box.rb in hexapdf-0.34.0

- old
+ new

@@ -125,26 +125,40 @@
 
       # Hash with custom properties. The keys should be strings and can be arbitrary.
       #
       # This can be used to store arbitrary information on boxes for later use. For example, a
       # generic style layer could use one or more custom properties for its work.
+      #
+      # The Box class itself uses the following properties:
+      #
+      # optional_content::
+      #
+      #       If this property is set, it needs to be an optional content group dictionary, a String
+      #       defining an (optionally existing) optional content group dictionary, or an optional
+      #       content membership dictionary.
+      #
+      #       The whole content of the box, i.e. including padding, border, background..., is
+      #       wrapped with the appropriate commands so that the optional content group or membership
+      #       dictionary specifies whether the content is shown or not.
+      #
+      #       See: HexaPDF::Type::OptionalContentProperties
       attr_reader :properties
 
       # :call-seq:
-      #    Box.new(width: 0, height: 0, style: nil, properties: {}) {|canv, box| block} -> box
+      #    Box.new(width: 0, height: 0, style: nil, properties: nil) {|canv, box| block} -> box
       #
       # Creates a new Box object with the given width and height that uses the provided block when
       # it is asked to draw itself on a canvas (see #draw).
       #
       # Since the final location of the box is not known beforehand, the drawing operations inside
       # the block should draw inside the rectangle (0, 0, content_width, content_height) - note that
       # the width and height of the box may not be known beforehand.
-      def initialize(width: 0, height: 0, style: nil, properties: {}, &block)
+      def initialize(width: 0, height: 0, style: nil, properties: nil, &block)
         @width = @initial_width = width
         @height = @initial_height = height
         @style = Style.create(style)
-        @properties = properties
+        @properties = properties || {}
         @draw_block = block
         @fit_successful = false
         @split_box = false
       end
 
@@ -218,10 +232,14 @@
       # The block specified when creating the box is invoked with the canvas and the box as
       # arguments. Subclasses can specify an on-demand drawing method by setting the +@draw_block+
       # instance variable to +nil+ or a valid block. This is useful to avoid unnecessary set-up
       # operations when the block does nothing.
       def draw(canvas, x, y)
+        if (oc = properties['optional_content'])
+          canvas.optional_content(oc)
+        end
+
         if style.background_color? && style.background_color
           canvas.save_graphics_state do
             canvas.opacity(fill_alpha: style.background_alpha).
               fill_color(style.background_color).rectangle(x, y, width, height).fill
           end
@@ -231,9 +249,11 @@
         style.border.draw(canvas, x, y, width, height) if style.border?
 
         draw_content(canvas, x + reserved_width_left, y + reserved_height_bottom)
 
         style.overlays.draw(canvas, x, y, self) if style.overlays?
+
+        canvas.end_optional_content if oc
       end
 
       # Returns +true+ if no drawing operations are performed.
       def empty?
         !(@draw_block ||