gview.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

	r.min.x = screen->r.max.x - rt_border + framewd;
	r.max.y = y0 + dy;
	r.max.x = screen->r.max.x;
	for (i=0; i<n; i++) {
		draw(screen, r, clrtab[i].im, display->opaque, r.min);
		r.min.y = r.max.y;
		r.max.y += dy;
	}
	return dy;
}


Image* palette_color(Point pt, int dy, int n)
{				/* mouse at pt, patch size dy, n colors */
	int yy;
	if (screen->r.max.x - pt.x > rt_border - framewd)
		return 0;
	yy = pt.y - (screen->r.min.y + top_border);
	if (yy<0 || yy>=n*dy)
		return 0;
	return clrtab[yy/dy].im;
}


void all_set_clr(fpolygons* fps, Image* clr)
{
	fpolygon* p;
	for (p=fps->p; p!=0; p=p->link)
		p->clr = clr;
}
	

void do_recolor(int but, Mouse* m, int alluniv)
{
	int nclr = clr_id(DWhite);
	int dy = draw_palette(nclr);
	Image* clr;
	if (!get_1click(but, m, 0)) {
		eresized(0);
		return;
	}
	clr = palette_color(m->xy, dy, nclr);
	if (clr != 0) {
		if (alluniv)
			all_set_clr(&univ, clr);
		else	cur_sel.fp->clr = clr;
	}
	eresized(0);
	lift_button(but, m, Never);
}


/****************************** Move and rotate  ******************************/

void prepare_mv(const fpolygon* fp)
{
	Rectangle r = screen->r;
	Image* scr0;
	int dt = 1 + fp->thick;
	r.min.x+=lft_border-dt;  r.min.y+=top_border-dt;
	r.max.x-=rt_border-dt;   r.max.y-=bot_border-dt;
	if (mv_bkgd!=0 && mv_bkgd->repl==0)
		freeimage(mv_bkgd);
	mv_bkgd = allocimage(display, r, CMAP8, 0, DNofill);
	if (mv_bkgd==0)
		mv_bkgd = display->white;
	else {	transform tr = cur_trans();
		draw(mv_bkgd, r, screen, display->opaque, r.min);
		draw(mv_bkgd, sel_dot_box(&tr), sel_bkg, display->opaque, ZP);
		scr0 = screen;
		screen = mv_bkgd;
		draw_fpoly(fp, &tr, display->white);
		screen = scr0;
	}
}


void move_fp(fpolygon* fp, double dx, double dy)
{
	fpoint *p, *pn=fp->p+fp->n;
	for (p=fp->p; p<=pn; p++) {
		(p->x) += dx;
		(p->y) += dy;
	}
	(fp->bb.min.x)+=dx;  (fp->bb.min.y)+=dy;
	(fp->bb.max.x)+=dx;  (fp->bb.max.y)+=dy;
}


void rotate_fp(fpolygon* fp, fpoint o, double theta)
{
	double s=sin(theta), c=cos(theta);
	fpoint *p, *pn=fp->p+fp->n;
	for (p=fp->p; p<=pn; p++) {
		double x=p->x-o.x, y=p->y-o.y;
		(p->x) = o.x + c*x - s*y;
		(p->y) = o.y + s*x + c*y;
	}
	set_fbb(fp);
}


/* Move the selected fpolygon so the selected point tracks the mouse, and return
   the total amount of movement.  Button but has already been held down for at
   least Mv_delay milliseconds and the mouse might have moved some distance.
*/
fpoint do_move(int but, Mouse* m)
{
	transform tr = cur_trans();
	int bbit = Button_bit(but);
	fpolygon* fp = cur_sel.fp;
	fpoint loc, loc0=cur_sel.p;
	double tsav = cur_sel.t;
	unselect(&tr);
	do {	latest_mouse(but, m);
		(fp->thick)++;		/* line() DISAGREES WITH ITSELF */
		draw_fpoly(fp, &tr, mv_bkgd);
		(fp->thick)--;
		do_untransform(&loc, &tr, &m->xy);
		move_fp(fp, loc.x-cur_sel.p.x, loc.y-cur_sel.p.y);
		cur_sel.p = loc;
		draw_fpoly(fp, &tr, fp->clr);
	} while (m->buttons & bbit);
	cur_sel.t = tsav;
	reselect(&tr);
	loc.x -= loc0.x;
	loc.y -= loc0.y;
	return loc;
}


double dir_angle(const Point* pt, const transform* tr)
{
	fpoint p;
	double dy, dx;
	do_untransform(&p, tr, pt);
	dy=p.y-cur_sel.p.y;  dx=p.x-cur_sel.p.x;
	return (dx==0 && dy==0) ? 0.0 : atan2(dy, dx);
}


/* Rotate the selected fpolygon around the selection point so as to track the
   direction angle from the selected point to m->xy.  Stop when button but goes
   up and return the total amount of rotation in radians.
*/
double do_rotate(int but, Mouse* m)
{
	transform tr = cur_trans();
	int bbit = Button_bit(but);
	fpolygon* fp = cur_sel.fp;
	double theta0 = dir_angle(&m->xy, &tr);
	double th, theta = theta0;
	do {	latest_mouse(but, m);
		(fp->thick)++;		/* line() DISAGREES WITH ITSELF */
		draw_fpoly(fp, &tr, mv_bkgd);
		(fp->thick)--;
		th = dir_angle(&m->xy, &tr);
		rotate_fp(fp, cur_sel.p, th-theta);
		theta = th;
		draw_fpoly(fp, &tr, fp->clr);
	} while (m->buttons & bbit);
	unselect(&tr);
	cur_sel = prev_sel;
	reselect(&tr);
	return theta - theta0;
}



/********************************* Edit menu  *********************************/

typedef enum e_index {
		Erecolor, Ethick, Edelete, Eundo, Erotate, Eoptions,
		Emove
} e_index;

char* e_items[Eoptions+1];

Menu e_menu = {e_items, 0, 0};


typedef struct e_action {
	e_index typ;			/* What type of action */
	fpolygon* fp;			/* fpolygon the action applies to */
	Image* clr;			/* color to use if typ==Erecolor */
	double amt;			/* rotation angle or line thickness */
	fpoint pt;			/* movement vector or rotation center */
	struct e_action* link;		/* next in a stack */
} e_action;

e_action* unact = 0;			/* heads a linked list of actions */
e_action* do_undo(e_action*);		/* pop off an e_action and (un)do it */
e_action* save_act(e_action*,e_index);	/* append new e_action for status quo */


void save_mv(fpoint movement)
{
	unact = save_act(unact, Emove);
	unact->pt = movement;
}


void init_e_menu(void)
{
	char* u = "can't undo";
	e_items[Erecolor] = "recolor";
	e_items[Edelete] = "delete";
	e_items[Erotate] = "rotate";
	e_items[Eoptions-cantmv] = 0;
	e_items[Ethick] = (cur_sel.fp->thick >0) ? "thin" : "thick";
	if (unact!=0)
		switch (unact->typ) {
		case Erecolor: u="uncolor"; break;
		case Ethick: u=(unact->fp->thick==0) ? "unthin" : "unthicken";
			break;
		case Edelete: u="undelete"; break;
		case Emove: u="unmove"; break;
		case Erotate: u="unrotate"; break;
		}
	e_items[Eundo] = u;
}


void do_emenu(int but, Mouse* m)
{
	int h;
	if (cur_sel.t < 0)
		return;
	init_e_menu();
	h = emenuhit(but, m, &e_menu);
	switch(h) {
	case Ethick: unact = save_act(unact, h);
		cur_sel.fp->thick ^= 1;
		eresized(0);
		break;
	case Edelete: unact = save_act(unact, h);
		fp_remove(&univ, cur_sel.fp);
		unselect(0);
		eresized(0);
		break;
	case Erecolor: unact = save_act(unact, h);
		do_recolor(but, m, 0);
		break;
	case Erotate: unact = save_act(unact, h);
		prepare_mv(cur_sel.fp);
		if (get_1click(but, m, 0)) {
			unact->pt = cur_sel.p;
			unact->amt = do_rotate(but, m);
		}
		break;
	case Eundo: unact = do_undo(unact);
		break;
	}
}



/******************************* Undoing edits  *******************************/

e_action* save_act(e_action* a0, e_index typ)
{					/* append new e_action for status quo */
	e_action* a = malloc(sizeof(e_action));
	a->link = a0;
	a->pt.x = a->pt.y = 0.0;
	a->amt = cur_sel.fp->thick;
	a->clr = cur_sel.fp->clr;
	a->fp = cur_sel.fp;
	a->typ = typ;
	return a;
}


/* This would be trivial except it's nice to preserve the selection in order to make
   it easy to undo a series of moves.  (There's no do_unrotate() because it's harder
   and less important to preserve the selection in that case.)
*/
void do_unmove(e_action* a)
{
	double tsav = cur_sel.t;
	unselect(0);
	move_fp(a->fp, -a->pt.x, -a->pt.y);
	if (a->fp == cur_sel.fp) {
		cur_sel.p.x -= a->pt.x;
		cur_sel.p.y -= a->pt.y;
	}
	cur_sel.t = tsav;
	reselect(0);
}


e_action* do_undo(e_action* a0)		/* pop off an e_action and (un)do it */
{
	e_action* a = a0;
	if (a==0)
		return 0;
	switch(a->typ) {
	case Ethick: a->fp->thick = a->amt;
		eresized(0);
		break;
	case Erecolor: a->fp->clr = a->clr;
		eresized(0);
		break;
	case Edelete: 
		a->fp->link = univ.p;
		univ.p = a->fp;
		grow_bb(&univ.bb, &a->fp->bb);
		eresized(0);
		break;
	case Emove:
		do_unmove(a);
		eresized(0);
		break;
	case Erotate:
		unselect(0);
		rotate_fp(a->fp, a->pt, -a->amt);
		eresized(0);
		break;
	}
	a0 = a->link;
	free(a);
	return a0;
}



/********************************* Main menu  *********************************/

enum m_index {     Mzoom_in,  Mzoom_out,  Munzoom,  Mslant,    Munslant,
		Msquare_up,  Mrecenter,  Mrecolor,  Mrestack,  Mread,
		Mwrite,      Mexit};
char* m_items[] = {"zoom in", "zoom out", "unzoom", "slant",   "unslant",
		"square up", "recenter", "recolor", "restack", "read",
		"write",     "exit", 0};

Menu m_menu = {m_items, 0, 0};


void do_mmenu(int but, Mouse* m)
{
	int e, h = emenuhit(but, m, &m_menu);
	switch (h) {
	case Mzoom_in:
		disp_zoomin(egetrect(but,m));
		eresized(0);
		break;
	case Mzoom_out:
		disp_zoomout(egetrect(but,m));
		eresized(0);
		break;
	case Msquare_up:
		disp_squareup();
		eresized(0);
		break;
	case Munzoom:
		init_disp();
		eresized(0);
		break;
	case Mrecenter:
		if (get_1click(but, m, &bullseye)) {
			recenter_disp(m->xy);
			eresized(0);
			lift_button(but, m, Never);
		}
		break;
	case Mslant:
		if (cur_sel.t>=0 && prev_sel.t>=0) {
			slant_disp(prev_sel.p, cur_sel.p);
			eresized(0);
		}
		break;
	case Munslant:
		univ.slant_ht = univ.disp.max.y - univ.disp.min.y;
		eresized(0);
		break;
	case Mrecolor:
		do_recolor(but, m, 1);
		break;
	case Mrestack:
		fps_invert(&univ);
		eresized(0);
		break;
	case Mread:
		e = doinput(prompt_text("File:"));
		if (e==0)
			eresized(0);
		else if (e<0)
			show_mytext(" - can't read");
		else {
			char ebuf[80];
			snprintf(ebuf, 80, " - error line %d", e);
			show_mytext(ebuf);
		}
		break;
	case Mwrite:
		if (!dooutput(prompt_text("File:")))
			show_mytext(" - can't write");
		break;
	case Mexit:
		exits("");
	}
}



/****************************** Handling events  ******************************/

void doevent(void)
{
	ulong etype;
	int mobile;
	ulong mvtime;
	Event	ev;

	etype = eread(Emouse|Ekeyboard, &ev);
	if(etype & Emouse) {
		if (ev.mouse.buttons & But1) {
			do_select(ev.mouse.xy);
			mvtime = Never;
			mobile = !cantmv && cur_sel.t>=0;
			if (mobile) {
				mvtime = ev.mouse.msec + Mv_delay;
				prepare_mv(cur_sel.fp);
			}
			if (!lift_button(1, &ev.mouse, mvtime) && mobile)
				save_mv(do_move(1, &ev.mouse));
		} else if (ev.mouse.buttons & But2)
			do_emenu(2, &ev.mouse);
		else if (ev.mouse.buttons & But3)
			do_mmenu(3, &ev.mouse);
	}
	/* no need to check (etype & Ekeyboard)--there are no keyboard commands */
}



/******************************** Main program ********************************/

extern char* argv0;

void usage(void)
{
	int i;
	fprintf(stderr,"Usage %s [options] [infile]\n", argv0);
	fprintf(stderr,
"option ::= -l logfile | -m | -p\n"
"\n"
"Read a polygonal line graph in an ASCII format (one x y pair per line, delimited\n"
"by spaces with a label after each polyline), and view it interactively.  Use\n"
"standard input if no infile is specified.\n"
"Option -l specifies a file in which to log the coordinates of each point selected.\n"
"(Clicking a point with button one selects it and displays its coordinates and\n"
"the label of its polylone.)  Option -m allows polylines to be moved and rotated.\n"
"The -p option plots only the vertices of the polygons.\n"
"The polyline labels can use the following color names:"
	);
	for (i=0; clrtab[i].c!=DNofill; i++)
		fprintf(stderr,"%s%8s", (i%8==0 ? "\n" : "  "), clrtab[i].nam);
	fputc('\n', stderr);
	exits("usage");
}

void main(int argc, char *argv[])
{
	int e;

	ARGBEGIN {
	case 'm':
		cantmv=0;
		break;
	case 'l':
		logfil = fopen(ARGF(),"w");
		break;
	case 'p':
		plotdots++;
		break;
	default:
		usage();
	} ARGEND;

	if(initdraw(0, 0, "gview") < 0)
		exits("initdraw");
	einit(Emouse|Ekeyboard);

	do {
		e = doinput(*argv ? *argv : "-");
		if (e < 0) {
			fprintf(stderr,"Cannot read input file %s\n", *argv);
			exits("no valid input file");
		} else if (e > 0) {
			fprintf(stderr,"Bad syntax at line %d of file %s\n", e, *argv ? *argv : "-");
			exits("bad syntax in input");
		}
	} while (*argv && *++argv);
	init_disp();
	init_clrtab();
	set_default_clrs(&univ, 0);
	adjust_border(display->defaultfont);
	cur_sel.t = prev_sel.t = -1;
	eresized(0);
	for(;;)
		doevent();
}