shithub: prez

ref: cb6f6fc863f56fecdf9adc97e0cd48255b14841c
dir: /canvas.c/

#include <u.h>
#include <libc.h>
#include <draw.h>
#include "dat.h"
#include "fns.h"

Image *back;
Image *canvas;
Image *canvas2;
Point spos;		/* position on screen */
Point cpos;		/* position on canvas */

static Image **pages;
static int npages;

static int nundo = 0;
static Image *undo[1024];

Point
s2c(Point p)
{
	p = subpt(p, spos);
	if(p.x < 0) p.x -= zoom-1;
	if(p.y < 0) p.y -= zoom-1;
	return addpt(divpt(p, zoom), cpos);
}

Point
c2s(Point p)
{
	return addpt(mulpt(subpt(p, cpos), zoom), spos);
}

Rectangle
c2sr(Rectangle r)
{
	return Rpt(c2s(r.min), c2s(r.max));
}

void
save(Rectangle r, int flip)
{
	Image *tmp;
	int x;

	if(canvas==nil || nundo<0)
		return;
	if(!rectclip(&r, canvas->r))
		return;
	if(flip){
		draw(canvas2, r, canvas, nil, ZP);
		return;
	}
	if((tmp = allocimage(display, r, canvas->chan, 0, DNofill)) == nil)
		return;
	draw(tmp, r, canvas, nil, r.min);
	x = nundo++ % nelem(undo);
	if(undo[x])
		freeimage(undo[x]);
	undo[x] = tmp;
}

void
shrinksaved(Rectangle r)
{
	Image *tmp;
	int x;

	if(canvas==nil || canvas2==nil)
		return;
	if(!rectclip(&r, canvas2->r))
		return;
	if((tmp = allocimage(display, r, canvas->chan, 0, DNofill)) == nil)
		return;
	draw(tmp, r, canvas2, nil, r.min);
	x = nundo++ % nelem(undo);
	if(undo[x])
		freeimage(undo[x]);
	undo[x] = tmp;
}

void
restore(int n)
{
	Image *tmp;
	int x;

	while(nundo > 0){
		if(n-- == 0)
			return;
		x = --nundo % nelem(undo);
		if((tmp = undo[x]) == nil)
			return;
		undo[x] = nil;
		if(canvas == nil || canvas->chan != tmp->chan){
			freeimage(canvas);
			canvas = tmp;
			update(nil);
		} else {
			expand(tmp->r);
			draw(canvas, tmp->r, tmp, nil, tmp->r.min);
			update(&tmp->r);
			freeimage(tmp);
		}
	}
}

// FIXME: don't change canvas size once set
void
expand(Rectangle r)
{
	Rectangle nr;
	Image *tmp;

	if(canvas==nil){
		if((canvas = allocimage(display, r, screen->chan, 0, DNofill)) == nil
		|| (canvas2 = allocimage(display, r, screen->chan, 0, DNofill)) == nil)
			sysfatal("allocimage: %r");
		draw(canvas, canvas->r, back, nil, ZP);
		return;
	}
	nr = canvas->r;
	combinerect(&nr, r);
	if(eqrect(nr, canvas->r))
		return;
	if((tmp = allocimage(display, nr, canvas->chan, 0, DNofill)) == nil)
		return;
	draw(tmp, canvas->r, canvas, nil, canvas->r.min);
	gendrawdiff(tmp, tmp->r, canvas->r, back, ZP, nil, ZP, SoverD);
	freeimage(canvas);
	canvas = tmp;
}

void
initcnv(Point sz, char *file)
{
	int fd;
	Rectangle r;

	if(file != nil){
		if((fd = open(file, OREAD)) < 0)
			sysfatal("open: %r");
		if((canvas = readimage(display, fd, 0)) == nil)
			sysfatal("readimage: %r");
		close(fd);
		if((canvas2 = allocimage(display, canvas->r, screen->chan, 0, DNofill)) == nil)
			sysfatal("allocimage: %r");
		return;
	}else if(!eqpt(sz, ZP))
		r = Rpt(ZP, sz);
	else
		r = rectsubpt(screen->r, screen->r.min);
	expand(r);
}