/* 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 <gst/gst.h> * #include <gst/video/video.h> * * ... * * 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, &state->width, &state->height); * state->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->valid) * return; * * scale = 2*(((timestamp/(int)1e7) % 70)+30)/100.0; * cairo_translate(cr, s->width/2, (s->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 ("cairooverlay", "overlay"); * * 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); * ... * * ]| * </refsect2> */ #ifdef HAVE_CONFIG_H #include "config.h" #endif #include "gstcairooverlay.h" #include <gst/video/video.h> #include <cairo.h> /* RGB16 is native-endianness in GStreamer */ #if G_BYTE_ORDER == G_LITTLE_ENDIAN #define TEMPLATE_CAPS GST_VIDEO_CAPS_MAKE("{ BGRx, BGRA, RGB16 }") #else #define TEMPLATE_CAPS GST_VIDEO_CAPS_MAKE("{ xRGB, ARGB, RGB16 }") #endif static GstStaticPadTemplate gst_cairo_overlay_src_template = GST_STATIC_PAD_TEMPLATE ("src", GST_PAD_SRC, GST_PAD_ALWAYS, GST_STATIC_CAPS (TEMPLATE_CAPS) ); static GstStaticPadTemplate gst_cairo_overlay_sink_template = GST_STATIC_PAD_TEMPLATE ("sink", GST_PAD_SINK, GST_PAD_ALWAYS, GST_STATIC_CAPS (TEMPLATE_CAPS) ); G_DEFINE_TYPE (GstCairoOverlay, gst_cairo_overlay, 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_info (GstVideoFilter * vfilter, GstCaps * in_caps, GstVideoInfo * in_info, GstCaps * out_caps, GstVideoInfo * out_info) { GstCairoOverlay *overlay = GST_CAIRO_OVERLAY (vfilter); g_signal_emit (overlay, gst_cairo_overlay_signals[SIGNAL_CAPS_CHANGED], 0, in_caps, NULL); return TRUE; } static GstFlowReturn gst_cairo_overlay_transform_frame_ip (GstVideoFilter * vfilter, GstVideoFrame * frame) { GstCairoOverlay *overlay = GST_CAIRO_OVERLAY (vfilter); cairo_surface_t *surface; cairo_t *cr; cairo_format_t format; switch (GST_VIDEO_FRAME_FORMAT (frame)) { case GST_VIDEO_FORMAT_ARGB: case GST_VIDEO_FORMAT_BGRA: format = CAIRO_FORMAT_ARGB32; break; case GST_VIDEO_FORMAT_xRGB: case GST_VIDEO_FORMAT_BGRx: format = CAIRO_FORMAT_RGB24; break; case GST_VIDEO_FORMAT_RGB16: format = CAIRO_FORMAT_RGB16_565; break; default: { GST_WARNING ("No matching cairo format for %s", gst_video_format_to_string (GST_VIDEO_FRAME_FORMAT (frame))); return GST_FLOW_ERROR; } } surface = cairo_image_surface_create_for_data (GST_VIDEO_FRAME_PLANE_DATA (frame, 0), format, GST_VIDEO_FRAME_WIDTH (frame), GST_VIDEO_FRAME_HEIGHT (frame), GST_VIDEO_FRAME_PLANE_STRIDE (frame, 0)); 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_PTS (frame->buffer), GST_BUFFER_DURATION (frame->buffer), NULL); cairo_destroy (cr); cairo_surface_destroy (surface); return GST_FLOW_OK; } static void gst_cairo_overlay_class_init (GstCairoOverlayClass * klass) { GstVideoFilterClass *vfilter_class; GstElementClass *element_class; vfilter_class = (GstVideoFilterClass *) klass; element_class = (GstElementClass *) klass; vfilter_class->set_info = gst_cairo_overlay_set_info; vfilter_class->transform_frame_ip = gst_cairo_overlay_transform_frame_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, g_cclosure_marshal_generic, 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 #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, g_cclosure_marshal_generic, G_TYPE_NONE, 1, GST_TYPE_CAPS); 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_static_pad_template (element_class, &gst_cairo_overlay_sink_template); gst_element_class_add_static_pad_template (element_class, &gst_cairo_overlay_src_template); } static void gst_cairo_overlay_init (GstCairoOverlay * overlay) { /* nothing to do */ }