/*  * 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 <libc.h>#include <draw.h>#include <event.h> enum {	Edge = 5,	Maxmag = 16}; enum {	Mzoom,	Munzoom,	Mgrid,	Mredraw,	Mexit}; char *menustr[] = {	"zoom",	"unzoom",	"grid",	"redraw",	"exit",	nil}; Menu menu = {	menustr,	nil,	-1}; Point lastp;Image *red;Image *tmp;Image *grid;Image *chequer;int	screenfd;int	mag = 4;int	showgrid = 0;Rectangle	screenr;uchar	*screenbuf; void	magnify(void);void makegrid(void); voiddrawit(void){	Rectangle r;	border(screen, screen->r, Edge, red, ZP);	magnify();	r = insetrect(screen->r, Edge);	draw(screen, r, tmp, nil, tmp->r.min);	flushimage(display, 1);} int bypp; voidmain(int argc, char *argv[]){	Event e;	char buf[5*12];	ulong chan;	int d; 	USED(argc, argv);	if(initdraw(nil, nil, "lens") < 0){		fprint(2, "lens: initdraw failed: %r\n");		exits("initdraw");	}	einit(Emouse|Ekeyboard);	red = allocimage(display, Rect(0, 0, 1, 1), CMAP8, 1, DRed);	chequer = allocimage(display, Rect(0, 0, 2, 2), GREY1, 1, DBlack);	draw(chequer, Rect(0, 0, 1, 1), display->white, nil, ZP);	draw(chequer, Rect(1, 1, 2, 2), display->white, nil, ZP);	lastp = divpt(addpt(screen->r.min, screen->r.max), 2);	screenfd = open("/dev/screen", OREAD);	if(screenfd < 0){		fprint(2, "lens: can't open /dev/screen: %r\n");		exits("screen");	}	if(read(screenfd, buf, sizeof buf) != sizeof buf){		fprint(2, "lens: can't read /dev/screen: %r\n");		exits("screen");	}	chan = strtochan(buf);	d = chantodepth(chan);	if(d < 8){		fprint(2, "lens: can't handle screen format %11.11s\n", buf);		exits("screen");	}	bypp = d/8;	screenr.min.x = atoi(buf+1*12);	screenr.min.y = atoi(buf+2*12);	screenr.max.x = atoi(buf+3*12);	screenr.max.y = atoi(buf+4*12);	screenbuf = malloc(bypp*Dx(screenr)*Dy(screenr));	if(screenbuf == nil){		fprint(2, "lens: buffer malloc failed: %r\n");		exits("malloc");	}	eresized(0); 	for(;;)		switch(event(&e)){		case Ekeyboard:			switch(e.kbdc){			case 'q':			case 0x7f:			case '\04':			caseexit:				exits(nil);			case '=':			case '+':			casezoom:				if(mag < Maxmag){					mag++;					makegrid();					drawit();				}				break;			case 'g':			casegrid:				showgrid = !showgrid;				makegrid();				drawit();				break;			case '-':			case '_':			caseunzoom:				if(mag > 1){					mag--;					makegrid();					drawit();				}				break;			case '.':			case ' ':			caseredraw:				drawit();				break;			case '1': case '2': case '3': case '4': case '5': case '6': case '7': case '8': case '9': case'0':				mag = e.kbdc-'0';				if(mag == 0)					mag = 10;				makegrid();				drawit();				break;			}			break;		case Emouse:			if(e.mouse.buttons & 1){				lastp = e.mouse.xy;				drawit();			}			if(e.mouse.buttons & 4)				switch(emenuhit(3, &e.mouse, &menu)){				case Mzoom:					goto casezoom;				case Munzoom:					goto caseunzoom;				case Mgrid:					goto casegrid;				case Mredraw:					goto caseredraw;				case Mexit:					goto caseexit;				}			break;		}} voidmakegrid(void){	int m;	if (grid != nil) {		freeimage(grid);		grid = nil;	}	if (showgrid) {		m = mag;		if (m < 5)			m *= 10;		grid = allocimage(display, Rect(0, 0, m, m),			CHAN2(CGrey, 8, CAlpha, 8), 1, DTransparent);		if (grid != nil){			draw(grid, Rect(0, 0, m, 1), chequer, nil, ZP);			draw(grid, Rect(0, 1, 1, m), chequer, nil, ZP);		}	}} voideresized(int new){	if(new && getwindow(display, Refnone) < 0){		fprint(2, "lens: can't reattach to window: %r\n");		exits("attach");	}	freeimage(tmp);	tmp = allocimage(display, Rect(0, 0, Dx(screen->r)-Edge, Dy(screen->r)-Edge+Maxmag), screen->chan, 0, DNofill);	if(tmp == nil){		fprint(2, "lens: allocimage failed: %r\n");		exits("allocimage");	}	drawit();} voidmagnify(void){	int x, y, xx, yy, dd, i;	int dx, dy;	int xoff, yoff;	uchar out[8192];	uchar sp[4]; 	dx = (Dx(tmp->r)+mag-1)/mag;	dy = (Dy(tmp->r)+mag-1)/mag;	xoff = lastp.x-Dx(tmp->r)/(mag*2);	yoff  = lastp.y-Dy(tmp->r)/(mag*2); 	yy = yoff;	dd = dy;	if(yy < 0){		dd += dy;		yy = 0;	}	if(yy+dd > Dy(screenr))		dd = Dy(screenr)-yy;	seek(screenfd, 5*12+bypp*yy*Dx(screenr), 0);	if(readn(screenfd, screenbuf+bypp*yy*Dx(screenr), bypp*Dx(screenr)*dd) != bypp*Dx(screenr)*dd){		fprint(2, "lens: can't read screen: %r\n");		return;	} 	for(y=0; y<dy; y++){		yy = yoff+y;		if(yy>=0 && yy<Dy(screenr))			for(x=0; x<dx; x++){				xx = xoff+x;				if(xx>=0 && xx<Dx(screenr))	/* snarf pixel at xx, yy */					for(i=0; i<bypp; i++)						sp[i] = screenbuf[bypp*(yy*Dx(screenr)+xx)+i];				else					sp[0] = sp[1] = sp[2] = sp[3] = 0; 				for(xx=0; xx<mag; xx++)					if(x*mag+xx < tmp->r.max.x)						for(i=0; i<bypp; i++)							out[(x*mag+xx)*bypp+i] = sp[i];			}		else			memset(out, 0, bypp*Dx(tmp->r));		for(yy=0; yy<mag && y*mag+yy<Dy(tmp->r); yy++){			werrstr("no error");			if(loadimage(tmp, Rect(0, y*mag+yy, Dx(tmp->r), y*mag+yy+1), out, bypp*Dx(tmp->r)) != bypp*Dx(tmp->r)){				exits("load");			}		}	}	if (showgrid && mag && grid)		draw(tmp, tmp->r, grid, nil, mulpt(Pt(xoff, yoff), mag));}