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)



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# 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.



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# 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.



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# File 'lib/hexapdf/layout/style.rb', line 1554

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.



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

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.



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

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.



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# File 'lib/hexapdf/layout/style.rb', line 1543

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.



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

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.



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

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.



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# File 'lib/hexapdf/layout/style.rb', line 1653

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.



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# 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.



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# File 'lib/hexapdf/layout/style.rb', line 1419

[
  [: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]}],
  [:overflow, :error],
].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.



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

def scaled_character_spacing
  @scaled_character_spacing ||= character_spacing * scaled_horizontal_scaling
end

#scaled_font_ascender ⇒ Object

The ascender of the font scaled appropriately.



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

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.



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# File 'lib/hexapdf/layout/style.rb', line 1614

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.



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

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.



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# File 'lib/hexapdf/layout/style.rb', line 1603

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.



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# File 'lib/hexapdf/layout/style.rb', line 1638

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.



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# File 'lib/hexapdf/layout/style.rb', line 1598

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.



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# File 'lib/hexapdf/layout/style.rb', line 1628

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.



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# File 'lib/hexapdf/layout/style.rb', line 1621

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.



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

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