document_sizing.rb in prawn-svg-0.27.1

- old
+ new
@@ -26,24 +26,38 @@
       @x_scale = @y_scale = 1
 
       container_width = @requested_width || @bounds[0]
       container_height = @requested_height || @bounds[1]
 
-      @output_width = Pixels::Measurement.to_pixels(@document_width || container_width, container_width)
-      @output_height = Pixels::Measurement.to_pixels(@document_height || container_height, container_height)
+      @output_width = Pixels::Measurement.to_pixels(@document_width || @requested_width, container_width)
+      @output_height = Pixels::Measurement.to_pixels(@document_height || @requested_height, container_height)
 
       if @view_box
         values = @view_box.strip.split(Prawn::SVG::Elements::COMMA_WSP_REGEXP)
         @x_offset, @y_offset, @viewport_width, @viewport_height = values.map {|value| value.to_f}
 
         if @viewport_width > 0 && @viewport_height > 0
+          # If neither the width nor height was specified, use the entire space available
+          if @output_width.nil? && @output_height.nil?
+            @output_width = container_width
+            @output_height = container_height
+          end
+
+          # If one of the output dimensions is missing, calculate it from the other one
+          # using the ratio of the viewport width to height.
+          @output_width ||= @output_height * @viewport_width / @viewport_height
+          @output_height ||= @output_width * @viewport_height / @viewport_width
+
           aspect = AspectRatio.new(@preserve_aspect_ratio, [@output_width, @output_height], [@viewport_width, @viewport_height])
           @x_scale = aspect.width / @viewport_width
           @y_scale = aspect.height / @viewport_height
           @x_offset -= aspect.x / @x_scale
           @y_offset -= aspect.y / @y_scale
         end
       else
+        @output_width ||= container_width
+        @output_height ||= container_height
+
         @viewport_width = @output_width
         @viewport_height = @output_height
       end
 
       return if invalid?