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354f2b65fa
gtk/demos/gtk-demo/images.c
Matthias Clasen 354f2b65fa gtk-demo: Reanimate floppy buddy 
Implement a GdkPaintable wrapper around GdkPixbufAnimation,
so floppy buddy can waive again.
2020-11-02 21:38:02 -05:00

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/* Images
* #Keywords: GdkPaintable, GtkWidgetPaintable
*
* GtkImage and GtkPicture are used to display an image; the image can be
* in a number of formats.
*
* GtkImage is the widget used to display icons or images that should be
* sized and styled like an icon, while GtkPicture is used for images
* that should be displayed as-is.
*
* This demo code shows some of the more obscure cases, in the simple
* case a call to gtk_picture_new_for_file() or
* gtk_image_new_from_icon_name() is all you need.
*/
#include <gtk/gtk.h>
#include <glib/gstdio.h>
#include <stdio.h>
#include <errno.h>
#include "pixbufpaintable.h"
static GtkWidget *window = NULL;
static GdkPixbufLoader *pixbuf_loader = NULL;
static guint load_timeout = 0;
static GInputStream * image_stream = NULL;
static void
progressive_prepared_callback (GdkPixbufLoader *loader,
gpointer data)
{
GdkPixbuf *pixbuf;
GtkWidget *picture;
picture = 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_picture_set_pixbuf (GTK_PICTURE (picture), pixbuf);
}
static void
progressive_updated_callback (GdkPixbufLoader *loader,
int x,
int y,
int width,
int height,
gpointer data)
{
GtkWidget *picture;
GdkPixbuf *pixbuf;
picture = GTK_WIDGET (data);
pixbuf = gdk_pixbuf_loader_get_pixbuf (loader);
gtk_picture_set_pixbuf (GTK_PICTURE (picture), NULL);
gtk_picture_set_pixbuf (GTK_PICTURE (picture), pixbuf);
}
static int
progressive_timeout (gpointer data)
{
GtkWidget *picture;
picture = 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)
{
gssize bytes_read;
guchar buf[256];
GError *error = NULL;
bytes_read = g_input_stream_read (image_stream, buf, 256, NULL, &error);
if (bytes_read < 0)
{
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",
error->message);
g_error_free (error);
g_signal_connect (dialog, "response",
G_CALLBACK (gtk_window_destroy), NULL);
g_object_unref (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_window_destroy), NULL);
g_object_unref (image_stream);
image_stream = NULL;
gtk_widget_show (dialog);
load_timeout = 0;
return FALSE; /* uninstall the timeout */
}
if (bytes_read == 0)
{
/* 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 (!g_input_stream_close (image_stream, NULL, &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_window_destroy), NULL);
gtk_widget_show (dialog);
g_object_unref (image_stream);
image_stream = NULL;
g_object_unref (pixbuf_loader);
pixbuf_loader = NULL;
load_timeout = 0;
return FALSE; /* uninstall the timeout */
}
g_object_unref (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_window_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
{
GError *error = NULL;
image_stream = g_resources_open_stream ("/images/alphatest.png", 0, &error);
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_error_free (error);
g_signal_connect (dialog, "response",
G_CALLBACK (gtk_window_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 = gdk_pixbuf_loader_new ();
g_signal_connect_object (pixbuf_loader, "area-prepared",
G_CALLBACK (progressive_prepared_callback), picture, 0);
g_signal_connect_object (pixbuf_loader, "area-updated",
G_CALLBACK (progressive_updated_callback), picture, 0);
}
/* leave timeout installed */
return TRUE;
}
static void
start_progressive_loading (GtkWidget *picture)
{
/* 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 = g_timeout_add (300, progressive_timeout, picture);
g_source_set_name_by_id (load_timeout, "[gtk] progressive_timeout");
}
static void
cleanup_callback (gpointer data,
GObject *former_object)
{
*(gpointer**)data = NULL;
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)
{
g_object_unref (image_stream);
image_stream = NULL;
}
}
static void
toggle_sensitivity_callback (GtkWidget *togglebutton,
gpointer user_data)
{
GtkWidget *child;
for (child = gtk_widget_get_first_child (GTK_WIDGET (user_data));
child != NULL;
child = gtk_widget_get_next_sibling (child))
{
/* don't disable our toggle */
if (child != togglebutton)
gtk_widget_set_sensitive (child, !gtk_toggle_button_get_active (GTK_TOGGLE_BUTTON (togglebutton)));
}
}
GtkWidget *
do_images (GtkWidget *do_widget)
{
GtkWidget *video;
GtkWidget *frame;
GtkWidget *vbox;
GtkWidget *hbox;
GtkWidget *base_vbox;
GtkWidget *image;
GtkWidget *picture;
GtkWidget *label;
GtkWidget *button;
GdkPaintable *paintable;
GIcon *gicon;
if (!window)
{
window = gtk_window_new ();
gtk_window_set_display (GTK_WINDOW (window),
gtk_widget_get_display (do_widget));
gtk_window_set_title (GTK_WINDOW (window), "Images");
g_object_weak_ref (G_OBJECT (window), cleanup_callback, &window);
base_vbox = gtk_box_new (GTK_ORIENTATION_VERTICAL, 8);
gtk_widget_set_margin_start (base_vbox, 16);
gtk_widget_set_margin_end (base_vbox, 16);
gtk_widget_set_margin_top (base_vbox, 16);
gtk_widget_set_margin_bottom (base_vbox, 16);
gtk_window_set_child (GTK_WINDOW (window), base_vbox);
hbox = gtk_box_new (GTK_ORIENTATION_HORIZONTAL, 16);
gtk_box_append (GTK_BOX (base_vbox), hbox);
vbox = gtk_box_new (GTK_ORIENTATION_VERTICAL, 8);
gtk_box_append (GTK_BOX (hbox), vbox);
label = gtk_label_new ("Image loaded from a file");
gtk_widget_add_css_class (label, "heading");
gtk_box_append (GTK_BOX (vbox), label);
frame = gtk_frame_new (NULL);
gtk_widget_set_halign (frame, GTK_ALIGN_CENTER);
gtk_widget_set_valign (frame, GTK_ALIGN_CENTER);
gtk_box_append (GTK_BOX (vbox), frame);
image = gtk_image_new_from_icon_name ("gtk3-demo");
gtk_image_set_icon_size (GTK_IMAGE (image), GTK_ICON_SIZE_LARGE);
gtk_frame_set_child (GTK_FRAME (frame), image);
/* Animation */
label = gtk_label_new ("Animation loaded from a file");
gtk_widget_add_css_class (label, "heading");
gtk_box_append (GTK_BOX (vbox), label);
frame = gtk_frame_new (NULL);
gtk_widget_set_halign (frame, GTK_ALIGN_CENTER);
gtk_widget_set_valign (frame, GTK_ALIGN_CENTER);
gtk_box_append (GTK_BOX (vbox), frame);
paintable = pixbuf_paintable_new_from_resource ("/images/floppybuddy.gif");
picture = gtk_picture_new_for_paintable (paintable);
g_object_unref (paintable);
gtk_frame_set_child (GTK_FRAME (frame), picture);
/* Symbolic icon */
label = gtk_label_new ("Symbolic themed icon");
gtk_widget_add_css_class (label, "heading");
gtk_box_append (GTK_BOX (vbox), label);
frame = gtk_frame_new (NULL);
gtk_widget_set_halign (frame, GTK_ALIGN_CENTER);
gtk_widget_set_valign (frame, GTK_ALIGN_CENTER);
gtk_box_append (GTK_BOX (vbox), frame);
gicon = g_themed_icon_new_with_default_fallbacks ("battery-caution-charging-symbolic");
image = gtk_image_new_from_gicon (gicon);
gtk_image_set_icon_size (GTK_IMAGE (image), GTK_ICON_SIZE_LARGE);
gtk_frame_set_child (GTK_FRAME (frame), image);
/* Progressive */
vbox = gtk_box_new (GTK_ORIENTATION_VERTICAL, 8);
gtk_box_append (GTK_BOX (hbox), vbox);
label = gtk_label_new ("Progressive image loading");
gtk_widget_add_css_class (label, "heading");
gtk_box_append (GTK_BOX (vbox), label);
frame = gtk_frame_new (NULL);
gtk_widget_set_halign (frame, GTK_ALIGN_CENTER);
gtk_widget_set_valign (frame, GTK_ALIGN_CENTER);
gtk_box_append (GTK_BOX (vbox), frame);
/* Create an empty image for now; the progressive loader
* will create the pixbuf and fill it in.
*/
picture = gtk_picture_new ();
gtk_picture_set_alternative_text (GTK_PICTURE (picture), "A slowly loading image");
gtk_frame_set_child (GTK_FRAME (frame), picture);
start_progressive_loading (picture);
/* Video */
vbox = gtk_box_new (GTK_ORIENTATION_VERTICAL, 8);
gtk_box_append (GTK_BOX (hbox), vbox);
label = gtk_label_new ("Displaying video");
gtk_widget_add_css_class (label, "heading");
gtk_box_append (GTK_BOX (vbox), label);
frame = gtk_frame_new (NULL);
gtk_widget_set_halign (frame, GTK_ALIGN_CENTER);
gtk_widget_set_valign (frame, GTK_ALIGN_CENTER);
gtk_box_append (GTK_BOX (vbox), frame);
video = gtk_video_new_for_resource ("/images/gtk-logo.webm");
gtk_media_stream_set_loop (gtk_video_get_media_stream (GTK_VIDEO (video)), TRUE);
gtk_frame_set_child (GTK_FRAME (frame), video);
/* Widget paintables */
vbox = gtk_box_new (GTK_ORIENTATION_VERTICAL, 8);
gtk_box_append (GTK_BOX (hbox), vbox);
label = gtk_label_new ("GtkWidgetPaintable");
gtk_widget_add_css_class (label, "heading");
gtk_box_append (GTK_BOX (vbox), label);
paintable = gtk_widget_paintable_new (do_widget);
picture = gtk_picture_new_for_paintable (paintable);
gtk_widget_set_size_request (picture, 100, 100);
gtk_widget_set_valign (picture, GTK_ALIGN_START);
gtk_box_append (GTK_BOX (vbox), picture);
/* Sensitivity control */
button = gtk_toggle_button_new_with_mnemonic ("_Insensitive");
gtk_box_append (GTK_BOX (base_vbox), button);
g_signal_connect (button, "toggled",
G_CALLBACK (toggle_sensitivity_callback),
base_vbox);
}
if (!gtk_widget_get_visible (window))
gtk_widget_show (window);
else
gtk_window_destroy (GTK_WINDOW (window));
return window;
}
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