2 * Copyright (C) <1999> Erik Walthinsen <omega@cse.ogi.edu>
3 * Copyright (C) <2003> David Schleef <ds@schleef.org>
4 * Copyright (C) <2009> Young-Ho Cha <ganadist@gmail.com>
6 * This library is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Library General Public
8 * License as published by the Free Software Foundation; either
9 * version 2 of the License, or (at your option) any later version.
11 * This library is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Library General Public License for more details.
16 * You should have received a copy of the GNU Library General Public
17 * License along with this library; if not, write to the
18 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
19 * Boston, MA 02111-1307, USA.
24 * SECTION:element-textrender
25 * @see_also: #GstTextOverlay
27 * This plugin renders text received on the text sink pad to a video
28 * buffer (retaining the alpha channel), so it can later be overlayed
29 * on top of video streams using other elements.
31 * The text can contain newline characters. (FIXME: What about text
32 * wrapping? It does not make sense in this context)
35 * <title>Example launch lines</title>
37 * gst-launch -v filesrc location=subtitles.srt ! subparse ! textrender ! xvimagesink
47 #include <gst/video/video.h>
49 #include "gsttextrender.h"
52 #if G_BYTE_ORDER == G_LITTLE_ENDIAN
53 # define CAIRO_ARGB_A 3
54 # define CAIRO_ARGB_R 2
55 # define CAIRO_ARGB_G 1
56 # define CAIRO_ARGB_B 0
58 # define CAIRO_ARGB_A 0
59 # define CAIRO_ARGB_R 1
60 # define CAIRO_ARGB_G 2
61 # define CAIRO_ARGB_B 3
64 GST_DEBUG_CATEGORY_EXTERN (pango_debug);
65 #define GST_CAT_DEFAULT pango_debug
67 #define MINIMUM_OUTLINE_OFFSET 1.0
69 #define DEFAULT_PROP_VALIGNMENT GST_TEXT_RENDER_VALIGN_BASELINE
70 #define DEFAULT_PROP_HALIGNMENT GST_TEXT_RENDER_HALIGN_CENTER
71 #define DEFAULT_PROP_LINE_ALIGNMENT GST_TEXT_RENDER_LINE_ALIGN_CENTER
72 #define DEFAULT_PROP_XPAD 25
73 #define DEFAULT_PROP_YPAD 25
75 #define DEFAULT_RENDER_WIDTH 720
76 #define DEFAULT_RENDER_HEIGHT 576
90 static GstStaticPadTemplate src_template_factory =
91 GST_STATIC_PAD_TEMPLATE ("src",
94 GST_STATIC_CAPS (GST_VIDEO_CAPS_YUV ("AYUV") ";" GST_VIDEO_CAPS_ARGB)
97 static GstStaticPadTemplate sink_template_factory =
98 GST_STATIC_PAD_TEMPLATE ("sink",
101 GST_STATIC_CAPS ("text/x-pango-markup; text/plain")
104 #define GST_TYPE_TEXT_RENDER_VALIGN (gst_text_render_valign_get_type())
106 gst_text_render_valign_get_type (void)
108 static GType text_render_valign_type = 0;
109 static const GEnumValue text_render_valign[] = {
110 {GST_TEXT_RENDER_VALIGN_BASELINE, "baseline", "baseline"},
111 {GST_TEXT_RENDER_VALIGN_BOTTOM, "bottom", "bottom"},
112 {GST_TEXT_RENDER_VALIGN_TOP, "top", "top"},
116 if (!text_render_valign_type) {
117 text_render_valign_type =
118 g_enum_register_static ("GstTextRenderVAlign", text_render_valign);
120 return text_render_valign_type;
123 #define GST_TYPE_TEXT_RENDER_HALIGN (gst_text_render_halign_get_type())
125 gst_text_render_halign_get_type (void)
127 static GType text_render_halign_type = 0;
128 static const GEnumValue text_render_halign[] = {
129 {GST_TEXT_RENDER_HALIGN_LEFT, "left", "left"},
130 {GST_TEXT_RENDER_HALIGN_CENTER, "center", "center"},
131 {GST_TEXT_RENDER_HALIGN_RIGHT, "right", "right"},
135 if (!text_render_halign_type) {
136 text_render_halign_type =
137 g_enum_register_static ("GstTextRenderHAlign", text_render_halign);
139 return text_render_halign_type;
142 #define GST_TYPE_TEXT_RENDER_LINE_ALIGN (gst_text_render_line_align_get_type())
144 gst_text_render_line_align_get_type (void)
146 static GType text_render_line_align_type = 0;
147 static const GEnumValue text_render_line_align[] = {
148 {GST_TEXT_RENDER_LINE_ALIGN_LEFT, "left", "left"},
149 {GST_TEXT_RENDER_LINE_ALIGN_CENTER, "center", "center"},
150 {GST_TEXT_RENDER_LINE_ALIGN_RIGHT, "right", "right"},
154 if (!text_render_line_align_type) {
155 text_render_line_align_type =
156 g_enum_register_static ("GstTextRenderLineAlign",
157 text_render_line_align);
159 return text_render_line_align_type;
162 static void gst_text_render_adjust_values_with_fontdesc (GstTextRender *
163 render, PangoFontDescription * desc);
165 GST_BOILERPLATE (GstTextRender, gst_text_render, GstElement, GST_TYPE_ELEMENT);
167 static void gst_text_render_finalize (GObject * object);
168 static void gst_text_render_set_property (GObject * object,
169 guint prop_id, const GValue * value, GParamSpec * pspec);
170 static void gst_text_render_get_property (GObject * object,
171 guint prop_id, GValue * value, GParamSpec * pspec);
174 gst_text_render_base_init (gpointer g_class)
176 GstElementClass *element_class = GST_ELEMENT_CLASS (g_class);
178 gst_element_class_add_pad_template (element_class,
179 gst_static_pad_template_get (&src_template_factory));
180 gst_element_class_add_pad_template (element_class,
181 gst_static_pad_template_get (&sink_template_factory));
183 gst_element_class_set_details_simple (element_class, "Text renderer",
184 "Filter/Editor/Video",
185 "Renders a text string to an image bitmap",
186 "David Schleef <ds@schleef.org>, "
187 "Ronald S. Bultje <rbultje@ronald.bitfreak.net>");
191 gst_text_render_class_init (GstTextRenderClass * klass)
193 GObjectClass *gobject_class;
194 GstElementClass *gstelement_class;
195 PangoFontMap *fontmap;
197 gobject_class = (GObjectClass *) klass;
198 gstelement_class = (GstElementClass *) klass;
200 parent_class = g_type_class_peek_parent (klass);
202 gobject_class->finalize = gst_text_render_finalize;
203 gobject_class->set_property = gst_text_render_set_property;
204 gobject_class->get_property = gst_text_render_get_property;
206 fontmap = pango_cairo_font_map_get_default ();
207 klass->pango_context =
208 pango_cairo_font_map_create_context (PANGO_CAIRO_FONT_MAP (fontmap));
209 g_object_class_install_property (G_OBJECT_CLASS (klass), PROP_FONT_DESC,
210 g_param_spec_string ("font-desc", "font description",
211 "Pango font description of font "
212 "to be used for rendering. "
213 "See documentation of "
214 "pango_font_description_from_string"
215 " for syntax.", "", G_PARAM_WRITABLE | G_PARAM_STATIC_STRINGS));
216 g_object_class_install_property (G_OBJECT_CLASS (klass), PROP_VALIGNMENT,
217 g_param_spec_enum ("valignment", "vertical alignment",
218 "Vertical alignment of the text", GST_TYPE_TEXT_RENDER_VALIGN,
219 DEFAULT_PROP_VALIGNMENT, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
220 g_object_class_install_property (G_OBJECT_CLASS (klass), PROP_HALIGNMENT,
221 g_param_spec_enum ("halignment", "horizontal alignment",
222 "Horizontal alignment of the text", GST_TYPE_TEXT_RENDER_HALIGN,
223 DEFAULT_PROP_HALIGNMENT, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
224 g_object_class_install_property (G_OBJECT_CLASS (klass), PROP_XPAD,
225 g_param_spec_int ("xpad", "horizontal paddding",
226 "Horizontal paddding when using left/right alignment", 0, G_MAXINT,
227 DEFAULT_PROP_XPAD, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
228 g_object_class_install_property (G_OBJECT_CLASS (klass), PROP_YPAD,
229 g_param_spec_int ("ypad", "vertical padding",
230 "Vertical padding when using top/bottom alignment", 0, G_MAXINT,
231 DEFAULT_PROP_YPAD, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
232 g_object_class_install_property (G_OBJECT_CLASS (klass), PROP_LINE_ALIGNMENT,
233 g_param_spec_enum ("line-alignment", "line alignment",
234 "Alignment of text lines relative to each other.",
235 GST_TYPE_TEXT_RENDER_LINE_ALIGN, DEFAULT_PROP_LINE_ALIGNMENT,
236 G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
240 gst_text_render_adjust_values_with_fontdesc (GstTextRender * render,
241 PangoFontDescription * desc)
243 gint font_size = pango_font_description_get_size (desc) / PANGO_SCALE;
245 render->shadow_offset = (double) (font_size) / 13.0;
246 render->outline_offset = (double) (font_size) / 15.0;
247 if (render->outline_offset < MINIMUM_OUTLINE_OFFSET)
248 render->outline_offset = MINIMUM_OUTLINE_OFFSET;
252 gst_text_render_render_pangocairo (GstTextRender * render)
255 cairo_surface_t *surface;
257 cairo_surface_t *surface_shadow;
258 PangoRectangle ink_rect, logical_rect;
261 pango_layout_get_pixel_extents (render->layout, &ink_rect, &logical_rect);
263 width = logical_rect.width + render->shadow_offset;
264 height = logical_rect.height + logical_rect.y + render->shadow_offset;
266 surface_shadow = cairo_image_surface_create (CAIRO_FORMAT_A8, width, height);
267 cr_shadow = cairo_create (surface_shadow);
269 /* clear shadow surface */
270 cairo_set_operator (cr_shadow, CAIRO_OPERATOR_CLEAR);
271 cairo_paint (cr_shadow);
272 cairo_set_operator (cr_shadow, CAIRO_OPERATOR_OVER);
274 /* draw shadow text */
275 cairo_save (cr_shadow);
276 cairo_set_source_rgba (cr_shadow, 0.0, 0.0, 0.0, 0.5);
277 cairo_translate (cr_shadow, render->shadow_offset, render->shadow_offset);
278 pango_cairo_show_layout (cr_shadow, render->layout);
279 cairo_restore (cr_shadow);
281 /* draw outline text */
282 cairo_save (cr_shadow);
283 cairo_set_source_rgb (cr_shadow, 0.0, 0.0, 0.0);
284 cairo_set_line_width (cr_shadow, render->outline_offset);
285 pango_cairo_layout_path (cr_shadow, render->layout);
286 cairo_stroke (cr_shadow);
287 cairo_restore (cr_shadow);
289 cairo_destroy (cr_shadow);
291 render->text_image = g_realloc (render->text_image, 4 * width * height);
293 surface = cairo_image_surface_create_for_data (render->text_image,
294 CAIRO_FORMAT_ARGB32, width, height, width * 4);
295 cr = cairo_create (surface);
296 cairo_set_operator (cr, CAIRO_OPERATOR_CLEAR);
298 cairo_set_operator (cr, CAIRO_OPERATOR_OVER);
300 /* set default color */
301 cairo_set_source_rgb (cr, 1.0, 1.0, 1.0);
305 pango_cairo_show_layout (cr, render->layout);
308 /* composite shadow with offset */
309 cairo_set_operator (cr, CAIRO_OPERATOR_DEST_OVER);
310 cairo_set_source_surface (cr, surface_shadow, 0.0, 0.0);
314 cairo_surface_destroy (surface_shadow);
315 cairo_surface_destroy (surface);
316 render->image_width = width;
317 render->image_height = height;
321 gst_text_render_check_argb (GstTextRender * render)
324 peer_caps = gst_pad_get_allowed_caps (render->srcpad);
325 if (G_LIKELY (peer_caps)) {
328 n = gst_caps_get_size (peer_caps);
329 GST_DEBUG_OBJECT (render, "peer allowed caps (%u structure(s)) are %"
330 GST_PTR_FORMAT, n, peer_caps);
332 /* Check if AYUV or ARGB is first */
333 for (i = 0; i < n; i++) {
334 GstStructure *s = gst_caps_get_structure (peer_caps, i);
335 if (gst_structure_has_name (s, "video/x-raw-rgb") &&
336 gst_structure_has_field (s, "alpha_mask")) {
337 render->use_ARGB = TRUE;
339 } else if (gst_structure_has_name (s, "video/x-raw-yuv")) {
341 if (gst_structure_get_fourcc (s, "format", &fourcc) &&
342 fourcc == GST_MAKE_FOURCC ('A', 'Y', 'U', 'V')) {
343 render->use_ARGB = FALSE;
348 gst_caps_unref (peer_caps);
353 gst_text_render_setcaps (GstPad * pad, GstCaps * caps)
355 GstTextRender *render = GST_TEXT_RENDER (gst_pad_get_parent (pad));
356 GstStructure *structure;
357 gboolean ret = FALSE;
358 gint width = 0, height = 0;
360 structure = gst_caps_get_structure (caps, 0);
361 gst_structure_get_int (structure, "width", &width);
362 gst_structure_get_int (structure, "height", &height);
364 GST_DEBUG ("Got caps %" GST_PTR_FORMAT, caps);
366 if (width >= render->image_width && height >= render->image_height) {
367 render->width = width;
368 render->height = height;
372 gst_text_render_check_argb (render);
374 gst_object_unref (render);
379 gst_text_render_fixate_caps (GstPad * pad, GstCaps * caps)
381 GstTextRender *render = GST_TEXT_RENDER (gst_pad_get_parent (pad));
382 GstStructure *s = gst_caps_get_structure (caps, 0);
384 GST_DEBUG ("Fixating caps %" GST_PTR_FORMAT, caps);
385 gst_structure_fixate_field_nearest_int (s, "width", render->image_width);
386 gst_structure_fixate_field_nearest_int (s, "height", render->image_height);
387 GST_DEBUG ("Fixated to %" GST_PTR_FORMAT, caps);
389 gst_object_unref (render);
393 gst_text_renderer_image_to_ayuv (GstTextRender * render, guchar * pixbuf,
394 int xpos, int ypos, int stride)
396 int y; /* text bitmap coordinates */
401 width = render->image_width;
402 height = render->image_height;
403 bitp = render->text_image;
405 for (y = 0; y < height; y++) {
407 p = pixbuf + (ypos + y) * stride + xpos * 4;
408 for (n = 0; n < width; n++) {
409 b = bitp[CAIRO_ARGB_B];
410 g = bitp[CAIRO_ARGB_G];
411 r = bitp[CAIRO_ARGB_R];
412 a = bitp[CAIRO_ARGB_A];
416 *p++ = CLAMP ((int) (((19595 * r) >> 16) + ((38470 * g) >> 16) +
417 ((7471 * b) >> 16)), 0, 255);
418 *p++ = CLAMP ((int) (-((11059 * r) >> 16) - ((21709 * g) >> 16) +
419 ((32768 * b) >> 16) + 128), 0, 255);
420 *p++ = CLAMP ((int) (((32768 * r) >> 16) - ((27439 * g) >> 16) -
421 ((5329 * b) >> 16) + 128), 0, 255);
427 gst_text_renderer_image_to_argb (GstTextRender * render, guchar * pixbuf,
428 int xpos, int ypos, int stride)
434 width = render->image_width;
435 height = render->image_height;
436 bitp = render->text_image;
438 for (i = 0; i < height; i++) {
439 p = pixbuf + (ypos + i) * stride + xpos * 4;
440 for (j = 0; j < width; j++) {
441 p[0] = bitp[CAIRO_ARGB_A];
442 p[1] = bitp[CAIRO_ARGB_R];
443 p[2] = bitp[CAIRO_ARGB_G];
444 p[3] = bitp[CAIRO_ARGB_B];
453 gst_text_render_chain (GstPad * pad, GstBuffer * inbuf)
455 GstTextRender *render;
458 GstCaps *caps = NULL;
459 guint8 *data = GST_BUFFER_DATA (inbuf);
460 guint size = GST_BUFFER_SIZE (inbuf);
464 render = GST_TEXT_RENDER (gst_pad_get_parent (pad));
466 /* somehow pango barfs over "\0" buffers... */
468 (data[size - 1] == '\r' ||
469 data[size - 1] == '\n' || data[size - 1] == '\0')) {
474 GST_DEBUG ("rendering '%*s'", size, data);
475 pango_layout_set_markup (render->layout, (gchar *) data, size);
476 gst_text_render_render_pangocairo (render);
478 gst_text_render_check_argb (render);
480 if (!render->use_ARGB) {
482 gst_video_format_new_caps (GST_VIDEO_FORMAT_AYUV, render->width,
483 render->height, 1, 1, 1, 1);
486 gst_video_format_new_caps (GST_VIDEO_FORMAT_ARGB, render->width,
487 render->height, 1, 1, 1, 1);
490 if (!gst_pad_set_caps (render->srcpad, caps)) {
491 gst_caps_unref (caps);
492 GST_ELEMENT_ERROR (render, CORE, NEGOTIATION, (NULL), (NULL));
493 ret = GST_FLOW_ERROR;
497 GST_DEBUG ("Allocating buffer WxH = %dx%d", render->width, render->height);
499 gst_pad_alloc_buffer_and_set_caps (render->srcpad, GST_BUFFER_OFFSET_NONE,
500 render->width * render->height * 4, caps, &outbuf);
502 if (ret != GST_FLOW_OK)
505 gst_buffer_copy_metadata (outbuf, inbuf, GST_BUFFER_COPY_TIMESTAMPS);
506 data = GST_BUFFER_DATA (outbuf);
508 if (render->use_ARGB) {
509 memset (data, 0, render->width * render->height * 4);
511 for (n = 0; n < render->width * render->height; n++) {
512 data[n * 4] = data[n * 4 + 1] = 0;
513 data[n * 4 + 2] = data[n * 4 + 3] = 128;
517 switch (render->halign) {
518 case GST_TEXT_RENDER_HALIGN_LEFT:
521 case GST_TEXT_RENDER_HALIGN_CENTER:
522 xpos = (render->width - render->image_width) / 2;
524 case GST_TEXT_RENDER_HALIGN_RIGHT:
525 xpos = render->width - render->image_width - render->xpad;
531 switch (render->valign) {
532 case GST_TEXT_RENDER_VALIGN_BOTTOM:
533 ypos = render->height - render->image_height - render->ypad;
535 case GST_TEXT_RENDER_VALIGN_BASELINE:
536 ypos = render->height - (render->image_height + render->ypad);
538 case GST_TEXT_RENDER_VALIGN_TOP:
546 if (render->text_image) {
547 if (render->use_ARGB) {
548 gst_text_renderer_image_to_argb (render, data, xpos, ypos,
551 gst_text_renderer_image_to_ayuv (render, data, xpos, ypos,
556 ret = gst_pad_push (render->srcpad, outbuf);
560 gst_caps_unref (caps);
561 gst_buffer_unref (inbuf);
562 gst_object_unref (render);
567 gst_text_render_finalize (GObject * object)
569 GstTextRender *render = GST_TEXT_RENDER (object);
571 g_free (render->text_image);
574 g_object_unref (render->layout);
576 G_OBJECT_CLASS (parent_class)->finalize (object);
580 gst_text_render_init (GstTextRender * render, GstTextRenderClass * klass)
582 GstPadTemplate *template;
585 template = gst_static_pad_template_get (&sink_template_factory);
586 render->sinkpad = gst_pad_new_from_template (template, "sink");
587 gst_object_unref (template);
588 gst_pad_set_chain_function (render->sinkpad,
589 GST_DEBUG_FUNCPTR (gst_text_render_chain));
590 gst_element_add_pad (GST_ELEMENT (render), render->sinkpad);
593 template = gst_static_pad_template_get (&src_template_factory);
594 render->srcpad = gst_pad_new_from_template (template, "src");
595 gst_object_unref (template);
596 gst_pad_set_fixatecaps_function (render->srcpad,
597 GST_DEBUG_FUNCPTR (gst_text_render_fixate_caps));
598 gst_pad_set_setcaps_function (render->srcpad,
599 GST_DEBUG_FUNCPTR (gst_text_render_setcaps));
601 gst_element_add_pad (GST_ELEMENT (render), render->srcpad);
603 render->line_align = DEFAULT_PROP_LINE_ALIGNMENT;
605 pango_layout_new (GST_TEXT_RENDER_GET_CLASS (render)->pango_context);
606 pango_layout_set_alignment (render->layout,
607 (PangoAlignment) render->line_align);
609 render->halign = DEFAULT_PROP_HALIGNMENT;
610 render->valign = DEFAULT_PROP_VALIGNMENT;
611 render->xpad = DEFAULT_PROP_XPAD;
612 render->ypad = DEFAULT_PROP_YPAD;
614 render->width = DEFAULT_RENDER_WIDTH;
615 render->height = DEFAULT_RENDER_HEIGHT;
617 render->use_ARGB = FALSE;
621 gst_text_render_set_property (GObject * object, guint prop_id,
622 const GValue * value, GParamSpec * pspec)
624 GstTextRender *render = GST_TEXT_RENDER (object);
627 case PROP_VALIGNMENT:
628 render->valign = g_value_get_enum (value);
630 case PROP_HALIGNMENT:
631 render->halign = g_value_get_enum (value);
633 case PROP_LINE_ALIGNMENT:
634 render->line_align = g_value_get_enum (value);
635 pango_layout_set_alignment (render->layout,
636 (PangoAlignment) render->line_align);
639 render->xpad = g_value_get_int (value);
642 render->ypad = g_value_get_int (value);
646 PangoFontDescription *desc;
648 desc = pango_font_description_from_string (g_value_get_string (value));
650 GST_LOG ("font description set: %s", g_value_get_string (value));
651 GST_OBJECT_LOCK (render);
652 pango_layout_set_font_description (render->layout, desc);
653 gst_text_render_adjust_values_with_fontdesc (render, desc);
654 pango_font_description_free (desc);
655 gst_text_render_render_pangocairo (render);
656 GST_OBJECT_UNLOCK (render);
658 GST_WARNING ("font description parse failed: %s",
659 g_value_get_string (value));
670 gst_text_render_get_property (GObject * object, guint prop_id,
671 GValue * value, GParamSpec * pspec)
673 GstTextRender *render = GST_TEXT_RENDER (object);
676 case PROP_VALIGNMENT:
677 g_value_set_enum (value, render->valign);
679 case PROP_HALIGNMENT:
680 g_value_set_enum (value, render->halign);
682 case PROP_LINE_ALIGNMENT:
683 g_value_set_enum (value, render->line_align);
686 g_value_set_int (value, render->xpad);
689 g_value_set_int (value, render->ypad);
692 G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);