/* Images * * GtkImage is used to display an image; the image can be in a number of formats. * Typically, you load an image into a GdkPixbuf, then display the pixbuf. * * This demo code shows some of the more obscure cases, in the simple * case a call to gtk_image_new_from_file() is all you need. * * If you want to put image data in your program as a C variable, * use the make-inline-pixbuf program that comes with GTK+. * This way you won't need to depend on loading external files, your * application binary can be self-contained. */#include <gtk/gtk.h>#include <glib/gstdio.h>#include <stdio.h>#include <errno.h>#include "demo-common.h"static GtkWidget *window = NULL;static GdkPixbufLoader *pixbuf_loader = NULL;static guint load_timeout = 0;static FILE* image_stream = NULL;static voidprogressive_prepared_callback (GdkPixbufLoader *loader,			       gpointer		data){  GdkPixbuf *pixbuf;  GtkWidget *image;  image = GTK_WIDGET (data);  pixbuf = gdk_pixbuf_loader_get_pixbuf (loader);  /* Avoid displaying random memory contents, since the pixbuf   * isn't filled in yet.   */  gdk_pixbuf_fill (pixbuf, 0xaaaaaaff);  gtk_image_set_from_pixbuf (GTK_IMAGE (image), pixbuf);}static voidprogressive_updated_callback (GdkPixbufLoader *loader,                              gint		   x,                              gint		   y,                              gint		   width,                              gint		   height,                              gpointer	   data){  GtkWidget *image;  image = GTK_WIDGET (data);  /* We know the pixbuf inside the GtkImage has changed, but the image   * itself doesn't know this; so queue a redraw.  If we wanted to be   * really efficient, we could use a drawing area or something   * instead of a GtkImage, so we could control the exact position of   * the pixbuf on the display, then we could queue a draw for only   * the updated area of the image.   */  gtk_widget_queue_draw (image);}static gintprogressive_timeout (gpointer data){  GtkWidget *image;  image = GTK_WIDGET (data);  /* This shows off fully-paranoid error handling, so looks scary.   * You could factor out the error handling code into a nice separate   * function to make things nicer.   */  if (image_stream)    {      size_t bytes_read;      guchar buf[256];      GError *error = NULL;      bytes_read = fread (buf, 1, 256, image_stream);      if (ferror (image_stream))	{	  GtkWidget *dialog;	  dialog = gtk_message_dialog_new (GTK_WINDOW (window),					   GTK_DIALOG_DESTROY_WITH_PARENT,					   GTK_MESSAGE_ERROR,					   GTK_BUTTONS_CLOSE,					   "Failure reading image file 'alphatest.png': %s",					   g_strerror (errno));	  g_signal_connect (dialog, "response",			    G_CALLBACK (gtk_widget_destroy), NULL);	  fclose (image_stream);	  image_stream = NULL;	  gtk_widget_show (dialog);	  load_timeout = 0;	  return FALSE; /* uninstall the timeout */	}      if (!gdk_pixbuf_loader_write (pixbuf_loader,				    buf, bytes_read,				    &error))	{	  GtkWidget *dialog;	  dialog = gtk_message_dialog_new (GTK_WINDOW (window),					   GTK_DIALOG_DESTROY_WITH_PARENT,					   GTK_MESSAGE_ERROR,					   GTK_BUTTONS_CLOSE,					   "Failed to load image: %s",					   error->message);	  g_error_free (error);	  g_signal_connect (dialog, "response",			    G_CALLBACK (gtk_widget_destroy), NULL);	  fclose (image_stream);	  image_stream = NULL;	  gtk_widget_show (dialog);	  load_timeout = 0;	  return FALSE; /* uninstall the timeout */	}      if (feof (image_stream))	{	  fclose (image_stream);	  image_stream = NULL;	  /* Errors can happen on close, e.g. if the image	   * file was truncated we'll know on close that	   * it was incomplete.	   */	  error = NULL;	  if (!gdk_pixbuf_loader_close (pixbuf_loader,					&error))	    {	      GtkWidget *dialog;	      dialog = gtk_message_dialog_new (GTK_WINDOW (window),					       GTK_DIALOG_DESTROY_WITH_PARENT,					       GTK_MESSAGE_ERROR,					       GTK_BUTTONS_CLOSE,					       "Failed to load image: %s",					       error->message);	      g_error_free (error);	      g_signal_connect (dialog, "response",				G_CALLBACK (gtk_widget_destroy), NULL);	      gtk_widget_show (dialog);	      g_object_unref (pixbuf_loader);	      pixbuf_loader = NULL;	      load_timeout = 0;	      return FALSE; /* uninstall the timeout */	    }	  g_object_unref (pixbuf_loader);	  pixbuf_loader = NULL;	}    }  else    {      gchar *filename;      gchar *error_message = NULL;      GError *error = NULL;      /* demo_find_file() looks in the current directory first,       * so you can run gtk-demo without installing GTK, then looks       * in the location where the file is installed.       */      filename = demo_find_file ("alphatest.png", &error);      if (error)	{	  error_message = g_strdup (error->message);	  g_error_free (error);	}      else	{	  image_stream = g_fopen (filename, "rb");	  g_free (filename);	  if (!image_stream)	    error_message = g_strdup_printf ("Unable to open image file 'alphatest.png': %s",					     g_strerror (errno));	}      if (image_stream == NULL)	{	  GtkWidget *dialog;	  dialog = gtk_message_dialog_new (GTK_WINDOW (window),					   GTK_DIALOG_DESTROY_WITH_PARENT,					   GTK_MESSAGE_ERROR,					   GTK_BUTTONS_CLOSE,					   "%s", error_message);	  g_free (error_message);	  g_signal_connect (dialog, "response",			    G_CALLBACK (gtk_widget_destroy), NULL);	  gtk_widget_show (dialog);	  load_timeout = 0;	  return FALSE; /* uninstall the timeout */	}      if (pixbuf_loader)	{	  gdk_pixbuf_loader_close (pixbuf_loader, NULL);	  g_object_unref (pixbuf_loader);	  pixbuf_loader = NULL;	}      pixbuf_loader = gdk_pixbuf_loader_new ();      g_signal_connect (pixbuf_loader, "area-prepared",			G_CALLBACK (progressive_prepared_callback), image);      g_signal_connect (pixbuf_loader, "area-updated",			G_CALLBACK (progressive_updated_callback), image);    }  /* leave timeout installed */  return TRUE;}static voidstart_progressive_loading (GtkWidget *image){  /* This is obviously totally contrived (we slow down loading   * on purpose to show how incremental loading works).   * The real purpose of incremental loading is the case where   * you are reading data from a slow source such as the network.   * The timeout simply simulates a slow data source by inserting   * pauses in the reading process.   */  load_timeout = gdk_threads_add_timeout (150,				progressive_timeout,				image);}static voidcleanup_callback (GtkObject *object,		  gpointer   data){  if (load_timeout)    {      g_source_remove (load_timeout);      load_timeout = 0;    }  if (pixbuf_loader)    {      gdk_pixbuf_loader_close (pixbuf_loader, NULL);      g_object_unref (pixbuf_loader);      pixbuf_loader = NULL;    }  if (image_stream)    fclose (image_stream);  image_stream = NULL;}static voidtoggle_sensitivity_callback (GtkWidget *togglebutton,                             gpointer   user_data){  GtkContainer *container = user_data;  GList *list;  GList *tmp;  list = gtk_container_get_children (container);  tmp = list;  while (tmp != NULL)    {      /* don't disable our toggle */      if (GTK_WIDGET (tmp->data) != togglebutton)        gtk_widget_set_sensitive (GTK_WIDGET (tmp->data),                                  !gtk_toggle_button_get_active (GTK_TOGGLE_BUTTON (togglebutton)));      tmp = tmp->next;    }  g_list_free (list);}GtkWidget *do_images (GtkWidget *do_widget){  GtkWidget *frame;  GtkWidget *vbox;  GtkWidget *image;  GtkWidget *label;  GtkWidget *align;  GtkWidget *button;  GdkPixbuf *pixbuf;  GError *error = NULL;  char *filename;  if (!window)    {      window = gtk_window_new (GTK_WINDOW_TOPLEVEL);      gtk_window_set_screen (GTK_WINDOW (window),			     gtk_widget_get_screen (do_widget));      gtk_window_set_title (GTK_WINDOW (window), "Images");      g_signal_connect (window, "destroy",			G_CALLBACK (gtk_widget_destroyed), &window);      g_signal_connect (window, "destroy",			G_CALLBACK (cleanup_callback), NULL);      gtk_container_set_border_width (GTK_CONTAINER (window), 8);      vbox = gtk_vbox_new (FALSE, 8);      gtk_container_set_border_width (GTK_CONTAINER (vbox), 8);      gtk_container_add (GTK_CONTAINER (window), vbox);      label = gtk_label_new (NULL);      gtk_label_set_markup (GTK_LABEL (label),			    "<u>Image loaded from a file</u>");      gtk_box_pack_start (GTK_BOX (vbox), label, FALSE, FALSE, 0);      frame = gtk_frame_new (NULL);      gtk_frame_set_shadow_type (GTK_FRAME (frame), GTK_SHADOW_IN);      /* The alignment keeps the frame from growing when users resize       * the window       */      align = gtk_alignment_new (0.5, 0.5, 0, 0);      gtk_container_add (GTK_CONTAINER (align), frame);      gtk_box_pack_start (GTK_BOX (vbox), align, FALSE, FALSE, 0);      /* demo_find_file() looks in the current directory first,       * so you can run gtk-demo without installing GTK, then looks       * in the location where the file is installed.       */      pixbuf = NULL;      filename = demo_find_file ("gtk-logo-rgb.gif", &error);      if (filename)	{	  pixbuf = gdk_pixbuf_new_from_file (filename, &error);	  g_free (filename);	}      if (error)	{	  /* This code shows off error handling. You can just use	   * gtk_image_new_from_file() instead if you don't want to report	   * errors to the user. If the file doesn't load when using	   * gtk_image_new_from_file(), a "missing image" icon will	   * be displayed instead.	   */	  GtkWidget *dialog;	  dialog = gtk_message_dialog_new (GTK_WINDOW (window),					   GTK_DIALOG_DESTROY_WITH_PARENT,					   GTK_MESSAGE_ERROR,					   GTK_BUTTONS_CLOSE,					   "Unable to open image file 'gtk-logo-rgb.gif': %s",					   error->message);	  g_error_free (error);	  g_signal_connect (dialog, "response",			    G_CALLBACK (gtk_widget_destroy), NULL);	  gtk_widget_show (dialog);	}      image = gtk_image_new_from_pixbuf (pixbuf);      gtk_container_add (GTK_CONTAINER (frame), image);      /* Animation */      label = gtk_label_new (NULL);      gtk_label_set_markup (GTK_LABEL (label),			    "<u>Animation loaded from a file</u>");      gtk_box_pack_start (GTK_BOX (vbox), label, FALSE, FALSE, 0);      frame = gtk_frame_new (NULL);      gtk_frame_set_shadow_type (GTK_FRAME (frame), GTK_SHADOW_IN);      /* The alignment keeps the frame from growing when users resize       * the window       */      align = gtk_alignment_new (0.5, 0.5, 0, 0);      gtk_container_add (GTK_CONTAINER (align), frame);      gtk_box_pack_start (GTK_BOX (vbox), align, FALSE, FALSE, 0);      filename = demo_find_file ("floppybuddy.gif", NULL);      image = gtk_image_new_from_file (filename);      g_free (filename);      gtk_container_add (GTK_CONTAINER (frame), image);      /* Progressive */      label = gtk_label_new (NULL);      gtk_label_set_markup (GTK_LABEL (label),			    "<u>Progressive image loading</u>");      gtk_box_pack_start (GTK_BOX (vbox), label, FALSE, FALSE, 0);      frame = gtk_frame_new (NULL);      gtk_frame_set_shadow_type (GTK_FRAME (frame), GTK_SHADOW_IN);      /* The alignment keeps the frame from growing when users resize       * the window       */      align = gtk_alignment_new (0.5, 0.5, 0, 0);      gtk_container_add (GTK_CONTAINER (align), frame);      gtk_box_pack_start (GTK_BOX (vbox), align, FALSE, FALSE, 0);      /* Create an empty image for now; the progressive loader       * will create the pixbuf and fill it in.       */      image = gtk_image_new_from_pixbuf (NULL);      gtk_container_add (GTK_CONTAINER (frame), image);      start_progressive_loading (image);      /* Sensitivity control */      button = gtk_toggle_button_new_with_mnemonic ("_Insensitive");      gtk_box_pack_start (GTK_BOX (vbox), button, FALSE, FALSE, 0);      g_signal_connect (button, "toggled",                        G_CALLBACK (toggle_sensitivity_callback),                        vbox);    }  if (!GTK_WIDGET_VISIBLE (window))    {      gtk_widget_show_all (window);    }  else    {      gtk_widget_destroy (window);      window = NULL;    }  return window;}