Class: HexaPDF::Type::AcroForm::ButtonField

Inherits:
Field show all
Defined in:
lib/hexapdf/type/acro_form/button_field.rb

Overview

AcroForm button fields represent interactive controls to be used with the mouse.

They are divided into push buttons (things to click on), check boxes and radio buttons. All of these are represented with this class.

To create a push button, check box or radio button field, use the appropriate convenience methods on the main Form instance (HexaPDF::Document#acro_form). By using those methods, everything needed is automatically set up.

Type Specific Field Flags

:no_toggle_to_off

Only used with radio buttons fields. If this flag is set, one button needs to be selected at all times. Otherwise, clicking on the selected button deselects it.

:radio

If this flag is set, the field is a set of radio buttons. Otherwise it is a check box. Additionally, the :pushbutton flag needs to be clear.

:push_button

The field represents a pushbutton without a permanent value.

:radios_in_unison

A group of radio buttons with the same value for the on state will turn on or off in unison.

See: PDF1.7 s12.7.4.2

Constant Summary collapse

INHERITABLE_FIELDS =

All inheritable dictionary fields for button fields.

(superclass::INHERITABLE_FIELDS + [:Opt]).freeze
FLAGS_BIT_MAPPING =

Updated list of field flags.

superclass::FLAGS_BIT_MAPPING.merge(
  {
    no_toggle_to_off: 14,
    radio: 15,
    push_button: 16,
    radios_in_unison: 25,
  }
).freeze

Constants included from DictionaryFields

DictionaryFields::Boolean, DictionaryFields::PDFByteString, DictionaryFields::PDFDate

Instance Attribute Summary

Attributes inherited from Object

#data, #document, #must_be_indirect

Instance Method Summary collapse

Methods inherited from Field

#[], #alternate_field_name, #alternate_field_name=, #delete_widget, #each_widget, #embedded_widget?, #field_name, #field_type, #flags, #full_field_name, inherited_value, #must_be_indirect?, #terminal_field?

Methods included from Utils::BitField

#bit_field

Methods inherited from Dictionary

#[], #[]=, define_field, define_type, #delete, #each, each_field, #empty?, field, #key?, #to_h, type, #type

Methods inherited from Object

#<=>, #==, #cache, #cached?, #clear_cache, deep_copy, #deep_copy, #document?, #eql?, #gen, #gen=, #hash, #indirect?, #initialize, #inspect, #must_be_indirect?, #null?, #oid, #oid=, #type, #validate, #value, #value=

Constructor Details

This class inherits a constructor from HexaPDF::Object

Instance Method Details

#check_box? ⇒ Boolean

Returns true if this button field represents a check box.

Returns:



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# File 'lib/hexapdf/type/acro_form/button_field.rb', line 121

def check_box?
  !push_button? && !flagged?(:radio)
end

#check_box_on_name ⇒ Object

Returns the name (a Symbol) used for setting the check box to the on state.

Defaults to :Yes if no other name could be determined.



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# File 'lib/hexapdf/type/acro_form/button_field.rb', line 186

def check_box_on_name
  each_widget.to_a.first&.appearance&.normal_appearance&.value&.each_key&.
    find {|key| key != :Off } || :Yes
end

#concrete_field_type ⇒ Object

Returns the concrete button field type, either :push_button, :check_box or :radio_button.



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# File 'lib/hexapdf/type/acro_form/button_field.rb', line 173

def concrete_field_type
  if push_button?
    :push_button
  elsif radio_button?
    :radio_button
  else
    :check_box
  end
end

#create_appearances(force: false) ⇒ Object

Creates appropriate appearances for all widgets if they don’t already exist.

The created appearance streams depend on the actual type of the button field. See AppearanceGenerator for the details.

By setting force to true the creation of the appearances can be forced.



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# File 'lib/hexapdf/type/acro_form/button_field.rb', line 233

def create_appearances(force: false)
  appearance_generator_class = document.config.constantize('acro_form.appearance_generator')
  each_widget do |widget|
    next if !force && widget.appearance?
    if check_box?
      appearance_generator_class.new(widget).create_check_box_appearances
    elsif radio_button?
      appearance_generator_class.new(widget).create_radio_button_appearances
    else
      raise HexaPDF::Error, "Push buttons not yet supported"
    end
  end
end

#create_widget(page, defaults: true, value: nil, **values) ⇒ Object

Creates a widget for the button field.

If defaults is true, then default values will be set on the widget so that it uses a default appearance.

If the widget is created for a radio button field, the value argument needs to set to the value (a Symbol or an object responding to #to_sym) this widget represents. It can be used with #field_value= to set this specific widget of the radio button set to on.

See: Field#create_widget, AppearanceGenerator button field methods



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# File 'lib/hexapdf/type/acro_form/button_field.rb', line 209

def create_widget(page, defaults: true, value: nil, **values)
  super(page, allow_embedded: !radio_button?, **values).tap do |widget|
    if check_box?
      widget[:AP] = {N: {Yes: nil, Off: nil}}
    elsif radio_button?
      unless value.respond_to?(:to_sym)
        raise ArgumentError, "Argument 'value' has to be provided for radio buttons " \
          "and needs to respond to #to_sym"
      end
      widget[:AP] = {N: {value.to_sym => nil, Off: nil}}
    end
    next unless defaults
    widget.border_style(color: 0, width: 1, style: (push_button? ? :beveled : :solid))
    widget.background_color(push_button? ? 0.5 : 255)
    widget.marker_style(style: check_box? ? :check : :circle) unless push_button?
  end
end

#default_field_value ⇒ Object

Returns the default field value.

See: #field_value



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# File 'lib/hexapdf/type/acro_form/button_field.rb', line 161

def default_field_value
  normalized_field_value(:DV)
end

#default_field_value=(value) ⇒ Object

Sets the default field value.

See: #field_value=



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# File 'lib/hexapdf/type/acro_form/button_field.rb', line 168

def default_field_value=(value)
  normalized_field_value_set(:DV, value)
end

#field_value ⇒ Object

Returns the field value which depends on the concrete type.

Push buttons

They don’t have a value, so nil is always returned.

Check boxes

For check boxes that are in the on state the value true is returned. Otherwise false is returned.

Radio buttons

If no radio button is selected, nil is returned. Otherwise the value (a Symbol) of the specific radio button that is selected is returned.



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# File 'lib/hexapdf/type/acro_form/button_field.rb', line 139

def field_value
  normalized_field_value(:V)
end

#field_value=(value) ⇒ Object

Sets the field value which depends on the concrete type.

Push buttons

Since push buttons don’t store any value, the given value is ignored and nothing is stored for them (e.g a no-op).

Check boxes

Use true for checking the box, i.e. toggling it to the on state, and false for unchecking it.

Radio buttons

To turn all radio buttons off, provide nil as value. Otherwise provide the value (a Symbol or an object responding to #to_sym) of a radio button that should be turned on.



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# File 'lib/hexapdf/type/acro_form/button_field.rb', line 154

def field_value=(value)
  normalized_field_value_set(:V, value)
end

#initialize_as_check_box ⇒ Object

Initializes the button field to be a check box.

This method should only be called directly after creating a new button field because it doesn’t completely reset the object.



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# File 'lib/hexapdf/type/acro_form/button_field.rb', line 99

def initialize_as_check_box
  self[:V] = :Off
  unflag(:push_button)
  unflag(:radio)
end

#initialize_as_push_button ⇒ Object

Initializes the button field to be a push button.

This method should only be called directly after creating a new button field because it doesn’t completely reset the object.



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# File 'lib/hexapdf/type/acro_form/button_field.rb', line 89

def initialize_as_push_button
  self[:V] = nil
  flag(:push_button)
  unflag(:radio)
end

#initialize_as_radio_button ⇒ Object

Initializes the button field to be a radio button.

This method should only be called directly after creating a new button field because it doesn’t completely reset the object.



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# File 'lib/hexapdf/type/acro_form/button_field.rb', line 109

def initialize_as_radio_button
  self[:V] = :Off
  unflag(:push_button)
  flag(:radio)
end

#push_button? ⇒ Boolean

Returns true if this button field represents a push button.

Returns:



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# File 'lib/hexapdf/type/acro_form/button_field.rb', line 116

def push_button?
  flagged?(:push_button)
end

#radio_button? ⇒ Boolean

Returns true if this button field represents a radio button set.

Returns:



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# File 'lib/hexapdf/type/acro_form/button_field.rb', line 126

def radio_button?
  !push_button? && flagged?(:radio)
end

#radio_button_values ⇒ Object

Returns the array of Symbol values that can be used for the field value of the radio button.



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# File 'lib/hexapdf/type/acro_form/button_field.rb', line 193

def radio_button_values
  each_widget.map do |widget|
    widget.appearance&.normal_appearance&.value&.each_key&.find {|key| key != :Off }
  end.compact
end

#update_widgets ⇒ Object

Updates the widgets so that they reflect the current field value.



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# File 'lib/hexapdf/type/acro_form/button_field.rb', line 248

def update_widgets
  return if push_button?
  create_appearances
  value = self[:V]
  each_widget do |widget|
    widget[:AS] = (widget.appearance&.normal_appearance&.value&.key?(value) ? value : :Off)
  end
end