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/* GStreamer
* Copyright (C) 2011 Jon Nordby <jononor@gmail.com>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
/*
* Example showing usage of the cairooverlay element
*/
#include <gst/gst.h>
#include <gst/video/video.h>
#include <cairo.h>
#include <cairo-gobject.h>
#include <glib.h>
static gboolean
on_message (GstBus * bus, GstMessage * message, gpointer user_data)
{
GMainLoop *loop = (GMainLoop *) user_data;
switch (GST_MESSAGE_TYPE (message)) {
case GST_MESSAGE_ERROR:{
GError *err = NULL;
gchar *debug;
gst_message_parse_error (message, &err, &debug);
g_critical ("Got ERROR: %s (%s)", err->message, GST_STR_NULL (debug));
g_main_loop_quit (loop);
break;
}
case GST_MESSAGE_WARNING:{
GError *err = NULL;
gchar *debug;
gst_message_parse_warning (message, &err, &debug);
g_warning ("Got WARNING: %s (%s)", err->message, GST_STR_NULL (debug));
g_main_loop_quit (loop);
break;
}
case GST_MESSAGE_EOS:
g_main_loop_quit (loop);
break;
default:
break;
}
return TRUE;
}
/* Datastructure to share the state we are interested in between
* prepare and render function. */
typedef struct
{
gboolean valid;
GstVideoInfo vinfo;
} CairoOverlayState;
/* Store the information from the caps that we are interested in. */
static void
prepare_overlay (GstElement * overlay, GstCaps * caps, gpointer user_data)
{
CairoOverlayState *state = (CairoOverlayState *) user_data;
state->valid = gst_video_info_from_caps (&state->vinfo, caps);
}
/* Draw the overlay.
* This function draws a cute "beating" heart. */
static void
draw_overlay (GstElement * overlay, cairo_t * cr, guint64 timestamp,
guint64 duration, gpointer user_data)
{
CairoOverlayState *s = (CairoOverlayState *) user_data;
double scale;
int width, height;
if (!s->valid)
return;
width = GST_VIDEO_INFO_WIDTH (&s->vinfo);
height = GST_VIDEO_INFO_HEIGHT (&s->vinfo);
scale = 2 * (((timestamp / (int) 1e7) % 70) + 30) / 100.0;
cairo_translate (cr, width / 2, (height / 2) - 30);
/* FIXME: this assumes a pixel-aspect-ratio of 1/1 */
cairo_scale (cr, scale, scale);
cairo_move_to (cr, 0, 0);
cairo_curve_to (cr, 0, -30, -50, -30, -50, 0);
cairo_curve_to (cr, -50, 30, 0, 35, 0, 60);
cairo_curve_to (cr, 0, 35, 50, 30, 50, 0);
cairo_curve_to (cr, 50, -30, 0, -30, 0, 0);
cairo_set_source_rgba (cr, 0.9, 0.0, 0.1, 0.7);
cairo_fill (cr);
}
static GstElement *
setup_gst_pipeline (CairoOverlayState * overlay_state)
{
GstElement *pipeline;
GstElement *cairo_overlay;
GstElement *source, *adaptor1, *adaptor2, *sink;
pipeline = gst_pipeline_new ("cairo-overlay-example");
/* Adaptors needed because cairooverlay only supports ARGB data */
source = gst_element_factory_make ("videotestsrc", "source");
adaptor1 = gst_element_factory_make ("videoconvert", "adaptor1");
cairo_overlay = gst_element_factory_make ("cairooverlay", "overlay");
adaptor2 = gst_element_factory_make ("videoconvert", "adaptor2");
sink = gst_element_factory_make ("ximagesink", "sink");
if (sink == NULL)
sink = gst_element_factory_make ("autovideosink", "sink");
/* If failing, the element could not be created */
g_assert (cairo_overlay);
/* Hook up the necessary signals for cairooverlay */
g_signal_connect (cairo_overlay, "draw",
G_CALLBACK (draw_overlay), overlay_state);
g_signal_connect (cairo_overlay, "caps-changed",
G_CALLBACK (prepare_overlay), overlay_state);
gst_bin_add_many (GST_BIN (pipeline), source, adaptor1,
cairo_overlay, adaptor2, sink, NULL);
if (!gst_element_link_many (source, adaptor1,
cairo_overlay, adaptor2, sink, NULL)) {
g_warning ("Failed to link elements!");
}
return pipeline;
}
int
main (int argc, char **argv)
{
GMainLoop *loop;
GstElement *pipeline;
GstBus *bus;
CairoOverlayState *overlay_state;
gst_init (&argc, &argv);
loop = g_main_loop_new (NULL, FALSE);
/* allocate on heap for pedagogical reasons, makes code easier to transfer */
overlay_state = g_new0 (CairoOverlayState, 1);
pipeline = setup_gst_pipeline (overlay_state);
bus = gst_pipeline_get_bus (GST_PIPELINE (pipeline));
gst_bus_add_signal_watch (bus);
g_signal_connect (G_OBJECT (bus), "message", G_CALLBACK (on_message), loop);
gst_object_unref (GST_OBJECT (bus));
gst_element_set_state (pipeline, GST_STATE_PLAYING);
g_main_loop_run (loop);
gst_element_set_state (pipeline, GST_STATE_NULL);
gst_object_unref (pipeline);
g_free (overlay_state);
return 0;
}
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