codec/svg.c: Add svg decoder.

modules/codec/svg.c

+/*****************************************************************************
+ * svg.c: svg decoder module making use of librsvg2.
+ *****************************************************************************
+ * Copyright (C) 2014 VLC authors and VideoLAN
+ *
+ * Authors: Adam Leggett <adamvleggett@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation; either version 2.1 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
+ *****************************************************************************/
+
+/*****************************************************************************
+ * Preamble
+ *****************************************************************************/
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+
+#include <vlc_common.h>
+#include <vlc_plugin.h>
+#include <vlc_codec.h>
+
+#include <glib.h>
+#include <glib/gstdio.h>
+#include <glib-object.h>                                  /* g_object_unref( ) */
+
+#include <librsvg/rsvg.h>
+#include <cairo/cairo.h>
+
+/*****************************************************************************
+ * decoder_sys_t : svg decoder descriptor
+ *****************************************************************************/
+struct decoder_sys_t
+{
+};
+
+/*****************************************************************************
+ * Local prototypes
+ *****************************************************************************/
+static int  OpenDecoder   ( vlc_object_t * );
+static void CloseDecoder  ( vlc_object_t * );
+
+static picture_t *DecodeBlock  ( decoder_t *, block_t ** );
+
+/*****************************************************************************
+ * Module descriptor
+ *****************************************************************************/
+vlc_module_begin ()
+    set_category( CAT_INPUT )
+    set_subcategory( SUBCAT_INPUT_VCODEC )
+    set_description( N_("SVG video decoder") )
+    set_capability( "decoder", 100 )
+    set_callbacks( OpenDecoder, CloseDecoder )
+    add_shortcut( "svg" )
+vlc_module_end ()
+
+/*****************************************************************************
+ * OpenDecoder: probe the decoder and return score
+ *****************************************************************************/
+static int OpenDecoder( vlc_object_t *p_this )
+{
+    decoder_t *p_dec = (decoder_t*)p_this;
+
+    if( p_dec->fmt_in.i_codec != VLC_CODEC_SVG )
+    {
+        return VLC_EGENERIC;
+    }
+
+    /* Initialize library */
+    rsvg_init();
+
+    /* Set output properties */
+
+    p_dec->fmt_out.i_cat = VIDEO_ES;
+    p_dec->fmt_out.i_codec = VLC_CODEC_RGBA;
+
+    /* Set callbacks */
+    p_dec->pf_decode_video = DecodeBlock;
+
+    return VLC_SUCCESS;
+}
+
+static void rsvg_cairo_size_callback(int *width, int *height, gpointer data)
+{
+    RsvgDimensionData *dim = data;
+    *width = dim->width;
+    *height = dim->height;
+}
+
+/****************************************************************************
+ * DecodeBlock: the whole thing
+ ****************************************************************************
+ * This function must be fed with a complete image.
+ ****************************************************************************/
+static picture_t *DecodeBlock( decoder_t *p_dec, block_t **pp_block )
+{
+    block_t *p_block;
+    picture_t *p_pic = NULL;
+
+    RsvgHandle *rsvg = NULL;
+    cairo_surface_t *surface = NULL;
+    cairo_t *cr = NULL;
+    int stride = 0;
+
+    if( !pp_block || !*pp_block ) return NULL;
+
+    p_block = *pp_block;
+    *pp_block = NULL;
+
+    if( p_block->i_flags & BLOCK_FLAG_DISCONTINUITY )
+    {
+        block_Release( p_block );
+        return NULL;
+    }
+
+    rsvg = rsvg_handle_new_from_data(p_block->p_buffer, p_block->i_buffer, NULL);
+    if( !rsvg )
+        goto done;
+
+    RsvgDimensionData dim;
+    rsvg_handle_get_dimensions(rsvg, &dim);
+    rsvg_handle_set_size_callback(rsvg, rsvg_cairo_size_callback, &dim, NULL);
+
+    p_dec->fmt_out.i_codec = VLC_CODEC_RGBA;
+    p_dec->fmt_out.video.i_width = dim.width;
+    p_dec->fmt_out.video.i_height = dim.height;
+    p_dec->fmt_out.video.i_sar_num = 1;
+    p_dec->fmt_out.video.i_sar_den = 1;
+    p_dec->fmt_out.video.i_rmask = 0x000000ff;
+    p_dec->fmt_out.video.i_gmask = 0x0000ff00;
+    p_dec->fmt_out.video.i_bmask = 0x00ff0000;
+
+    /* Get a new picture */
+    p_pic = decoder_NewPicture( p_dec );
+    if( !p_pic )
+        goto done;
+
+    stride = cairo_format_stride_for_width(CAIRO_FORMAT_ARGB32, dim.width);
+    surface = cairo_image_surface_create_for_data(p_pic->p->p_pixels,
+                                                  CAIRO_FORMAT_ARGB32,
+                                                  dim.width, dim.height,
+                                                  stride);
+    if( !surface )
+    {
+        p_pic = NULL;
+        goto done;
+    }
+
+    /* Decode picture */
+    cr = cairo_create(surface);
+    if( !cr )
+    {
+        p_pic = NULL;
+        goto done;
+    }
+
+    rsvg_handle_render_cairo(rsvg, cr);
+
+    p_pic->date = p_block->i_pts > VLC_TS_INVALID ? p_block->i_pts : p_block->i_dts;
+
+done:
+    if( rsvg )
+        g_object_unref( G_OBJECT( rsvg ) );
+    if( cr )
+        cairo_destroy( cr );
+    if( surface )
+        cairo_surface_destroy( surface );
+
+    block_Release( p_block );
+    return p_pic;
+}
+
+/*****************************************************************************
+ * CloseDecoder: png decoder destruction
+ *****************************************************************************/
+static void CloseDecoder( vlc_object_t *p_this )
+{
+    VLC_UNUSED( p_this );
+    rsvg_term();
+}