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by kksou
Sample Code 227: How to set the tab position for GtkTextView - Part 2 - at every 4th character? |
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Written by kksou
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Monday, 07 May 2007 |
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Problem By default, GtkTreeView sets the tab at every eighth character as shown below:
Suppose you would like to set the tab position at every fourth character instead as shown below:
Solution
- Create a new PangoTabArray on the GtkTreeView.
- Calculate the width of the font. With this information, we can calculate the width in pixels for every fourth character.
- Set each tab position with PangoTabArray::set_tab()
- Then impose the tabs on the textview with GtkTextView::set_tabs() on the GtkTreeView.
Sample Code 1
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| <?php
$window = new GtkWindow();
$window->set_size_request(400, 240);
$window->connect_simple('destroy', array('Gtk','main_quit'));
$window->add($vbox = new GtkVBox());
// display title
$title = new GtkLabel("Set the Tab Position of GtkTextView\n".
"Part 2 - at every 4th character");
$title->modify_font(new PangoFontDescription("Times New Roman Italic 10"));
$title->modify_fg(Gtk::STATE_NORMAL, GdkColor::parse("#0000ff"));
$title->set_size_request(-1, 40);
$title->set_justify(Gtk::JUSTIFY_CENTER);
$alignment = new GtkAlignment(0.5, 0, 0, 0);
$alignment->add($title);
$vbox->pack_start($alignment, 0, 0);
$vbox->pack_start(new GtkLabel(), 0, 0);
// Create a new buffer and a new view to show the buffer.
$buffer = new GtkTextBuffer();
$view = new GtkTextView();
$view->set_buffer($buffer);
$view->modify_font(new PangoFontDescription("Courier New 16")); // note 6
$view->set_wrap_mode(Gtk::WRAP_WORD);
$buffer->set_text("123456781234567812345678\n");
$scrolled_win = new GtkScrolledWindow();
$scrolled_win->set_policy( Gtk::POLICY_AUTOMATIC, Gtk::POLICY_AUTOMATIC);
$vbox->pack_start($scrolled_win);
$scrolled_win->add($view);
$window->show_all();
$style = $view->get_style();
$font = $view->get_style()->font_desc;
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- Note that this is only 70% of the sample code. You have to be a registered member to see the entire sample code. Please login or register.
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Explanation
- Get the font size. Note that this is in pango unit.
- Convert from pango unit to pixels.
- Note that we are using fixed-width font here. So we simply multiply the font width by 4.
- Set the tab positions. In this example, we set a tab for every 100 pixels.
- Set the tab on the treeview.
- Try changing this to other font size. You will see that the tab will always be set at every fourth character.
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