/* GStreamer

 * Copyright (C) <1999> Erik Walthinsen <omega@cse.ogi.edu>

 * Copyright (C) <2003> David Schleef <ds@schleef.org>

 *

 * 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-textrender

 * @see_also: #GstTextOverlay

 *

 * <refsect2>

 * <para>

 * This plugin renders text received on the text sink pad to a video

 * buffer (retaining the alpha channel), so it can later be overlayed

 * on top of video streams using other elements.

 * </para>

 * <para>

 * The text can contain newline characters. (FIXME: What about text 

 * wrapping? It does not make sense in this context)

 * </para>

 * <para>

 * Example pipeline:

 * <programlisting>

 * gst-launch -v filesrc location=subtitles.srt ! subparse ! textrender ! xvimagesink

 * </programlisting>

 * </para>

 * </refsect2>

 */

#ifdef HAVE_CONFIG_H

#include <config.h>

#endif

#include <gst/gst.h>

#include <gst/video/video.h>

#include "gsttextrender.h"

GST_DEBUG_CATEGORY_EXTERN (pango_debug);

#define GST_CAT_DEFAULT pango_debug

static const GstElementDetails text_render_details =

GST_ELEMENT_DETAILS ("Text renderer",

    "Filter/Editor/Video",

    "Renders a text string to an image bitmap",

    "David Schleef <ds@schleef.org>, "

    "Ronald S. Bultje <rbultje@ronald.bitfreak.net>");

enum

{

  ARG_0,

  ARG_FONT_DESC

};

static GstStaticPadTemplate src_template_factory =

GST_STATIC_PAD_TEMPLATE ("src",

    GST_PAD_SRC,

    GST_PAD_ALWAYS,

    GST_STATIC_CAPS (GST_VIDEO_CAPS_YUV ("AYUV"))

    );

static GstStaticPadTemplate sink_template_factory =

    GST_STATIC_PAD_TEMPLATE ("sink",

    GST_PAD_SINK,

    GST_PAD_ALWAYS,

    GST_STATIC_CAPS ("text/x-pango-markup; text/plain")

    );

GST_BOILERPLATE (GstTextRender, gst_text_render, GstElement, GST_TYPE_ELEMENT)

     static void gst_text_render_finalize (GObject * object);

     static void gst_text_render_set_property (GObject * object,

    guint prop_id, const GValue * value, GParamSpec * pspec);

     static void gst_text_render_base_init (gpointer g_class)

{

  GstElementClass *element_class = GST_ELEMENT_CLASS (g_class);

  gst_element_class_add_pad_template (element_class,

      gst_static_pad_template_get (&src_template_factory));

  gst_element_class_add_pad_template (element_class,

      gst_static_pad_template_get (&sink_template_factory));

  gst_element_class_set_details (element_class, &text_render_details);

}

static void

gst_text_render_class_init (GstTextRenderClass * klass)

{

  GObjectClass *gobject_class;

  GstElementClass *gstelement_class;

  gobject_class = (GObjectClass *) klass;

  gstelement_class = (GstElementClass *) klass;

  parent_class = g_type_class_peek_parent (klass);

  gobject_class->finalize = gst_text_render_finalize;

  gobject_class->set_property = gst_text_render_set_property;

  klass->pango_context = pango_ft2_get_context (72, 72);

  g_object_class_install_property (G_OBJECT_CLASS (klass), ARG_FONT_DESC,

      g_param_spec_string ("font-desc", "font description",

          "Pango font description of font "

          "to be used for rendering. "

          "See documentation of "

          "pango_font_description_from_string"

          " for syntax.", "", G_PARAM_WRITABLE));

}

static void

resize_bitmap (GstTextRender * render, gint width, gint height)

{

  FT_Bitmap *bitmap = &render->bitmap;

  gint pitch = (width | 3) + 1;

  gint size = pitch * height;

  /* no need to keep reallocating; just keep the maximum size so far */

  if (size <= render->bitmap_buffer_size) {

    bitmap->rows = height;

    bitmap->width = width;

    bitmap->pitch = pitch;

    memset (bitmap->buffer, 0, render->bitmap_buffer_size);

    return;

  }

  if (!bitmap->buffer) {

    /* initialize */

    bitmap->pixel_mode = ft_pixel_mode_grays;

    bitmap->num_grays = 256;

  }

  if (bitmap->buffer)

    bitmap->buffer = g_realloc (bitmap->buffer, size);

  else

    bitmap->buffer = g_malloc (size);

  bitmap->rows = height;

  bitmap->width = width;

  bitmap->pitch = pitch;

  memset (bitmap->buffer, 0, size);

  render->bitmap_buffer_size = size;

}

static void

gst_text_render_render_text (GstTextRender * render)

{

  PangoRectangle ink_rect, logical_rect;

  pango_layout_get_pixel_extents (render->layout, &ink_rect, &logical_rect);

  resize_bitmap (render, ink_rect.width, ink_rect.height + ink_rect.y);

  pango_ft2_render_layout (&render->bitmap, render->layout, -ink_rect.x, 0);

  render->baseline_y = ink_rect.y;

}

static gboolean

gst_text_render_setcaps (GstPad * pad, GstCaps * caps)

{

  GstTextRender *render = GST_TEXT_RENDER (gst_pad_get_parent (pad));

  GstStructure *structure;

  gboolean ret = FALSE;

  gint width = 0, height = 0;

  structure = gst_caps_get_structure (caps, 0);

  gst_structure_get_int (structure, "width", &width);

  gst_structure_get_int (structure, "height", &height);

  GST_DEBUG ("Got caps %" GST_PTR_FORMAT, caps);

  if (width >= render->bitmap.width && height >= render->bitmap.rows) {

    render->width = width;

    render->height = height;

    ret = TRUE;

  }

  gst_object_unref (render);

  return ret;

}

static void

gst_text_render_fixate_caps (GstPad * pad, GstCaps * caps)

{

  GstTextRender *render = GST_TEXT_RENDER (gst_pad_get_parent (pad));

  GstStructure *s = gst_caps_get_structure (caps, 0);

  GST_DEBUG ("Fixating caps %" GST_PTR_FORMAT, caps);

  gst_structure_fixate_field_nearest_int (s, "width", render->bitmap.width);

  gst_structure_fixate_field_nearest_int (s, "height", render->bitmap.rows);

  GST_DEBUG ("Fixated to    %" GST_PTR_FORMAT, caps);

  gst_object_unref (render);

}

static void

gst_text_renderer_bitmap_to_ayuv (GstTextRender * render, FT_Bitmap * bitmap,

    guchar * pixbuf)

{

  int y;                        /* text bitmap coordinates */

  int rowinc, bit_rowinc;

  guchar *p, *bitp;

  guchar v;

  rowinc = render->width - bitmap->width;

  bit_rowinc = bitmap->pitch - bitmap->width;

  bitp = bitmap->buffer;

  p = pixbuf;

  for (y = 0; y < bitmap->rows; y++) {

    int n;

    for (n = bitmap->width; n > 0; --n) {

      v = *bitp;

      if (v) {

        p[0] = v;

        p[1] = 255;

        p[2] = 0x80;

        p[3] = 0x80;

      }

      p += 4;

      bitp++;

    }

    p += rowinc * 4;

    bitp += bit_rowinc;

  }

}

static GstFlowReturn

gst_text_render_chain (GstPad * pad, GstBuffer * inbuf)

{

  GstTextRender *render;

  GstFlowReturn ret;

  GstBuffer *outbuf;

  GstCaps *caps = NULL;

  guint8 *data = GST_BUFFER_DATA (inbuf);

  guint size = GST_BUFFER_SIZE (inbuf);

  gint n;

  render = GST_TEXT_RENDER (gst_pad_get_parent (pad));

  /* somehow pango barfs over "\0" buffers... */

  while (size > 0 &&

      (data[size - 1] == '\r' ||

          data[size - 1] == '\n' || data[size - 1] == '\0')) {

    size--;

  }

  /* render text */

  GST_DEBUG ("rendering '%*s'", size, data);

  pango_layout_set_markup (render->layout, (gchar *) data, size);

  gst_text_render_render_text (render);

  caps = gst_caps_new_simple ("video/x-raw-yuv", "format", GST_TYPE_FOURCC,

      GST_MAKE_FOURCC ('A', 'Y', 'U', 'V'), "width", G_TYPE_INT,

      render->bitmap.width, "height", G_TYPE_INT, render->bitmap.rows,

      "framerate", GST_TYPE_FRACTION, 1, 1, NULL);

  if (!gst_pad_set_caps (render->srcpad, caps)) {

    gst_caps_unref (caps);

    GST_ELEMENT_ERROR (render, CORE, NEGOTIATION, (NULL), (NULL));

    ret = GST_FLOW_ERROR;

    goto done;

  }

  GST_DEBUG ("Allocating AYUV buffer WxH = %dx%d", render->width,

      render->height);

  ret =

      gst_pad_alloc_buffer_and_set_caps (render->srcpad, GST_BUFFER_OFFSET_NONE,

      render->width * render->height * 4, caps, &outbuf);

  if (ret != GST_FLOW_OK)

    goto done;

  gst_buffer_copy_metadata (outbuf, inbuf, GST_BUFFER_COPY_TIMESTAMPS);

  data = GST_BUFFER_DATA (outbuf);

  for (n = 0; n < render->width * render->height; n++) {

    data[n * 4] = 0;

    data[n * 4 + 1] = 0;

    data[n * 4 + 2] = data[n * 4 + 3] = 128;

  }

  if (render->bitmap.buffer) {

    gst_text_renderer_bitmap_to_ayuv (render, &render->bitmap, data);

  }

  ret = gst_pad_push (render->srcpad, outbuf);

done:

  if (caps)

    gst_caps_unref (caps);

  gst_buffer_unref (inbuf);

  gst_object_unref (render);

  return ret;

}

static void

gst_text_render_finalize (GObject * object)

{

  GstTextRender *render = GST_TEXT_RENDER (object);

  g_free (render->bitmap.buffer);

  if (render->layout)

    g_object_unref (render->layout);

  G_OBJECT_CLASS (parent_class)->finalize (object);

}

static void

gst_text_render_init (GstTextRender * render, GstTextRenderClass * klass)

{

  GstPadTemplate *template;

  /* sink */

  template = gst_static_pad_template_get (&sink_template_factory);

  render->sinkpad = gst_pad_new_from_template (template, "sink");

  gst_object_unref (template);

  gst_pad_set_chain_function (render->sinkpad,

      GST_DEBUG_FUNCPTR (gst_text_render_chain));

  gst_element_add_pad (GST_ELEMENT (render), render->sinkpad);

  /* source */

  template = gst_static_pad_template_get (&src_template_factory);

  render->srcpad = gst_pad_new_from_template (template, "src");

  gst_object_unref (template);

  gst_pad_set_fixatecaps_function (render->srcpad,

      GST_DEBUG_FUNCPTR (gst_text_render_fixate_caps));

  gst_pad_set_setcaps_function (render->srcpad,

      GST_DEBUG_FUNCPTR (gst_text_render_setcaps));

  gst_element_add_pad (GST_ELEMENT (render), render->srcpad);

  render->layout =

      pango_layout_new (GST_TEXT_RENDER_GET_CLASS (render)->pango_context);

  memset (&render->bitmap, 0, sizeof (render->bitmap));

}

static void

gst_text_render_set_property (GObject * object, guint prop_id,

    const GValue * value, GParamSpec * pspec)

{

  GstTextRender *render = GST_TEXT_RENDER (object);

  switch (prop_id) {

    case ARG_FONT_DESC:

    {

      PangoFontDescription *desc;

      desc = pango_font_description_from_string (g_value_get_string (value));

      if (desc) {

        GST_LOG ("font description set: %s", g_value_get_string (value));

        GST_OBJECT_LOCK (render);

        pango_layout_set_font_description (render->layout, desc);

        pango_font_description_free (desc);

        gst_text_render_render_text (render);

        GST_OBJECT_UNLOCK (render);

      } else {

        GST_WARNING ("font description parse failed: %s",

            g_value_get_string (value));

      }

      break;

    }

    default:

      break;

  }

}