Text Widget

Gtk::Text is the widget to edit multi-lines text. Gtk::Text.new creates Text widget.

Program text.rb:

require 'gtk'

window = Gtk::Window.new(Gtk::WINDOW_TOPLEVEL)

text = Gtk::Text.new

window.add(text)
text.show
window.show
Gtk.main

Result

Text widget doesn't receive user's input as default. It is done by using "set_editable" method.

text = Gtk::Text.new
text.set_editable true

Gtk::Adjustment class represents abstruct data structure to fetch a part of fuge data (Gtk::Adjustment is NOT a widget).

Using the Gtk::Adjustment enable to scroll text in Text widget.

Here's a sample of Text widget with a scroll bar.

Program text3.rb:

require 'gtk'

window = Gtk::Window.new(Gtk::WINDOW_TOPLEVEL)

vadj = Gtk::Adjustment.new(0,0,0,0,0,0)
text = Gtk::Text.new(nil, vadj)
vs = Gtk::VScrollbar.new(vadj)

text.set_editable true

hbox = Gtk::HBox.new(false, 0)
hbox.pack_start text, true, true, 0
hbox.pack_start vs, false, false, 0

window.add hbox
text.show
vs.show
hbox.show
window.show
Gtk.main

Result

Discription

• vadj = Gtk::Adjustment.new(0,0,0,0,0,0)
  This creates Adjustment object. Both Text widget and Scrollbar widget owns this object.
• text = Gtk::Text.new(nil, vadj)
  This creates Text widget. First argument is the Adjustment for horizontal direction, and second is also the Adjustmen for vertical direction. Argument "nil" means using default adjustments. (attention: Text widget does not support horizontal Adjustment yet)
• vs = Gtk::VScrollbar.new(vadj)
  This creates scrollbar. VScrollbar is vertical scrollbar, HScrollbar is horizontal one. Argument "vadj" is the Adjustment object which is same one for Text widget.
• hbox = Gtk::HBox.new(false, 0)
  
• hbox.pack_start text, true, true, 0
  
• hbox.pack_start vs, false, false, 0
  This creates horizontal box and pack Text and Scrollbar.

Here's main methods of Text widget.

text.set_point(index)

This method set the "inserting point". index is the index of the string in Text widget.

index = text.get_point

This method returns the current "inserting point".

length = text.get_length

This method returns the length of the string in Text widget. It also includes the length of carrige return or line feed.

text.insert_text(chars, index)

This method insert string to Text widget. It is inherited from Gtk::Editable. This insert the string chars into the index.

text.get_chars(start_pos, end_pos)

This method returns the string from start_pos to end_pos. Gtk::Text.get_chars is inherited from Gtk::Editable.

text.insert(font, fore, back, ch ars)

This method inserts string into current "inserting point". Font, foreground color, Background color, can be designated. font is Gdk::Font, fore and back is Gdk::Color object. Argument "nil" for font/color means using default value (one of widget style).

text.backward_delete(nchars)

text.forward_delete(nchars)

These methods delete nchars characters from current "inserting point". "backward_delete" delete string from right to left. "forward_delete" delete string from left to right.