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1 /* GStreamer
2  * Copyright (C) <1999> Erik Walthinsen <omega@cse.ogi.edu>
3  * Copyright (C) <2003> David Schleef <ds@schleef.org>
4  * Copyright (C) <2006> Julien Moutte <julien@moutte.net>
5  * Copyright (C) <2006> Zeeshan Ali <zeeshan.ali@nokia.com>
6  * Copyright (C) <2006-2008> Tim-Philipp Müller <tim centricular net>
7  * Copyright (C) <2009> Young-Ho Cha <ganadist@gmail.com>
8  * Copyright (C) <2011> Sebastian Dröge <sebastian.droege@collabora.co.uk>
9  *
10  * This library is free software; you can redistribute it and/or
11  * modify it under the terms of the GNU Library General Public
12  * License as published by the Free Software Foundation; either
13  * version 2 of the License, or (at your option) any later version.
14  *
15  * This library is distributed in the hope that it will be useful,
16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
18  * Library General Public License for more details.
19  *
20  * You should have received a copy of the GNU Library General Public
21  * License along with this library; if not, write to the
22  * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
23  * Boston, MA 02110-1301, USA.
24  */
25 
26 /**
27  * SECTION:element-textoverlay
28  * @title: textoverlay
29  * @see_also: #GstTextRender, #GstTextOverlay, #GstTimeOverlay, #GstSubParse
30  *
31  * This plugin renders text on top of a video stream. This can be either
32  * static text or text from buffers received on the text sink pad, e.g.
33  * as produced by the subparse element. If the text sink pad is not linked,
34  * the text set via the "text" property will be rendered. If the text sink
35  * pad is linked, text will be rendered as it is received on that pad,
36  * honouring and matching the buffer timestamps of both input streams.
37  *
38  * The text can contain newline characters and text wrapping is enabled by
39  * default.
40  *
41  * ## Example launch lines
42  * |[
43  * gst-launch-1.0 -v videotestsrc ! textoverlay text="Room A" valignment=top halignment=left font-desc="Sans, 72" ! autovideosink
44  * ]|
45  * Here is a simple pipeline that displays a static text in the top left
46  * corner of the video picture
47  * |[
48  * gst-launch-1.0 -v filesrc location=subtitles.srt ! subparse ! txt.   videotestsrc ! timeoverlay ! textoverlay name=txt shaded-background=yes ! autovideosink
49  * ]|
50  * Here is another pipeline that displays subtitles from an .srt subtitle
51  * file, centered at the bottom of the picture and with a rectangular shading
52  * around the text in the background:
53  *
54  * If you do not have such a subtitle file, create one looking like this
55  * in a text editor:
56  * |[
57  * 1
58  * 00:00:03,000 --> 00:00:05,000
59  * Hello? (3-5s)
60  *
61  * 2
62  * 00:00:08,000 --> 00:00:13,000
63  * Yes, this is a subtitle. Don&apos;t
64  * you like it? (8-13s)
65  *
66  * 3
67  * 00:00:18,826 --> 00:01:02,886
68  * Uh? What are you talking about?
69  * I don&apos;t understand  (18-62s)
70  * ]|
71  *
72  */
73 
74 #ifdef HAVE_CONFIG_H
75 #include "config.h"
76 #endif
77 
78 #include "gsttextoverlay.h"
79 #include "gstpangoelements.h"
80 
81 static GstStaticPadTemplate text_sink_template_factory =
82 GST_STATIC_PAD_TEMPLATE ("text_sink",
83     GST_PAD_SINK,
84     GST_PAD_ALWAYS,
85     GST_STATIC_CAPS ("text/x-raw, format = { pango-markup, utf8 }")
86     );
87 
88 G_DEFINE_TYPE (GstTextOverlay, gst_text_overlay, GST_TYPE_BASE_TEXT_OVERLAY);
89 GST_ELEMENT_REGISTER_DEFINE_WITH_CODE (textoverlay, "textoverlay",
90     GST_RANK_NONE, GST_TYPE_TEXT_OVERLAY, pango_element_init (plugin));
91 
92 static void
gst_text_overlay_class_init(GstTextOverlayClass * klass)93 gst_text_overlay_class_init (GstTextOverlayClass * klass)
94 {
95   GstElementClass *element_class = (GstElementClass *) klass;
96 
97   gst_element_class_add_static_pad_template (element_class,
98       &text_sink_template_factory);
99 
100   gst_element_class_set_static_metadata (element_class, "Text overlay",
101       "Filter/Editor/Video",
102       "Adds text strings on top of a video buffer",
103       "David Schleef <ds@schleef.org>, " "Zeeshan Ali <zeeshan.ali@nokia.com>");
104 }
105 
106 static void
gst_text_overlay_init(GstTextOverlay * overlay)107 gst_text_overlay_init (GstTextOverlay * overlay)
108 {
109 }
110