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Getting (x,y) coordinates when clicking on images

Fri, 28/09/2007 - 11:49 — Marco Rossetti

I wrote an application where the user clicks on a GtkImage, and I want to know *where* the user clicked. Here's a simple object extending GtkAlignment.

I'm extending GtkAlignment, because you have to place the image in 0,0 to get the correct coordinates. Also, keep in mind that (0,0) is the top left corner of the image.

<?php
class xyGtkImage extends GtkAlignment {
    var $eventbox;
    var $image;  

   
    function __construct($imagefile=NULL)
    {
        GtkAlignment::__construct(0,0,0,0);
       
        // create a new eventbox
        $this->eventbox = &new GtkEventBox;
        $this->add($this->eventbox);
        $this->eventbox->set_events(Gdk::BUTTON_PRESS_MASK);
        $this->eventbox->connect ('button-press-event', array($this, "print_coordinates"));
       
        // creating the gtkimage
        $this->image = &new GtkImage();
       
        // if you set $imagefile then image will be automatically loaded
        if ($imagefile !== NULL ) $this->image->set_from_file($imagefile);
        $this->eventbox->add ($this->image);
    }
   
    function print_coordinates($widget, $event)
    {
        echo "You have just clicked on (" . $event->x . "," . $event->y .")\n";
    }
       
   
}
?>

Using the class is pretty simple :D

<?php

$window = &new GtkWindow();
$window->set_position(Gtk::WIN_POS_CENTER);
$window->set_default_size (640, 480);
$window->set_title("xyGtkImage Example");
$window->connect('destroy', 'close_win');

$img = new xyGtkImage('/path/to/yourimage.png');
$window->add($img);


$window->show_all();
gtk::main();
function close_win ()
{
    gtk::main_quit();
}
?>