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: PDF1.7 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 443

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 355

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 341

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 371

def character_spacing
  @character_spacing
end

#ctm ⇒ Object

The current transformation matrix.



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# File 'lib/hexapdf/content/graphics_state.rb', line 310

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 351

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 316

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 389

def font
  @font
end

#font_size ⇒ Object

The font size.



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# File 'lib/hexapdf/content/graphics_state.rb', line 392

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 381

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 386

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 322

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 331

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 325

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 319

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 328

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 335

def rendering_intent
  @rendering_intent
end

#scaled_character_spacing ⇒ Object (readonly)

The scaled character spacing used in glyph displacement calculations.

This returns the value T_c multiplied by #scaled_horizontal_scaling.

See PDF1.7 s9.4.4



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# File 'lib/hexapdf/content/graphics_state.rb', line 418

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 value T_fs / 1000 multiplied by #scaled_horizontal_scaling.

See PDF1.7 s9.4.4



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# File 'lib/hexapdf/content/graphics_state.rb', line 432

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 PDF1.7 s9.4.4



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# File 'lib/hexapdf/content/graphics_state.rb', line 440

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 value T_w multiplied by #scaled_horizontal_scaling.

See PDF1.7 s9.4.4



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# File 'lib/hexapdf/content/graphics_state.rb', line 425

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 345

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 338

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 348

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 313

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 411

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 398

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 404

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 365

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 360

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 376

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 534

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 538

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 495

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 480

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 510

def saved_states?
  !@stack.empty?
end

#stroke_color_space ⇒ Object

:nodoc:



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# File 'lib/hexapdf/content/graphics_state.rb', line 520

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 524

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