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

#define RGBA rgba
#define MIN(a,b) ((a)<(b)?(a):(b))

int rgba(int r, int g, int b, int a)
{
	int c;

	r = (r*a)/255;
	g = (g*a)/255;
	b = (b*a)/255;
	c= (r<<24) | (g<<16) | (b<<8) | (a);
	return c;	
}

enum { Nbg = 3 };
Image *fg[2][2][3];
Image *bg[Nbg];

void main(int argc, char *argv[])
{
	Event e;
	Rectangle r1 = Rect(0,0,1,1);
	Image **i;

	USED(argc, argv);

	if (initdraw(nil, nil, "blend") < 0) {
		fprint(2, "initdraw failed: %r\n");
		exits("initdraw");
	}
	einit(Emouse|Ekeyboard);

	bg[0] = allocimage(display, r1, RGBA32, 1, DBlack);
	bg[1] = allocimage(display, r1, RGBA32, 1, DWhite);
	bg[2] = allocimage(display, r1, RGBA32, 1, RGBA(0,0,0,64));

	// Pure CMY
	i = fg[0][0];
	*i++ = allocimage(display, r1, RGBA32, 1, RGBA(255,255,0,255));
	*i++  = allocimage(display, r1, RGBA32, 1, RGBA(0,255,255,255));		
	*i++  = allocimage(display, r1, RGBA32, 1, RGBA(255,0,255,255));
	// 50% CMY
	i = fg[0][1];
	*i++  = allocimage(display, r1, RGBA32, 1, RGBA(255,255,0,127));
	*i++  = allocimage(display, r1, RGBA32, 1, RGBA(0,255,255,127));		
	*i++  = allocimage(display, r1, RGBA32, 1, RGBA(255,0,255,127));
	// Pure RGB
	i = fg[1][0];
	*i++  = allocimage(display, r1, RGBA32, 1, RGBA(255,0,0,255));
	*i++ = allocimage(display, r1, RGBA32, 1, RGBA(0,255,0,255));		
	*i++  = allocimage(display, r1, RGBA32, 1, RGBA(0,0,255,255));
	// 50% RGB
	i = fg[1][1];
	*i++  = allocimage(display, r1, RGBA32, 1, RGBA(255,0,0,127));
	*i++ = allocimage(display, r1, RGBA32, 1, RGBA(0,255,0,127));		
	*i++  = allocimage(display, r1, RGBA32, 1, RGBA(0,0,255,127));

	eresized(0);
	for (;;) {
		switch(event(&e)){
		case Ekeyboard:
			switch(e.kbdc){
			case 'q':
			case '\04':
				exits(nil);
			}
			break;
		case Emouse:
			if(e.mouse.buttons){
			}
			break;
		}
	}
	exits(nil);
}

void spots(Point o, int R, Image *bg, Image **fg)
{
	Rectangle r = Rpt(o, addpt(o, Pt(3*R, 3*R)));

	draw(screen, r, bg, nil, ZP);

	fillellipse(screen, addpt(o,Pt(1*R,2*R)), R,R, fg[0], ZP);
	fillellipse(screen, addpt(o,Pt(2*R,2*R)), R,R, fg[1], ZP);
	fillellipse(screen, addpt(o,Pt(1.5*R,1*R)), R,R, fg[2], ZP);
}

void redraw(Image *screen)
{
	Rectangle r = screen->r;
	int dX = r.max.x-r.min.x;
	int dY = r.max.y-r.min.y;
	int R = MIN(dX,dY)/4/3;
	int x, y;

	fprint(2, "s=%R, R=%d\n", screen->r, R);
	// draw(screen, r, bg[2], nil, ZP);

	for (x=0; x<4; ++x)
		for (y=0; y<4; ++y)
			spots(addpt(r.min, Pt(x*3*R, y*3*R)),  R,
				bg[(x<2)+(y<2)], fg[y%2][x%2]);
	//flushimage(display, 1);
}

void
eresized(int new)
{
	if(new && getwindow(display, Refnone) < 0){
		fprint(2, "can't reattach to window: %r\n");
		exits("attach");
	}
	redraw(screen);
}