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 #define gst_text_render_parent_class parent_class
166 G_DEFINE_TYPE (GstTextRender, gst_text_render, GST_TYPE_ELEMENT);
168 static void gst_text_render_finalize (GObject * object);
169 static void gst_text_render_set_property (GObject * object,
170 guint prop_id, const GValue * value, GParamSpec * pspec);
171 static void gst_text_render_get_property (GObject * object,
172 guint prop_id, GValue * value, GParamSpec * pspec);
175 gst_text_render_class_init (GstTextRenderClass * klass)
177 GObjectClass *gobject_class;
178 GstElementClass *gstelement_class;
179 PangoFontMap *fontmap;
181 gobject_class = (GObjectClass *) klass;
182 gstelement_class = (GstElementClass *) klass;
184 parent_class = g_type_class_peek_parent (klass);
186 gobject_class->finalize = gst_text_render_finalize;
187 gobject_class->set_property = gst_text_render_set_property;
188 gobject_class->get_property = gst_text_render_get_property;
190 gst_element_class_add_pad_template (gstelement_class,
191 gst_static_pad_template_get (&src_template_factory));
192 gst_element_class_add_pad_template (gstelement_class,
193 gst_static_pad_template_get (&sink_template_factory));
195 gst_element_class_set_details_simple (gstelement_class, "Text renderer",
196 "Filter/Editor/Video",
197 "Renders a text string to an image bitmap",
198 "David Schleef <ds@schleef.org>, "
199 "GStreamer maintainers <gstreamer-devel@lists.sourceforge.net>");
201 fontmap = pango_cairo_font_map_get_default ();
202 klass->pango_context =
203 pango_cairo_font_map_create_context (PANGO_CAIRO_FONT_MAP (fontmap));
204 g_object_class_install_property (G_OBJECT_CLASS (klass), PROP_FONT_DESC,
205 g_param_spec_string ("font-desc", "font description",
206 "Pango font description of font "
207 "to be used for rendering. "
208 "See documentation of "
209 "pango_font_description_from_string"
210 " for syntax.", "", G_PARAM_WRITABLE | G_PARAM_STATIC_STRINGS));
211 g_object_class_install_property (G_OBJECT_CLASS (klass), PROP_VALIGNMENT,
212 g_param_spec_enum ("valignment", "vertical alignment",
213 "Vertical alignment of the text", GST_TYPE_TEXT_RENDER_VALIGN,
214 DEFAULT_PROP_VALIGNMENT, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
215 g_object_class_install_property (G_OBJECT_CLASS (klass), PROP_HALIGNMENT,
216 g_param_spec_enum ("halignment", "horizontal alignment",
217 "Horizontal alignment of the text", GST_TYPE_TEXT_RENDER_HALIGN,
218 DEFAULT_PROP_HALIGNMENT, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
219 g_object_class_install_property (G_OBJECT_CLASS (klass), PROP_XPAD,
220 g_param_spec_int ("xpad", "horizontal paddding",
221 "Horizontal paddding when using left/right alignment", 0, G_MAXINT,
222 DEFAULT_PROP_XPAD, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
223 g_object_class_install_property (G_OBJECT_CLASS (klass), PROP_YPAD,
224 g_param_spec_int ("ypad", "vertical padding",
225 "Vertical padding when using top/bottom alignment", 0, G_MAXINT,
226 DEFAULT_PROP_YPAD, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
227 g_object_class_install_property (G_OBJECT_CLASS (klass), PROP_LINE_ALIGNMENT,
228 g_param_spec_enum ("line-alignment", "line alignment",
229 "Alignment of text lines relative to each other.",
230 GST_TYPE_TEXT_RENDER_LINE_ALIGN, DEFAULT_PROP_LINE_ALIGNMENT,
231 G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
235 gst_text_render_adjust_values_with_fontdesc (GstTextRender * render,
236 PangoFontDescription * desc)
238 gint font_size = pango_font_description_get_size (desc) / PANGO_SCALE;
240 render->shadow_offset = (double) (font_size) / 13.0;
241 render->outline_offset = (double) (font_size) / 15.0;
242 if (render->outline_offset < MINIMUM_OUTLINE_OFFSET)
243 render->outline_offset = MINIMUM_OUTLINE_OFFSET;
247 gst_text_render_render_pangocairo (GstTextRender * render)
250 cairo_surface_t *surface;
252 cairo_surface_t *surface_shadow;
253 PangoRectangle ink_rect, logical_rect;
256 pango_layout_get_pixel_extents (render->layout, &ink_rect, &logical_rect);
258 width = logical_rect.width + render->shadow_offset;
259 height = logical_rect.height + logical_rect.y + render->shadow_offset;
261 surface_shadow = cairo_image_surface_create (CAIRO_FORMAT_A8, width, height);
262 cr_shadow = cairo_create (surface_shadow);
264 /* clear shadow surface */
265 cairo_set_operator (cr_shadow, CAIRO_OPERATOR_CLEAR);
266 cairo_paint (cr_shadow);
267 cairo_set_operator (cr_shadow, CAIRO_OPERATOR_OVER);
269 /* draw shadow text */
270 cairo_save (cr_shadow);
271 cairo_set_source_rgba (cr_shadow, 0.0, 0.0, 0.0, 0.5);
272 cairo_translate (cr_shadow, render->shadow_offset, render->shadow_offset);
273 pango_cairo_show_layout (cr_shadow, render->layout);
274 cairo_restore (cr_shadow);
276 /* draw outline text */
277 cairo_save (cr_shadow);
278 cairo_set_source_rgb (cr_shadow, 0.0, 0.0, 0.0);
279 cairo_set_line_width (cr_shadow, render->outline_offset);
280 pango_cairo_layout_path (cr_shadow, render->layout);
281 cairo_stroke (cr_shadow);
282 cairo_restore (cr_shadow);
284 cairo_destroy (cr_shadow);
286 render->text_image = g_realloc (render->text_image, 4 * width * height);
288 surface = cairo_image_surface_create_for_data (render->text_image,
289 CAIRO_FORMAT_ARGB32, width, height, width * 4);
290 cr = cairo_create (surface);
291 cairo_set_operator (cr, CAIRO_OPERATOR_CLEAR);
293 cairo_set_operator (cr, CAIRO_OPERATOR_OVER);
295 /* set default color */
296 cairo_set_source_rgb (cr, 1.0, 1.0, 1.0);
300 pango_cairo_show_layout (cr, render->layout);
303 /* composite shadow with offset */
304 cairo_set_operator (cr, CAIRO_OPERATOR_DEST_OVER);
305 cairo_set_source_surface (cr, surface_shadow, 0.0, 0.0);
309 cairo_surface_destroy (surface_shadow);
310 cairo_surface_destroy (surface);
311 render->image_width = width;
312 render->image_height = height;
316 gst_text_render_check_argb (GstTextRender * render)
319 peer_caps = gst_pad_get_allowed_caps (render->srcpad);
320 if (G_LIKELY (peer_caps)) {
323 n = gst_caps_get_size (peer_caps);
324 GST_DEBUG_OBJECT (render, "peer allowed caps (%u structure(s)) are %"
325 GST_PTR_FORMAT, n, peer_caps);
327 /* Check if AYUV or ARGB is first */
328 for (i = 0; i < n; i++) {
329 GstStructure *s = gst_caps_get_structure (peer_caps, i);
330 if (gst_structure_has_name (s, "video/x-raw-rgb") &&
331 gst_structure_has_field (s, "alpha_mask")) {
332 render->use_ARGB = TRUE;
334 } else if (gst_structure_has_name (s, "video/x-raw-yuv")) {
336 if (gst_structure_get_fourcc (s, "format", &fourcc) &&
337 fourcc == GST_MAKE_FOURCC ('A', 'Y', 'U', 'V')) {
338 render->use_ARGB = FALSE;
343 gst_caps_unref (peer_caps);
348 gst_text_render_src_setcaps (GstTextRender * render, GstCaps * caps)
350 GstStructure *structure;
352 gint width = 0, height = 0;
354 structure = gst_caps_get_structure (caps, 0);
355 gst_structure_get_int (structure, "width", &width);
356 gst_structure_get_int (structure, "height", &height);
358 GST_DEBUG_OBJECT (render, "Got caps %" GST_PTR_FORMAT, caps);
360 if (width >= render->image_width && height >= render->image_height) {
361 render->width = width;
362 render->height = height;
365 gst_text_render_check_argb (render);
367 ret = gst_pad_push_event (render->srcpad, gst_event_new_caps (caps));
373 gst_text_render_fixate_caps (GstPad * pad, GstCaps * caps)
375 GstTextRender *render = GST_TEXT_RENDER (gst_pad_get_parent (pad));
376 GstStructure *s = gst_caps_get_structure (caps, 0);
378 GST_DEBUG ("Fixating caps %" GST_PTR_FORMAT, caps);
379 gst_structure_fixate_field_nearest_int (s, "width", MAX (render->image_width,
380 DEFAULT_RENDER_WIDTH));
381 gst_structure_fixate_field_nearest_int (s, "height",
382 MAX (render->image_height + render->ypad, DEFAULT_RENDER_HEIGHT));
383 GST_DEBUG ("Fixated to %" GST_PTR_FORMAT, caps);
385 gst_object_unref (render);
388 #define CAIRO_UNPREMULTIPLY(a,r,g,b) G_STMT_START { \
389 b = (a > 0) ? MIN ((b * 255 + a / 2) / a, 255) : 0; \
390 g = (a > 0) ? MIN ((g * 255 + a / 2) / a, 255) : 0; \
391 r = (a > 0) ? MIN ((r * 255 + a / 2) / a, 255) : 0; \
395 gst_text_renderer_image_to_ayuv (GstTextRender * render, guchar * pixbuf,
396 int xpos, int ypos, int stride)
398 int y; /* text bitmap coordinates */
403 width = render->image_width;
404 height = render->image_height;
406 for (y = 0; y < height && ypos + y < render->height; y++) {
408 p = pixbuf + (ypos + y) * stride + xpos * 4;
409 bitp = render->text_image + y * width * 4;
410 for (n = 0; n < width && n < render->width; n++) {
411 b = bitp[CAIRO_ARGB_B];
412 g = bitp[CAIRO_ARGB_G];
413 r = bitp[CAIRO_ARGB_R];
414 a = bitp[CAIRO_ARGB_A];
417 /* Cairo uses pre-multiplied ARGB, unpremultiply it */
418 CAIRO_UNPREMULTIPLY (a, r, g, b);
421 *p++ = CLAMP ((int) (((19595 * r) >> 16) + ((38470 * g) >> 16) +
422 ((7471 * b) >> 16)), 0, 255);
423 *p++ = CLAMP ((int) (-((11059 * r) >> 16) - ((21709 * g) >> 16) +
424 ((32768 * b) >> 16) + 128), 0, 255);
425 *p++ = CLAMP ((int) (((32768 * r) >> 16) - ((27439 * g) >> 16) -
426 ((5329 * b) >> 16) + 128), 0, 255);
432 gst_text_renderer_image_to_argb (GstTextRender * render, guchar * pixbuf,
433 int xpos, int ypos, int stride)
439 width = render->image_width;
440 height = render->image_height;
442 for (i = 0; i < height && ypos + i < render->height; i++) {
443 p = pixbuf + (ypos + i) * stride + xpos * 4;
444 bitp = render->text_image + i * width * 4;
445 for (j = 0; j < width && j < render->width; j++) {
446 p[0] = bitp[CAIRO_ARGB_A];
447 p[1] = bitp[CAIRO_ARGB_R];
448 p[2] = bitp[CAIRO_ARGB_G];
449 p[3] = bitp[CAIRO_ARGB_B];
451 /* Cairo uses pre-multiplied ARGB, unpremultiply it */
452 CAIRO_UNPREMULTIPLY (p[0], p[1], p[2], p[3]);
461 gst_text_render_chain (GstPad * pad, GstBuffer * inbuf)
463 GstTextRender *render;
466 GstCaps *caps = NULL, *padcaps;
472 render = GST_TEXT_RENDER (gst_pad_get_parent (pad));
474 data = gst_buffer_map (inbuf, &size, NULL, GST_MAP_READ);
476 /* somehow pango barfs over "\0" buffers... */
478 (data[size - 1] == '\r' ||
479 data[size - 1] == '\n' || data[size - 1] == '\0')) {
484 GST_DEBUG ("rendering '%*s'", size, data);
485 pango_layout_set_markup (render->layout, (gchar *) data, size);
486 gst_text_render_render_pangocairo (render);
487 gst_buffer_unmap (inbuf, data, size);
489 gst_text_render_check_argb (render);
491 padcaps = gst_pad_get_caps (render->srcpad, NULL);
492 caps = gst_pad_peer_get_caps (render->srcpad, padcaps);
493 gst_caps_unref (padcaps);
495 if (!caps || gst_caps_is_empty (caps)) {
496 GST_ELEMENT_ERROR (render, CORE, NEGOTIATION, (NULL), (NULL));
497 ret = GST_FLOW_ERROR;
501 gst_caps_truncate (caps);
502 gst_pad_fixate_caps (render->srcpad, caps);
504 if (!gst_text_render_src_setcaps (render, caps)) {
505 GST_ELEMENT_ERROR (render, CORE, NEGOTIATION, (NULL), (NULL));
506 ret = GST_FLOW_ERROR;
510 GST_DEBUG ("Allocating buffer WxH = %dx%d", render->width, render->height);
511 outbuf = gst_buffer_new_and_alloc (render->width * render->height * 4);
513 gst_buffer_copy_into (outbuf, inbuf, GST_BUFFER_COPY_TIMESTAMPS, 0, -1);
514 data = gst_buffer_map (outbuf, &size, NULL, GST_MAP_WRITE);
516 if (render->use_ARGB) {
517 memset (data, 0, render->width * render->height * 4);
519 for (n = 0; n < render->width * render->height; n++) {
520 data[n * 4] = data[n * 4 + 1] = 0;
521 data[n * 4 + 2] = data[n * 4 + 3] = 128;
525 switch (render->halign) {
526 case GST_TEXT_RENDER_HALIGN_LEFT:
529 case GST_TEXT_RENDER_HALIGN_CENTER:
530 xpos = (render->width - render->image_width) / 2;
532 case GST_TEXT_RENDER_HALIGN_RIGHT:
533 xpos = render->width - render->image_width - render->xpad;
539 switch (render->valign) {
540 case GST_TEXT_RENDER_VALIGN_BOTTOM:
541 ypos = render->height - render->image_height - render->ypad;
543 case GST_TEXT_RENDER_VALIGN_BASELINE:
544 ypos = render->height - (render->image_height + render->ypad);
546 case GST_TEXT_RENDER_VALIGN_TOP:
554 if (render->text_image) {
555 if (render->use_ARGB) {
556 gst_text_renderer_image_to_argb (render, data, xpos, ypos,
559 gst_text_renderer_image_to_ayuv (render, data, xpos, ypos,
563 gst_buffer_unmap (outbuf, data, size);
565 ret = gst_pad_push (render->srcpad, outbuf);
569 gst_caps_unref (caps);
570 gst_buffer_unref (inbuf);
571 gst_object_unref (render);
576 gst_text_render_finalize (GObject * object)
578 GstTextRender *render = GST_TEXT_RENDER (object);
580 g_free (render->text_image);
583 g_object_unref (render->layout);
585 G_OBJECT_CLASS (parent_class)->finalize (object);
589 gst_text_render_init (GstTextRender * render)
591 GstPadTemplate *template;
594 template = gst_static_pad_template_get (&sink_template_factory);
595 render->sinkpad = gst_pad_new_from_template (template, "sink");
596 gst_object_unref (template);
597 gst_pad_set_chain_function (render->sinkpad,
598 GST_DEBUG_FUNCPTR (gst_text_render_chain));
599 gst_element_add_pad (GST_ELEMENT (render), render->sinkpad);
602 template = gst_static_pad_template_get (&src_template_factory);
603 render->srcpad = gst_pad_new_from_template (template, "src");
604 gst_object_unref (template);
605 gst_pad_set_fixatecaps_function (render->srcpad,
606 GST_DEBUG_FUNCPTR (gst_text_render_fixate_caps));
608 gst_element_add_pad (GST_ELEMENT (render), render->srcpad);
610 render->line_align = DEFAULT_PROP_LINE_ALIGNMENT;
612 pango_layout_new (GST_TEXT_RENDER_GET_CLASS (render)->pango_context);
613 pango_layout_set_alignment (render->layout,
614 (PangoAlignment) render->line_align);
616 render->halign = DEFAULT_PROP_HALIGNMENT;
617 render->valign = DEFAULT_PROP_VALIGNMENT;
618 render->xpad = DEFAULT_PROP_XPAD;
619 render->ypad = DEFAULT_PROP_YPAD;
621 render->width = DEFAULT_RENDER_WIDTH;
622 render->height = DEFAULT_RENDER_HEIGHT;
624 render->use_ARGB = FALSE;
628 gst_text_render_set_property (GObject * object, guint prop_id,
629 const GValue * value, GParamSpec * pspec)
631 GstTextRender *render = GST_TEXT_RENDER (object);
634 case PROP_VALIGNMENT:
635 render->valign = g_value_get_enum (value);
637 case PROP_HALIGNMENT:
638 render->halign = g_value_get_enum (value);
640 case PROP_LINE_ALIGNMENT:
641 render->line_align = g_value_get_enum (value);
642 pango_layout_set_alignment (render->layout,
643 (PangoAlignment) render->line_align);
646 render->xpad = g_value_get_int (value);
649 render->ypad = g_value_get_int (value);
653 PangoFontDescription *desc;
655 desc = pango_font_description_from_string (g_value_get_string (value));
657 GST_LOG ("font description set: %s", g_value_get_string (value));
658 GST_OBJECT_LOCK (render);
659 pango_layout_set_font_description (render->layout, desc);
660 gst_text_render_adjust_values_with_fontdesc (render, desc);
661 pango_font_description_free (desc);
662 gst_text_render_render_pangocairo (render);
663 GST_OBJECT_UNLOCK (render);
665 GST_WARNING ("font description parse failed: %s",
666 g_value_get_string (value));
677 gst_text_render_get_property (GObject * object, guint prop_id,
678 GValue * value, GParamSpec * pspec)
680 GstTextRender *render = GST_TEXT_RENDER (object);
683 case PROP_VALIGNMENT:
684 g_value_set_enum (value, render->valign);
686 case PROP_HALIGNMENT:
687 g_value_set_enum (value, render->halign);
689 case PROP_LINE_ALIGNMENT:
690 g_value_set_enum (value, render->line_align);
693 g_value_set_int (value, render->xpad);
696 g_value_set_int (value, render->ypad);
699 G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);