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PHP GTK Tutorial #3

In the previous tutorial, I left you with a problem to solve, namely how to get a button and a text box into a single window. Alright, I cheated a bit as you've probably found it isn't possible wihout adding another bit of code. Position of widgets within a window is controlled by providing a table of cells to contain the widgets not unlike layout managers in Java if you are familiar with the Java language. These can either be stacked upon each other or side by side. First to display widgets (in this text boxes) side by side:-

<>#! /usr/bin/php -q

<?php
# display text boxes in a horizontal container

if (!class_exists('gtk'))
{
    if (strtoupper(substr(PHP_OS, 0,3) == 'WIN'))
        dl('php_gtk.dll');
      else
            dl('php_gtk.so');
}

if (!extension_loaded('gtk'))
{
    dl( 'php_gtk.' . PHP_SHLIB_SUFFIX);
}

function destroy()
{
    Gtk::main_quit();
}

$window = &new GtkWindow();
$window->set_position(GTK_WIN_POS_CENTER);
$window->set_title("Test App");
$window->set_usize(300, 100);
$window->set_border_width(10);
$window->connect('destroy', 'destroy');

$text1 = &new GtkText();
$text1->insert_text("Text1",0);
$text2 = &new GtkText();
$text2->insert_text("Text2",0);

$hbox = &new GtkHBox(false, 5);
$window->add($hbox);

$hbox->pack_start($text1, true, true, 1);
$text1->show();

$hbox->pack_start($text2, true, true, 1);
$text2->show();

$window->show_all();

Gtk::main();
?>

Most of this should be familiar to you. The new bits are:-

$hbox = &new GtkHBox(false, 5);
$window->add($hbox);

$hbox->pack_start($text1, true, true, 1);
$text1->show();

$hbox->pack_start($text2, true, true, 1);
$text2->show();

These work like this:-

$hbox = &new GtkHBox(false, 5);

This creates a new variable that contains a reference to a new horizontal box. The parameter false if set to true would set the size of all the widgets to the size of the largest one. The other parameter sets a spacing between the various widgets. The box is then added to the window. Now to populate the box container.

$hbox->pack_start($text1, true, true, 1);

This will pack the container with widgets starting at the top corner. The first parameter specifies the widget to be packed. The second parameter specifies whether the widget will be allowed to resize if the main window is resized. The third parameter doesn't really concern us and is always true. Finally, the number of pixels to srround the widget is sepcified which in this case is 1. The textbox is then displayed and the same is commands are applied to the second text box. This then displays two text boxes side by side. Now we move on to stacking the widgets vertically which will look something like this-

This is achieved using the following code which also has some added functions:-

#! /usr/bin/php -q

<?php
# Display text boxes vertically

if (!class_exists('gtk'))
{
    if (strtoupper(substr(PHP_OS, 0,3) == 'WIN'))
        dl('php_gtk.dll');
      else
            dl('php_gtk.so');
}

if (!extension_loaded('gtk'))
{
    dl( 'php_gtk.' . PHP_SHLIB_SUFFIX);
}

function destroy()
{
    Gtk::main_quit();
}

function btnClicked($text1)
{
    $text1->insert_text('Hello world!',0);
}

$window = &new GtkWindow();
$window->set_position(GTK_WIN_POS_CENTER);
$window->set_title("Test App");
$window->set_usize(300, 200);
$window->set_border_width(10);
$window->connect('destroy', 'destroy');

$text1 = &new GtkText();
$text1->set_editable(true);
$text1->set_word_wrap(true);

$button = &new GtkButton('Hello World!');
$button->connect_object('clicked', 'btnClicked', $text1);

$vbox = &new GtkVBox(false, 5);
$window->add($vbox);

$vbox->pack_start($text1, true, true, 1);
$text1->show();

$vbox->pack_start($button, true, true, 1);
$button->show();

$window->show_all();

Gtk::main();
?>

Just take a moment to see if you can understand what is going on before reading any further.

Right, done that? Need some help? OK, the window is setup in the usual way as is the text box and a button object is created. Now comes a slightly strange bit:-

$button->connect_object('clicked', 'btnClicked', $text1);

This is an slightly different version of the connect command we used earlier which enables us to pass a parameter to the event function btnClicked we have written to respond to the user clicking on the button. The third parameter $text1 is a reference to the text box that is passed to the btnClicked that is above this main code which looks like this:-

function btnClicked($text1)
{
    $text1->insert_text('Hello world!',0);
}

Now, we have passed the reference to the text box that can now be used within this function. This then inserts the specified text (just had to squeeze a Hello World! program in here somewhere!) into the text box (note the zero). The packing of the VBox works in the same way as the previous example except that widgets are stacked on on top of the other.

And that's it for another tutorial.

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