gtk2/demos/gtk-demo/images.c
Matthias Clasen d732c869c2 gtk-demo: Add keywords to demos
Add the names of the main widgets as keywords to
our demos, but also things like "game". This helps
finding relevant demos in our growing list. You
can now for example type "label", and find the
"error states" and "links" demos showing GtkLabel
features.
2020-09-13 15:00:14 -04:00

470 lines
14 KiB
C

/* 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>
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), 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 (1500, 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 (NULL);
gtk_label_set_markup (GTK_LABEL (label),
"<u>Image loaded from a file</u>");
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 (NULL);
gtk_label_set_markup (GTK_LABEL (label),
"<u>Animation loaded from a file</u>");
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);
picture = gtk_picture_new_for_resource ("/images/floppybuddy.gif");
gtk_frame_set_child (GTK_FRAME (frame), picture);
/* Symbolic icon */
label = gtk_label_new (NULL);
gtk_label_set_markup (GTK_LABEL (label),
"<u>Symbolic themed icon</u>");
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 (NULL);
gtk_label_set_markup (GTK_LABEL (label),
"<u>Progressive image loading</u>");
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_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 (NULL);
gtk_label_set_markup (GTK_LABEL (label),
"<u>Displaying video</u>");
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 (NULL);
gtk_label_set_markup (GTK_LABEL (label),
"<u>GtkWidgetPaintable</u>");
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;
}