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#include <u.h>
#include <libc.h>
#include <draw.h>
#include <event.h>
#include <keyboard.h>
typedef struct Point2 Point2;
typedef struct Bézier Bézier;
struct Point2
{
double x, y, w;
};
struct Bézier
{
Point2 p0, p1, p2, p3;
};
enum {
Cbg,
Cctl,
Cbez,
NCOLOR
};
Image *pal[NCOLOR];
Bézier *bezs;
Point2 pts[4];
ulong nbez, npt;
Point2
Pt2(double x, double y, double w)
{
return (Point2){x,y,w};
}
Point
toscreen(Point2 p)
{
return addpt(screen->r.min, Pt(p.x,p.y));
}
Point2
fromscreen(Point p)
{
p = subpt(p, screen->r.min);
return Pt2(p.x,p.y,1);
}
void
initpalette(void)
{
pal[Cbg] = allocimage(display, Rect(0,0,1,1), screen->chan, 1, 0x000000ff);
pal[Cctl] = allocimage(display, Rect(0,0,1,1), screen->chan, 1, 0x00ff00ff);
pal[Cbez] = allocimage(display, Rect(0,0,1,1), screen->chan, 1, 0xff0000ff);
}
void
redraw(void)
{
int i;
draw(screen, screen->r, pal[Cbg], nil, ZP);
for(i = 0; i < nbez; i++)
bezier(screen, toscreen(bezs[i].p0), toscreen(bezs[i].p1), toscreen(bezs[i].p2), toscreen(bezs[i].p3), Endsquare, Endsquare, 0, pal[Cbez], ZP);
for(i = 0; i < npt; i++)
fillellipse(screen, toscreen(pts[i]), 2, 2, pal[Cctl], ZP);
flushimage(display, 1);
}
void
usage(void)
{
fprint(2, "usage: %s\n", argv0);
exits("usage");
}
void
main(int argc, char *argv[])
{
Event e;
Bézier b;
ARGBEGIN{
default: usage();
}ARGEND;
if(argc > 0)
usage();
if(initdraw(nil, nil, nil) < 0)
sysfatal("initdraw: %r");
initpalette();
einit(Emouse|Ekeyboard);
redraw();
for(;;)
switch(event(&e)){
case Emouse:
if((e.mouse.buttons&1) != 0){
pts[npt++] = fromscreen(e.mouse.xy);
if(npt >= nelem(pts)){
b.p0 = pts[0];
b.p1 = pts[1];
b.p2 = pts[2];
b.p3 = pts[3];
bezs = realloc(bezs, ++nbez*sizeof(Bézier));
bezs[nbez-1] = b;
npt = 0;
}
redraw();
}
break;
case Ekeyboard:
switch(e.kbdc){
case 'q':
case Kdel:
exits(0);
}
break;
}
}
void
eresized(int)
{
if(getwindow(display, Refnone) < 0)
sysfatal("resize failed");
redraw();
}
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