Updated Jun 08, 2008 by b100dian
Labels:	Featured

Example

gtkaml example

What is gtkaml

Gtkaml is an XML syntax + a preprocessor that transforms an UI description into Vala code.

Example of gtkaml syntax

Which would produce this:

MyVBox.gtkaml

Here is what you write: (note: this is a gtkaml 0.2 example. To compile this in 0.1, replace hyphens with underscores)

<VBox xmlns="Gtk" xmlns:glib="GLib" xmlns:class="http://gtkaml.org/0.2" 
class:name="MyVBox">
	<Label use-markup="true" label="&lt;b&gt;Dialog Box Title Here&lt;/b&gt;" expand="false" fill="false" padding="0" />
	<Notebook can-focus="true" tab-vborder="1">
		<Label>
			<tab-label>
			    <Label label="Page 1"/>
			</tab-label>
			<label>label
multilne</label>
		</Label>
		<HBox homogeneous="false" spacing="0">
			<tab-label>
			    <CheckButton label="check button" active="true" />
			</tab-label>
			<Label label="Nothing to see here, please move along" />
		</HBox>
	</Notebook>
	<HButtonBox>
		<Button with-mnemonic="true" label="_abort" clicked="on_click()"/>
		<Button label="gtk-redo" use-stock="true"/>
		<Button label="fail"/>
	</HButtonBox>
<![CDATA[
	private void on_click() { message("you clicked me!"); }

	static int main (string[] args) 
	{
		Gtk.init (ref args);
		Window w = new Gtk.Window (WindowType.TOPLEVEL);
		w.delete_event += (x,y) => { Gtk.main_quit(); };
		MyVBox v = new MyVBox ();
		w.add (v);
		w.show_all ();
		Gtk.main ();
		return 0;
	}
		
]]>
</VBox>

Um.. what was that again? Here's what happens (same source, annotated):

<!-- MyVBox class extends VBox and imports the Gtk and GLib namespaces -->
<VBox class:name="MyVBox" xmlns="Gtk" xmlns:glib="GLib" xmlns:class="http://gtkaml.org/0.2">
	<!-- a label is added to the VBox, you can see the box_pack_start () parameters -->
	<Label use-markup="true" label="&lt;b&gt;Dialog Box Title Here&lt;/b&gt;" expand="false" fill="false" padding="0" />
	<!-- then a notebook (tab navigator) is added, with box_pack_start_defaults () -->
	<Notebook can-focus="true" tab-vborder="1">
		<!-- the first page in the notebook is only a label -->
		<Label>
			<!-- this is the widget used for notebook tab label -->
			<tab-label>
			    <!-- this label's text is set using the attribute label="" -->
			    <Label label="Page 1"/>
			</tab-label>
			<!-- the parent's text label is set using this sub-tag -->
			<label>label
multilne</label>
		</Label>
		<!-- the second page is an HBox -->
		<HBox homogeneous="false" spacing="0">
			<!-- actually this sub-tag is a parameter to gtk_notebook_append_page (notebook, child, tab_label) -->
			<tab-label>
			    <!-- this uses a check button as its notebook tab -->
			    <CheckButton label="check button" active="true" />
			</tab-label>
			<!-- this is what the HBox contains -->
			<Label label="Nothing to see here, please move along" />
		</HBox>
	</Notebook>
	<!-- next we add an HButtonBox to our VBox -->
	<HButtonBox>
		<!-- this button is created with gtk_button_new_with_mnemonic () 
		     'clicked' contains the body of the event handler lambda function -->
		<Button with-mnemonic="true" label="_abort" clicked="on_click()"/>
		<Button label="gtk-redo" use-stock="true"/>
		<Button label="fail"/>
	</HButtonBox>
<!-- cdata sections are used for Vala code -->
<![CDATA[
	private void on_click() { stdout.printf("you clicked me!"); }

	static int main (string[] args) 
	{
		Gtk.init (ref args);
		Window w = new Gtk.Window (WindowType.TOPLEVEL);
		w.delete_event += (x,y) => { Gtk.main_quit(); };
		MyVBox v = new MyVBox ();
		w.add (v);
		w.show_all ();
		Gtk.main ();
		return 0;
	}
		
]]>
</VBox>

and the output of

$ gtkamlc --pkg gtk+2.0 MyVBox.gtkaml

is the following MyVBox.vala file (along with MyVBox.c and MyVBox.h).

(to compile the executable you need to run

$ gcc `pkg-config --cflags gtk+-2.0` MyVBox.c -o myvbox `pkg-config --libs gtk+-2.0`

then ./myvbox will execute it)

MyVBox.vala

using Gtk;
using GLib;

public class MyVBox : Gtk.VBox
{
	private void on_click() { stdout.printf("you clicked me!"); }

	static int main (string[] args) 
	{
		Gtk.init (ref args);
		Window w = new Gtk.Window (WindowType.TOPLEVEL);
		MyVBox v = new MyVBox ();
		w.add (v);
		w.show_all ();
		Gtk.main ();
		return 0;
	}

	construct {
		Gtk.Label _label0;
		Gtk.Notebook _notebook0;
		Gtk.Label _label1;
		Gtk.Label _label2;
		Gtk.HBox _hbox0;
		Gtk.CheckButton _checkbutton0;
		Gtk.Label _label3;
		Gtk.HButtonBox _hbuttonbox0;
		Gtk.Button _button0;
		Gtk.Button _button1;
		Gtk.Button _button2;

		_label0 = new Gtk.Label ("<b>Dialog Box Title Here</b>");
		_notebook0 = new Gtk.Notebook ();
		_label2 = new Gtk.Label ("label for a tab");
		_label1 = new Gtk.Label ("label\nmultilne");
		_checkbutton0 = new Gtk.CheckButton.with_label ("check button");
		_hbox0 = new Gtk.HBox (false, 0);
		_label3 = new Gtk.Label ("Nothing to see here, please move along");
		_hbuttonbox0 = new Gtk.HButtonBox ();
		_button0 = new Gtk.Button.with_mnemonic ("_abort");
		_button1 = new Gtk.Button.with_label ("gtk-redo");
		_button2 = new Gtk.Button.with_label ("fail");

		this.name = "MyVBox";
		_label0.use_markup = true;
		this.pack_start (_label0, false, false, 0);

		_notebook0.can_focus = true;
		_notebook0.tab_vborder = 1;
		this.pack_start_defaults (_notebook0);

		_notebook0.append_page (_label1, _label2);

		_checkbutton0.active = true;
		_notebook0.append_page (_hbox0, _checkbutton0);

		_hbox0.pack_start_defaults (_label3);

		this.pack_start_defaults (_hbuttonbox0);

		_button0.has_default = true;
		_button0.clicked += target => { on_click(); };
		_hbuttonbox0.pack_start_defaults (_button0);

		_button1.use_stock = true;
		_hbuttonbox0.pack_start_defaults (_button1);

		_hbuttonbox0.pack_start_defaults (_button2);
	}
}

Why?

Beacause vala further transforms the source into .c and .h and gcc compiles them (of course) to native code;)