cairooverlay: Add generic Cairo overlay video element.

Allows applications to connect to the "draw" signal of
the element and do their custom drawing there.
Includes an example application demonstrating usage.

Fixes: https://bugzilla.gnome.org/show_bug.cgi?id=595520

6 files changed, 350 insertions, 7 deletions

diff --git a/ext/cairo/.gitignore b/ext/cairo/.gitignore
new file mode 100644
index 000000000..662efe7ac
--- /dev/null
+++ b/ext/cairo/.gitignore
@@ -0,0 +1,2 @@
+gstcairo-marshal.c
+gstcairo-marshal.h
diff --git a/ext/cairo/Makefile.am b/ext/cairo/Makefile.am
index 40eb01bb7..b9d97e624 100644
--- a/ext/cairo/Makefile.am
+++ b/ext/cairo/Makefile.am
@@ -1,20 +1,45 @@
 plugin_LTLIBRARIES = libgstcairo.la
 
-noinst_HEADERS = gsttimeoverlay.h gsttextoverlay.h gstcairorender.h
+if USE_CAIRO_GOBJECT
+glib_enum_define = GST_CAIRO
+glib_gen_prefix = gst_cairo
+glib_gen_basename = gstcairo
 
+include $(top_srcdir)/common/gst-glib-gen.mak
+
+built_sources = gstcairo-marshal.c
+built_headers = gstcairo-marshal.h
+
+BUILT_SOURCES = $(built_sources) $(built_headers)
+
+gstcairo_gobject_dep_sources = gstcairooverlay.c
+gstcairo_gobject_dep_headers = gstcairooverlay.h
+
+CLEANFILES = $(BUILT_SOURCES)
+endif
+
+noinst_HEADERS = \
+	gsttimeoverlay.h \
+	gsttextoverlay.h \
+	gstcairorender.h \
+	$(gstcairo_gobject_dep_headers)
 libgstcairo_la_SOURCES = \
 	gstcairo.c \
 	gsttimeoverlay.c \
 	gsttextoverlay.c \
-	gstcairorender.c
-
+	gstcairorender.c \
+	$(gstcairo_gobject_dep_sources)
+nodist_libgstcairo_la_SOURCES = \
+    $(built_sources)
 libgstcairo_la_CFLAGS = \
-        $(GST_PLUGINS_BASE_CFLAGS) \
+	$(GST_PLUGINS_BASE_CFLAGS) \
 	$(GST_BASE_CFLAGS) \
-	$(GST_CFLAGS) $(CAIRO_CFLAGS)
+	$(GST_CFLAGS) $(CAIRO_CFLAGS) $(CAIRO_GOBJECT_CFLAGS)
 libgstcairo_la_LIBADD = \
-  $(GST_BASE_LIBS) \
-  $(GST_LIBS) $(CAIRO_LIBS) $(LIBM)
+	$(GST_BASE_LIBS) -lgstvideo-$(GST_MAJORMINOR) \
+	$(GST_LIBS) $(CAIRO_LIBS) $(CAIRO_GOBJECT_LIBS) $(LIBM)
 libgstcairo_la_LDFLAGS = $(GST_PLUGIN_LDFLAGS)
 libgstcairo_la_LIBTOOLFLAGS = --tag=disable-static
 
+EXTRA_DIST = cairo-marshal.list
+
diff --git a/ext/cairo/gstcairo-marshal.list b/ext/cairo/gstcairo-marshal.list
new file mode 100644
index 000000000..b6378703b
--- /dev/null
+++ b/ext/cairo/gstcairo-marshal.list
@@ -0,0 +1,2 @@
+VOID:BOXED,UINT64,UINT64
+VOID:BOXED
diff --git a/ext/cairo/gstcairo.c b/ext/cairo/gstcairo.c
index d821728f3..5d4c323f0 100644
--- a/ext/cairo/gstcairo.c
+++ b/ext/cairo/gstcairo.c
@@ -25,6 +25,11 @@
 #include <gsttimeoverlay.h>
 #include <gsttextoverlay.h>
 #include <gstcairorender.h>
+
+#ifdef HAVE_CAIRO_GOBJECT
+#include <gstcairooverlay.h>
+#endif
+
 #include <string.h>
 #include <math.h>
 
@@ -37,6 +42,10 @@ plugin_init (GstPlugin * plugin)
       GST_TYPE_CAIRO_TEXT_OVERLAY);
   gst_element_register (plugin, "cairotimeoverlay", GST_RANK_NONE,
       GST_TYPE_CAIRO_TIME_OVERLAY);
+#ifdef HAVE_CAIRO_GOBJECT
+  gst_element_register (plugin, "cairooverlay", GST_RANK_NONE,
+      GST_TYPE_CAIRO_OVERLAY);
+#endif
   gst_element_register (plugin, "cairorender", GST_RANK_SECONDARY,
       GST_TYPE_CAIRO_RENDER);
 
diff --git a/ext/cairo/gstcairooverlay.c b/ext/cairo/gstcairooverlay.c
new file mode 100644
index 000000000..7bddb30b7
--- /dev/null
+++ b/ext/cairo/gstcairooverlay.c
@@ -0,0 +1,245 @@
+/* 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., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, 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
+#define ARGB_CAPS GST_VIDEO_CAPS_BGRx " ; " GST_VIDEO_CAPS_BGRA " ; "
+#else
+#define ARGB_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,
+    GST_STATIC_CAPS (ARGB_CAPS)
+    );
+
+static GstStaticPadTemplate gst_cairo_overlay_sink_template =
+GST_STATIC_PAD_TEMPLATE ("sink",
+    GST_PAD_SINK,
+    GST_PAD_ALWAYS,
+    GST_STATIC_CAPS (ARGB_CAPS)
+    );
+
+
+GST_BOILERPLATE (GstCairoOverlay, gst_cairo_overlay, GstVideoFilter,
+    GST_TYPE_VIDEO_FILTER);
+
+enum
+{
+  SIGNAL_DRAW,
+  SIGNAL_CAPS_CHANGED,
+  N_SIGNALS
+};
+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);
+  GstStructure *s = gst_caps_get_structure (incaps, 0);
+
+  if (!gst_structure_get_int (s, "bpp", &(overlay->bpp))) {
+    return FALSE;
+  }
+
+  g_signal_emit (overlay, gst_cairo_overlay_signals[SIGNAL_CAPS_CHANGED], 0,
+      incaps, NULL);
+
+  return G_LIKELY (gst_video_format_parse_caps (incaps,
+          &overlay->caps_format, &overlay->caps_width, &overlay->caps_height));
+}
+
+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;
+
+  format = (overlay->bpp == 32) ? CAIRO_FORMAT_ARGB32 : CAIRO_FORMAT_RGB24;
+
+  surface =
+      cairo_image_surface_create_for_data (GST_BUFFER_DATA (buf), format,
+      overlay->caps_width, overlay->caps_height, overlay->caps_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);
+  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_details_simple (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.
+   * @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.
+   * @caps: The caps 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)
+{
+}
diff --git a/ext/cairo/gstcairooverlay.h b/ext/cairo/gstcairooverlay.h
new file mode 100644
index 000000000..a29350713
--- /dev/null
+++ b/ext/cairo/gstcairooverlay.h
@@ -0,0 +1,60 @@
+/* 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., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#ifndef __GST_CAIRO_OVERLAY_H__
+#define __GST_CAIRO_OVERLAY_H__
+
+#include <gst/gst.h>
+#include <gst/video/video.h>
+#include <gst/video/gstvideofilter.h>
+
+#include <cairo.h>
+#include <cairo-gobject.h>
+
+G_BEGIN_DECLS
+
+#define GST_TYPE_CAIRO_OVERLAY \
+  (gst_cairo_overlay_get_type())
+#define GST_CAIRO_OVERLAY(obj) \
+  (G_TYPE_CHECK_INSTANCE_CAST((obj),GST_TYPE_CAIRO_OVERLAY,GstCairoOverlay))
+#define GST_CAIRO_OVERLAY_CLASS(klass) \
+  (G_TYPE_CHECK_CLASS_CAST((klass),GST_TYPE_CAIRO_OVERLAY,GstCairoOverlayClass))
+#define GST_IS_CAIRO_OVERLAY(obj) \
+  (G_TYPE_CHECK_INSTANCE_TYPE((obj),GST_TYPE_CAIRO_OVERLAY))
+#define GST_IS_CAIRO_OVERLAY_CLASS(klass) \
+  (G_TYPE_CHECK_CLASS_TYPE((klass),GST_TYPE_CAIRO_OVERLAY))
+
+typedef struct _GstCairoOverlay {
+  GstVideoFilter parent_instance;
+  /* < private > */
+  GstVideoFormat caps_format;
+  int caps_width;
+  int caps_height;
+  int bpp;
+} GstCairoOverlay;
+
+typedef struct _GstCairoOverlayClass {
+  GstVideoFilterClass parent_class;
+} GstCairoOverlayClass;
+
+GType gst_cairo_overlay_get_type(void);
+
+G_END_DECLS
+
+#endif /* __GST_CAIRO_OVERLAY_H__ */