Class: HexaPDF::Content::GraphicsState

Inherits:
Object
  • Object
show all
Defined in:
lib/hexapdf/content/graphics_state.rb

Overview

A GraphicsState object holds all the graphic control parameters needed for correct operation when parsing or creating a content stream with a Processor object.

While a content stream is parsed/created, operations may use the current parameters or modify them.

The device-dependent graphics state parameters have not been implemented!

See: PDF2.0 s8.4.1

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ GraphicsState

Initializes the graphics state parameters to their default values.



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# File 'lib/hexapdf/content/graphics_state.rb', line 580

def initialize
  @ctm = TransformationMatrix.new
  @stroke_color = @fill_color =
    GlobalConfiguration.constantize('color_space.map', :DeviceGray).new.default_color
  @line_width = 1.0
  @line_cap_style = LineCapStyle::BUTT_CAP
  @line_join_style = LineJoinStyle::MITER_JOIN
  @miter_limit = 10.0
  @line_dash_pattern = LineDashPattern.new
  @rendering_intent = RenderingIntent::RELATIVE_COLORIMETRIC
  @stroke_adjustment = false
  @blend_mode = :Normal
  @soft_mask = :None
  @stroke_alpha = @fill_alpha = 1.0
  @alpha_source = false

  @tm = nil
  @tlm = nil
  @character_spacing = 0
  @word_spacing = 0
  @horizontal_scaling = 100
  @leading = 0
  @font = nil
  @font_size = 0
  @text_rendering_mode = TextRenderingMode::FILL
  @text_rise = 0
  @text_knockout = true

  @scaled_character_spacing = 0
  @scaled_word_spacing = 0
  @scaled_font_size = 0
  @scaled_horizontal_scaling = 1

  @stack = []
end

Instance Attribute Details

#alpha_source ⇒ Object

A boolean specifying whether the current soft mask and alpha parameters should be interpreted as shape values or opacity values.



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# File 'lib/hexapdf/content/graphics_state.rb', line 490

def alpha_source
  @alpha_source
end

#blend_mode ⇒ Object

The current blend mode for the transparent imaging model.



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# File 'lib/hexapdf/content/graphics_state.rb', line 476

def blend_mode
  @blend_mode
end

#character_spacing ⇒ Object

The character spacing in unscaled text units.

It specifies the additional spacing used for the horizontal or vertical displacement of glyphs.



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# File 'lib/hexapdf/content/graphics_state.rb', line 506

def character_spacing
  @character_spacing
end

#ctm ⇒ Object

The current transformation matrix.



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# File 'lib/hexapdf/content/graphics_state.rb', line 445

def ctm
  @ctm
end

#fill_alpha ⇒ Object

The alpha constant for non-stroking operations in the transparent imaging model.



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# File 'lib/hexapdf/content/graphics_state.rb', line 486

def fill_alpha
  @fill_alpha
end

#fill_color ⇒ Object

The current color used for all other (i.e. non-stroking) painting operations.



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# File 'lib/hexapdf/content/graphics_state.rb', line 451

def fill_color
  @fill_color
end

#font ⇒ Object

The font for the text.



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# File 'lib/hexapdf/content/graphics_state.rb', line 524

def font
  @font
end

#font_size ⇒ Object

The font size.



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# File 'lib/hexapdf/content/graphics_state.rb', line 527

def font_size
  @font_size
end

#horizontal_scaling ⇒ Object

The horizontal text scaling.

The value specifies the percentage of the normal width that should be used.



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# File 'lib/hexapdf/content/graphics_state.rb', line 516

def horizontal_scaling
  @horizontal_scaling
end

#leading ⇒ Object

The leading in unscaled text units.

It specifies the distance between the baselines of adjacent lines of text.



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# File 'lib/hexapdf/content/graphics_state.rb', line 521

def leading
  @leading
end

#line_cap_style ⇒ Object

The current line cap style (for the available values see LineCapStyle).



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# File 'lib/hexapdf/content/graphics_state.rb', line 457

def line_cap_style
  @line_cap_style
end

#line_dash_pattern ⇒ Object

The line dash pattern (see LineDashPattern).



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# File 'lib/hexapdf/content/graphics_state.rb', line 466

def line_dash_pattern
  @line_dash_pattern
end

#line_join_style ⇒ Object

The current line join style (for the available values see LineJoinStyle).



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# File 'lib/hexapdf/content/graphics_state.rb', line 460

def line_join_style
  @line_join_style
end

#line_width ⇒ Object

The current line width in user space units.



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# File 'lib/hexapdf/content/graphics_state.rb', line 454

def line_width
  @line_width
end

#miter_limit ⇒ Object

The maximum line length of mitered line joins for stroked paths.



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# File 'lib/hexapdf/content/graphics_state.rb', line 463

def miter_limit
  @miter_limit
end

#rendering_intent ⇒ Object

The rendering intent (only used for CIE-based colors; for the available values see RenderingIntent).



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# File 'lib/hexapdf/content/graphics_state.rb', line 470

def rendering_intent
  @rendering_intent
end

#scaled_character_spacing ⇒ Object (readonly)

The scaled character spacing used in glyph displacement calculations.

This returns the character spacing multiplied by #scaled_horizontal_scaling.

See PDF2.0 s9.4.4



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# File 'lib/hexapdf/content/graphics_state.rb', line 553

def scaled_character_spacing
  @scaled_character_spacing
end

#scaled_font_size ⇒ Object (readonly)

The scaled font size used in glyph displacement calculations.

This returns the font size multiplied by the scaling factor from glyph space to text space (0.001 for all fonts except Type3 fonts or the scaling specified in /FontMatrix for Type3 fonts) and multiplied by #scaled_horizontal_scaling.

See PDF2.0 s9.4.4, HexaPDF::Type::FontType3



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# File 'lib/hexapdf/content/graphics_state.rb', line 569

def scaled_font_size
  @scaled_font_size
end

#scaled_horizontal_scaling ⇒ Object (readonly)

The scaled horizontal scaling used in glyph displacement calculations.

Since the horizontal scaling attribute is stored in percent of 100, this method returns the correct value for calculations.

See PDF2.0 s9.4.4



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# File 'lib/hexapdf/content/graphics_state.rb', line 577

def scaled_horizontal_scaling
  @scaled_horizontal_scaling
end

#scaled_word_spacing ⇒ Object (readonly)

The scaled word spacing used in glyph displacement calculations.

This returns the word spacing multiplied by #scaled_horizontal_scaling.

See PDF2.0 s9.4.4



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# File 'lib/hexapdf/content/graphics_state.rb', line 560

def scaled_word_spacing
  @scaled_word_spacing
end

#soft_mask ⇒ Object

The soft mask specifying the mask shape or mask opacity value to be used in the transparent imaging model.



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# File 'lib/hexapdf/content/graphics_state.rb', line 480

def soft_mask
  @soft_mask
end

#stroke_adjustment ⇒ Object

The stroke adjustment for very small line width.



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# File 'lib/hexapdf/content/graphics_state.rb', line 473

def stroke_adjustment
  @stroke_adjustment
end

#stroke_alpha ⇒ Object

The alpha constant for stroking operations in the transparent imaging model.



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# File 'lib/hexapdf/content/graphics_state.rb', line 483

def stroke_alpha
  @stroke_alpha
end

#stroke_color ⇒ Object

The current color used for stroking operations during painting.



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# File 'lib/hexapdf/content/graphics_state.rb', line 448

def stroke_color
  @stroke_color
end

#text_knockout ⇒ Object

The text knockout, a boolean value.

It specifies whether each glyph should be treated as separate elementary object for the purpose of color compositing in the transparent imaging model (knockout = false) or if all glyphs together are treated as one elementary object (knockout = true).



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# File 'lib/hexapdf/content/graphics_state.rb', line 546

def text_knockout
  @text_knockout
end

#text_rendering_mode ⇒ Object

The text rendering mode.

It determines if and how the glyphs of a text should be shown (for all available values see TextRenderingMode).



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# File 'lib/hexapdf/content/graphics_state.rb', line 533

def text_rendering_mode
  @text_rendering_mode
end

#text_rise ⇒ Object

The text rise distance in unscaled text units.

It specifies the distance that the baseline should be moved up or down from its default location.



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# File 'lib/hexapdf/content/graphics_state.rb', line 539

def text_rise
  @text_rise
end

#tlm ⇒ Object

The text line matrix which captures the state of the text matrix at the beginning of a line.

As with the text matrix the text line matrix is non-nil only when inside a text object.



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# File 'lib/hexapdf/content/graphics_state.rb', line 500

def tlm
  @tlm
end

#tm ⇒ Object

The text matrix.

This attribute is non-nil only when inside a text object.



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# File 'lib/hexapdf/content/graphics_state.rb', line 495

def tm
  @tm
end

#word_spacing ⇒ Object

The word spacing in unscaled text units.

It works like the character spacing but is only applied to the ASCII space character.



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# File 'lib/hexapdf/content/graphics_state.rb', line 511

def word_spacing
  @word_spacing
end

Instance Method Details

#fill_color_space ⇒ Object

:nodoc:



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# File 'lib/hexapdf/content/graphics_state.rb', line 671

def fill_color_space
  @fill_color.color_space
end

#fill_color_space=(color_space) ⇒ Object

:nodoc:



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# File 'lib/hexapdf/content/graphics_state.rb', line 675

def fill_color_space=(color_space) #:nodoc:
  self.fill_color = color_space.default_color
end

#restore ⇒ Object

Restores the graphics state from the internal stack.

Raises an error if the stack is empty.



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# File 'lib/hexapdf/content/graphics_state.rb', line 632

def restore
  if @stack.empty?
    raise HexaPDF::Error, "Can't restore graphics state because the stack is empty"
  end
  @ctm, @stroke_color, @fill_color,
    @line_width, @line_cap_style, @line_join_style, @miter_limit, @line_dash_pattern,
    @rendering_intent, @stroke_adjustment, @blend_mode,
    @soft_mask, @stroke_alpha, @fill_alpha, @alpha_source,
    @character_spacing, @word_spacing, @horizontal_scaling, @leading,
    @font, @font_size, @text_rendering_mode, @text_rise, @text_knockout,
    @scaled_character_spacing, @scaled_word_spacing, @scaled_font_size,
    @scaled_horizontal_scaling = @stack.pop
end

#save ⇒ Object

Saves the current graphics state on the internal stack.



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# File 'lib/hexapdf/content/graphics_state.rb', line 617

def save
  @stack.push([@ctm, @stroke_color, @fill_color,
               @line_width, @line_cap_style, @line_join_style, @miter_limit,
               @line_dash_pattern, @rendering_intent, @stroke_adjustment, @blend_mode,
               @soft_mask, @stroke_alpha, @fill_alpha, @alpha_source,
               @character_spacing, @word_spacing, @horizontal_scaling, @leading,
               @font, @font_size, @text_rendering_mode, @text_rise, @text_knockout,
               @scaled_character_spacing, @scaled_word_spacing, @scaled_font_size,
               @scaled_horizontal_scaling])
  @ctm = @ctm.dup
end

#saved_states? ⇒ Boolean

Returns true if the internal stack of saved graphic states contains entries.

Returns:

  • (Boolean) 


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# File 'lib/hexapdf/content/graphics_state.rb', line 647

def saved_states?
  !@stack.empty?
end

#stroke_color_space ⇒ Object

:nodoc:



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# File 'lib/hexapdf/content/graphics_state.rb', line 657

def stroke_color_space
  @stroke_color.color_space
end

#stroke_color_space=(color_space) ⇒ Object

:nodoc:



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# File 'lib/hexapdf/content/graphics_state.rb', line 661

def stroke_color_space=(color_space) # :nodoc:
  self.stroke_color = color_space.default_color
end