span>

  <span class='comment'># Since this &quot;sprite&quot; itself won&#39;t actually be drawn, we can use the positioning attributes to control the
</span>  <span class='comment'># contained sprites.
</span>  <span class='comment'># x/y: linear offset
</span>  <span class='comment'># w/h: used for #zoom_factor, derived with comparison to source_w/h (Sprite method)
</span>  <span class='comment'># source_x/y: position of visible window
</span>  <span class='comment'># source_w/h: extent of visible window