====== Proportional scaling of rectangular objects ======

//Calculation proof for scaling images, with a quadratic destination image and different sized source images.//

===== Thesis =====

  * destination image size: $dest_width = 360 = $new_width, $dest_height = 360 (ie. quadratic), scaling is always done with the width
  * source image size: $source_width / $source_height = $source_aspect_ratio
  * calculation: $new_width / $source_aspect_ratio = $new_height

===== Notes =====

  * eg. width: 360, height = 360 (ball.svg), but auto.svg is more like 600 width, 150 height => 600 / 150 = 4 = $source_aspect_ratio (= seitenverhältnis)
    * => auto.svg would be scaled to: 360 width, $new_width / $source_aspect_ratio 
       * eg. width 400, height 150, ie. 400 / 150 = 2.667 
       * => (new_width = 360) / ($source_aspect_ratio = 2.667) => 
				
    * eg. width 200, height 400, ie. 200 / 400 = 0.5
  * => (new_width = 360) / ($source_aspect_ratio = 0.5) = 720 => new_height