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<title>/usr/web/sources/contrib/cinap_lenrek/paint.c - Plan 9 from Bell Labs</title>


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<a href="/plan9/">Plan 9 from Bell Labs</a>’s /usr/web/sources/contrib/cinap_lenrek/paint.c


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Copyright © 2009 Alcatel-Lucent. 
Distributed under the
<a href="/plan9/license.html">Lucent Public License version 1.02</a>.
 
<a href="/plan9/download.html">Download the Plan 9 distribution.</a>

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#include <u.h>
#include <libc.h>
#include <draw.h>
#include <event.h>
#include <keyboard.h>

char *filename;
int zoom = 1;
int brush = 1;
Point spos; /* position on screen */
Point cpos; /* position on canvas */
Image *canvas;
Image *ink;
Image *back;
Image *pal[16]; /* palette */
Rectangle palr; /* palette rect on screen */
Rectangle penr; /* pen size rect on screen */
enum {
NBRUSH = 10+1,
};

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

int c64[] = { /* c64 color palette */
0x000000,
0xFFFFFF,
0x68372B,
0x70A4B2,
0x6F3D86,
0x588D43,
0x352879,
0xB8C76F,
0x6F4F25,
0x433900,
0x9A6759,
0x444444,
0x6C6C6C,
0x9AD284,
0x6C5EB5,
0x959595,
};

/*
* 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;

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;
}
}

int
alphachan(ulong chan)
{
for(; chan; chan >>= 8)
if(TYPE(chan) == CAlpha)
return 1;
return 0;
}

void
zoomdraw(Image *d, Rectangle r, Rectangle top, Image *b, Image *s, Point sp, int f)
{
Rectangle dr;
Image *t;
Point a;
int w;

a = ZP;
if(r.min.x < d->r.min.x){
sp.x += (d->r.min.x - r.min.x)/f;
a.x = (d->r.min.x - r.min.x)%f;
r.min.x = d->r.min.x;
}
if(r.min.y < d->r.min.y){
sp.y += (d->r.min.y - r.min.y)/f;
a.y = (d->r.min.y - r.min.y)%f;
r.min.y = d->r.min.y;
}
rectclip(&r, d->r);
w = s->r.max.x - sp.x;
if(w > Dx(r))
w = Dx(r);
dr = r;
dr.max.x = dr.min.x+w;
if(!alphachan(s->chan))
b = nil;
if(f <= 1){
if(b) gendrawdiff(d, dr, top, b, sp, nil, ZP, SoverD);
gendrawdiff(d, dr, top, s, sp, nil, ZP, SoverD);
return;
}
if((t = allocimage(display, dr, s->chan, 0, 0)) == nil)
return;
for(; dr.min.y < r.max.y; dr.min.y++){
dr.max.y = dr.min.y+1;
draw(t, dr, s, nil, sp);
if(++a.y == f){
a.y = 0;
sp.y++;
}
}
dr = r;
for(sp=dr.min; dr.min.x < r.max.x; sp.x++){
dr.max.x = dr.min.x+1;
if(b) gendrawdiff(d, dr, top, b, sp, nil, ZP, SoverD);
gendrawdiff(d, dr, top, t, sp, nil, ZP, SoverD);
for(dr.min.x++; ++a.x < f && dr.min.x < r.max.x; dr.min.x++){
dr.max.x = dr.min.x+1;
gendrawdiff(d, dr, top, d, Pt(dr.min.x-1, dr.min.y), nil, ZP, SoverD);
}
a.x = 0;
}
freeimage(t);
}

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
update(Rectangle *rp){
if(canvas==nil)
draw(screen, screen->r, back, nil, ZP);
else {
if(rp == nil)
rp = &canvas->r;
gendrawdiff(screen, screen->r, c2sr(canvas->r), back, ZP, nil, ZP, SoverD);
zoomdraw(screen, c2sr(*rp), ZR, back, canvas, rp->min, zoom);
}
flushimage(display, 1);
}

void
expand(Rectangle r)
{
Rectangle nr;
Image *tmp;

if(canvas==nil){
if((canvas = 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
save(Rectangle r, int mark)
{
Image *tmp;
int x;

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

typedef struct {
Rectangle r;
Rectangle r0;
Image* dst;

int yscan; /* current scanline */
int wscan; /* bscan width in bytes */
Image* iscan; /* scanline image */
uchar* bscan; /* scanline buffer */

int nmask; /* size of bmask in bytes */
int wmask; /* width of bmask in bytes */
Image* imask; /* mask image */
uchar* bmask; /* mask buffer */

int ncmp;
uchar bcmp[4];
} Filldata;

void
fillscan(Filldata *f, Point p0)
{
int x, y;
uchar *b;

x = p0.x;
y = p0.y;
b = f->bmask + y*f->wmask;
if(b[x/8] & 0x80>>(x%8))
return;

if(f->yscan != y){
draw(f->iscan, f->iscan->r, f->dst, nil, Pt(f->r.min.x, f->r.min.y+y));
if(unloadimage(f->iscan, f->iscan->r, f->bscan, f->wscan) < 0)
return;
f->yscan = y;
}

for(x = p0.x; x >= 0; x--){
if(memcmp(f->bscan + x*f->ncmp, f->bcmp, f->ncmp))
break;
b[x/8] |= 0x80>>(x%8);
}
for(x = p0.x+1; x < f->r0.max.x; x++){
if(memcmp(f->bscan + x*f->ncmp, f->bcmp, f->ncmp))
break;
b[x/8] |= 0x80>>(x%8);
}

y = p0.y-1;
if(y >= 0){
for(x = p0.x; x >= 0; x--){
if((b[x/8] & 0x80>>(x%8)) == 0)
break;
fillscan(f, Pt(x, y));
}
for(x = p0.x+1; x < f->r0.max.x; x++){
if((b[x/8] & 0x80>>(x%8)) == 0)
break;
fillscan(f, Pt(x, y));
}
}

y = p0.y+1;
if(y < f->r0.max.y){
for(x = p0.x; x >= 0; x--){
if((b[x/8] & 0x80>>(x%8)) == 0)
break;
fillscan(f, Pt(x, y));
}
for(x = p0.x+1; x < f->r0.max.x; x++){
if((b[x/8] & 0x80>>(x%8)) == 0)
break;
fillscan(f, Pt(x, y));
}
}
}

void
floodfill(Image *dst, Rectangle r, Point p, Image *src)
{
Filldata f;

if(!rectclip(&r, dst->r))
return;
if(!ptinrect(p, r))
return;
memset(&f, 0, sizeof(f));
f.dst = dst;
f.r = r;
f.r0 = rectsubpt(r, r.min);
f.wmask = bytesperline(f.r0, 1);
f.nmask = f.wmask*f.r0.max.y;
if((f.bmask = mallocz(f.nmask, 1)) == nil)
goto out;
if((f.imask = allocimage(display, f.r0, GREY1, 0, DNofill)) == nil)
goto out;

r = f.r0;
r.max.y = 1;
if((f.iscan = allocimage(display, r, RGB24, 0, DNofill)) == nil)
goto out;
f.yscan = -1;
f.wscan = bytesperline(f.iscan->r, f.iscan->depth);
if((f.bscan = mallocz(f.wscan, 0)) == nil)
goto out;

r = Rect(0,0,1,1);
f.ncmp = (f.iscan->depth+7) / 8;
draw(f.iscan, r, dst, nil, p);
if(unloadimage(f.iscan, r, f.bcmp, sizeof(f.bcmp)) < 0)
goto out;

fillscan(&f, subpt(p, f.r.min));

loadimage(f.imask, f.imask->r, f.bmask, f.nmask);
draw(f.dst, f.r, src, f.imask, f.imask->r.min);
out:
free(f.bmask);
free(f.bscan);
if(f.iscan)
freeimage(f.iscan);
if(f.imask)
freeimage(f.imask);
}

void
translate(Point d)
{
Rectangle r, nr;

if(canvas==nil || d.x==0 && d.y==0)
return;
r = c2sr(canvas->r);
nr = rectaddpt(r, d);
rectclip(&r, screen->clipr);
draw(screen, rectaddpt(r, d), screen, nil, r.min);
zoomdraw(screen, nr, rectaddpt(r, d), back, canvas, canvas->r.min, zoom);
gendrawdiff(screen, screen->r, nr, back, ZP, nil, ZP, SoverD);
spos = addpt(spos, d);
flushimage(display, 1);
}

void
setzoom(Point o, int z)
{
if(z < 1)
return;
cpos = s2c(o);
spos = o;
zoom = z;
update(nil);
}

void
center(void)
{
cpos = ZP;
if(canvas)
cpos = addpt(canvas->r.min,
divpt(subpt(canvas->r.max, canvas->r.min), 2));
spos = addpt(screen->r.min,
divpt(subpt(screen->r.max, screen->r.min), 2));
update(nil);
}

void
drawpal(void)
{
Rectangle r, rr;
int i;

r = screen->r;
r.min.y = r.max.y - 20;
replclipr(screen, 0, r);

penr = r;
penr.min.x = r.max.x - NBRUSH*Dy(r);

palr = r;
palr.max.x = penr.min.x;

r = penr;
draw(screen, r, back, nil, ZP);
for(i=0; i<10; i++){
r.max.x = penr.min.x + (i+1)*Dx(penr) / NBRUSH;
rr = r;
if(i == brush)
rr.min.y += Dy(r)/3;
fillellipse(screen, addpt(rr.min, divpt(subpt(rr.max, rr.min), 2)), i, i, ink, ZP);
r.min.x = r.max.x;
}
r.max.x = penr.min.x + (i+1)*Dx(penr) / NBRUSH;
rr = r;
if(i == brush)
rr.min.y += Dy(r)/3;
draw(screen, rr, ink, nil, ZP);

r = palr;
for(i=1; i<=nelem(pal); i++){
r.max.x = palr.min.x + i*Dx(palr) / nelem(pal);
rr = r;
if(ink == pal[i-1])
rr.min.y += Dy(r)/3;
draw(screen, rr, pal[i-1], nil, ZP);
gendrawdiff(screen, r, rr, back, ZP, nil, ZP, SoverD);
r.min.x = r.max.x;
}

r = screen->r;
r.max.y -= Dy(palr);
replclipr(screen, 0, r);
}

int
hitpal(Mouse m)
{
if(ptinrect(m.xy, penr)){
if(m.buttons & 7){
brush = ((m.xy.x - penr.min.x) * NBRUSH) / Dx(penr);
drawpal();
}
return 1;
}
if(ptinrect(m.xy, palr)){
Image *col;

col = pal[(m.xy.x - palr.min.x) * nelem(pal) / Dx(palr)];
switch(m.buttons & 7){
case 1:
ink = col;
drawpal();
break;
case 2:
back = col;
drawpal();
update(nil);
break;
}
return 1;
}
return 0;
}

void
catch(void *, char *msg)
{
if(strstr(msg, "closed pipe"))
noted(NCONT);
noted(NDFLT);
}

int
pipeline(char *fmt, ...)
{
char buf[1024];
va_list a;
int p[2];

va_start(a, fmt);
vsnprint(buf, sizeof(buf), fmt, a);
va_end(a);
if(pipe(p) < 0)
return -1;
switch(rfork(RFPROC|RFMEM|RFFDG|RFNOTEG)){
case -1:
close(p[0]);
close(p[1]);
return -1;
case 0:
close(p[1]);
dup(p[0], 0);
dup(p[0], 1);
close(p[0]);
execl("/bin/rc", "rc", "-c", buf, nil);
exits("exec");
}
close(p[0]);
return p[1];
}

void
usage(void)
{
fprint(2, "usage: %s [ file ]\n", argv0);
exits("usage");
}

void
main(int argc, char *argv[])
{
char *s, buf[1024];
Rectangle r;
Image *img;
int i, fd;
Event e;
Mouse m;
Point p, d;

ARGBEGIN {
default:
usage();
} ARGEND;

if(argc == 1)
filename = strdup(argv[0]);
else if(argc != 0)
usage();

if(initdraw(0, 0, "paint") < 0)
sysfatal("initdraw: %r");

if(filename){
if((fd = open(filename, OREAD)) < 0)
sysfatal("open: %r");
if((canvas = readimage(display, fd, 0)) == nil)
sysfatal("readimage: %r");
close(fd);
}

/* palette initialization */
for(i=0; i<nelem(pal); i++){
pal[i] = allocimage(display, Rect(0, 0, 1, 1), RGB24, 1,
c64[i % nelem(c64)]<<8 | 0xFF);
if(pal[i] == nil)
sysfatal("allocimage: %r");
}
ink = pal[0];
back = pal[1];
drawpal();
center();

einit(Emouse | Ekeyboard);

notify(catch);
for(;;) {
switch(event(&e)){
case Emouse:
if(hitpal(e.mouse))
continue;

img = ink;
switch(e.mouse.buttons & 7){
case 2:
img = back;
/* no break */
case 1:
p = s2c(e.mouse.xy);
if(brush >= 10){
/* flood fill brush */
if(canvas == nil || !ptinrect(p, canvas->r)){
back = img;
drawpal();
update(nil);
break;
}
r = canvas->r;
save(r, 1);
floodfill(canvas, r, p, img);
update(&r);

/* wait for mouse release */
while(event(&e) == Emouse && (e.mouse.buttons & 7) != 0)
;
break;
}
r = Rect(p.x-brush, p.y-brush, p.x+brush+1, p.y+brush+1);
expand(r);
save(r, 1);
fillellipse(canvas, p, brush, brush, img, ZP);
update(&r);
for(;;){
m = e.mouse;
if(event(&e) != Emouse)
break;
if((e.mouse.buttons ^ m.buttons) & 7)
break;
d = s2c(e.mouse.xy);
if(eqpt(d, p))
continue;
r = canonrect(Rpt(p, d));
r.min.x -= brush;
r.min.y -= brush;
r.max.x += brush+1;
r.max.y += brush+1;
expand(r);
save(r, 0);
line(canvas, p, d, Enddisc, Enddisc, brush, img, ZP);
update(&r);
p = d;
}
break;
case 4:
for(;;){
m = e.mouse;
if(event(&e) != Emouse)
break;
if((e.mouse.buttons & 7) != 4)
break;
translate(subpt(e.mouse.xy, m.xy));
}
break;
}
break;
case Ekeyboard:
switch(e.kbdc){
case Kesc:
zoom = 1;
center();
break;
case '+':
setzoom(e.mouse.xy, zoom*2);
break;
case '-':
setzoom(e.mouse.xy, zoom/2);
break;
case 'c':
if(canvas == nil)
break;
save(canvas->r, 1);
freeimage(canvas);
canvas = nil;
update(nil);
break;
case 'u':
restore(16);
break;
case 'f':
brush = 10;
drawpal();
break;
case '0': case '1': case '2': case '3': case '4':
case '5': case '6': case '7': case '8': case '9':
brush = e.kbdc - '0';
drawpal();
break;
default:
if(e.kbdc == Kdel)
e.kbdc = 'q';
buf[0] = 0;
if(filename && (e.kbdc == 'r' || e.kbdc == 'w'))
snprint(buf, sizeof(buf), "%C %s", e.kbdc, filename);
else if(e.kbdc > 0x20 && e.kbdc < 0x7f)
snprint(buf, sizeof(buf), "%C", e.kbdc);
if(eenter("Cmd", buf, sizeof(buf), &e.mouse) <= 0)
break;
if(strcmp(buf, "q") == 0)
exits(nil);
s = buf+1;
while(*s == ' ' || *s == '\t')
s++;
if(*s == 0)
break;
switch(buf[0]){
case 'r':
if((fd = open(s, OREAD)) < 0){
Error:
snprint(buf, sizeof(buf), "%r");
eenter(buf, nil, 0, &e.mouse);
break;
}
free(filename);
filename = strdup(s);
Readimage:
unlockdisplay(display);
img = readimage(display, fd, 1);
close(fd);
lockdisplay(display);
if(img == nil){
werrstr("readimage: %r");
goto Error;
}
if(canvas){
save(canvas->r, 1);
freeimage(canvas);
}
canvas = img;
center();
break;
case 'w':
if((fd = create(s, OWRITE, 0660)) < 0)
goto Error;
free(filename);
filename = strdup(s);
Writeimage:
if(canvas)
if(writeimage(fd, canvas, 0) < 0){
close(fd);
werrstr("writeimage: %r");
goto Error;
}
close(fd);
break;
case '<':
if((fd = pipeline("%s", s)) < 0)
goto Error;
goto Readimage;
case '>':
if((fd = pipeline("%s", s)) < 0)
goto Error;
goto Writeimage;
case '|':
if(canvas == nil)
break;
if((fd = pipeline("%s", s)) < 0)
goto Error;
switch(rfork(RFMEM|RFPROC|RFFDG)){
case -1:
close(fd);
werrstr("rfork: %r");
goto Error;
case 0:
writeimage(fd, canvas, 1);
exits(nil);
}
goto Readimage;
}
break;
}
break;
}
}
}

void
eresized(int)
{
if(getwindow(display, Refnone) < 0)
sysfatal("resize failed");
drawpal();
update(nil);
}

</pre>
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