, &r, &havemin) < 0)
330 			sysfatal("%r");
331 	}else{
332 		/*
333 		 * Parse the various X resources.  Thanks to Peter Canning.
334 		 */
335 		char *screen_resources, *display_resources, *geom, 
336 			*geomrestype, *home, *file;
337 		XrmDatabase database;
338 		XrmValue geomres;
339 
340 		database = XrmGetDatabase(_x.display);
341 		screen_resources = XScreenResourceString(xscreen);
342 		if(screen_resources != nil){
343 			XrmCombineDatabase(XrmGetStringDatabase(screen_resources), &database, False);
344 			XFree(screen_resources);
345 		}
346 
347 		display_resources = XResourceManagerString(_x.display);
348 		if(display_resources == nil){
349 			home = getenv("home");
350 			if(home == nil)
351 				home = getenv("HOME");
352 			if(home!=nil && (file=smprint("%s/.Xdefaults", home)) != nil){
353 				XrmCombineFileDatabase(file, &database, False);
354 				free(file);
355 			}
356 			free(home);
357 		}else
358 			XrmCombineDatabase(XrmGetStringDatabase(display_resources), &database, False);
359 
360 		geom = smprint("%s.geometry", label);
361 		if(geom && XrmGetResource(database, geom, nil, &geomrestype, &geomres))
362 			mask = XParseGeometry(geomres.addr, &x, &y, &width, &height);
363 		free(geom);
364 
365 		if((mask & WidthValue) && (mask & HeightValue)){
366 			r = Rect(0, 0, width, height);
367 		}else{
368 			r = Rect(0, 0, WidthOfScreen(xscreen)*3/4,
369 					HeightOfScreen(xscreen)*3/4);
370 			if(Dx(r) > Dy(r)*3/2)
371 				r.max.x = r.min.x + Dy(r)*3/2;
372 			if(Dy(r) > Dx(r)*3/2)
373 				r.max.y = r.min.y + Dx(r)*3/2;
374 		}
375 		if(mask & XNegative){
376 			x += WidthOfScreen(xscreen);
377 		}
378 		if(mask & YNegative){
379 			y += HeightOfScreen(xscreen);
380 		}
381 		havemin = 0;
382 	}
383 
384 	memset(&attr, 0, sizeof attr);
385 	attr.colormap = _x.cmap;
386 	attr.background_pixel = ~0;
387 	attr.border_pixel = 0;
388 	_x.drawable = XCreateWindow(
389 		_x.display,	/* display */
390 		xrootwin,	/* parent */
391 		x,		/* x */
392 		y,		/* y */
393 		Dx(r),		/* width */
394 	 	Dy(r),		/* height */
395 		0,		/* border width */
396 		_x.depth,	/* depth */
397 		InputOutput,	/* class */
398 		_x.vis,		/* visual */
399 				/* valuemask */
400 		CWBackPixel|CWBorderPixel|CWColormap,
401 		&attr		/* attributes (the above aren't?!) */
402 	);
403 
404 	/*
405 	 * Label and other properties required by ICCCCM.
406 	 */
407 	memset(&name, 0, sizeof name);
408 	if(label == nil)
409 		label = "pjw-face-here";
410 	name.value = (uchar*)label;
411 	name.encoding = XA_STRING;
412 	name.format = 8;
413 	name.nitems = strlen((char*)name.value);
414 
415 	memset(&normalhint, 0, sizeof normalhint);
416 	normalhint.flags = PSize|PMaxSize;
417 	if(winsize){
418 		normalhint.flags &= ~PSize;
419 		normalhint.flags |= USSize;
420 		normalhint.width = Dx(r);
421 		normalhint.height = Dy(r);
422 	}else{
423 		if((mask & WidthValue) && (mask & HeightValue)){
424 			normalhint.flags &= ~PSize;
425 			normalhint.flags |= USSize;
426 			normalhint.width = width;
427 			normalhint.height = height;
428 		}
429 		if((mask & WidthValue) && (mask & HeightValue)){
430 			normalhint.flags |= USPosition;
431 			normalhint.x = x;
432 			normalhint.y = y;
433 		}
434 	}
435 
436 	normalhint.max_width = WidthOfScreen(xscreen);
437 	normalhint.max_height = HeightOfScreen(xscreen);
438 
439 	memset(&hint, 0, sizeof hint);
440 	hint.flags = InputHint|StateHint;
441 	hint.input = 1;
442 	hint.initial_state = NormalState;
443 
444 	memset(&classhint, 0, sizeof classhint);
445 	classhint.res_name = label;
446 	classhint.res_class = label;
447 
448 	argv[0] = label;
449 	argv[1] = nil;
450 
451 	XSetWMProperties(
452 		_x.display,	/* display */
453 		_x.drawable,	/* window */
454 		&name,		/* XA_WM_NAME property */
455 		&name,		/* XA_WM_ICON_NAME property */
456 		argv,		/* XA_WM_COMMAND */
457 		1,		/* argc */
458 		&normalhint,	/* XA_WM_NORMAL_HINTS */
459 		&hint,		/* XA_WM_HINTS */
460 		&classhint	/* XA_WM_CLASSHINTS */
461 	);
462 	XFlush(_x.display);
463 
464 	if(havemin){
465 		XWindowChanges ch;
466 
467 		memset(&ch, 0, sizeof ch);
468 		ch.x = r.min.x;
469 		ch.y = r.min.y;
470 		XConfigureWindow(_x.display, _x.drawable, CWX|CWY, &ch);
471 	}
472 	/*
473 	 * Look up clipboard atom.
474 	 */
475 	_x.clipboard = XInternAtom(_x.display, "CLIPBOARD", False);
476 	_x.utf8string = XInternAtom(_x.display, "UTF8_STRING", False);
477 	_x.targets = XInternAtom(_x.display, "TARGETS", False);
478 	_x.text = XInternAtom(_x.display, "TEXT", False);
479 	_x.compoundtext = XInternAtom(_x.display, "COMPOUND_TEXT", False);
480 	_x.takefocus = XInternAtom(_x.display, "WM_TAKE_FOCUS", False);
481 	_x.losefocus = XInternAtom(_x.display, "_9WM_LOSE_FOCUS", False);
482 	_x.wmprotos = XInternAtom(_x.display, "WM_PROTOCOLS", False);
483 
484 	atoms[0] = _x.takefocus;
485 	atoms[1] = _x.losefocus;
486 	XChangeProperty(_x.display, _x.drawable, _x.wmprotos, XA_ATOM, 32,
487 		PropModeReplace, (uchar*)atoms, 2);
488 
489 	/*
490 	 * Put the window on the screen, check to see what size we actually got.
491 	 */
492 	XMapWindow(_x.display, _x.drawable);
493 	XSync(_x.display, False);
494 
495 	if(!XGetWindowAttributes(_x.display, _x.drawable, &wattr))
496 		fprint(2, "XGetWindowAttributes failed\n");
497 	else if(wattr.width && wattr.height){
498 		if(wattr.width != Dx(r) || wattr.height != Dy(r)){
499 			r.max.x = wattr.width;
500 			r.max.y = wattr.height;
501 		}
502 	}else
503 		fprint(2, "XGetWindowAttributes: bad attrs\n");
504 
505 	/*
506 	 * Allocate our local backing store.
507 	 */
508 	_x.screenr = r;
509 	_x.screenpm = XCreatePixmap(_x.display, _x.drawable, Dx(r), Dy(r), _x.depth);
510 	_x.nextscreenpm = _x.screenpm;
511 	_x.screenimage = _xallocmemimage(r, _x.chan, _x.screenpm);
512 
513 	/*
514 	 * Allocate some useful graphics contexts for the future.
515 	 */
516 	_x.gcfill	= xgc(_x.screenpm, FillSolid, -1);
517 	_x.gccopy	= xgc(_x.screenpm, -1, -1);
518 	_x.gcsimplesrc 	= xgc(_x.screenpm, FillStippled, -1);
519 	_x.gczero	= xgc(_x.screenpm, -1, -1);
520 	_x.gcreplsrc	= xgc(_x.screenpm, FillTiled, -1);
521 
522 	pmid = XCreatePixmap(_x.display, _x.drawable, 1, 1, 1);
523 	_x.gcfill0	= xgc(pmid, FillSolid, 0);
524 	_x.gccopy0	= xgc(pmid, -1, -1);
525 	_x.gcsimplesrc0	= xgc(pmid, FillStippled, -1);
526 	_x.gczero0	= xgc(pmid, -1, -1);
527 	_x.gcreplsrc0	= xgc(pmid, FillTiled, -1);
528 	XFreePixmap(_x.display, pmid);
529 
530 	/*
531 	 * Lots of display connections for various procs.
532 	 */
533 	_x.kbdcon	= XOpenDisplay(NULL);
534 	_x.mousecon	= XOpenDisplay(NULL);
535 	_x.snarfcon	= XOpenDisplay(NULL);
536 
537 	if(0) fprint(2, "x: display=%p kbd=%p mouse=%p snarf=%p\n",
538 		_x.display, _x.kbdcon, _x.mousecon, _x.snarfcon);
539 
540 	_x.black	= xscreen->black_pixel;
541 	_x.white	= xscreen->white_pixel;
542 
543 	return _x.screenimage;
544 
545 err0:
546 fprint(2, "%r\n");
547 	/*
548 	 * Should do a better job of cleaning up here.
549 	 */
550 	XCloseDisplay(_x.display);
551 	return nil;
552 }
553 
554 int
555 drawsetlabel(Display *d, char *label)
556 {
557 	char *argv[2];
558 	XClassHint classhint;
559 	XTextProperty name;
560 
561 	/*
562 	 * Label and other properties required by ICCCCM.
563 	 */
564 	memset(&name, 0, sizeof name);
565 	if(label == nil)
566 		label = "pjw-face-here";
567 	name.value = (uchar*)label;
568 	name.encoding = XA_STRING;
569 	name.format = 8;
570 	name.nitems = strlen((char*)name.value);
571 
572 	memset(&classhint, 0, sizeof classhint);
573 	classhint.res_name = label;
574 	classhint.res_class = label;
575 
576 	argv[0] = label;
577 	argv[1] = nil;
578 
579 	XSetWMProperties(
580 		_x.display,	/* display */
581 		_x.drawable,	/* window */
582 		&name,		/* XA_WM_NAME property */
583 		&name,		/* XA_WM_ICON_NAME property */
584 		argv,		/* XA_WM_COMMAND */
585 		1,		/* argc */
586 		nil,		/* XA_WM_NORMAL_HINTS */
587 		nil,		/* XA_WM_HINTS */
588 		&classhint	/* XA_WM_CLASSHINTS */
589 	);
590 	XFlush(_x.display);
591 	return 0;
592 }
593 
594 /*
595  * Create a GC with a particular fill style and XXX.
596  * Disable generation of GraphicsExpose/NoExpose events in the GC.
597  */
598 static XGC
599 xgc(XDrawable d, int fillstyle, int foreground)
600 {
601 	XGC gc;
602 	XGCValues v;
603 
604 	memset(&v, 0, sizeof v);
605 	v.function = GXcopy;
606 	v.graphics_exposures = False;
607 	gc = XCreateGC(_x.display, d, GCFunction|GCGraphicsExposures, &v);
608 	if(fillstyle != -1)
609 		XSetFillStyle(_x.display, gc, fillstyle);
610 	if(foreground != -1)
611 		XSetForeground(_x.display, gc, 0);
612 	return gc;
613 }
614 
615 
616 /*
617  * Initialize map with the Plan 9 rgbv color map.
618  */
619 static void
620 plan9cmap(void)
621 {
622 	int r, g, b, cr, cg, cb, v, num, den, idx, v7, idx7;
623 	static int once;
624 
625 	if(once)
626 		return;
627 	once = 1;
628 
629 	for(r=0; r!=4; r++)
630 	for(g = 0; g != 4; g++)
631 	for(b = 0; b!=4; b++)
632 	for(v = 0; v!=4; v++){
633 		den=r;
634 		if(g > den)
635 			den=g;
636 		if(b > den)
637 			den=b;
638 		/* divide check -- pick grey shades */
639 		if(den==0)
640 			cr=cg=cb=v*17;
641 		else {
642 			num=17*(4*den+v);
643 			cr=r*num/den;
644 			cg=g*num/den;
645 			cb=b*num/den;
646 		}
647 		idx = r*64 + v*16 + ((g*4 + b + v - r) & 15);
648 		_x.map[idx].red = cr*0x0101;
649 		_x.map[idx].green = cg*0x0101;
650 		_x.map[idx].blue = cb*0x0101;
651 		_x.map[idx].pixel = idx;
652 		_x.map[idx].flags = DoRed|DoGreen|DoBlue;
653 
654 		v7 = v >> 1;
655 		idx7 = r*32 + v7*16 + g*4 + b;
656 		if((v & 1) == v7){
657 			_x.map7to8[idx7][0] = idx;
658 			if(den == 0) { 		/* divide check -- pick grey shades */
659 				cr = ((255.0/7.0)*v7)+0.5;
660 				cg = cr;
661 				cb = cr;
662 			}
663 			else {
664 				num=17*15*(4*den+v7*2)/14;
665 				cr=r*num/den;
666 				cg=g*num/den;
667 				cb=b*num/den;
668 			}
669 			_x.map7[idx7].red = cr*0x0101;
670 			_x.map7[idx7].green = cg*0x0101;
671 			_x.map7[idx7].blue = cb*0x0101;
672 			_x.map7[idx7].pixel = idx7;
673 			_x.map7[idx7].flags = DoRed|DoGreen|DoBlue;
674 		}
675 		else
676 			_x.map7to8[idx7][1] = idx;
677 	}
678 }
679 
680 /*
681  * Initialize and install the rgbv color map as a private color map
682  * for this application.  It gets the best colors when it has the
683  * cursor focus.
684  *
685  * We always choose the best depth possible, but that might not
686  * be the default depth.  On such "suboptimal" systems, we have to allocate an
687  * empty color map anyway, according to Axel Belinfante.
688  */
689 static int 
690 setupcmap(XWindow w)
691 {
692 	char buf[30];
693 	int i;
694 	u32int p, pp;
695 	XColor c;
696 
697 	if(_x.depth <= 1)
698 		return 0;
699 
700 	if(_x.depth >= 24) {
701 		if(_x.usetable == 0)
702 			_x.cmap = XCreateColormap(_x.display, w, _x.vis, AllocNone); 
703 
704 		/*
705 		 * The pixel value returned from XGetPixel needs to
706 		 * be converted to RGB so we can call rgb2cmap()
707 		 * to translate between 24 bit X and our color. Unfortunately,
708 		 * the return value appears to be display server endian 
709 		 * dependant. Therefore, we run some heuristics to later
710 		 * determine how to mask the int value correctly.
711 		 * Yeah, I know we can look at _x.vis->byte_order but 
712 		 * some displays say MSB even though they run on LSB.
713 		 * Besides, this is more anal.
714 		 */
715 		c = _x.map[19];	/* known to have different R, G, B values */
716 		if(!XAllocColor(_x.display, _x.cmap, &c)){
717 			werrstr("XAllocColor: %r");
718 			return -1;
719 		}
720 		p  = c.pixel;
721 		pp = rgb2cmap((p>>16)&0xff,(p>>8)&0xff,p&0xff);
722 		if(pp != _x.map[19].pixel) {
723 			/* check if endian is other way */
724 			pp = rgb2cmap(p&0xff,(p>>8)&0xff,(p>>16)&0xff);
725 			if(pp != _x.map[19].pixel){
726 				werrstr("cannot detect X server byte order");
727 				return -1;
728 			}
729 
730 			switch(_x.chan){
731 			case RGB24:
732 				_x.chan = BGR24;
733 				break;
734 			case XRGB32:
735 				_x.chan = XBGR32;
736 				break;
737 			default:
738 				werrstr("cannot byteswap channel %s",
739 					chantostr(buf, _x.chan));
740 				break;
741 			}
742 		}
743 	}else if(_x.vis->class == TrueColor || _x.vis->class == DirectColor){
744 		/*
745 		 * Do nothing.  We have no way to express a
746 		 * mixed-endian 16-bit screen, so pretend they don't exist.
747 		 */
748 		if(_x.usetable == 0)
749 			_x.cmap = XCreateColormap(_x.display, w, _x.vis, AllocNone);
750 	}else if(_x.vis->class == PseudoColor){
751 		if(_x.usetable == 0){
752 			_x.cmap = XCreateColormap(_x.display, w, _x.vis, AllocAll); 
753 			XStoreColors(_x.display, _x.cmap, _x.map, 256);
754 			for(i = 0; i < 256; i++){
755 				_x.tox11[i] = i;
756 				_x.toplan9[i] = i;
757 			}
758 		}else{
759 			for(i = 0; i < 128; i++){
760 				c = _x.map7[i];
761 				if(!XAllocColor(_x.display, _x.cmap, &c)){
762 					werrstr("can't allocate colors in 7-bit map");
763 					return -1;
764 				}
765 				_x.tox11[_x.map7to8[i][0]] = c.pixel;
766 				_x.tox11[_x.map7to8[i][1]] = c.pixel;
767 				_x.toplan9[c.pixel] = _x.map7to8[i][0];
768 			}
769 		}
770 	}else{
771 		werrstr("unsupported visual class %d", _x.vis->class);
772 		return -1;
773 	}
774 	return 0;
775 }
776 
777 void
778 flushmemscreen(Rectangle r)
779 {
780 	if(_x.nextscreenpm != _x.screenpm){
781 		qlock(&_x.screenlock);
782 		XSync(_x.display, False);
783 		XFreePixmap(_x.display, _x.screenpm);
784 		_x.screenpm = _x.nextscreenpm;
785 		qunlock(&_x.screenlock);
786 	}
787 
788 	if(r.min.x >= r.max.x || r.min.y >= r.max.y)
789 		return;
790 	XCopyArea(_x.display, _x.screenpm, _x.drawable, _x.gccopy, r.min.x, r.min.y,
791 		Dx(r), Dy(r), r.min.x, r.min.y);
792 	XFlush(_x.display);
793 }
794 
795 void
796 _xexpose(XEvent *e, XDisplay *xd)
797 {
798 	XExposeEvent *xe;
799 	Rectangle r;
800 
801 	qlock(&_x.screenlock);
802 	if(_x.screenpm != _x.nextscreenpm){
803 		qunlock(&_x.screenlock);
804 		return;
805 	}
806 	xe = (XExposeEvent*)e;
807 	r.min.x = xe->x;
808 	r.min.y = xe->y;
809 	r.max.x = xe->x+xe->width;
810 	r.max.y = xe->y+xe->height;
811 	XCopyArea(xd, _x.screenpm, _x.drawable, _x.gccopy, r.min.x, r.min.y,
812 		Dx(r), Dy(r), r.min.x, r.min.y);
813 	XSync(xd, False);
814 	qunlock(&_x.screenlock);
815 }
816 
817 int
818 _xdestroy(XEvent *e, XDisplay *xd)
819 {
820 	XDestroyWindowEvent *xe;
821 
822 	xe = (XDestroyWindowEvent*)e;
823 	if(xe->window == _x.drawable){
824 		_x.destroyed = 1;
825 		return 1;
826 	}
827 	return 0;
828 }
829 
830 int
831 _xconfigure(XEvent *e, XDisplay *xd)
832 {
833 	Rectangle r;
834 	XConfigureEvent *xe = (XConfigureEvent*)e;
835 
836 	if(xe->width == Dx(_x.screenr) && xe->height == Dy(_x.screenr))
837 		return 0;
838 	if(xe->width==0 || xe->height==0)
839 		fprint(2, "ignoring resize to %dx%d\n", xe->width, xe->height);
840 	r = Rect(0, 0, xe->width, xe->height);
841 	qlock(&_x.screenlock);
842 	if(_x.screenpm != _x.nextscreenpm){
843 		XCopyArea(xd, _x.screenpm, _x.drawable, _x.gccopy, r.min.x, r.min.y,
844 			Dx(r), Dy(r), r.min.x, r.min.y);
845 		XSync(xd, False);
846 	}
847 	qunlock(&_x.screenlock);
848 	_x.newscreenr = r;
849 	return 1;
850 }
851 
852 static int
853 xreplacescreenimage(void)
854 {
855 	Memimage *m;
856 	XDrawable pixmap;
857 	Rectangle r;
858 
859 	r = _x.newscreenr;
860 	if(eqrect(_x.screenr, r))
861 		return 0;
862 
863 	pixmap = XCreatePixmap(_x.display, _x.drawable, Dx(r), Dy(r), _x.depth);
864 	m = _xallocmemimage(r, _x.chan, pixmap);
865 	if(_x.nextscreenpm != _x.screenpm)
866 		XFreePixmap(_x.display, _x.nextscreenpm);
867 	_x.nextscreenpm = pixmap;
868 	_x.screenr = r;
869 	_drawreplacescreenimage(m);
870 	return 1;
871 }
872 
873 static int
874 parsewinsize(char *s, Rectangle *r, int *havemin)
875 {
876 	char c, *os;
877 	int i, j, k, l;
878 
879 	os = s;
880 	*havemin = 0;
881 	*r = Rect(0,0,0,0);
882 	if(!isdigit(*s))
883 		goto oops;
884 	i = strtol(s, &s, 0);
885 	if(*s == 'x'){
886 		s++;
887 		if(!isdigit(*s))
888 			goto oops;
889 		j = strtol(s, &s, 0);
890 		r->max.x = i;
891 		r->max.y = j;
892 		if(*s == 0)
893 			return 0;
894 		if(*s != '@')
895 			goto oops;
896 
897 		s++;
898 		if(!isdigit(*s))
899 			goto oops;
900 		i = strtol(s, &s, 0);
901 		if(*s != ',' && *s != ' ')
902 			goto oops;
903 		s++;
904 		if(!isdigit(*s))
905 			goto oops;
906 		j = strtol(s, &s, 0);
907 		if(*s != 0)
908 			goto oops;
909 		*r = rectaddpt(*r, Pt(i,j));
910 		*havemin = 1;
911 		return 0;
912 	}
913 
914 	c = *s;
915 	if(c != ' ' && c != ',')
916 		goto oops;
917 	s++;
918 	if(!isdigit(*s))
919 		goto oops;
920 	j = strtol(s, &s, 0);
921 	if(*s != c)
922 		goto oops;
923 	s++;
924 	if(!isdigit(*s))
925 		goto oops;
926 	k = strtol(s, &s, 0);
927 	if(*s != c)
928 		goto oops;
929 	s++;
930 	if(!isdigit(*s))
931 		goto oops;
932 	l = strtol(s, &s, 0);
933 	if(*s != 0)
934 		goto oops;
935 	*r = Rect(i,j,k,l);
936 	*havemin = 1;
937 	return 0;
938 
939 oops:
940 	werrstr("bad syntax in window size '%s'", os);
941 	return -1;
942 }