scaleProportion.coffee

# Returns an object with a new width and height
# constraining the proportions of the given max width
# and max height
#
# examples:
# Util.scaleProportion(200, 200, 2000, 2000);
# > Object {width: 200, height: 200}
# scaleProportion(200, 200, 2582, 2394)
# > Object {width: 200, height: 185}
#
Util.scaleProportion = (maxW, maxH, currW, currH) ->
  ratio = currH / currW

  if currW >= maxW and ratio <= 1
    currW = maxW
    currH = currW * ratio
  else if currH >= maxH
    currH = maxH
    currW = currH / ratio

  width: ~~currW, height: ~~currH