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Problem In Part 1, you have highlighted enclosing curly brackets in a GtkTextView.
However, pressing the button when the cursor is at "else" should not highlight anything. We'll fix this in this article as shown below:
Solution
- On the left, we need to make sure that there's no "}" after the "{" by using the method.
- Similarly, on the right, we need to make sure that there's no "{" before the "}".
- GtkTextiter::compare() is the method that allows us to compare the position of two iters.
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("Find matching curly bracket - Part 2\n".
"Place the cursor on 'else' and press the button.\n".
"Nothing will be highlighted.");
$title->modify_font(new PangoFontDescription("Times New Roman Italic 10"));
$title->modify_fg(Gtk::STATE_NORMAL, GdkColor::parse("#0000ff"));
$title->set_size_request(-1, 60);
$title->set_justify(Gtk::JUSTIFY_CENTER);
$alignment = new GtkAlignment(0.5, 0.5, 0, 0);
$alignment->add($title);
$vbox->pack_start($alignment);
$left_start_iter = $left_end_iter = null;
$right_start_iter = $right_end_iter = null;
// Create a new buffer and a new view to show the buffer.
$buffer = new GtkTextBuffer();
$buffer->set_text('if ($i==1) {
test();
} else {
test2();
}');
$view = new GtkTextView();
$view->set_buffer($buffer);
$view->modify_font(new PangoFontDescription("Arial 10"));
$view->set_wrap_mode(Gtk::WRAP_WORD);
$hbox = new GtkHBox();
$hbox->pack_start($button = new GtkButton('Find enclosing bracket'), 0);
$vbox->pack_start($hbox, 0);
$button->connect('clicked', 'on_button', $buffer);
$scrolled_win = new GtkScrolledWindow();
$scrolled_win->set_policy( Gtk::POLICY_AUTOMATIC, Gtk::POLICY_AUTOMATIC);
$vbox->pack_start($scrolled_win);
$scrolled_win->add($view);
$tag_table = $buffer->get_tag_table();
$tag['highlight'] = new GtkTextTag();
$tag['highlight']->set_property('background', "#ffff00");
$tag_table->add($tag['highlight']);
$window->show_all();
Gtk::main();
function find_left_bracket($iter, $buffer) {
global $tag;
$iter2 = $iter->copy();
$match_start = $iter->copy();
$match_end = $iter->copy();
// check left { first
$found = $iter->backward_search('{', 0, $match_start,
$match_end, null);
if (!$found) return null;
// check if there's a } on the left
$match_start2 = $iter->copy();
$match_end2 = $iter->copy();
$found2 = $iter2->backward_search('}', 0, $match_start2, // note 1
$match_end2, null);
if ($found2 && $match_start->compare($match_start2)!=1) // note 2
return null;
$buffer->apply_tag($tag['highlight'], $match_start, $match_end);
return array($match_start, $match_end);
}
function find_right_bracket($iter, $buffer) {
global $tag;
$iter2 = $iter->copy();
$match_start = $iter->copy();
$match_end = $iter->copy();
// check right } first
$found = $iter->forward_search('}', 0, $match_start,
$match_end, null);
if (!$found) return null;
// check if there's a { on the right
$match_start2 = $iter->copy();
$match_end2 = $iter->copy();
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Explanation
- Check if there's a "}" on the left.
- If the } comes after the {, we do not highlight the curly bracket.
- Check if there's a "{" on the right.
- If the { comes after the }, we do not highlight the curly bracket.
Note
There is one more thing we need to improve:
- When the user moves the cursor (by mouse or keyboard), the highlight should disappear.
We will fix this in the next article.
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