gstreamer/ext/pango/gsttextoverlay.c

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <gst/gst.h>
#include "gsttextoverlay.h"
/*#include "gsttexttestsrc.h"*/
/*#include "gstsubparse.h"*/
/*#include "SDL_blit.h"*/

static GstElementDetails textoverlay_details = {
    "Text Overlay",
    "Filter/Editor/Video",
    "Adds text strings on top of a video buffer",
    "Gustavo J. A. M. Carneiro <gjc@inescporto.pt>"
};

enum {
    ARG_0,
    ARG_TEXT, 
    ARG_VALIGN, 
    ARG_HALIGN, 
    ARG_X0, 
    ARG_Y0, 
    ARG_FONT_DESC, 
};


static GstStaticPadTemplate textoverlay_src_template_factory =
GST_STATIC_PAD_TEMPLATE (
    "src",
    GST_PAD_SRC,
    GST_PAD_ALWAYS,
    GST_STATIC_CAPS ("video/x-raw-yuv, "
      "format = (fourcc) I420, "
      "width = (int) [ 1, MAX ], "
      "height = (int) [ 1, MAX ]")
);

static GstStaticPadTemplate video_sink_template_factory =
GST_STATIC_PAD_TEMPLATE (
    "video_sink",
    GST_PAD_SINK,
    GST_PAD_ALWAYS,
    GST_STATIC_CAPS ("video/x-raw-yuv, "
      "format = (fourcc) I420, "
      "width = (int) [ 1, MAX ], "
      "height = (int) [ 1, MAX ]")
);

static GstStaticPadTemplate text_sink_template_factory =
GST_STATIC_PAD_TEMPLATE (
    "text_sink",
    GST_PAD_SINK,
    GST_PAD_ALWAYS,
    GST_STATIC_CAPS ("text/x-pango-markup; text/plain")
);

static void                  gst_textoverlay_base_init (gpointer g_class);
static void                  gst_textoverlay_class_init(GstTextOverlayClass *klass);
static void                  gst_textoverlay_init(GstTextOverlay      *overlay);
static void                  gst_textoverlay_set_property(GObject             *object, 
							   guint                prop_id, 
							   const GValue        *value, 
							   GParamSpec          *pspec);
static void                  gst_textoverlay_get_property(GObject             *object, 
							   guint                prop_id, 
							   GValue              *value, 
							   GParamSpec          *pspec);
static GstElementStateReturn gst_textoverlay_change_state(GstElement          *element);
static void                  gst_textoverlay_finalize(GObject             *object);


static GstElementClass *parent_class = NULL;
/*static guint gst_textoverlay_signals[LAST_SIGNAL] = { 0 }; */


GType
gst_textoverlay_get_type(void)
{
    static GType textoverlay_type = 0;

    if (!textoverlay_type) {
	static const GTypeInfo textoverlay_info = {
	    sizeof(GstTextOverlayClass), 
	    gst_textoverlay_base_init,
	    NULL,
	    (GClassInitFunc)gst_textoverlay_class_init,
	    NULL,
	    NULL,
	    sizeof(GstTextOverlay),
	    0,
	    (GInstanceInitFunc)gst_textoverlay_init,
	};
	textoverlay_type = g_type_register_static(GST_TYPE_ELEMENT, "GstTextOverlay", 
						  &textoverlay_info, 0);
    }
    return textoverlay_type;
}

static void
gst_textoverlay_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 (&textoverlay_src_template_factory));
    gst_element_class_add_pad_template (element_class,
	gst_static_pad_template_get (&video_sink_template_factory));
    gst_element_class_add_pad_template (element_class,
	gst_static_pad_template_get (&text_sink_template_factory));

    gst_element_class_set_details (element_class, &textoverlay_details);
}

static void
gst_textoverlay_class_init(GstTextOverlayClass *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_textoverlay_finalize;
    gobject_class->set_property = gst_textoverlay_set_property;
    gobject_class->get_property = gst_textoverlay_get_property;

    gstelement_class->change_state = gst_textoverlay_change_state;
    klass->pango_context = pango_ft2_get_context(72, 72);
    g_object_class_install_property(G_OBJECT_CLASS(klass), ARG_TEXT, 
				    g_param_spec_string("text", "text", 
							"Text to be display,"
							" in pango markup format.", 
							"", G_PARAM_WRITABLE));
    g_object_class_install_property(G_OBJECT_CLASS(klass), ARG_VALIGN, 
				    g_param_spec_string("valign", "vertical alignment", 
							"Vertical alignment of the text. "
							"Can be either 'baseline', 'bottom', or 'top'", 
							"baseline", G_PARAM_WRITABLE));
    g_object_class_install_property(G_OBJECT_CLASS(klass), ARG_HALIGN, 
				    g_param_spec_string("halign", "horizontal alignment", 
							"Horizontal alignment of the text. "
							"Can be either 'left', 'right', or 'center'", 
							"center", G_PARAM_WRITABLE));
    g_object_class_install_property(G_OBJECT_CLASS(klass), ARG_X0, 
				    g_param_spec_int("x0", "X position", 
						     "Initial X position."
						     " Horizontal aligment takes this point"
						     " as reference.", 
						     G_MININT, G_MAXINT, 0, G_PARAM_WRITABLE));
    g_object_class_install_property(G_OBJECT_CLASS(klass), ARG_Y0, 
				    g_param_spec_int("y0", "Y position", 
						     "Initial Y position."
						     " Vertical aligment takes this point"
						     " as reference.", 
						     G_MININT, G_MAXINT, 0, G_PARAM_WRITABLE));
    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(GstTextOverlay *overlay, int width, int height)
{
    FT_Bitmap *bitmap = &overlay->bitmap;
    int        pitch = (width|3) + 1;
    int        size = pitch*height;

    /* no need to keep reallocating; just keep the maximum size so far */
    if (size <= overlay->bitmap_buffer_size) {
	bitmap->rows = height;
	bitmap->width = width;
	bitmap->pitch = pitch;
	memset(bitmap->buffer, 0, overlay->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);
    overlay->bitmap_buffer_size = size;
}

static void
render_text(GstTextOverlay *overlay)
{
    PangoRectangle ink_rect, logical_rect;

    pango_layout_get_pixel_extents(overlay->layout, &ink_rect, &logical_rect);
    resize_bitmap(overlay, ink_rect.width, ink_rect.height + ink_rect.y);
    pango_ft2_render_layout(&overlay->bitmap, overlay->layout, 0, 0);
    overlay->baseline_y = ink_rect.y;
}

/* static GstPadLinkReturn */
/* gst_textoverlay_text_sinkconnect (GstPad *pad, GstCaps *caps) */
/* { */
/*     return GST_PAD_LINK_DONE; */
/* } */


static GstPadLinkReturn
gst_textoverlay_video_sinkconnect(GstPad *pad, const GstCaps *caps)
{
    GstTextOverlay *overlay;
    GstStructure *structure;

    overlay = GST_TEXTOVERLAY(gst_pad_get_parent(pad));

    structure = gst_caps_get_structure (caps, 0);
    overlay->width = overlay->height = 0;
    gst_structure_get_int (structure, "width", &overlay->width);
    gst_structure_get_int (structure, "height", &overlay->height);

    return gst_pad_try_set_caps(overlay->srcpad, caps);
}


static void
gst_text_overlay_blit_yuv420(GstTextOverlay *overlay, FT_Bitmap *bitmap,
			     guchar *pixbuf, int x0, int y0)
{
    int y;			/* text bitmap coordinates */
    int x1, y1;			/* video buffer coordinates */
    int rowinc, bit_rowinc, uv_rowinc;
    guchar *p, *bitp, *u_p;
    int video_width = overlay->width, video_height = overlay->height;
    int bitmap_x0 = x0 < 1? -(x0 - 1) : 1; /* 1 pixel border */
    int bitmap_y0 = y0 < 1? -(y0 - 1) : 1; /* 1 pixel border */
    int bitmap_width = bitmap->width - bitmap_x0;
    int bitmap_height = bitmap->rows - bitmap_y0;
    int u_plane_size;
    int skip_y, skip_x;
    guchar v;

    if (x0 + bitmap_x0 + bitmap_width > video_width - 1) /* 1 pixel border */
	bitmap_width -= x0 + bitmap_x0 + bitmap_width - video_width + 1;
    if (y0 + bitmap_y0 + bitmap_height > video_height - 1) /* 1 pixel border */
	bitmap_height -= y0 + bitmap_y0 + bitmap_height - video_height + 1;

    rowinc = video_width - bitmap_width;
    uv_rowinc = video_width / 2 - bitmap_width / 2;
    bit_rowinc = bitmap->pitch - bitmap_width;
    u_plane_size = (video_width / 2)*(video_height / 2);

    y1 = y0 + bitmap_y0;
    x1 = x0 + bitmap_x0;
    p = pixbuf + video_width*y1 + x1;
    bitp = bitmap->buffer + bitmap->pitch*bitmap_y0 + bitmap_x0;
    for (y = bitmap_y0; y < bitmap_height; y++){
      int n;
      for(n=bitmap_width; n>0; --n){
	v = *bitp;
	if (v) {
	  p[-1] = CLAMP(p[-1] - v, 0, 255);
	  p[ 1] = CLAMP(p[ 1] - v, 0, 255);
	  p[-video_width] = CLAMP(p[-video_width] - v, 0, 255);
	  p[ video_width] = CLAMP(p[ video_width] - v, 0, 255);
	}
	p++;
	bitp++;
      }
      p += rowinc;
      bitp += bit_rowinc;
    }

    y = bitmap_y0;
    y1 = y0 + bitmap_y0;
    x1 = x0 + bitmap_x0;
    bitp = bitmap->buffer + bitmap->pitch*bitmap_y0 + bitmap_x0;
    p = pixbuf + video_width*y1 + x1;
    u_p = pixbuf + video_width*video_height + (video_width >> 1)*(y1 >> 1) + (x1 >> 1);
    skip_y = 0;
    skip_x = 0;

    for ( ; y < bitmap_height; y++){
      int n;
      x1 = x0 + bitmap_x0;
      skip_x = 0;
      for(n = bitmap_width; n>0; --n){
	v = *bitp;
	if (v) {
	  *p = v;
	  if (!skip_y) {
	    u_p[0] = u_p[u_plane_size] = 0x80;
	  }
	}
	if (!skip_y) {
	  skip_x = !skip_x;
	  if (!skip_x) u_p++;
	}
	p++;
	bitp++;
      }
      /*if (!skip_x && !skip_y) u_p--; */
      p += rowinc;
      bitp += bit_rowinc;
      skip_y = !skip_y;
      u_p += skip_y? uv_rowinc : 0;
    }
}


static void
gst_textoverlay_video_chain(GstPad *pad, GstData *_data)
{
    GstBuffer *buf = GST_BUFFER (_data);
    GstTextOverlay *overlay;
    guchar         *pixbuf;
    gint            x0, y0;

    g_return_if_fail(pad != NULL);
    g_return_if_fail(GST_IS_PAD(pad));
    g_return_if_fail(buf != NULL);
    overlay = GST_TEXTOVERLAY(gst_pad_get_parent(pad));
    g_return_if_fail(overlay != NULL);
    g_return_if_fail(GST_IS_TEXTOVERLAY(overlay));

    pixbuf = GST_BUFFER_DATA(buf);

    x0 = overlay->x0;
    y0 = overlay->y0;
    switch (overlay->valign)
    {
    case GST_TEXT_OVERLAY_VALIGN_BOTTOM:
	y0 += overlay->bitmap.rows;
	break;
    case GST_TEXT_OVERLAY_VALIGN_BASELINE:
	y0 -= (overlay->bitmap.rows - overlay->baseline_y);
	break;
    case GST_TEXT_OVERLAY_VALIGN_TOP:
	break;
    }

    switch (overlay->halign)
    {
    case GST_TEXT_OVERLAY_HALIGN_LEFT:
	break;
    case GST_TEXT_OVERLAY_HALIGN_RIGHT:
	x0 -= overlay->bitmap.width;
	break;
    case GST_TEXT_OVERLAY_HALIGN_CENTER:
	x0 -= overlay->bitmap.width / 2;
	break;
    }

    if (overlay->bitmap.buffer)
	gst_text_overlay_blit_yuv420(overlay, &overlay->bitmap, pixbuf, x0, y0);

    gst_pad_push(overlay->srcpad, GST_DATA (buf));
}

#define PAST_END(buffer, time) \
  (GST_BUFFER_TIMESTAMP (buffer) != GST_CLOCK_TIME_NONE && \
   GST_BUFFER_DURATION (buffer) != GST_CLOCK_TIME_NONE && \
   GST_BUFFER_TIMESTAMP (buffer) + GST_BUFFER_DURATION (buffer) \
     < (time))

static void
gst_textoverlay_loop(GstElement *element)
{
    GstTextOverlay *overlay;
    GstBuffer      *video_frame;
    guint64         now;

    g_return_if_fail(element != NULL);
    g_return_if_fail(GST_IS_TEXTOVERLAY(element));
    overlay = GST_TEXTOVERLAY(element);

    video_frame = GST_BUFFER (gst_pad_pull(overlay->video_sinkpad));
    now = GST_BUFFER_TIMESTAMP(video_frame);

    /*
     * This state machine has a bug that can't be resolved easily.
     * (Needs a more complicated state machine.)  Basically, if the
     * text that came from a buffer from the sink pad is being
     * displayed, and the default text is changed by set_parameter,
     * we'll incorrectly display the default text.
     *
     * Otherwise, this is a pretty decent state machine that handles
     * buffer timestamps and durations correctly.  (I think)
     */

    while (overlay->next_buffer == NULL){
      GST_DEBUG("attempting to pull a buffer");

      /* read all text buffers until we get one "in the future" */
      if(!GST_PAD_IS_USABLE(overlay->text_sinkpad)){
        break;
      }
      overlay->next_buffer = GST_BUFFER (gst_pad_pull(overlay->text_sinkpad));
      if (!overlay->next_buffer)
	break;

      if (PAST_END(overlay->next_buffer, now)){
	gst_buffer_unref(overlay->next_buffer);
	overlay->next_buffer = NULL;
      }
    }

    if (overlay->next_buffer && 
	(GST_BUFFER_TIMESTAMP(overlay->next_buffer) <= now ||
        GST_BUFFER_TIMESTAMP(overlay->next_buffer) == GST_CLOCK_TIME_NONE)){
      GST_DEBUG("using new buffer");

      if (overlay->current_buffer){
	gst_buffer_unref (overlay->current_buffer);
      }
      overlay->current_buffer = overlay->next_buffer;
      overlay->next_buffer = NULL;

      GST_DEBUG ( "rendering '%*s'", 
	  GST_BUFFER_SIZE(overlay->current_buffer),
	  GST_BUFFER_DATA(overlay->current_buffer));
      pango_layout_set_markup(overlay->layout,
	  GST_BUFFER_DATA(overlay->current_buffer),
	  GST_BUFFER_SIZE(overlay->current_buffer));
      render_text(overlay);
      overlay->need_render = FALSE;
    }

    if (overlay->current_buffer && PAST_END(overlay->current_buffer, now)){
      GST_DEBUG("dropping old buffer");

      gst_buffer_unref(overlay->current_buffer);
      overlay->current_buffer = NULL;

      overlay->need_render = TRUE;
    }

    if(overlay->need_render){
      GST_DEBUG ( "rendering '%s'", overlay->default_text);
      pango_layout_set_markup(overlay->layout,
	  overlay->default_text, strlen(overlay->default_text));
      render_text(overlay);

      overlay->need_render = FALSE;
    }

    gst_textoverlay_video_chain(overlay->srcpad, GST_DATA (video_frame));
}


static GstElementStateReturn
gst_textoverlay_change_state(GstElement *element)
{
    GstTextOverlay *overlay;

    overlay = GST_TEXTOVERLAY(element);

    switch (GST_STATE_TRANSITION(element))
    {
    case GST_STATE_PAUSED_TO_PLAYING:
	break;
    case GST_STATE_PLAYING_TO_PAUSED:
	break;
    case GST_STATE_PAUSED_TO_READY:
	break;
    }

    parent_class->change_state(element);

    return GST_STATE_SUCCESS;
}

static void
gst_textoverlay_finalize(GObject *object)
{
    GstTextOverlay *overlay = GST_TEXTOVERLAY(object);

    if (overlay->layout) {
	g_object_unref(overlay->layout);
	overlay->layout = NULL;
    }
    if (overlay->bitmap.buffer) {
	g_free(overlay->bitmap.buffer);
	overlay->bitmap.buffer = NULL;
    }

    G_OBJECT_CLASS(parent_class)->finalize(object);
}

static void
gst_textoverlay_init(GstTextOverlay *overlay)
{
    /* video sink */
    overlay->video_sinkpad = gst_pad_new_from_template(
	gst_static_pad_template_get (&video_sink_template_factory), "video_sink");
/*     gst_pad_set_chain_function(overlay->video_sinkpad, gst_textoverlay_video_chain); */
    gst_pad_set_link_function(overlay->video_sinkpad, gst_textoverlay_video_sinkconnect);
    gst_element_add_pad(GST_ELEMENT(overlay), overlay->video_sinkpad);

    /* text sink */
    overlay->text_sinkpad = gst_pad_new_from_template(
	gst_static_pad_template_get (&text_sink_template_factory), "text_sink");
/*     gst_pad_set_link_function(overlay->text_sinkpad, gst_textoverlay_text_sinkconnect); */
    gst_element_add_pad(GST_ELEMENT(overlay), overlay->text_sinkpad);

    /* (video) source */
    overlay->srcpad = gst_pad_new_from_template(
	gst_static_pad_template_get (&textoverlay_src_template_factory), "src");
    gst_element_add_pad(GST_ELEMENT(overlay), overlay->srcpad);

    overlay->layout = pango_layout_new(GST_TEXTOVERLAY_GET_CLASS(overlay)->pango_context);
    memset(&overlay->bitmap, 0, sizeof(overlay->bitmap));

    overlay->halign = GST_TEXT_OVERLAY_HALIGN_CENTER;
    overlay->valign = GST_TEXT_OVERLAY_VALIGN_BASELINE;
    overlay->x0 = overlay->y0 = 0;

    overlay->default_text = g_strdup("");
    overlay->need_render = TRUE;

    gst_element_set_loop_function(GST_ELEMENT(overlay), gst_textoverlay_loop);
}


static void
gst_textoverlay_set_property(GObject *object, guint prop_id, const GValue *value, GParamSpec *pspec)
{
    GstTextOverlay *overlay;

    /* it's not null if we got it, but it might not be ours */
    g_return_if_fail(GST_IS_TEXTOVERLAY(object));
    overlay = GST_TEXTOVERLAY(object);

    switch (prop_id)
    {

    case ARG_TEXT:
        if(overlay->default_text){
	  g_free(overlay->default_text);
	}
        overlay->default_text = g_strdup(g_value_get_string(value));
	overlay->need_render = TRUE;
	break;

    case ARG_VALIGN:
	if (strcasecmp(g_value_get_string(value), "baseline") == 0)
	    overlay->valign = GST_TEXT_OVERLAY_VALIGN_BASELINE;
	else if (strcasecmp(g_value_get_string(value), "bottom") == 0)
	    overlay->valign = GST_TEXT_OVERLAY_VALIGN_BOTTOM;
	else if (strcasecmp(g_value_get_string(value), "top") == 0)
	    overlay->valign = GST_TEXT_OVERLAY_VALIGN_TOP;
	else
	    g_warning("Invalid 'valign' property value: %s", 
		      g_value_get_string(value));
	break;

    case ARG_HALIGN:
	if (strcasecmp(g_value_get_string(value), "left") == 0)
	    overlay->halign = GST_TEXT_OVERLAY_HALIGN_LEFT;
	else if (strcasecmp(g_value_get_string(value), "right") == 0)
	    overlay->halign = GST_TEXT_OVERLAY_HALIGN_RIGHT;
	else if (strcasecmp(g_value_get_string(value), "center") == 0)
	    overlay->halign = GST_TEXT_OVERLAY_HALIGN_CENTER;
	else
	    g_warning("Invalid 'halign' property value: %s", 
		      g_value_get_string(value));
	break;

    case ARG_X0:
	overlay->x0 = g_value_get_int(value);
	break;

    case ARG_Y0:
	overlay->y0 = g_value_get_int(value);
	break;

    case ARG_FONT_DESC:
    {
	PangoFontDescription *desc;
	desc = pango_font_description_from_string(g_value_get_string(value));
	if (desc) {
	    g_message("font description set: %s", g_value_get_string(value));
	    pango_layout_set_font_description(overlay->layout, desc);
	    pango_font_description_free(desc);
	    render_text(overlay);
	} else
	    g_warning("font description parse failed: %s", g_value_get_string(value));
	break;
    }

    default:
	break;
    }
}

static void
gst_textoverlay_get_property(GObject *object, guint prop_id, GValue *value, GParamSpec *pspec)
{
    GstTextOverlay *overlay;

    /* it's not null if we got it, but it might not be ours */
    g_return_if_fail(GST_IS_TEXTOVERLAY(object));
    overlay = GST_TEXTOVERLAY(object);

    switch (prop_id) {
    default:
	G_OBJECT_WARN_INVALID_PROPERTY_ID(object, prop_id, pspec);
	break;
    }
}

static gboolean
plugin_init(GstPlugin *plugin)
{
    if (!gst_element_register (plugin, "textoverlay", GST_RANK_PRIMARY, GST_TYPE_TEXTOVERLAY))
	return FALSE;

    /*texttestsrc_plugin_init(module, plugin);*/
    /*subparse_plugin_init(module, plugin);*/
    return TRUE;
}

GST_PLUGIN_DEFINE (
    GST_VERSION_MAJOR,
    GST_VERSION_MINOR,
    "textoverlay",
    "Text overlay",
    plugin_init,
    VERSION,
    "GPL",
    GST_PACKAGE,
    GST_ORIGIN)