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Filename : rvg.rb
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#--############################################################################
# $Id: rvg.rb,v 1.10 2009/02/28 23:52:28 rmagick Exp $
#
#                    Copyright (C) 2009 by Timothy P. Hunter
#
# Permission is hereby granted, free of charge, to any person obtaining a
# copy of this software and associated documentation files (the
# "Software"), to deal in the Software without restriction, including
# without limitation the rights to use, copy, modify, merge, publish,
# distribute, sublicense, and/or sell copies of the Software, and to
# permit persons to whom the Software is furnished to do so, subject to
# the following conditions:
#
# The above copyright notice and this permission notice shall be included
# in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
# OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
# IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
# CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
# TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
# SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
#
#
# This software is OSI Certified Open Source Software.
# OSI Certified is a certification mark of the Open Source Initiative.
#
#++############################################################################
require 'rmagick'
require 'rvg/misc'
require 'rvg/describable'
require 'rvg/stylable'
require 'rvg/transformable'
require 'rvg/stretchable'
require 'rvg/text'
require 'rvg/embellishable'
require 'rvg/container'
require 'rvg/pathdata'
require 'rvg/clippath'
require 'rvg/paint'
require 'rvg/units'

require 'pp' if ENV['debug_rvg']

# RVG is the main class in this library. All graphic elements
# must be contained within an RVG object.
module Magick
  class RVG
    include Stylable
    include Transformable
    include Stretchable
    include Embellishable
    include Describable
    include Duplicatable

    private

    # background_fill defaults to 'none'. If background_fill has been set to something
    # else, combine it with the background_fill_opacity.
    def bgfill
      if @background_fill.nil?
        color = Magick::Pixel.new(0, 0, 0, Magick::OpaqueAlpha)
      else
        color = @background_fill
        color.alpha = @background_fill_opacity * Magick::OpaqueAlpha
      end
      color
    end

    def new_canvas
      if @background_pattern
        canvas = Magick::Image.new(@width, @height, @background_pattern)
      elsif @background_image
        canvas = if @width != @background_image.columns || @height != @background_image.rows
                   case @background_position
                   when :scaled
                     @background_image.resize(@width, @height)
                   when :tiled
                     Magick::Image.new(@width, @height, Magick::TextureFill.new(@background_image))
                   when :fit
                     width = @width
                     height = @height
                     bgcolor = bgfill
                     @background_image.change_geometry(Magick::Geometry.new(width, height)) do |new_cols, new_rows|
                       bg_image = @background_image.resize(new_cols, new_rows)
                       if bg_image.columns != width || bg_image.rows != height
                         bg = Magick::Image.new(width, height) { |options| options.background_color = bgcolor }
                         bg_image = bg.composite!(bg_image, Magick::CenterGravity, Magick::OverCompositeOp)
                       end
                       bg_image
                     end
                   end
                 else
                   @background_image.copy
                 end
      else
        bgcolor = bgfill
        canvas = Magick::Image.new(Integer(@width), Integer(@height)) { |options| options.background_color = bgcolor }
      end
      canvas[:desc] = @desc if @desc
      canvas[:title] = @title if @title
      canvas[:metadata] = @metadata if @metadata
      canvas
    end

    if ENV['debug_prim']
      def print_gc(gc)
        primitives = gc.inspect.split(/\n/)
        indent = 0
        primitives.each do |cmd|
          indent -= 1 if cmd['pop ']
          print(('   ' * indent), cmd, "\n")
          indent += 1 if cmd['push ']
        end
      end
    end

    public

    WORD_SEP = / / # Regexp to separate words

    # The background image specified by background_image=
    attr_reader :background_image
    # The background image layout specified by background_position=
    attr_reader :background_position
    # The background fill color specified by background_fill=
    attr_reader :background_fill
    # The background fill color opacity specified by background_fill_opacity=
    attr_reader :background_fill_opacity
    # The image after drawing has completed
    attr_reader :canvas
    # For embedded RVG objects, the x-axis coordinate of the upper-left corner
    attr_reader :x
    # For embedded RVG objects, the x-axis coordinate of the upper-left corner
    attr_reader :y
    attr_reader :width, :height

    # Sets an image to use as the canvas background. See background_position= for layout options.
    def background_image=(bg_image)
      warn 'background_image= has no effect in nested RVG objects' if @nested
      raise ArgumentError, "background image must be an Image (got #{bg_image.class})" if bg_image && !bg_image.is_a?(Magick::Image)

      @background_image = bg_image
    end

    # Sets an object to use to fill the canvas background.
    # The object must have a <tt>fill</tt> method. See the <b>Fill Classes</b>
    # section in the RMagick doc for more information.
    def background_pattern=(filler)
      warn 'background_pattern= has no effect in nested RVG objects' if @nested
      @background_pattern = filler
    end

    # How to position the background image on the canvas. One of the following symbols:
    # [:scaled] Scale the image to the canvas width and height.
    # [:tiled]  Tile the image across the canvas.
    # [:fit] Scale the image to fit within the canvas while retaining the
    #        image proportions. Center the image on the canvas. Color any part of
    #        the canvas not covered by the image with the background color.
    def background_position=(pos)
      warn 'background_position= has no effect in nested RVG objects' if @nested
      bg_pos = pos.to_s.downcase
      raise ArgumentError, "background position must be `scaled', `tiled', or `fit' (#{pos} given)" unless %w[scaled tiled fit].include?(bg_pos)

      @background_position = bg_pos.to_sym
    end

    # Sets the canvas background color. Either a Magick::Pixel or a color name.
    # The default fill is "none", that is, transparent black.
    def background_fill=(color)
      warn 'background_fill= has no effect in nested RVG objects' if @nested
      if !color.is_a?(Magick::Pixel)
        begin
          @background_fill = Magick::Pixel.from_color(color)
        rescue Magick::ImageMagickError
          raise ArgumentError, "unknown color `#{color}'"
        rescue TypeError
          raise TypeError, "cannot convert #{color.class} into Pixel"
        rescue StandardError
          raise ArgumentError, "argument must be a color name or a Pixel (got #{color.class})"
        end
      else
        @background_fill = color
      end
    end

    # Opacity of the background fill color, a number between 0.0 (transparent) and
    # 1.0 (opaque). The default is 1.0 when the background_fill= attribute has been set.
    def background_fill_opacity=(opacity)
      warn 'background_fill_opacity= has no effect in nested RVG objects' if @nested
      begin
        @background_fill_opacity = Float(opacity)
      rescue ArgumentError
        raise ArgumentError, "background_fill_opacity must be a number between 0 and 1 (#{opacity} given)"
      end
    end

    # Draw a +width+ x +height+ image. The image is specified by calling
    # one or more drawing methods on the RVG object.
    # You can group the drawing method calls in the optional associated block.
    # The +x+ and +y+ arguments have no meaning for the outermost RVG object.
    # On nested RVG objects [+x+, +y+] is the coordinate of the upper-left
    # corner in the containing canvas on which the nested RVG object is placed.
    #
    # Drawing occurs on a +canvas+ created by the #draw method. By default the
    # canvas is transparent. You can specify a different canvas with the
    # #background_fill= or #background_image= methods.
    #
    # RVG objects are _containers_. That is, styles and transforms defined
    # on the object are used by contained objects such as shapes, text, and
    # groups unless overridden by an inner container or the object itself.
    def initialize(width = nil, height = nil)
      super
      @width = width
      @height = height
      @content = Content.new
      @canvas = nil
      @background_fill = nil
      @background_fill_opacity = 1.0 # applies only if background_fill= is used
      @background_position = :scaled
      @background_pattern, @background_image, @desc, @title, @metadata = nil
      @x = 0.0
      @y = 0.0
      @nested = false
      yield(self) if block_given?
    end

    # Construct a canvas or reuse an existing canvas.
    # Execute drawing commands. Return the canvas.
    def draw
      raise StandardError, 'draw not permitted in nested RVG objects' if @nested

      @canvas ||= new_canvas # allow drawing over existing canvas
      gc = Utility::GraphicContext.new
      add_outermost_primitives(gc)
      pp(self) if ENV['debug_rvg']
      print_gc(gc) if ENV['debug_prim']
      gc.draw(@canvas)
      @canvas
    end

    # Accept #use arguments. Use (x,y) to generate an additional translate.
    # Override @width and @height if new values are supplied.
    # @private
    def ref(x, y, rw, rh)
      translate(x, y) if x != 0 || y != 0
      @width = rw if rw
      @height = rh if rh
    end

    # Used by Magick::Embellishable.rvg to set non-0 x- and y-coordinates
    # @private
    def corner(x, y)
      @nested = true
      @x = Float(x)
      @y = Float(y)
      translate(@x, @y) if @x != 0.0 || @y != 0.0
    end

    # Primitives for the outermost RVG object
    # @private
    def add_outermost_primitives(gc)
      add_transform_primitives(gc)
      gc.push
      add_viewbox_primitives(@width, @height, gc)
      add_style_primitives(gc)
      @content.each { |element| element.add_primitives(gc) }
      gc.pop
      self
    end

    # Primitives for nested RVG objects
    # @private
    def add_primitives(gc)
      raise ArgumentError, 'RVG width or height undefined' if @width.nil? || @height.nil?
      return self if @width.zero? || @height.zero?

      gc.push
      add_outermost_primitives(gc)
      gc.pop
    end
  end # end class RVG
end # end module Magick