[libchamplain] Firt version of the demo that downloads an image

[Pierre-Luc Beaudoin <plbeaudoin src gnome org>]

commit 828937764879410cba6425f509edee379c7cad2d
Author: Emmanuel Rodriguez <emmanuel rodriguez gmail com>
Date:   Wed Apr 15 20:30:35 2009 +0200

    Firt version of the demo that downloads an image

 demos/image.c |  214 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 214 insertions(+), 0 deletions(-)
---
diff --git a/demos/image.c b/demos/image.c
new file mode 100644
index 0000000..47e10c7
--- /dev/null
+++ b/demos/image.c
@@ -0,0 +1,214 @@
+/*
+ * Copyright (C) 2009 Emmanuel Rodriguez <emmanuel rodriguez gmail com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+#include <champlain/champlain.h>
+#include <libsoup/soup.h>
+#include <gdk-pixbuf/gdk-pixbuf.h>
+
+
+/**
+ * Transforms a pixbuf into a Clutter texture.
+ */
+static ClutterActor*
+pixbuf_to_texture (GdkPixbuf *pixbuf, GError **error)
+{
+	ClutterActor *texture = NULL;
+	const guchar *data;
+	gboolean has_alpha, success;
+	int width, height, rowstride;
+	ClutterTextureFlags flags = 0;
+
+	data = gdk_pixbuf_get_pixels (pixbuf);
+	width = gdk_pixbuf_get_width (pixbuf);
+	height = gdk_pixbuf_get_height (pixbuf);
+	has_alpha = gdk_pixbuf_get_has_alpha (pixbuf);
+	rowstride = gdk_pixbuf_get_rowstride (pixbuf);
+
+	texture = clutter_texture_new ();
+	success = clutter_texture_set_from_rgb_data (CLUTTER_TEXTURE (texture),
+		data,
+		has_alpha,
+		width,
+		height,
+		rowstride,
+		(has_alpha ? 4 : 3),
+		flags,
+		error);
+	if (! success) {
+		g_print ("Failed to create the texture\n");
+		clutter_actor_destroy (CLUTTER_ACTOR (texture));
+		return NULL;
+	}
+
+	g_print ("Created the texture\n");
+	return texture;
+}
+
+
+/**
+ * Called when an image has been downloaded. This callback will transform the
+ * image data (binary chunk sent by the remote web server) into a valid Clutter
+ * actor (a texture) and will use this as the source image for a new marker. The
+ * marker will then be added to an existing layer.
+ *
+ * This callback expects the parameter data to be a valid ChamplainLayer.
+ */
+static void
+image_downloaded_cb (SoupSession *session,
+                     SoupMessage *message,
+										 gpointer data)
+{
+  ChamplainLayer *layer = NULL;
+	SoupURI *uri = NULL;
+	char *url = NULL;
+	const gchar *mime_type = NULL;
+	GdkPixbufLoader *loader = NULL;
+	GError *error = NULL;
+	GdkPixbuf *pixbuf = NULL;
+	ClutterActor *texture = NULL;
+	ClutterActor *marker = NULL;
+
+	g_print("Downloaded the image\n");
+	if (data == NULL) {
+		g_print ("Missing the data pointer\n");
+		goto cleanup;
+	}
+	
+	/* Deal only with finished messages */
+	g_print ("message->status_code = %d\n", message->status_code);
+	if (! SOUP_STATUS_IS_SUCCESSFUL(message->status_code)) {
+		g_print ("SOUP message isn't finished\n");
+		goto cleanup;
+	}
+	
+	uri = soup_message_get_uri (message);
+	url = soup_uri_to_string (uri, FALSE);
+
+	/*  Deal only with successful messages */
+	if (! SOUP_STATUS_IS_SUCCESSFUL (message->status_code)) {
+		g_print ("Skipping download of %s since server returned error code %d\n", url, message->status_code);
+		goto cleanup;
+	}
+
+	/*  Make sure that we downloaded an image */
+	mime_type = soup_message_headers_get (message->response_headers, "Content-Type");
+
+
+	/*  First transform the image into a pixbuf */
+	loader = gdk_pixbuf_loader_new_with_mime_type (mime_type, &error);
+	if (error) {
+		g_print ("Can't build a PixbufLoader that will parse a %s image %s\n", mime_type, error->message);
+		if (loader) {gdk_pixbuf_loader_close (loader, NULL);}
+		goto cleanup;
+	}
+	gdk_pixbuf_loader_write (
+		loader, 
+		message->response_body->data,
+		message->response_body->length, 
+		&error);
+	if (error) {
+		g_print ("Can't parse the image %s: %s\n", url, error->message);
+		gdk_pixbuf_loader_close (loader, NULL);
+		goto cleanup;
+	}
+
+	gdk_pixbuf_loader_close (loader, &error);
+	if (error) {
+		g_print ("Can't close the parser for image %s: %s\n", url, error->message);
+		goto cleanup;
+	}
+	pixbuf = gdk_pixbuf_loader_get_pixbuf (loader);
+	if (pixbuf == NULL) {
+		goto cleanup;
+	}
+	g_print ("Got a pixbuf\n");
+
+	/* Then transform the pixbuf into a texture */
+	texture = pixbuf_to_texture (pixbuf, &error);
+	if (error) {
+		g_print ("Can't convert the pixbuf into a texture for image %s: %s\n", url, error->message);
+		goto cleanup;
+	}
+	g_print ("Got a texture\n");
+
+	/* Finally create a marker with the texture */
+	layer = CHAMPLAIN_LAYER (data);
+	marker = champlain_marker_new_with_image (texture);
+	texture = NULL;
+  champlain_base_marker_set_position (CHAMPLAIN_BASE_MARKER (marker), 45.466, -73.75);
+  clutter_container_add (CLUTTER_CONTAINER (layer), marker, NULL);
+	clutter_actor_show_all (marker);
+
+	/* Cleanup part, the function will always exit here even in case of error */
+	cleanup:
+		g_free (url);
+		if (loader) {g_object_unref (G_OBJECT (loader));}
+		if (texture) {clutter_actor_destroy (CLUTTER_ACTOR (texture));}
+		return;
+}
+
+
+static void
+create_marker_from_url (ChamplainLayer *layer,
+                        SoupSession *session,
+                        const gchar *url)
+{
+  SoupMessage *message;
+	
+	message = soup_message_new ("GET", url);
+	soup_session_queue_message (session, message, image_downloaded_cb, layer);
+	g_print ("Downloading %s\n",  url);
+}
+
+
+int
+main (int argc, char *argv[])
+{
+  ClutterActor* actor, *stage;
+  ChamplainLayer *layer;
+	SoupSession *session;
+
+  g_thread_init (NULL);
+  clutter_init (&argc, &argv);
+
+  stage = clutter_stage_get_default ();
+  clutter_actor_set_size (stage, 800, 600);
+
+  /* Create the map view */
+  actor = champlain_view_new ();
+  champlain_view_set_size (CHAMPLAIN_VIEW (actor), 800, 600);
+  clutter_container_add_actor (CLUTTER_CONTAINER (stage), actor);
+
+  /* Create the markers and marker layer */
+  layer = champlain_layer_new ();
+  champlain_view_add_layer (CHAMPLAIN_VIEW (actor), layer);
+	session = soup_session_async_new ();
+	create_marker_from_url (layer, session, "http://hexten.net/cpan-faces/potyl.jpg";);
+
+  /* Finish initialising the map view */
+  g_object_set (G_OBJECT (actor), "zoom-level", 12,
+      "scroll-mode", CHAMPLAIN_SCROLL_MODE_KINETIC, NULL);
+  champlain_view_center_on (CHAMPLAIN_VIEW(actor), 45.466, -73.75);
+
+  clutter_actor_show (stage);
+  clutter_main ();
+	
+	g_object_unref (session);
+
+  return 0;
+}