/* GStreamer * Copyright (C) <1999> Erik Walthinsen * Copyright (C) <2003> David Schleef * * 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 * * * * 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. * * * The text can contain newline characters. (FIXME: What about text * wrapping? It does not make sense in this context) * * * Example pipeline: * * gst-launch -v filesrc location=subtitles.srt ! subparse ! textrender ! xvimagesink * * * */ #ifdef HAVE_CONFIG_H #include #endif #include #include #include "gsttextrender.h" GST_DEBUG_CATEGORY_EXTERN (pango_debug); #define GST_CAT_DEFAULT pango_debug static GstElementDetails text_render_details = { "Text Render", "Filter/Editor/Video", "Renders a text string to an image bitmap", "David Schleef , " "Ronald S. Bultje " }; 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_stamp (outbuf, inbuf); 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) { /* sink */ render->sinkpad = gst_pad_new_from_template (gst_static_pad_template_get (&sink_template_factory), "sink"); gst_pad_set_chain_function (render->sinkpad, GST_DEBUG_FUNCPTR (gst_text_render_chain)); gst_element_add_pad (GST_ELEMENT (render), render->sinkpad); /* source */ render->srcpad = gst_pad_new_from_template (gst_static_pad_template_get (&src_template_factory), "src"); 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; } }