# File lib/rubygame/gfx.rb, line 555
  def zoom_to( width, height, smooth=false )
    zoomx = case width
            when nil;      1.0
            when Numeric;  width.to_f / @struct.w
            end
             
    zoomy = case height
            when nil;      1.0
            when Numeric;  height.to_f / @struct.h
            end

    return self.zoom( [zoomx, zoomy], smooth )
  end