Class: PSD::Renderer::Blender

Inherits:
Object
  • Object
show all
Defined in:
lib/psd/renderer/blender.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(fg, bg) ⇒ Blender

Takes a foreground Canvas and a background Canvas



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# File 'lib/psd/renderer/blender.rb', line 7

def initialize(fg, bg)
  @fg = fg
  @bg = bg

  @opacity = @fg.opacity.to_i
  @fill_opacity = @fg.fill_opacity.to_i
  PSD.logger.debug "Blender: name = #{fg.node.name}, opacity = #{@opacity}, fill opacity = #{@fill_opacity}"
end

Instance Attribute Details

#bg ⇒ Object (readonly)

Returns the value of attribute bg.



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# File 'lib/psd/renderer/blender.rb', line 4

def bg
  @bg
end

#fg ⇒ Object (readonly)

Returns the value of attribute fg.



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# File 'lib/psd/renderer/blender.rb', line 4

def fg
  @fg
end

Instance Method Details

#compose! ⇒ Object

Composes the foreground Canvas onto the background Canvas using the blending mode specified by the foreground.



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# File 'lib/psd/renderer/blender.rb', line 18

def compose!
  PSD.logger.debug "#{fg.node.debug_name} -> #{bg.node.debug_name}: #{fg.node.blending_mode} blending"
  PSD.logger.debug "fg: (#{fg.left}, #{fg.top}) #{fg.width}x#{fg.height}; bg: (#{bg.left}, #{bg.top}) #{bg.width}x#{bg.height}"

  offset_x = fg.left - bg.left
  offset_y = fg.top - bg.top

  fg.height.times do |y|
    fg.width.times do |x|
      base_x = x + offset_x
      base_y = y + offset_y

      next if base_x < 0 || base_y < 0 || base_x >= bg.width || base_y >= bg.height

      color = Compose.send(
        fg.node.blending_mode,
        fg.get_pixel(x, y),
        bg.get_pixel(base_x, base_y),
        calculated_opacity
      )

      bg.set_pixel base_x, base_y, color
    end
  end
end