58b5405bd2
* demos/*.c demos/gdk-pixbuf/*.c: Eliminate gtk_signal_*
in favor of g_signal_*, gtk_object_* in favor of
g_object_*.
419 lines
11 KiB
C
419 lines
11 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 <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 FILE* 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 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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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 queue a redraw. If we wanted to be
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* really efficient, we could use a drawing area or something
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* instead of a GtkImage, so we could control the exact position of
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* the pixbuf on the display, then we could queue a draw for only
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* the updated area of the image.
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*/
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gtk_widget_queue_draw (image);
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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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size_t bytes_read;
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guchar buf[256];
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GError *error = NULL;
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bytes_read = fread (buf, 1, 256, image_stream);
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if (ferror (image_stream))
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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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g_strerror (errno));
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g_signal_connect (dialog, "response",
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G_CALLBACK (gtk_widget_destroy), NULL);
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fclose (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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fclose (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 (feof (image_stream))
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{
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fclose (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 (G_OBJECT (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 (G_OBJECT (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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const gchar *filename;
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if (g_file_test ("./alphatest.png", G_FILE_TEST_EXISTS))
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filename = "./alphatest.png";
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else
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filename = DEMOCODEDIR"/alphatest.png";
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image_stream = fopen (filename, "r");
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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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"Unable to open image file 'alphatest.png': %s",
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g_strerror (errno));
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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 (G_OBJECT (pixbuf_loader));
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pixbuf_loader = NULL;
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}
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pixbuf_loader = gdk_pixbuf_loader_new ();
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g_signal_connect (G_OBJECT (pixbuf_loader), "area_prepared",
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G_CALLBACK (progressive_prepared_callback), image);
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g_signal_connect (G_OBJECT (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 = g_timeout_add (150,
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progressive_timeout,
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image);
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}
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static void
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cleanup_callback (GtkObject *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 (G_OBJECT (pixbuf_loader));
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pixbuf_loader = NULL;
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}
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if (image_stream)
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fclose (image_stream);
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image_stream = NULL;
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}
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GtkWidget *
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do_images (void)
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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 *align;
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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_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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gtk_container_set_border_width (GTK_CONTAINER (window), 8);
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vbox = gtk_vbox_new (FALSE, 8);
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gtk_container_set_border_width (GTK_CONTAINER (vbox), 8);
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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, FALSE, FALSE, 0);
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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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/* The alignment keeps the frame from growing when users resize
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* the window
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*/
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align = gtk_alignment_new (0.5, 0.5, 0, 0);
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gtk_container_add (GTK_CONTAINER (align), frame);
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gtk_box_pack_start (GTK_BOX (vbox), align, FALSE, FALSE, 0);
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/* We look for the image in the current directory first,
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* so you can run gtk-demo without installing GTK
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*/
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if (g_file_test ("./gtk-logo-rgb.gif", G_FILE_TEST_EXISTS))
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{
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/* This code shows off error handling. You can just use
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* gtk_image_new_from_file() instead if you don't want to report
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* errors to the user. If the file doesn't load when using
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* gtk_image_new_from_file(), a "missing image" icon will
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* be displayed instead.
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*/
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GdkPixbuf *pixbuf;
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GError *error = NULL;
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pixbuf = gdk_pixbuf_new_from_file ("./gtk-logo-rgb.gif",
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&error);
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if (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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"Unable to open image file 'gtk-logo-rgb.gif': %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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}
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image = gtk_image_new_from_pixbuf (pixbuf);
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}
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else
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{
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/* This is the simpler code, with no error handling.
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* Here we're loading the installed gtk-logo-rgb.gif instead
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* of the one in the current directory.
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*/
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image = gtk_image_new_from_file (DEMOCODEDIR"/gtk-logo-rgb.gif");
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}
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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, FALSE, FALSE, 0);
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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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/* The alignment keeps the frame from growing when users resize
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* the window
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*/
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align = gtk_alignment_new (0.5, 0.5, 0, 0);
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gtk_container_add (GTK_CONTAINER (align), frame);
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gtk_box_pack_start (GTK_BOX (vbox), align, FALSE, FALSE, 0);
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/* We look for the image in the current directory first,
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* so you can run gtk-demo without installing GTK
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*/
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if (g_file_test ("./floppybuddy.gif", G_FILE_TEST_EXISTS))
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image = gtk_image_new_from_file ("./floppybuddy.gif");
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else
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image = gtk_image_new_from_file (DEMOCODEDIR"/floppybuddy.gif");
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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, FALSE, FALSE, 0);
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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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/* The alignment keeps the frame from growing when users resize
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* the window
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*/
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align = gtk_alignment_new (0.5, 0.5, 0, 0);
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gtk_container_add (GTK_CONTAINER (align), frame);
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gtk_box_pack_start (GTK_BOX (vbox), align, FALSE, FALSE, 0);
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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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}
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if (!GTK_WIDGET_VISIBLE (window))
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{
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gtk_widget_show_all (window);
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}
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else
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{
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gtk_widget_destroy (window);
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window = NULL;
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}
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return window;
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}
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