mirror of
https://gitlab.gnome.org/GNOME/gtk.git
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443 lines
14 KiB
C
443 lines
14 KiB
C
/* Images
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*
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* GtkImage is used to display an image; the image can be in a number of formats.
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* Typically, you load an image into a GdkPixbuf, then display the pixbuf.
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*
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* This demo code shows some of the more obscure cases, in the simple
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* case a call to gtk_image_new_from_file() is all you need.
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*
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* If you want to put image data in your program as a C variable,
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* use the make-inline-pixbuf program that comes with GTK+.
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* This way you won't need to depend on loading external files, your
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* application binary can be self-contained.
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*/
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#include <gtk/gtk.h>
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#include <glib/gstdio.h>
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#include <stdio.h>
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#include <errno.h>
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static GtkWidget *window = NULL;
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static GdkPixbufLoader *pixbuf_loader = NULL;
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static guint load_timeout = 0;
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static GInputStream * image_stream = NULL;
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static void
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progressive_prepared_callback (GdkPixbufLoader *loader,
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gpointer data)
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{
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GdkPixbuf *pixbuf;
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GtkWidget *image;
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image = GTK_WIDGET (data);
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pixbuf = gdk_pixbuf_loader_get_pixbuf (loader);
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/* Avoid displaying random memory contents, since the pixbuf
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* isn't filled in yet.
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*/
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gdk_pixbuf_fill (pixbuf, 0xaaaaaaff);
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gtk_image_set_from_pixbuf (GTK_IMAGE (image), pixbuf);
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}
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static void
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progressive_updated_callback (GdkPixbufLoader *loader,
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gint x,
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gint y,
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gint width,
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gint height,
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gpointer data)
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{
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GtkWidget *image;
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GdkPixbuf *pixbuf;
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image = GTK_WIDGET (data);
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/* We know the pixbuf inside the GtkImage has changed, but the image
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* itself doesn't know this; so give it a hint by setting the pixbuf
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* again. Queuing a redraw used to be sufficient, but nowadays GtkImage
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* uses GtkIconHelper which caches the pixbuf state and will just redraw
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* from the cache.
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*/
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pixbuf = gtk_image_get_pixbuf (GTK_IMAGE (image));
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g_object_ref (pixbuf);
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gtk_image_set_from_pixbuf (GTK_IMAGE (image), pixbuf);
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g_object_unref (pixbuf);
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}
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static gint
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progressive_timeout (gpointer data)
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{
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GtkWidget *image;
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image = GTK_WIDGET (data);
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/* This shows off fully-paranoid error handling, so looks scary.
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* You could factor out the error handling code into a nice separate
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* function to make things nicer.
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*/
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if (image_stream)
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{
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gssize bytes_read;
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guchar buf[256];
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GError *error = NULL;
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bytes_read = g_input_stream_read (image_stream, buf, 256, NULL, &error);
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if (bytes_read < 0)
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{
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GtkWidget *dialog;
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dialog = gtk_message_dialog_new (GTK_WINDOW (window),
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GTK_DIALOG_DESTROY_WITH_PARENT,
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GTK_MESSAGE_ERROR,
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GTK_BUTTONS_CLOSE,
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"Failure reading image file 'alphatest.png': %s",
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error->message);
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g_error_free (error);
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g_signal_connect (dialog, "response",
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G_CALLBACK (gtk_widget_destroy), NULL);
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g_object_unref (image_stream);
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image_stream = NULL;
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gtk_widget_show (dialog);
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load_timeout = 0;
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return FALSE; /* uninstall the timeout */
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}
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if (!gdk_pixbuf_loader_write (pixbuf_loader,
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buf, bytes_read,
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&error))
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{
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GtkWidget *dialog;
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dialog = gtk_message_dialog_new (GTK_WINDOW (window),
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GTK_DIALOG_DESTROY_WITH_PARENT,
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GTK_MESSAGE_ERROR,
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GTK_BUTTONS_CLOSE,
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"Failed to load image: %s",
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error->message);
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g_error_free (error);
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g_signal_connect (dialog, "response",
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G_CALLBACK (gtk_widget_destroy), NULL);
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g_object_unref (image_stream);
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image_stream = NULL;
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gtk_widget_show (dialog);
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load_timeout = 0;
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return FALSE; /* uninstall the timeout */
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}
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if (bytes_read == 0)
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{
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/* Errors can happen on close, e.g. if the image
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* file was truncated we'll know on close that
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* it was incomplete.
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*/
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error = NULL;
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if (!g_input_stream_close (image_stream, NULL, &error))
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{
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GtkWidget *dialog;
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dialog = gtk_message_dialog_new (GTK_WINDOW (window),
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GTK_DIALOG_DESTROY_WITH_PARENT,
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GTK_MESSAGE_ERROR,
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GTK_BUTTONS_CLOSE,
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"Failed to load image: %s",
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error->message);
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g_error_free (error);
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g_signal_connect (dialog, "response",
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G_CALLBACK (gtk_widget_destroy), NULL);
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gtk_widget_show (dialog);
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g_object_unref (image_stream);
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image_stream = NULL;
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g_object_unref (pixbuf_loader);
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pixbuf_loader = NULL;
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load_timeout = 0;
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return FALSE; /* uninstall the timeout */
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}
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g_object_unref (image_stream);
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image_stream = NULL;
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/* Errors can happen on close, e.g. if the image
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* file was truncated we'll know on close that
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* it was incomplete.
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*/
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error = NULL;
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if (!gdk_pixbuf_loader_close (pixbuf_loader,
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&error))
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{
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GtkWidget *dialog;
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dialog = gtk_message_dialog_new (GTK_WINDOW (window),
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GTK_DIALOG_DESTROY_WITH_PARENT,
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GTK_MESSAGE_ERROR,
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GTK_BUTTONS_CLOSE,
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"Failed to load image: %s",
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error->message);
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g_error_free (error);
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g_signal_connect (dialog, "response",
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G_CALLBACK (gtk_widget_destroy), NULL);
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gtk_widget_show (dialog);
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g_object_unref (pixbuf_loader);
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pixbuf_loader = NULL;
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load_timeout = 0;
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return FALSE; /* uninstall the timeout */
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}
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g_object_unref (pixbuf_loader);
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pixbuf_loader = NULL;
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}
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}
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else
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{
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GError *error = NULL;
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image_stream = g_resources_open_stream ("/images/alphatest.png", 0, &error);
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if (image_stream == NULL)
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{
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GtkWidget *dialog;
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dialog = gtk_message_dialog_new (GTK_WINDOW (window),
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GTK_DIALOG_DESTROY_WITH_PARENT,
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GTK_MESSAGE_ERROR,
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GTK_BUTTONS_CLOSE,
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"%s", error->message);
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g_error_free (error);
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g_signal_connect (dialog, "response",
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G_CALLBACK (gtk_widget_destroy), NULL);
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gtk_widget_show (dialog);
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load_timeout = 0;
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return FALSE; /* uninstall the timeout */
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}
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if (pixbuf_loader)
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{
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gdk_pixbuf_loader_close (pixbuf_loader, NULL);
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g_object_unref (pixbuf_loader);
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}
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pixbuf_loader = gdk_pixbuf_loader_new ();
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g_signal_connect (pixbuf_loader, "area-prepared",
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G_CALLBACK (progressive_prepared_callback), image);
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g_signal_connect (pixbuf_loader, "area-updated",
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G_CALLBACK (progressive_updated_callback), image);
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}
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/* leave timeout installed */
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return TRUE;
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}
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static void
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start_progressive_loading (GtkWidget *image)
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{
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/* This is obviously totally contrived (we slow down loading
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* on purpose to show how incremental loading works).
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* The real purpose of incremental loading is the case where
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* you are reading data from a slow source such as the network.
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* The timeout simply simulates a slow data source by inserting
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* pauses in the reading process.
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*/
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load_timeout = gdk_threads_add_timeout (150,
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progressive_timeout,
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image);
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g_source_set_name_by_id (load_timeout, "[gtk+] progressive_timeout");
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}
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static void
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cleanup_callback (GObject *object,
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gpointer data)
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{
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if (load_timeout)
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{
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g_source_remove (load_timeout);
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load_timeout = 0;
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}
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if (pixbuf_loader)
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{
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gdk_pixbuf_loader_close (pixbuf_loader, NULL);
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g_object_unref (pixbuf_loader);
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pixbuf_loader = NULL;
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}
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if (image_stream)
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{
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g_object_unref (image_stream);
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image_stream = NULL;
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}
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}
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static void
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toggle_sensitivity_callback (GtkWidget *togglebutton,
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gpointer user_data)
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{
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GtkContainer *container = user_data;
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GList *list;
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GList *tmp;
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list = gtk_container_get_children (container);
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tmp = list;
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while (tmp != NULL)
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{
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/* don't disable our toggle */
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if (GTK_WIDGET (tmp->data) != togglebutton)
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gtk_widget_set_sensitive (GTK_WIDGET (tmp->data),
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!gtk_toggle_button_get_active (GTK_TOGGLE_BUTTON (togglebutton)));
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tmp = tmp->next;
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}
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g_list_free (list);
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}
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GtkWidget *
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do_images (GtkWidget *do_widget)
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{
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GtkWidget *frame;
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GtkWidget *vbox;
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GtkWidget *image;
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GtkWidget *label;
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GtkWidget *button;
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GIcon *gicon;
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if (!window)
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{
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window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
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gtk_window_set_screen (GTK_WINDOW (window),
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gtk_widget_get_screen (do_widget));
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gtk_window_set_title (GTK_WINDOW (window), "Images");
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g_signal_connect (window, "destroy",
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G_CALLBACK (gtk_widget_destroyed), &window);
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g_signal_connect (window, "destroy",
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G_CALLBACK (cleanup_callback), NULL);
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vbox = gtk_box_new (GTK_ORIENTATION_VERTICAL, 8);
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g_object_set (vbox, "margin", 16, NULL);
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gtk_container_add (GTK_CONTAINER (window), vbox);
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label = gtk_label_new (NULL);
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gtk_label_set_markup (GTK_LABEL (label),
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"<u>Image loaded from a file</u>");
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gtk_box_pack_start (GTK_BOX (vbox), label);
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frame = gtk_frame_new (NULL);
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gtk_frame_set_shadow_type (GTK_FRAME (frame), GTK_SHADOW_IN);
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gtk_widget_set_halign (frame, GTK_ALIGN_CENTER);
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gtk_widget_set_valign (frame, GTK_ALIGN_CENTER);
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gtk_box_pack_start (GTK_BOX (vbox), frame);
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image = gtk_image_new_from_icon_name ("gtk3-demo", GTK_ICON_SIZE_DIALOG);
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gtk_container_add (GTK_CONTAINER (frame), image);
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/* Animation */
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label = gtk_label_new (NULL);
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gtk_label_set_markup (GTK_LABEL (label),
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"<u>Animation loaded from a file</u>");
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gtk_box_pack_start (GTK_BOX (vbox), label);
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frame = gtk_frame_new (NULL);
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gtk_frame_set_shadow_type (GTK_FRAME (frame), GTK_SHADOW_IN);
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gtk_widget_set_halign (frame, GTK_ALIGN_CENTER);
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gtk_widget_set_valign (frame, GTK_ALIGN_CENTER);
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gtk_box_pack_start (GTK_BOX (vbox), frame);
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image = gtk_image_new_from_resource ("/images/floppybuddy.gif");
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gtk_container_add (GTK_CONTAINER (frame), image);
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/* Symbolic icon */
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label = gtk_label_new (NULL);
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gtk_label_set_markup (GTK_LABEL (label),
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"<u>Symbolic themed icon</u>");
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gtk_box_pack_start (GTK_BOX (vbox), label);
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frame = gtk_frame_new (NULL);
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gtk_frame_set_shadow_type (GTK_FRAME (frame), GTK_SHADOW_IN);
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gtk_widget_set_halign (frame, GTK_ALIGN_CENTER);
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gtk_widget_set_valign (frame, GTK_ALIGN_CENTER);
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gtk_box_pack_start (GTK_BOX (vbox), frame);
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gicon = g_themed_icon_new_with_default_fallbacks ("battery-caution-charging-symbolic");
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image = gtk_image_new_from_gicon (gicon, GTK_ICON_SIZE_DIALOG);
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gtk_container_add (GTK_CONTAINER (frame), image);
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/* Progressive */
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label = gtk_label_new (NULL);
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gtk_label_set_markup (GTK_LABEL (label),
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"<u>Progressive image loading</u>");
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gtk_box_pack_start (GTK_BOX (vbox), label);
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frame = gtk_frame_new (NULL);
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gtk_frame_set_shadow_type (GTK_FRAME (frame), GTK_SHADOW_IN);
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gtk_widget_set_halign (frame, GTK_ALIGN_CENTER);
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gtk_widget_set_valign (frame, GTK_ALIGN_CENTER);
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gtk_box_pack_start (GTK_BOX (vbox), frame);
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/* Create an empty image for now; the progressive loader
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* will create the pixbuf and fill it in.
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*/
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image = gtk_image_new_from_pixbuf (NULL);
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gtk_container_add (GTK_CONTAINER (frame), image);
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start_progressive_loading (image);
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/* Sensitivity control */
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button = gtk_toggle_button_new_with_mnemonic ("_Insensitive");
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gtk_box_pack_start (GTK_BOX (vbox), button);
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g_signal_connect (button, "toggled",
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G_CALLBACK (toggle_sensitivity_callback),
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vbox);
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}
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if (!gtk_widget_get_visible (window))
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gtk_widget_show (window);
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else
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gtk_widget_destroy (window);
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return window;
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}
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