document_sizing.rb in prawn-svg-0.20.0

- old
+ new

@@ -1,10 +1,13 @@
 module Prawn::Svg::Calculators
   class DocumentSizing
+    DEFAULT_WIDTH = 300
+    DEFAULT_HEIGHT = 150
+    DEFAULT_ASPECT_RATIO = "xMidYMid meet"
+
     attr_writer :document_width, :document_height
     attr_writer :view_box, :preserve_aspect_ratio
-    attr_writer :requested_width, :requested_height
 
     attr_reader :bounds
     attr_reader :x_offset, :y_offset, :x_scale, :y_scale
     attr_reader :viewport_width, :viewport_height, :viewport_diagonal, :output_width, :output_height
 
@@ -15,61 +18,82 @@
 
     def set_from_attributes(attributes)
       @document_width = attributes['width']
       @document_height = attributes['height']
       @view_box = attributes['viewBox']
-      @preserve_aspect_ratio = attributes['preserveAspectRatio']
+      @preserve_aspect_ratio = attributes['preserveAspectRatio'] || DEFAULT_ASPECT_RATIO
     end
 
     def calculate
       @x_offset = @y_offset = 0
       @x_scale = @y_scale = 1
 
-      width = Prawn::Svg::Calculators::Pixels.to_pixels(@document_width, @bounds[0])
-      height = Prawn::Svg::Calculators::Pixels.to_pixels(@document_height, @bounds[1])
+      container_width = @requested_width || @bounds[0]
+      container_height = @requested_height || @bounds[1]
 
-      default_aspect_ratio = "x#{width ? "Mid" : "Min"}Y#{height ? "Mid" : "Min"} meet"
+      @output_width = Pixels.to_pixels(@document_width || @requested_width, container_width)
+      @output_height = Pixels.to_pixels(@document_height || @requested_height, container_height)
 
-      width ||= @bounds[0]
-      height ||= @bounds[1]
-
       if @view_box
-        values = @view_box.strip.split(/\s+/)
+        values = @view_box.strip.split(Prawn::Svg::Parser::COMMA_WSP_REGEXP)
         @x_offset, @y_offset, @viewport_width, @viewport_height = values.map {|value| value.to_f}
         @x_offset = -@x_offset
 
-        @preserve_aspect_ratio ||= default_aspect_ratio
-        aspect = Prawn::Svg::Calculators::AspectRatio.new(@preserve_aspect_ratio, [width, height], [@viewport_width, @viewport_height])
-        @x_scale = aspect.width / @viewport_width
-        @y_scale = aspect.height / @viewport_height
-        @x_offset -= aspect.x
-        @y_offset -= aspect.y
+        if @viewport_width > 0 && @viewport_height > 0
+          @output_width ||= container_width
+          @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 ||= Pixels.to_pixels(DEFAULT_WIDTH, container_width)
+        @output_height ||= Pixels.to_pixels(DEFAULT_HEIGHT, container_height)
+
+        @viewport_width = @output_width
+        @viewport_height = @output_height
       end
 
-      @viewport_width ||= width
-      @viewport_height ||= height
+      return if invalid?
 
       # SVG 1.1 section 7.10
       @viewport_diagonal = Math.sqrt(@viewport_width**2 + @viewport_height**2) / Math.sqrt(2)
 
       if @requested_width
-        scale = @requested_width / width
-        width = @requested_width
-        height *= scale
+        scale = @requested_width / @output_width
+        @output_width = @requested_width
+        @output_height *= scale
         @x_scale *= scale
         @y_scale *= scale
 
       elsif @requested_height
-        scale = @requested_height / height
-        height = @requested_height
-        width *= scale
+        scale = @requested_height / @output_height
+        @output_height = @requested_height
+        @output_width *= scale
         @x_scale *= scale
         @y_scale *= scale
       end
 
-      @output_width = width
-      @output_height = height
-
       self
+    end
+
+    def invalid?
+      @viewport_width <= 0 ||
+        @viewport_height <= 0 ||
+        @output_width <= 0 ||
+        @output_height <= 0 ||
+        (@requested_width && @requested_width <= 0) ||
+        (@requested_height && @requested_height <= 0)
+    end
+
+    def requested_width=(value)
+      @requested_width = (value.to_f if value)
+    end
+
+    def requested_height=(value)
+      @requested_height = (value.to_f if value)
     end
   end
 end