/// rectangle_source(rect, x, y, w, h)

var rect = argument[0];
var xx = argument[1];
var yy = argument[2];
var ww = argument[3];
var hh = argument[4];

// outer rect x1,y1,x2,y2
var outer;
outer[0] = rect[0]
outer[1] = rect[1]
outer[2] = outer[0] + rect[2]
outer[3] = outer[1] + rect[3]

// inner rect x1,y1,x2,y2
var inner;
inner[0] = outer[0] + xx
inner[1] = outer[1] + yy
inner[2] = inner[0] + ww
inner[3] = inner[1] + hh

// clip inner rect to outer rect
inner[0] = max(inner[0], outer[0])
inner[1] = max(inner[1], outer[1])
inner[2] = min(inner[2], outer[2])
inner[3] = min(inner[3], outer[3])

// inner rect x,y,w,h
var new;
new[0] = inner[0]
new[1] = inner[1]
new[2] = inner[2] - inner[0]
new[3] = inner[3] - inner[1]

return new