gstreamer/ext/cairo/gstcairooverlay.c

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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.
*/
/**
* SECTION:element-cairooverlay
*
* cairooverlay renders an overlay using a application provided render function.
*
* The full example can be found in tests/examples/cairo/cairo_overlay.c
* <refsect2>
* <title>Example code</title>
* |[
*
* #include &lt;gst/gst.h&gt;
* #include &lt;gst/video/video.h&gt;
*
* ...
*
* typedef struct {
* gboolean valid;
* int width;
* int height;
* } CairoOverlayState;
*
* ...
*
* static void
* prepare_overlay (GstElement * overlay, GstCaps * caps, gpointer user_data)
* {
* CairoOverlayState *state = (CairoOverlayState *)user_data;
*
* gst_video_format_parse_caps (caps, NULL, &amp;state-&gt;width, &amp;state-&gt;height);
* state-&gt;valid = TRUE;
* }
*
* static void
* draw_overlay (GstElement * overlay, cairo_t * cr, guint64 timestamp,
* guint64 duration, gpointer user_data)
* {
* CairoOverlayState *s = (CairoOverlayState *)user_data;
* double scale;
*
* if (!s-&gt;valid)
* return;
*
* scale = 2*(((timestamp/(int)1e7) % 70)+30)/100.0;
* cairo_translate(cr, s-&gt;width/2, (s-&gt;height/2)-30);
* 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);
* }
*
* ...
*
* cairo_overlay = gst_element_factory_make (&quot;cairooverlay&quot;, &quot;overlay&quot;);
*
* g_signal_connect (cairo_overlay, &quot;draw&quot;, G_CALLBACK (draw_overlay),
* overlay_state);
* g_signal_connect (cairo_overlay, &quot;caps-changed&quot;,
* G_CALLBACK (prepare_overlay), overlay_state);
* ...
*
* ]|
* </refsect2>
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "gstcairooverlay.h"
#include "gstcairo-marshal.h"
#include <gst/video/video.h>
#include <cairo.h>
#if G_BYTE_ORDER == G_LITTLE_ENDIAN
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#define TEMPLATE_CAPS GST_VIDEO_CAPS_BGRx " ; " GST_VIDEO_CAPS_BGRA " ; "
#else
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#define TEMPLATE_CAPS GST_VIDEO_CAPS_xRGB " ; " GST_VIDEO_CAPS_ARGB " ; "
#endif
static GstStaticPadTemplate gst_cairo_overlay_src_template =
GST_STATIC_PAD_TEMPLATE ("src",
GST_PAD_SRC,
GST_PAD_ALWAYS,
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GST_STATIC_CAPS (TEMPLATE_CAPS)
);
static GstStaticPadTemplate gst_cairo_overlay_sink_template =
GST_STATIC_PAD_TEMPLATE ("sink",
GST_PAD_SINK,
GST_PAD_ALWAYS,
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GST_STATIC_CAPS (TEMPLATE_CAPS)
);
GST_BOILERPLATE (GstCairoOverlay, gst_cairo_overlay, GstVideoFilter,
GST_TYPE_VIDEO_FILTER);
enum
{
SIGNAL_DRAW,
SIGNAL_CAPS_CHANGED,
N_SIGNALS
};
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static guint gst_cairo_overlay_signals[N_SIGNALS];
static gboolean
gst_cairo_overlay_set_caps (GstBaseTransform * btrans, GstCaps * incaps,
GstCaps * outcaps)
{
GstCairoOverlay *overlay = GST_CAIRO_OVERLAY (btrans);
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gboolean ret;
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ret =
gst_video_format_parse_caps (incaps, &overlay->format, &overlay->width,
&overlay->height);
if (G_UNLIKELY (!ret))
return FALSE;
g_signal_emit (overlay, gst_cairo_overlay_signals[SIGNAL_CAPS_CHANGED], 0,
incaps, NULL);
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return ret;
}
static GstFlowReturn
gst_cairo_overlay_transform_ip (GstBaseTransform * btrans, GstBuffer * buf)
{
GstCairoOverlay *overlay = GST_CAIRO_OVERLAY (btrans);
cairo_surface_t *surface;
cairo_t *cr;
cairo_format_t format;
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format = (overlay->format == GST_VIDEO_FORMAT_ARGB
|| overlay->format == GST_VIDEO_FORMAT_BGRA) ?
CAIRO_FORMAT_ARGB32 : CAIRO_FORMAT_RGB24;
surface =
cairo_image_surface_create_for_data (GST_BUFFER_DATA (buf), format,
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overlay->width, overlay->height, overlay->width * 4);
if (G_UNLIKELY (!surface))
return GST_FLOW_ERROR;
cr = cairo_create (surface);
if (G_UNLIKELY (!cr)) {
cairo_surface_destroy (surface);
return GST_FLOW_ERROR;
}
g_signal_emit (overlay, gst_cairo_overlay_signals[SIGNAL_DRAW], 0,
cr, GST_BUFFER_TIMESTAMP (buf), GST_BUFFER_DURATION (buf), NULL);
cairo_destroy (cr);
cairo_surface_destroy (surface);
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return GST_FLOW_OK;
}
static void
gst_cairo_overlay_base_init (gpointer g_class)
{
GstElementClass *element_class = GST_ELEMENT_CLASS (g_class);
gst_element_class_set_static_metadata (element_class, "Cairo overlay",
"Filter/Editor/Video",
"Render overlay on a video stream using Cairo",
"Jon Nordby <jononor@gmail.com>");
gst_element_class_add_pad_template (element_class,
gst_static_pad_template_get (&gst_cairo_overlay_sink_template));
gst_element_class_add_pad_template (element_class,
gst_static_pad_template_get (&gst_cairo_overlay_src_template));
}
static void
gst_cairo_overlay_class_init (GstCairoOverlayClass * klass)
{
GstBaseTransformClass *trans_class;
trans_class = (GstBaseTransformClass *) klass;
trans_class->set_caps = gst_cairo_overlay_set_caps;
trans_class->transform_ip = gst_cairo_overlay_transform_ip;
/**
* GstCairoOverlay::draw:
* @overlay: Overlay element emitting the signal.
* @cr: Cairo context to draw to.
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* @timestamp: Timestamp (see #GstClockTime) of the current buffer.
* @duration: Duration (see #GstClockTime) of the current buffer.
*
* This signal is emitted when the overlay should be drawn.
*/
gst_cairo_overlay_signals[SIGNAL_DRAW] =
g_signal_new ("draw",
G_TYPE_FROM_CLASS (klass),
0,
0,
NULL,
NULL,
gst_cairo_marshal_VOID__BOXED_UINT64_UINT64,
G_TYPE_NONE, 3, CAIRO_GOBJECT_TYPE_CONTEXT, G_TYPE_UINT64, G_TYPE_UINT64);
/**
* GstCairoOverlay::caps-changed:
* @overlay: Overlay element emitting the signal.
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* @caps: The #GstCaps of the element.
*
* This signal is emitted when the caps of the element has changed.
*/
gst_cairo_overlay_signals[SIGNAL_CAPS_CHANGED] =
g_signal_new ("caps-changed",
G_TYPE_FROM_CLASS (klass),
0,
0,
NULL, NULL, gst_cairo_marshal_VOID__BOXED, G_TYPE_NONE, 1, GST_TYPE_CAPS);
}
static void
gst_cairo_overlay_init (GstCairoOverlay * overlay, GstCairoOverlayClass * klass)
{
}