[FFmpeg-devel] [PATCH 3/3] lavc: add a librsvg rasterization library wrapper

Rostislav Pehlivanov atomnuker at gmail.com
Tue May 16 13:44:43 EEST 2017


On 8 May 2017 at 05:46, Rostislav Pehlivanov <atomnuker at gmail.com> wrote:

> Enables rendering of SVG images. This is possible since SVG images
> still contain and specify the dimensions in pixels to which they've
> been drawn to and thus enable browsers to display them without any
> external data. Users can still override and generate images with
> arbitrary resolutions.
>
> Signed-off-by: Rostislav Pehlivanov <atomnuker at gmail.com>
> ---
>  configure               |   4 ++
>  libavcodec/Makefile     |   1 +
>  libavcodec/allcodecs.c  |   1 +
>  libavcodec/librsvgdec.c | 127 ++++++++++++++++++++++++++++++
> ++++++++++++++++++
>  4 files changed, 133 insertions(+)
>  create mode 100644 libavcodec/librsvgdec.c
>
> diff --git a/configure b/configure
> index 2e1786a6fc..4f20d177a5 100755
> --- a/configure
> +++ b/configure
> @@ -245,6 +245,7 @@ External library support:
>    --enable-libopenmpt      enable decoding tracked files via libopenmpt
> [no]
>    --enable-libopus         enable Opus de/encoding via libopus [no]
>    --enable-libpulse        enable Pulseaudio input via libpulse [no]
> +  --enable-librsvg         enable SVG rasterization via librsvg [no]
>    --enable-librubberband   enable rubberband needed for rubberband filter
> [no]
>    --enable-librtmp         enable RTMP[E] support via librtmp [no]
>    --enable-libschroedinger enable Dirac de/encoding via libschroedinger
> [no]
> @@ -1557,6 +1558,7 @@ EXTERNAL_LIBRARY_LIST="
>      libopenmpt
>      libopus
>      libpulse
> +    librsvg
>      librtmp
>      libschroedinger
>      libshine
> @@ -2867,6 +2869,7 @@ libopenmpt_demuxer_deps="libopenmpt"
>  libopus_decoder_deps="libopus"
>  libopus_encoder_deps="libopus"
>  libopus_encoder_select="audio_frame_queue"
> +librsvg_decoder_deps="librsvg"
>  libschroedinger_decoder_deps="libschroedinger"
>  libschroedinger_encoder_deps="libschroedinger"
>  libshine_encoder_deps="libshine"
> @@ -5819,6 +5822,7 @@ enabled libopus           && {
>      }
>  }
>  enabled libpulse          && require_pkg_config libpulse
> pulse/pulseaudio.h pa_context_new
> +enabled librsvg           && require_pkg_config librsvg-2.0
> librsvg-2.0/librsvg/rsvg.h rsvg_handle_render_cairo
>  enabled librtmp           && require_pkg_config librtmp librtmp/rtmp.h
> RTMP_Socket
>  enabled librubberband     && require_pkg_config "rubberband >= 1.8.1"
> rubberband/rubberband-c.h rubberband_new
>  enabled libschroedinger   && require_pkg_config schroedinger-1.0
> schroedinger/schro.h schro_init
> diff --git a/libavcodec/Makefile b/libavcodec/Makefile
> index b5c8cc1f98..5829063ee8 100644
> --- a/libavcodec/Makefile
> +++ b/libavcodec/Makefile
> @@ -550,6 +550,7 @@ OBJS-$(CONFIG_SUBVIEWER1_DECODER)      += textdec.o
> ass.o
>  OBJS-$(CONFIG_SUBVIEWER_DECODER)       += subviewerdec.o ass.o
>  OBJS-$(CONFIG_SUNRAST_DECODER)         += sunrast.o
>  OBJS-$(CONFIG_SUNRAST_ENCODER)         += sunrastenc.o
> +OBJS-$(CONFIG_LIBRSVG_DECODER)         += librsvgdec.o
>  OBJS-$(CONFIG_SVQ1_DECODER)            += svq1dec.o svq1.o svq13.o
> h263data.o
>  OBJS-$(CONFIG_SVQ1_ENCODER)            += svq1enc.o svq1.o  h263data.o  \
>                                            h263.o ituh263enc.o
> diff --git a/libavcodec/allcodecs.c b/libavcodec/allcodecs.c
> index 7fcc26f2c1..425a32c924 100644
> --- a/libavcodec/allcodecs.c
> +++ b/libavcodec/allcodecs.c
> @@ -319,6 +319,7 @@ static void register_all(void)
>      REGISTER_DECODER(SPEEDHQ,           speedhq);
>      REGISTER_DECODER(SRGC,              srgc);
>      REGISTER_ENCDEC (SUNRAST,           sunrast);
> +    REGISTER_DECODER(LIBRSVG,           librsvg);
>      REGISTER_ENCDEC (SVQ1,              svq1);
>      REGISTER_DECODER(SVQ3,              svq3);
>      REGISTER_ENCDEC (TARGA,             targa);
> diff --git a/libavcodec/librsvgdec.c b/libavcodec/librsvgdec.c
> new file mode 100644
> index 0000000000..29b771c5a3
> --- /dev/null
> +++ b/libavcodec/librsvgdec.c
> @@ -0,0 +1,127 @@
> +/*
> + * Librsvg rasterization wrapper
> + * Copyright (c) 2017 Rostislav Pehlivanov <atomnuker at gmail.com>
> + *
> + * This file is part of FFmpeg.
> + *
> + * FFmpeg 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.
> + *
> + * FFmpeg 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 FFmpeg; if not, write to the Free Software
> + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
> 02110-1301 USA
> + */
> +
> +#include "avcodec.h"
> +#include "internal.h"
> +#include "libavutil/opt.h"
> +#include "librsvg-2.0/librsvg/rsvg.h"
> +
> +typedef struct LibRSVGContext {
> +    AVClass *class;
> +
> +    int width;
> +    int height;
> +    int keep_ar;
> +} LibRSVGContext;
> +
> +static int librsvg_decode_frame(AVCodecContext *avctx, void *data, int
> *got_frame, AVPacket *pkt)
> +{
> +    int ret;
> +    LibRSVGContext *s = avctx->priv_data;
> +    AVFrame *frame = data;
> +
> +    RsvgHandle *handle;
> +    RsvgDimensionData unscaled_dimensions, dimensions;
> +    cairo_surface_t *image;
> +    cairo_t *crender = NULL;
> +    GError *error = NULL;
> +
> +    *got_frame = 0;
> +
> +    handle = rsvg_handle_new_from_data(pkt->data, pkt->size, &error);
> +    if (error) {
> +        av_log(avctx, AV_LOG_ERROR, "Error parsing svg!\n");
> +        g_error_free(error);
> +        return AVERROR_INVALIDDATA;
> +    }
> +
> +    rsvg_handle_get_dimensions(handle, &dimensions);
> +    rsvg_handle_get_dimensions(handle, &unscaled_dimensions);
> +    dimensions.width  = s->width  ? s->width  : dimensions.width;
> +    dimensions.height = s->height ? s->height : dimensions.height;
> +    if (s->keep_ar && (s->width || s->height)) {
> +        double default_ar = unscaled_dimensions.width/(
> double)unscaled_dimensions.height;
> +        if (!s->width)
> +            dimensions.width  = lrintf(dimensions.height * default_ar);
> +        else
> +            dimensions.height = lrintf(dimensions.width  / default_ar);
> +    }
> +
> +    if ((ret = ff_set_dimensions(avctx, dimensions.width,
> dimensions.height)))
> +        return ret;
> +    avctx->pix_fmt = AV_PIX_FMT_BGRA;
> +
> +    if ((ret = ff_get_buffer(avctx, frame, 0)))
> +        return ret;
> +    frame->pict_type = AV_PICTURE_TYPE_I;
> +    frame->key_frame = 1;
> +
> +    image = cairo_image_surface_create_for_data(frame->data[0],
> CAIRO_FORMAT_ARGB32,
> +                                                frame->width,
> frame->height,
> +                                                frame->linesize[0]);
> +    if (cairo_surface_status(image) != CAIRO_STATUS_SUCCESS)
> +        return AVERROR_INVALIDDATA;
> +
> +    crender = cairo_create(image);
> +
> +    cairo_set_source_rgba(crender, 0.0, 0.0, 0.0, 1.0f);
> +    cairo_paint_with_alpha(crender, 0.0f);
> +
> +    cairo_scale(crender, dimensions.width / (double)unscaled_dimensions.
> width,
> +                dimensions.height / (double)unscaled_dimensions.height);
> +
> +    rsvg_handle_render_cairo(handle, crender);
> +
> +    cairo_destroy(crender);
> +    cairo_surface_destroy(image);
> +    g_object_unref(handle);
> +
> +    *got_frame = 1;
> +
> +    return 0;
> +}
> +
> +#define OFFSET(x) offsetof(LibRSVGContext, x)
> +#define DEC (AV_OPT_FLAG_DECODING_PARAM | AV_OPT_FLAG_VIDEO_PARAM)
> +static const AVOption options[] = {
> +    { "width", "Width to render to (0 for default)", OFFSET(width),
> AV_OPT_TYPE_INT, { .i64 = 0 }, 0, INT_MAX, DEC },
> +    { "height", "Height to render to (0 for default)", OFFSET(height),
> AV_OPT_TYPE_INT, { .i64 = 0 }, 0, INT_MAX, DEC },
> +    { "keep_ar", "Keep aspect ratio with custom width/height",
> OFFSET(keep_ar), AV_OPT_TYPE_BOOL, { .i64 = 1 }, 0, 1, DEC },
> +    { NULL },
> +};
> +
> +static const AVClass librsvg_decoder_class = {
> +    .class_name = "Librsvg",
> +    .item_name  = av_default_item_name,
> +    .option     = options,
> +    .version    = LIBAVUTIL_VERSION_INT,
> +};
> +
> +AVCodec ff_librsvg_decoder = {
> +    .name           = "librsvg",
> +    .long_name      = NULL_IF_CONFIG_SMALL("Librsvg rasterizer"),
> +    .priv_class     = &librsvg_decoder_class,
> +    .type           = AVMEDIA_TYPE_VIDEO,
> +    .id             = AV_CODEC_ID_SVG,
> +    .decode         = librsvg_decode_frame,
> +    .priv_data_size = sizeof(LibRSVGContext),
> +    .capabilities   = AV_CODEC_CAP_LOSSLESS | AV_CODEC_CAP_DR1,
> +};
> --
> 2.13.0.rc1.294.g07d810a77f
>
>
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