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

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, align: :center, valign: center)



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# File 'lib/hexapdf/layout/style.rb', line 508

def initialize(**properties)
  update(properties)
  @scaled_item_widths = {}
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 923

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 940

def calculated_strikeout_position
  calculated_text_rise +
    calculated_font_size / 1000.0 * font.wrapped_font.strikeout_position *
    font.scaling_factor - 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 947

def calculated_strikeout_thickness
  calculated_font_size / 1000.0 * font.wrapped_font.strikeout_thickness * font.scaling_factor
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 912

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 928

def calculated_underline_position
  calculated_text_rise +
    calculated_font_size / 1000.0 * font.wrapped_font.underline_position *
    font.scaling_factor - 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 935

def calculated_underline_thickness
  calculated_font_size / 1000.0 * font.wrapped_font.underline_thickness * font.scaling_factor
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 1013

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

#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 819

[
  [:font, "raise HexaPDF::Error, 'No font set'"],
  [:font_size, 10],
  [:character_spacing, 0],
  [:word_spacing, 0],
  [:horizontal_scaling, 100],
  [:text_rise, 0],
  [:font_features, {}],
  [:text_rendering_mode, :fill],
  [:subscript, false, "value; superscript(false) if superscript"],
  [:superscript, false, "value; subscript(false) if subscript"],
  [:underline, false],
  [:strikeout, false],
  [:fill_color, "default_color"],
  [:fill_alpha, 1],
  [:stroke_color, "default_color"],
  [:stroke_alpha, 1],
  [:stroke_width, 1],
  [:stroke_cap_style, :butt],
  [:stroke_join_style, :miter],
  [:stroke_miter_limit, 10.0],
  [:stroke_dash_pattern, "Content::LineDashPattern.new",
   "Content::LineDashPattern.normalize(value, phase)", ", phase = 0"],
  [:align, :left],
  [:valign, :top],
  [:text_indent, 0],
  [:line_spacing, "LineSpacing.new(:single)",
   "LineSpacing.new(value, value: extra_arg)", ", extra_arg = nil"],
  [:background_color, nil],
  [:padding, "Quad.new(0)", "Quad.new(value)"],
  [:margin, "Quad.new(0)", "Quad.new(value)"],
  [:border, "Border.new", "Border.new(value)"],
  [:overlays, "Layers.new", "Layers.new(value)"],
  [:underlays, "Layers.new", "Layers.new(value)"],
  [:position, :default],
  [:position_hint, nil],
].each do |name, default, setter = "value", extra_args = ""|
  default = default.inspect unless default.kind_of?(String)
  module_eval(<<-EOF, __FILE__, __LINE__ + 1)
    def #{name}(value = UNSET#{extra_args})
      value == UNSET ? (@#{name} ||= #{default}) : (@#{name} = #{setter}; self)
    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 957

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 972

def scaled_font_ascender
  @scaled_font_ascender ||= font.wrapped_font.ascender * font.scaling_factor * font_size / 1000
end

#scaled_font_descender ⇒ Object

The descender of the font scaled appropriately.



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# File 'lib/hexapdf/layout/style.rb', line 977

def scaled_font_descender
  @scaled_font_descender ||= font.wrapped_font.descender * font.scaling_factor * font_size / 1000
end

#scaled_font_size ⇒ Object

The font size scaled appropriately.



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# File 'lib/hexapdf/layout/style.rb', line 952

def scaled_font_size
  @scaled_font_size ||= calculated_font_size / 1000.0 * scaled_horizontal_scaling
end

#scaled_horizontal_scaling ⇒ Object

The horizontal scaling scaled appropriately.



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# File 'lib/hexapdf/layout/style.rb', line 967

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 996

def scaled_item_width(item)
  @scaled_item_widths[item.object_id] ||=
    begin
      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
end

#scaled_word_spacing ⇒ Object

The word spacing scaled appropriately.



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# File 'lib/hexapdf/layout/style.rb', line 962

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 descender of the font.



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# File 'lib/hexapdf/layout/style.rb', line 987

def scaled_y_max
  @scaled_y_max ||= scaled_font_ascender + calculated_text_rise
end

#scaled_y_min ⇒ Object

The minimum y-coordinate, calculated using the scaled descender of the font.



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# File 'lib/hexapdf/layout/style.rb', line 982

def scaled_y_min
  @scaled_y_min ||= scaled_font_descender + 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 517

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