1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
|
/* 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 neccesary 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;
}
|
