int r = 5;
color nowcolor;
color mc[ ] = new color [5];
int mx = 750, my = 10, ms = 40;

void setup(){
	size(800,550);
	colorMode(HSB,360,100,100);
	background(0,0,100);  
	mc[0] = color(50,0,100);
	mc[1] = color(0, 100,100);
	mc[2] = color(300 ,100,100);
	mc[3] = color(39,100,100);
	mc[4] = color(0,0,100);
	nowcolor = color(0,0,100);
}

void draw(){
	if( isdrag == true ){
		stroke( nowcolor );
		strokeWeight( r );
		line( bx, by, mouseX, mouseY );
		bx = mouseX;
		by = mouseY;
	}else{
		stroke( 0,0,100 );
		for( int i = 0 ; i < 5 ; i++ ){
			fill( mc[i] );
			strokeWeight( 1 );
			rect( mx, my+(ms+10)*i, ms, ms );
		}
	}
}

boolean isdrag = false;
int bx, by;
void mousePressed(){
	int i = 5;
	if( mouseX >=mx && mouseX <= mx+ms ){
		for( i = 0 ; i < 5 ; i++ ){
			if( mouseY >= my+(ms+10)*i && mouseY <= my+(ms+10)*(i+1) ) break;
		}
	}
	if( i < 5 ){
		nowcolor = mc[i];
	}else{
		isdrag = true;
		bx = mouseX;
		by = mouseY;
	}
}

void mouseReleased(){
	isdrag = false;
}