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<?xml version="1.0"?>
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN"
"http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd">
<refentry id="goocanvas-simple-canvas">
<refmeta>
<refentrytitle>Simple Canvas Example</refentrytitle>
<manvolnum>3</manvolnum>
<refmiscinfo>GOOCANVAS Library</refmiscinfo>
</refmeta>
<refnamediv>
<refname>Simple Canvas Example</refname>
<refpurpose>how to create a simple canvas.</refpurpose>
</refnamediv>
<refsect1 id="simple-canvas-example">
<title>Simple Canvas Example</title>
<para>
Here's a complete example application that creates a <link linkend="GooCanvas"><type>GooCanvas</type></link> with a
rectangle and a text item in it:
</para>
<informalexample><programlisting>
#include <stdlib.h>
#include <goocanvas.h>
static gboolean on_rect_button_press (GooCanvasItem *view,
GooCanvasItem *target,
GdkEventButton *event,
gpointer data);
static gboolean on_delete_event (GtkWidget *window,
GdkEvent *event,
gpointer unused_data);
int
main (int argc, char *argv[])
{
GtkWidget *window, *scrolled_win, *canvas;
GooCanvasItem *root, *rect_item, *text_item;
/* Initialize GTK+. */
gtk_set_locale ();
gtk_init (&argc, &argv);
/* Create the window and widgets. */
window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
gtk_window_set_default_size (GTK_WINDOW (window), 640, 600);
gtk_widget_show (window);
g_signal_connect (window, "delete_event", (GtkSignalFunc) on_delete_event,
NULL);
scrolled_win = gtk_scrolled_window_new (NULL, NULL);
gtk_scrolled_window_set_shadow_type (GTK_SCROLLED_WINDOW (scrolled_win),
GTK_SHADOW_IN);
gtk_widget_show (scrolled_win);
gtk_container_add (GTK_CONTAINER (window), scrolled_win);
canvas = goo_canvas_new ();
gtk_widget_set_size_request (canvas, 600, 450);
goo_canvas_set_bounds (GOO_CANVAS (canvas), 0, 0, 1000, 1000);
gtk_widget_show (canvas);
gtk_container_add (GTK_CONTAINER (scrolled_win), canvas);
root = goo_canvas_get_root_item (GOO_CANVAS (canvas));
/* Add a few simple items. */
rect_item = goo_canvas_rect_new (root, 100, 100, 400, 400,
"line-width", 10.0,
"radius-x", 20.0,
"radius-y", 10.0,
"stroke-color", "yellow",
"fill-color", "red",
NULL);
text_item = goo_canvas_text_new (root, "Hello World", 300, 300, -1,
GTK_ANCHOR_CENTER,
"font", "Sans 24",
NULL);
goo_canvas_item_rotate (text_item, 45, 300, 300);
/* Connect a signal handler for the rectangle item. */
g_signal_connect (rect_item, "button_press_event",
(GtkSignalFunc) on_rect_button_press, NULL);
/* Pass control to the GTK+ main event loop. */
gtk_main ();
return 0;
}
/* This handles button presses in item views. We simply output a message to
the console. */
static gboolean
on_rect_button_press (GooCanvasItem *item,
GooCanvasItem *target,
GdkEventButton *event,
gpointer data)
{
g_print ("rect item received button press event\n");
return TRUE;
}
/* This is our handler for the "delete-event" signal of the window, which
is emitted when the 'x' close button is clicked. We just exit here. */
static gboolean
on_delete_event (GtkWidget *window,
GdkEvent *event,
gpointer unused_data)
{
exit (0);
}
</programlisting></informalexample>
</refsect1>
</refentry>
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