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.



446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
 
# File 'lib/hexapdf/content/graphics_state.rb', line 446

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.



358
359
360
 
# File 'lib/hexapdf/content/graphics_state.rb', line 358

def alpha_source
  @alpha_source
end

#blend_mode ⇒ Object

The current blend mode for the transparent imaging model.



344
345
346
 
# File 'lib/hexapdf/content/graphics_state.rb', line 344

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.



374
375
376
 
# File 'lib/hexapdf/content/graphics_state.rb', line 374

def character_spacing
  @character_spacing
end

#ctm ⇒ Object

The current transformation matrix.



313
314
315
 
# File 'lib/hexapdf/content/graphics_state.rb', line 313

def ctm
  @ctm
end

#fill_alpha ⇒ Object

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



354
355
356
 
# File 'lib/hexapdf/content/graphics_state.rb', line 354

def fill_alpha
  @fill_alpha
end

#fill_color ⇒ Object

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



319
320
321
 
# File 'lib/hexapdf/content/graphics_state.rb', line 319

def fill_color
  @fill_color
end

#font ⇒ Object

The font for the text.



392
393
394
 
# File 'lib/hexapdf/content/graphics_state.rb', line 392

def font
  @font
end

#font_size ⇒ Object

The font size.



395
396
397
 
# File 'lib/hexapdf/content/graphics_state.rb', line 395

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.



384
385
386
 
# File 'lib/hexapdf/content/graphics_state.rb', line 384

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.



389
390
391
 
# File 'lib/hexapdf/content/graphics_state.rb', line 389

def leading
  @leading
end

#line_cap_style ⇒ Object

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



325
326
327
 
# File 'lib/hexapdf/content/graphics_state.rb', line 325

def line_cap_style
  @line_cap_style
end

#line_dash_pattern ⇒ Object

The line dash pattern (see LineDashPattern).



334
335
336
 
# File 'lib/hexapdf/content/graphics_state.rb', line 334

def line_dash_pattern
  @line_dash_pattern
end

#line_join_style ⇒ Object

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



328
329
330
 
# File 'lib/hexapdf/content/graphics_state.rb', line 328

def line_join_style
  @line_join_style
end

#line_width ⇒ Object

The current line width in user space units.



322
323
324
 
# File 'lib/hexapdf/content/graphics_state.rb', line 322

def line_width
  @line_width
end

#miter_limit ⇒ Object

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



331
332
333
 
# File 'lib/hexapdf/content/graphics_state.rb', line 331

def miter_limit
  @miter_limit
end

#rendering_intent ⇒ Object

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



338
339
340
 
# File 'lib/hexapdf/content/graphics_state.rb', line 338

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



421
422
423
 
# File 'lib/hexapdf/content/graphics_state.rb', line 421

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



435
436
437
 
# File 'lib/hexapdf/content/graphics_state.rb', line 435

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



443
444
445
 
# File 'lib/hexapdf/content/graphics_state.rb', line 443

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



428
429
430
 
# File 'lib/hexapdf/content/graphics_state.rb', line 428

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.



348
349
350
 
# File 'lib/hexapdf/content/graphics_state.rb', line 348

def soft_mask
  @soft_mask
end

#stroke_adjustment ⇒ Object

The stroke adjustment for very small line width.



341
342
343
 
# File 'lib/hexapdf/content/graphics_state.rb', line 341

def stroke_adjustment
  @stroke_adjustment
end

#stroke_alpha ⇒ Object

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



351
352
353
 
# File 'lib/hexapdf/content/graphics_state.rb', line 351

def stroke_alpha
  @stroke_alpha
end

#stroke_color ⇒ Object

The current color used for stroking operations during painting.



316
317
318
 
# File 'lib/hexapdf/content/graphics_state.rb', line 316

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).



414
415
416
 
# File 'lib/hexapdf/content/graphics_state.rb', line 414

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).



401
402
403
 
# File 'lib/hexapdf/content/graphics_state.rb', line 401

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.



407
408
409
 
# File 'lib/hexapdf/content/graphics_state.rb', line 407

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.



368
369
370
 
# File 'lib/hexapdf/content/graphics_state.rb', line 368

def tlm
  @tlm
end

#tm ⇒ Object

The text matrix.

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



363
364
365
 
# File 'lib/hexapdf/content/graphics_state.rb', line 363

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.



379
380
381
 
# File 'lib/hexapdf/content/graphics_state.rb', line 379

def word_spacing
  @word_spacing
end

Instance Method Details

#fill_color_space ⇒ Object

:nodoc:



537
538
539
 
# File 'lib/hexapdf/content/graphics_state.rb', line 537

def fill_color_space
  @fill_color.color_space
end

#fill_color_space=(color_space) ⇒ Object

:nodoc:



541
542
543
 
# File 'lib/hexapdf/content/graphics_state.rb', line 541

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.



498
499
500
501
502
503
504
505
506
507
508
509
510
 
# File 'lib/hexapdf/content/graphics_state.rb', line 498

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.



483
484
485
486
487
488
489
490
491
492
493
 
# File 'lib/hexapdf/content/graphics_state.rb', line 483

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) 


513
514
515
 
# File 'lib/hexapdf/content/graphics_state.rb', line 513

def saved_states?
  !@stack.empty?
end

#stroke_color_space ⇒ Object

:nodoc:



523
524
525
 
# File 'lib/hexapdf/content/graphics_state.rb', line 523

def stroke_color_space
  @stroke_color.color_space
end

#stroke_color_space=(color_space) ⇒ Object

:nodoc:



527
528
529
 
# File 'lib/hexapdf/content/graphics_state.rb', line 527

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