view.c

这是一个同样来自贝尔实验室的和UNIX有着渊源的操作系统, 其简洁的设计和实现易于我们学习和理解

							break;
						/* use the smaller side to expand */
						if(Dx(r) < Dy(r))
							delta = (double)Dx(im->r)/(double)Dx(r);
						else
							delta = (double)Dy(im->r)/(double)Dy(r);

						esetcursor(&reading);
						tmp = xallocimage(display, 
								Rect(0, 0, (int)((double)Dx(im->r)*delta), (int)((double)Dy(im->r)*delta)), 
								im->chan, 0, DBlack);
						if(tmp == nil) {
							fprint(2, "out of memory during zoom: %r\n");
							wexits("memory");
						}
						resample(im, tmp);
						freeimage(im);
						im = tmp;
						esetcursor(nil);
						ul = screen->r.min;
						redraw(screen);
						flushimage(display, 1);
						break;
					}
				case Fit:	/* fit */
					{
						double delta;
						Rectangle r;
						
						delta = (double)Dx(screen->r)/(double)Dx(im->r);
						if((double)Dy(im->r)*delta > Dy(screen->r))
							delta = (double)Dy(screen->r)/(double)Dy(im->r);

						r = Rect(0, 0, (int)((double)Dx(im->r)*delta), (int)((double)Dy(im->r)*delta));
						esetcursor(&reading);
						tmp = xallocimage(display, r, im->chan, 0, DBlack);
						if(tmp == nil) {
							fprint(2, "out of memory during fit: %r\n");
							wexits("memory");
						}
						resample(im, tmp);
						freeimage(im);
						im = tmp;
						esetcursor(nil);
						ul = screen->r.min;
						redraw(screen);
						flushimage(display, 1);
						break;
					}
				case Rot:	/* rotate 90 */
					esetcursor(&reading);
					im = rot90(im);
					esetcursor(nil);
					angle = (angle+90) % 360;
					redraw(screen);
					flushimage(display, 1);
					break;
				case Upside: 	/* upside-down */
					if(im==nil)
						break;
					esetcursor(&reading);
					rot180(im);
					esetcursor(nil);
					angle = (angle+180) % 360;
					redraw(screen);
					flushimage(display, 1);
					break;
				case Restore:	/* restore */
					showpage(page, &menu);
					break;
				case Reverse:	/* reverse */
					if(doc->fwdonly)
						break;
					reverse = !reverse;
					menu.lasthit = doc->npage-1-menu.lasthit;
	
					if(page == 0 || page == doc->npage-1) {
						page = doc->npage-1-page;
						showpage(page, &menu);
					}
					break;
				case Write: /* write */
					esetcursor(&reading);
					s = writebitmap();
					if(s)
						string(screen, addpt(screen->r.min, Pt(5,5)), display->black, ZP,
							display->defaultfont, s);
					esetcursor(nil);
					flushimage(display, 1);
					break;
				case Del: /* delete */
					if(doc->rmpage && page < doc->npage) {
						if(doc->rmpage(doc, page) >= 0) {
							if(doc->npage < 0)
								wexits(0);
							if(page >= doc->npage)
								page = doc->npage-1;
							showpage(page, &menu);
						}
					}
					break;
				case Exit:	/* exit */
					return;
				case Empty1:
				case Empty2:
				case Empty3:
					break;

				}; 

	
	
			case Right:
				if(doc->npage == 0)
					break;

				oldpage = page;
				n = emenuhit(RMenu, &m, &menu);
				if(n == -1)
					break;
	
				if(doc->fwdonly) {
					switch(n){
					case 0:	/* this page */
						break;
					case 1:	/* next page */
						showpage(++page, &menu);
						break;
					case 2:	/* exit */
						return;
					}
					break;
				}
	
				if(n == doc->npage)
					return;
				else
					page = reverse ? doc->npage-1-n : n;
	
				if(oldpage != page)
					showpage(page, &menu);
				nxt = 0;
				break;
			}
			break;

		case Eplumb:
			pm = e.v;
			if(pm->ndata <= 0){
				plumbfree(pm);
				break;
			}
			if(showdata(pm)) {
				s = estrdup("/tmp/pageplumbXXXXXXX");
				fd = opentemp(s);
				write(fd, pm->data, pm->ndata);
				/* lose fd reference on purpose; the file is open ORCLOSE */
			} else if(pm->data[0] == '/') {
				s = estrdup(pm->data);
			} else {
				s = emalloc(strlen(pm->wdir)+1+pm->ndata+1);
				sprint(s, "%s/%s", pm->wdir, pm->data);
				cleanname(s);
			}
			if((i = doc->addpage(doc, s)) >= 0) {
				page = i;
				unhide();
				showpage(page, &menu);
			}
			free(s);
			plumbfree(pm);
			break;
		}
	}
}

Image *gray;

/*
 * A draw operation that touches only the area contained in bot but not in top.
 * mp and sp get aligned with bot.min.
 */
static void
gendrawdiff(Image *dst, Rectangle bot, Rectangle top, 
	Image *src, Point sp, Image *mask, Point mp, int op)
{
	Rectangle r;
	Point origin;
	Point delta;

	USED(op);

	if(Dx(bot)*Dy(bot) == 0)
		return;

	/* no points in bot - top */
	if(rectinrect(bot, top))
		return;

	/* bot - top ≡ bot */
	if(Dx(top)*Dy(top)==0 || rectXrect(bot, top)==0){
		gendrawop(dst, bot, src, sp, mask, mp, op);
		return;
	}

	origin = bot.min;
	/* split bot into rectangles that don't intersect top */
	/* left side */
	if(bot.min.x < top.min.x){
		r = Rect(bot.min.x, bot.min.y, top.min.x, bot.max.y);
		delta = subpt(r.min, origin);
		gendrawop(dst, r, src, addpt(sp, delta), mask, addpt(mp, delta), op);
		bot.min.x = top.min.x;
	}

	/* right side */
	if(bot.max.x > top.max.x){
		r = Rect(top.max.x, bot.min.y, bot.max.x, bot.max.y);
		delta = subpt(r.min, origin);
		gendrawop(dst, r, src, addpt(sp, delta), mask, addpt(mp, delta), op);
		bot.max.x = top.max.x;
	}

	/* top */
	if(bot.min.y < top.min.y){
		r = Rect(bot.min.x, bot.min.y, bot.max.x, top.min.y);
		delta = subpt(r.min, origin);
		gendrawop(dst, r, src, addpt(sp, delta), mask, addpt(mp, delta), op);
		bot.min.y = top.min.y;
	}

	/* bottom */
	if(bot.max.y > top.max.y){
		r = Rect(bot.min.x, top.max.y, bot.max.x, bot.max.y);
		delta = subpt(r.min, origin);
		gendrawop(dst, r, src, addpt(sp, delta), mask, addpt(mp, delta), op);
		bot.max.y = top.max.y;
	}
}

static void
drawdiff(Image *dst, Rectangle bot, Rectangle top, Image *src, Image *mask, Point p, int op)
{
	gendrawdiff(dst, bot, top, src, p, mask, p, op);
}

/*
 * Translate the image in the window by delta.
 */
static void
translate(Point delta)
{
	Point u;
	Rectangle r, or;

	if(im == nil)
		return;

	u = pclip(addpt(ul, delta), ulrange);
	delta = subpt(u, ul);
	if(delta.x == 0 && delta.y == 0)
		return;

	/*
	 * The upper left corner of the image is currently at ul.
	 * We want to move it to u.
	 */
	or = rectaddpt(Rpt(ZP, Pt(Dx(im->r), Dy(im->r))), ul);
	r = rectaddpt(or, delta);

	drawop(screen, r, screen, nil, ul, S);
	ul = u;

	/* fill in gray where image used to be but isn't. */
	drawdiff(screen, insetrect(or, -2), insetrect(r, -2), gray, nil, ZP, S);

	/* fill in black border */
	drawdiff(screen, insetrect(r, -2), r, display->black, nil, ZP, S);

	/* fill in image where it used to be off the screen. */
	if(rectclip(&or, screen->r))
		drawdiff(screen, r, rectaddpt(or, delta), im, nil, im->r.min, S);
	else
		drawop(screen, r, im, nil, im->r.min, S);
	flushimage(display, 1);
}

void
redraw(Image *screen)
{
	Rectangle r;

	if(im == nil)
		return;

	ulrange.max = screen->r.max;
	ulrange.min = subpt(screen->r.min, Pt(Dx(im->r), Dy(im->r)));

	ul = pclip(ul, ulrange);
	drawop(screen, screen->r, im, nil, subpt(im->r.min, subpt(ul, screen->r.min)), S);

	if(im->repl)
		return;

	/* fill in any outer edges */
	/* black border */
	r = rectaddpt(im->r, subpt(ul, im->r.min));
	border(screen, r, -2, display->black, ZP);
	r.min = subpt(r.min, Pt(2,2));
	r.max = addpt(r.max, Pt(2,2));

	/* gray for the rest */
	if(gray == nil) {
		gray = xallocimage(display, Rect(0,0,1,1), RGB24, 1, 0x888888FF);
		if(gray == nil) {
			fprint(2, "g out of memory: %r\n");
			wexits("mem");
		}
	}
	border(screen, r, -4000, gray, ZP);
//	flushimage(display, 0);	
}

void
eresized(int new)
{
	Rectangle r;
	r = screen->r;
	if(new && getwindow(display, Refnone) < 0)
		fprint(2,"can't reattach to window");
	ul = addpt(ul, subpt(screen->r.min, r.min));
	redraw(screen);
}

/* clip p to be in r */
Point
pclip(Point p, Rectangle r)
{
	if(p.x < r.min.x)
		p.x = r.min.x;
	else if(p.x >= r.max.x)
		p.x = r.max.x-1;

	if(p.y < r.min.y)
		p.y = r.min.y;
	else if(p.y >= r.max.y)
		p.y = r.max.y-1;

	return p;
}

/*
 * resize is perhaps a misnomer. 
 * this really just grows the window to be at least dx across
 * and dy high.  if the window hits the bottom or right edge,
 * it is backed up until it hits the top or left edge.
 */
void
resize(int dx, int dy)
{
	static Rectangle sr;
	Rectangle r, or;

	dx += 2*Borderwidth;
	dy += 2*Borderwidth;
	if(wctlfd < 0){
		wctlfd = open("/dev/wctl", OWRITE);
		if(wctlfd < 0)
			return;
	}

	r = insetrect(screen->r, -Borderwidth);
	if(Dx(r) >= dx && Dy(r) >= dy)
		return;

	if(Dx(sr)*Dy(sr) == 0)
		sr = screenrect();

	or = r;

	r.max.x = max(r.min.x+dx, r.max.x);
	r.max.y = max(r.min.y+dy, r.max.y);
	if(r.max.x > sr.max.x){
		if(Dx(r) > Dx(sr)){
			r.min.x = 0;
			r.max.x = sr.max.x;
		}else
			r = rectaddpt(r, Pt(sr.max.x-r.max.x, 0));
	}
	if(r.max.y > sr.max.y){
		if(Dy(r) > Dy(sr)){
			r.min.y = 0;
			r.max.y = sr.max.y;
		}else
			r = rectaddpt(r, Pt(0, sr.max.y-r.max.y));
	}

	/*
	 * Sometimes we can't actually grow the window big enough,
	 * and resizing it to the same shape makes it flash.
	 */
	if(Dx(r) == Dx(or) && Dy(r) == Dy(or))
		return;

	fprint(wctlfd, "resize -minx %d -miny %d -maxx %d -maxy %d\n",
		r.min.x, r.min.y, r.max.x, r.max.y);
}

/*
 * If we allocimage after a resize but before flushing the draw buffer,
 * we won't have seen the reshape event, and we won't have called
 * getwindow, and allocimage will fail.  So we flushimage before every alloc.
 */
Image*
xallocimage(Display *d, Rectangle r, ulong chan, int repl, ulong val)
{
	flushimage(display, 0);
	return allocimage(d, r, chan, repl, val);
}

/* all code below this line should be in the library, but is stolen from colors instead */
static char*
rdenv(char *name)
{
	char *v;
	int fd, size;

	fd = open(name, OREAD);
	if(fd < 0)
		return 0;
	size = seek(fd, 0, 2);
	v = malloc(size+1);
	if(v == 0){
		fprint(2, "page: can't malloc: %r\n");
		wexits("no mem");
	}
	seek(fd, 0, 0);
	read(fd, v, size);
	v[size] = 0;
	close(fd);
	return v;
}

void
newwin(void)
{
	char *srv, *mntsrv;
	char spec[100];
	int srvfd, cons, pid;

	switch(rfork(RFFDG|RFPROC|RFNAMEG|RFENVG|RFNOTEG|RFNOWAIT)){
	case -1:
		fprint(2, "page: can't fork: %r\n");
		wexits("no fork");
	case 0:
		break;
	default:
		wexits(0);
	}

	srv = rdenv("/env/wsys");
	if(srv == 0){
		mntsrv = rdenv("/mnt/term/env/wsys");
		if(mntsrv == 0){
			fprint(2, "page: can't find $wsys\n");
			wexits("srv");
		}
		srv = malloc(strlen(mntsrv)+10);
		sprint(srv, "/mnt/term%s", mntsrv);
		free(mntsrv);
		pid  = 0;			/* can't send notes to remote processes! */
	}else
		pid = getpid();
	srvfd = open(srv, ORDWR);
	free(srv);
	if(srvfd == -1){
		fprint(2, "page: can't open %s: %r\n", srv);
		wexits("no srv");
	}
	sprint(spec, "new -pid %d", pid);
	if(mount(srvfd, -1, "/mnt/wsys", 0, spec) == -1){
		fprint(2, "page: can't mount /mnt/wsys: %r (spec=%s)\n", spec);
		wexits("no mount");
	}
	close(srvfd);
	unmount("/mnt/acme", "/dev");
	bind("/mnt/wsys", "/dev", MBEFORE);
	cons = open("/dev/cons", OREAD);
	if(cons==-1){
	NoCons:
		fprint(2, "page: can't open /dev/cons: %r");
		wexits("no cons");
	}
	dup(cons, 0);
	close(cons);
	cons = open("/dev/cons", OWRITE);
	if(cons==-1)
		goto NoCons;
	dup(cons, 1);
	dup(cons, 2);
	close(cons);
//	wctlfd = open("/dev/wctl", OWRITE);
}

Rectangle
screenrect(void)
{
	int fd;
	char buf[12*5];

	fd = open("/dev/screen", OREAD);
	if(fd == -1)
		fd=open("/mnt/term/dev/screen", OREAD);
	if(fd == -1){
		fprint(2, "page: can't open /dev/screen: %r\n");
		wexits("window read");
	}
	if(read(fd, buf, sizeof buf) != sizeof buf){
		fprint(2, "page: can't read /dev/screen: %r\n");
		wexits("screen read");
	}
	close(fd);
	return Rect(atoi(buf+12), atoi(buf+24), atoi(buf+36), atoi(buf+48));
}

void
zerox(void)
{
	int pfd[2];

	pipe(pfd);
	switch(rfork(RFFDG|RFREND|RFPROC)) {
		case -1:
			wexits("cannot fork in zerox: %r");
		case 0: 
			dup(pfd[1], 0);
			close(pfd[0]);
			execl("/bin/page", "page", "-w", nil);
			wexits("cannot exec in zerox: %r\n");
		default:
			close(pfd[1]);
			writeimage(pfd[0], im, 0);
			close(pfd[0]);
			break;
	}
}