angle to rectangle perimeter position

[r043v]

hi dude, pretty nice tool !

i was need to write a similar code as your one for converting angle to rectangular perimeter coordinate,

basicaly the same way but maybe use a bit less cpu due to there is no need for a /
(you still need divide but depending stuff can be precomputed, based on canvas size)

a,b,c are the 3 first corner points, p is perimeter, rp the ratio between p and 360, pp is the position on the perimeter

/* convert angle to rectangle perimeter coordinates */
function angle2rect(angle,sx,sy){
    while(angle < 0) angle += 360; angle %= 360;

    var a = sy, b = a+sx, c = b+sy, p = (sx+sy)*2, rp = p/360;
    var pp = parseInt( ( (angle*rp)+(sy/2) )%p ,10);

    if(pp <= a) return { x:0,  y:sy - pp };
    if(pp <= b) return { y:0,  x:pp - a  };
    if(pp <= c) return { x:sx, y:pp - b  };
                return { y:sy, x:sx - ( pp - c ) };
}

http://jsfiddle.net/r043v/Z7Zg7/

[evictor]

Nice!