Class: HexaPDF::Layout::Style

Inherits:
Object
  • Object
show all
Defined in:
lib/hexapdf/layout/style.rb

Overview

A Style is a container for properties that describe the appearance of text or graphics.

Each property except #font has a default value, so only the desired properties need to be changed.

Each property has three associated methods:

property_name

Getter method.

property_name(*args) and property_name=

Setter method.

property_name?

Tester method to see if a value has been set or if the default value has already been used.

Defined Under Namespace

Classes: Border, Layers, LineSpacing, LinkLayer, Quad

Constant Summary collapse

UNSET =

:nodoc:

::Object.new

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(**properties) ⇒ Style

Creates a new Style object.

The properties hash may be used to set the initial values of properties by using keys equivalent to the property names.

Example:

Style.new(font_size: 15, text_align: :center, text_valign: center)



581
582
583
584
 
# File 'lib/hexapdf/layout/style.rb', line 581

def initialize(**properties)
  update(**properties)
  @scaled_item_widths = {}.compare_by_identity
end

Class Method Details

.create(style) ⇒ Object

:call-seq:

Style.create(style)     -> style
Style.create(properties_hash)   -> style

Creates a Style object based on the style argument and returns it:

  • If style is already a Style object, it is just returned.

  • If style is a hash, a new Style object with the style properties specified by the hash

  • is created.

  • If style is nil, a new Style object with only default values is created.



565
566
567
568
569
570
571
572
 
# File 'lib/hexapdf/layout/style.rb', line 565

def self.create(style)
  case style
  when self then style
  when Hash then new(**style)
  when nil then new
  else raise ArgumentError, "Invalid argument class #{style.class}"
  end
end

Instance Method Details

#calculated_font_size ⇒ Object

The calculated font size, taking superscript and subscript into account.



1532
1533
1534
 
# File 'lib/hexapdf/layout/style.rb', line 1532

def calculated_font_size
  (superscript || subscript ? 0.583 : 1) * font_size
end

#calculated_strikeout_position ⇒ Object

Returns the correct offset from the baseline for the strikeout line.



1551
1552
1553
1554
1555
1556
 
# File 'lib/hexapdf/layout/style.rb', line 1551

def calculated_strikeout_position
  calculated_text_rise +
    font.wrapped_font.strikeout_position * font.scaling_factor *
    font.pdf_object.glyph_scaling_factor * calculated_font_size -
    calculated_strikeout_thickness / 2.0
end

#calculated_strikeout_thickness ⇒ Object

Returns the correct thickness for the strikeout line.



1559
1560
1561
1562
 
# File 'lib/hexapdf/layout/style.rb', line 1559

def calculated_strikeout_thickness
  font.wrapped_font.strikeout_thickness * font.scaling_factor *
    font.pdf_object.glyph_scaling_factor * calculated_font_size
end

#calculated_text_rise ⇒ Object

The calculated text rise, taking superscript and subscript into account.



1521
1522
1523
1524
1525
1526
1527
1528
1529
 
# File 'lib/hexapdf/layout/style.rb', line 1521

def calculated_text_rise
  if superscript
    text_rise + font_size * 0.33
  elsif subscript
    text_rise - font_size * 0.20
  else
    text_rise
  end
end

#calculated_underline_position ⇒ Object

Returns the correct offset from the baseline for the underline.



1537
1538
1539
1540
1541
1542
 
# File 'lib/hexapdf/layout/style.rb', line 1537

def calculated_underline_position
  calculated_text_rise +
    font.wrapped_font.underline_position * font.scaling_factor *
    font.pdf_object.glyph_scaling_factor * calculated_font_size -
    calculated_underline_thickness / 2.0
end

#calculated_underline_thickness ⇒ Object

Returns the correct thickness for the underline.



1545
1546
1547
1548
 
# File 'lib/hexapdf/layout/style.rb', line 1545

def calculated_underline_thickness
  font.wrapped_font.underline_thickness * font.scaling_factor *
    font.pdf_object.glyph_scaling_factor * calculated_font_size
end

#clear_cache ⇒ Object

Clears all cached values.

This method needs to be called if the following style properties are changed and values were already cached: font, font_size, character_spacing, word_spacing, horizontal_scaling, ascender, descender.



1631
1632
1633
1634
1635
1636
 
# File 'lib/hexapdf/layout/style.rb', line 1631

def clear_cache
  @scaled_font_size = @scaled_character_spacing = @scaled_word_spacing = nil
  @scaled_horizontal_scaling = @scaled_font_ascender = @scaled_font_descender = nil
  @scaled_y_min = @scaled_y_max = nil
  @scaled_item_widths.clear
end

#initialize_copy(other) ⇒ Object

Duplicates the complex properties that can be modified, as well as the cache.



587
588
589
590
591
592
593
594
595
596
597
598
 
# File 'lib/hexapdf/layout/style.rb', line 587

def initialize_copy(other)
  super
  @scaled_item_widths = {}.compare_by_identity
  clear_cache

  @font_features = @font_features.dup if defined?(@font_features)
  @padding = @padding.dup if defined?(@padding)
  @margin = @margin.dup if defined?(@margin)
  @border = @border.dup if defined?(@border)
  @overlays = @overlays.dup if defined?(@overlays)
  @underlays = @underlays.dup if defined?(@underlays)
end

#name ⇒ Object

:method: text_line_wrapping_algorithm :call-seq:

text_line_wrapping_algorithm(algorithm = nil) {|items, width_block| block }

The line wrapping algorithm that should be used, defaults to TextLayouter::SimpleLineWrapping.

When setting the algorithm, either an object that responds to #call or a block can be used. See TextLayouter::SimpleLineWrapping#call for the needed method signature.



1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
 
# File 'lib/hexapdf/layout/style.rb', line 1398

[
  [:font, "raise HexaPDF::Error, 'No font set'"],
  [:font_size, 10],
  [:line_height, nil],
  [:character_spacing, 0],
  [:word_spacing, 0],
  [:horizontal_scaling, 100],
  [:text_rise, 0],
  [:font_features, {}],
  [:text_rendering_mode, "Content::TextRenderingMode::FILL",
   {setter: "Content::TextRenderingMode.normalize(value)"}],
  [:subscript, false,
   {setter: "value; superscript(false) if superscript",
    valid_values: [true, false]}],
  [:superscript, false,
   {setter: "value; subscript(false) if subscript",
    valid_values: [true, false]}],
  [:underline, false, {valid_values: [true, false]}],
  [:strikeout, false, {valid_values: [true, false]}],
  [:fill_color, "default_color"],
  [:fill_alpha, 1],
  [:stroke_color, "default_color"],
  [:stroke_alpha, 1],
  [:stroke_width, 1],
  [:stroke_cap_style, "Content::LineCapStyle::BUTT_CAP",
   {setter: "Content::LineCapStyle.normalize(value)"}],
  [:stroke_join_style, "Content::LineJoinStyle::MITER_JOIN",
   {setter: "Content::LineJoinStyle.normalize(value)"}],
  [:stroke_miter_limit, 10.0],
  [:stroke_dash_pattern, "Content::LineDashPattern.new",
   {setter: "Content::LineDashPattern.normalize(value, phase)", extra_args: ", phase = 0"}],
  [:text_align, :left, {valid_values: [:left, :center, :right, :justify]}],
  [:text_valign, :top, {valid_values: [:top, :center, :bottom]}],
  [:text_indent, 0],
  [:line_spacing, "LineSpacing.new(type: :single)",
   {setter: "LineSpacing.new(**(value.kind_of?(Symbol) || value.kind_of?(Numeric) ? " \
     "{type: value, value: extra_arg} : value))",
    extra_args: ", extra_arg = nil"}],
  [:last_line_gap, false, {valid_values: [true, false]}],
  [:fill_horizontal, nil],
  [:background_color, nil],
  [:background_alpha, 1],
  [:padding, "Quad.new(0)", {setter: "Quad.new(value)"}],
  [:margin, "Quad.new(0)", {setter: "Quad.new(value)"}],
  [:border, "Border.new", {setter: "Border.new(**value)"}],
  [:overlays, "Layers.new", {setter: "Layers.new(value)"}],
  [:underlays, "Layers.new", {setter: "Layers.new(value)"}],
  [:position, :default],
  [:align, :left, {valid_values: [:left, :center, :right]}],
  [:valign, :top, {valid_values: [:top, :center, :bottom]}],
  [:mask_mode, :default, {valid_values: [:default, :none, :box, :fill_horizontal,
                                         :fill_frame_horizontal, :fill_vertical, :fill]}],
].each do |name, default, options = {}|
  default = default.inspect unless default.kind_of?(String)
  setter = options.delete(:setter) || "value"
  extra_args = options.delete(:extra_args) || ""
  valid_values = options.delete(:valid_values)
  raise ArgumentError, "Invalid keywords: #{options.keys.join(', ')}" unless options.empty?
  valid_values_const = "#{name}_valid_values".upcase
  const_set(valid_values_const, valid_values)
  module_eval(<<-EOF, __FILE__, __LINE__ + 1)
    def #{name}(value = UNSET#{extra_args})
      if value == UNSET
        @#{name} ||= #{default}
      elsif #{valid_values_const} && !#{valid_values_const}.include?(value)
        raise ArgumentError, "\#{value.inspect} is not a valid #{name} value " \\
          "(\#{#{valid_values_const}.map(&:inspect).join(', ')})"
      else
        @#{name} = #{setter}
        self
      end
    end
    def #{name}?
      defined?(@#{name})
    end
  EOF
  alias_method("#{name}=", name)
end

#scaled_character_spacing ⇒ Object

The character spacing scaled appropriately.



1571
1572
1573
 
# File 'lib/hexapdf/layout/style.rb', line 1571

def scaled_character_spacing
  @scaled_character_spacing ||= character_spacing * scaled_horizontal_scaling
end

#scaled_font_ascender ⇒ Object

The ascender of the font scaled appropriately.



1586
1587
1588
1589
 
# File 'lib/hexapdf/layout/style.rb', line 1586

def scaled_font_ascender
  @scaled_font_ascender ||= font.wrapped_font.ascender * font.scaling_factor *
    font.pdf_object.glyph_scaling_factor * font_size
end

#scaled_font_descender ⇒ Object

The descender of the font scaled appropriately.



1592
1593
1594
1595
 
# File 'lib/hexapdf/layout/style.rb', line 1592

def scaled_font_descender
  @scaled_font_descender ||= font.wrapped_font.descender * font.scaling_factor *
    font.pdf_object.glyph_scaling_factor * font_size
end

#scaled_font_size ⇒ Object

The font size scaled appropriately.



1565
1566
1567
1568
 
# File 'lib/hexapdf/layout/style.rb', line 1565

def scaled_font_size
  @scaled_font_size ||= calculated_font_size * font.pdf_object.glyph_scaling_factor *
    scaled_horizontal_scaling
end

#scaled_horizontal_scaling ⇒ Object

The horizontal scaling scaled appropriately.



1581
1582
1583
 
# File 'lib/hexapdf/layout/style.rb', line 1581

def scaled_horizontal_scaling
  @scaled_horizontal_scaling ||= horizontal_scaling / 100.0
end

#scaled_item_width(item) ⇒ Object

Returns the width of the item scaled appropriately (by taking font size, characters spacing, word spacing and horizontal scaling into account).

The item may be a (singleton) glyph object or an integer/float, i.e. items that can appear inside a TextFragment.



1616
1617
1618
1619
1620
1621
1622
1623
1624
 
# File 'lib/hexapdf/layout/style.rb', line 1616

def scaled_item_width(item)
  @scaled_item_widths[item] ||=
    if item.kind_of?(Numeric)
      -item * scaled_font_size
    else
      item.width * scaled_font_size + scaled_character_spacing +
        (item.apply_word_spacing? ? scaled_word_spacing : 0)
    end
end

#scaled_word_spacing ⇒ Object

The word spacing scaled appropriately.



1576
1577
1578
 
# File 'lib/hexapdf/layout/style.rb', line 1576

def scaled_word_spacing
  @scaled_word_spacing ||= word_spacing * scaled_horizontal_scaling
end

#scaled_y_max ⇒ Object

The maximum y-coordinate, calculated using the scaled ascender of the font and the line height or font size.



1606
1607
1608
1609
 
# File 'lib/hexapdf/layout/style.rb', line 1606

def scaled_y_max
  @scaled_y_max ||= scaled_font_ascender * (line_height || font_size) / font_size.to_f +
    calculated_text_rise
end

#scaled_y_min ⇒ Object

The minimum y-coordinate, calculated using the scaled descender of the font and the line height or font size.



1599
1600
1601
1602
 
# File 'lib/hexapdf/layout/style.rb', line 1599

def scaled_y_min
  @scaled_y_min ||= scaled_font_descender * (line_height || font_size) / font_size.to_f +
    calculated_text_rise
end

#update(**properties) ⇒ Object

:call-seq:

style.update(**properties)    -> style

Updates the style’s properties using the key-value pairs specified by the properties hash.



604
605
606
607
 
# File 'lib/hexapdf/layout/style.rb', line 604

def update(**properties)
  properties.each {|key, value| send(key, value) }
  self
end