Learning_GTK4_tree/demos/gtk-demo/paintable_mediastream.c

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2023-12-12 11:36:42 +01:00
/* Paintable/Media Stream
*
* GdkPaintable is also used by the GtkMediaStream class.
*
* This demo code turns the nuclear media_stream into the object
* GTK uses for videos. This allows treating the icon like a
* regular video, so we can for example attach controls to it.
*
* After all, what good is a media_stream if one cannot pause
* it.
*/
#include <gtk/gtk.h>
#include "paintable.h"
static GtkWidget *window = NULL;
/* First, add the boilerplate for the object itself.
* This part would normally go in the header.
*/
#define GTK_TYPE_NUCLEAR_MEDIA_STREAM (gtk_nuclear_media_stream_get_type ())
G_DECLARE_FINAL_TYPE (GtkNuclearMediaStream, gtk_nuclear_media_stream, GTK, NUCLEAR_MEDIA_STREAM, GtkMediaStream)
/* Do a full rotation in 5 seconds.
*
* We do not save steps here but real timestamps.
* GtkMediaStream uses microseconds, so we will do so, too.
*/
#define DURATION (5 * G_USEC_PER_SEC)
/* Declare the struct. */
struct _GtkNuclearMediaStream
{
/* We now inherit from the media stream object. */
GtkMediaStream parent_instance;
/* This variable stores the progress of our video.
*/
gint64 progress;
/* This variable stores the timestamp of the last
* time we updated the progress variable when the
* video is currently playing.
* This is so that we can always accurately compute the
* progress we've had, even if the timeout does not
* exactly work.
*/
gint64 last_time;
/* This variable again holds the ID of the timer that
* updates our progress variable. Nothing changes about
* how this works compared to the previous example.
*/
guint source_id;
};
struct _GtkNuclearMediaStreamClass
{
GObjectClass parent_class;
};
/* GtkMediaStream is a GdkPaintable. So when we want to display video,
* we have to implement the interface, just like in the animation example.
*/
static void
gtk_nuclear_media_stream_snapshot (GdkPaintable *paintable,
GdkSnapshot *snapshot,
double width,
double height)
{
GtkNuclearMediaStream *nuclear = GTK_NUCLEAR_MEDIA_STREAM (paintable);
/* We call the function from the previous example here. */
gtk_nuclear_snapshot (snapshot,
&(GdkRGBA) { 0, 0, 0, 1 }, /* black */
&(GdkRGBA) { 0.9, 0.75, 0.15, 1.0 }, /* yellow */
width, height,
2 * G_PI * nuclear->progress / DURATION);
}
static GdkPaintable *
gtk_nuclear_media_stream_get_current_image (GdkPaintable *paintable)
{
GtkNuclearMediaStream *nuclear = GTK_NUCLEAR_MEDIA_STREAM (paintable);
/* Same thing as with the animation */
return gtk_nuclear_icon_new (2 * G_PI * nuclear->progress / DURATION);
}
static GdkPaintableFlags
gtk_nuclear_media_stream_get_flags (GdkPaintable *paintable)
{
/* And same thing as with the animation over here, too. */
return GDK_PAINTABLE_STATIC_SIZE;
}
static void
gtk_nuclear_media_stream_paintable_init (GdkPaintableInterface *iface)
{
iface->snapshot = gtk_nuclear_media_stream_snapshot;
iface->get_current_image = gtk_nuclear_media_stream_get_current_image;
iface->get_flags = gtk_nuclear_media_stream_get_flags;
}
/* This time, we inherit from GTK_TYPE_MEDIA_STREAM */
G_DEFINE_TYPE_WITH_CODE (GtkNuclearMediaStream, gtk_nuclear_media_stream, GTK_TYPE_MEDIA_STREAM,
G_IMPLEMENT_INTERFACE (GDK_TYPE_PAINTABLE,
gtk_nuclear_media_stream_paintable_init))
static gboolean
gtk_nuclear_media_stream_step (gpointer data)
{
GtkNuclearMediaStream *nuclear = data;
gint64 current_time;
/* Compute the time that has elapsed since the last time we were called
* and add it to our current progress.
*/
current_time = g_source_get_time (g_main_current_source ());
nuclear->progress += current_time - nuclear->last_time;
/* Check if we've ended */
if (nuclear->progress > DURATION)
{
if (gtk_media_stream_get_loop (GTK_MEDIA_STREAM (nuclear)))
{
/* We're looping. So make the progress loop using modulo */
nuclear->progress %= DURATION;
}
else
{
/* Just make sure we don't overflow */
nuclear->progress = DURATION;
}
}
/* Update the last time to the current timestamp. */
nuclear->last_time = current_time;
/* Update the timestamp of the media stream */
gtk_media_stream_update (GTK_MEDIA_STREAM (nuclear), nuclear->progress);
/* We also need to invalidate our contents again.
* After all, we are a video and not just an audio stream.
*/
gdk_paintable_invalidate_contents (GDK_PAINTABLE (nuclear));
/* Now check if we have finished playing and if so,
* tell the media stream. The media stream will then
* call our pause function to pause the stream.
*/
if (nuclear->progress >= DURATION)
gtk_media_stream_stream_ended (GTK_MEDIA_STREAM (nuclear));
/* The timeout function is removed by the pause function,
* so we can just always return this value.
*/
return G_SOURCE_CONTINUE;
}
static gboolean
gtk_nuclear_media_stream_play (GtkMediaStream *stream)
{
GtkNuclearMediaStream *nuclear = GTK_NUCLEAR_MEDIA_STREAM (stream);
/* If we're already at the end of the stream, we don't want
* to start playing and exit early.
*/
if (nuclear->progress >= DURATION)
return FALSE;
/* This time, we add the source only when we start playing.
*/
nuclear->source_id = g_timeout_add (10,
gtk_nuclear_media_stream_step,
nuclear);
/* We also want to initialize our time, so that we can
* do accurate updates.
*/
nuclear->last_time = g_get_monotonic_time ();
/* We successfully started playing, so we return TRUE here. */
return TRUE;
}
static void
gtk_nuclear_media_stream_pause (GtkMediaStream *stream)
{
GtkNuclearMediaStream *nuclear = GTK_NUCLEAR_MEDIA_STREAM (stream);
/* This function will be called when a playing stream
* gets paused.
* So we remove the updating source here and set it
* back to 0 so that the finalize function doesn't try
* to remove it again.
*/
g_source_remove (nuclear->source_id);
nuclear->source_id = 0;
nuclear->last_time = 0;
}
static void
gtk_nuclear_media_stream_seek (GtkMediaStream *stream,
gint64 timestamp)
{
GtkNuclearMediaStream *nuclear = GTK_NUCLEAR_MEDIA_STREAM (stream);
/* This is optional functionality for media streams,
* but not being able to seek is kinda boring.
* And it's trivial to implement, so let's go for it.
*/
nuclear->progress = timestamp;
/* Media streams are asynchronous, so seeking can take a while.
* We however don't need that functionality, so we can just
* report success.
*/
gtk_media_stream_seek_success (stream);
/* We also have to update our timestamp and tell the
* paintable interface about the seek
*/
gtk_media_stream_update (stream, nuclear->progress);
gdk_paintable_invalidate_contents (GDK_PAINTABLE (nuclear));
}
/* Again, we need to implement the finalize function.
*/
static void
gtk_nuclear_media_stream_finalize (GObject *object)
{
GtkNuclearMediaStream *nuclear = GTK_NUCLEAR_MEDIA_STREAM (object);
/* This time, we need to check if the source exists before
* removing it as it only exists while we are playing.
*/
if (nuclear->source_id > 0)
g_source_remove (nuclear->source_id);
/* Don't forget to chain up to the parent class' implementation
* of the finalize function.
*/
G_OBJECT_CLASS (gtk_nuclear_media_stream_parent_class)->finalize (object);
}
/* In the class declaration, we need to implement the media stream */
static void
gtk_nuclear_media_stream_class_init (GtkNuclearMediaStreamClass *klass)
{
GtkMediaStreamClass *stream_class = GTK_MEDIA_STREAM_CLASS (klass);
GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
stream_class->play = gtk_nuclear_media_stream_play;
stream_class->pause = gtk_nuclear_media_stream_pause;
stream_class->seek = gtk_nuclear_media_stream_seek;
gobject_class->finalize = gtk_nuclear_media_stream_finalize;
}
static void
gtk_nuclear_media_stream_init (GtkNuclearMediaStream *nuclear)
{
/* This time, we don't have to add a timer here, because media
* streams start paused.
*
* However, media streams need to tell GTK once they are initialized,
* so we do that here.
*/
gtk_media_stream_stream_prepared (GTK_MEDIA_STREAM (nuclear),
FALSE,
TRUE,
TRUE,
DURATION);
}
/* And finally, we add the simple constructor we declared in the header. */
GtkMediaStream *
gtk_nuclear_media_stream_new (void)
{
return g_object_new (GTK_TYPE_NUCLEAR_MEDIA_STREAM, NULL);
}
GtkWidget *
do_paintable_mediastream (GtkWidget *do_widget)
{
GtkMediaStream *nuclear;
GtkWidget *video;
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), "Nuclear MediaStream");
gtk_window_set_default_size (GTK_WINDOW (window), 300, 200);
g_object_add_weak_pointer (G_OBJECT (window), (gpointer *)&window);
nuclear = gtk_nuclear_media_stream_new ();
gtk_media_stream_set_loop (GTK_MEDIA_STREAM (nuclear), TRUE);
video = gtk_video_new_for_media_stream (nuclear);
gtk_window_set_child (GTK_WINDOW (window), video);
g_object_unref (nuclear);
}
if (!gtk_widget_get_visible (window))
gtk_widget_set_visible (window, TRUE);
else
gtk_window_destroy (GTK_WINDOW (window));
return window;
}