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_static_pad_template (element_class,
179 &src_template_factory);
180 gst_element_class_add_static_pad_template (element_class,
181 &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 "GStreamer maintainers <gstreamer-devel@lists.sourceforge.net>");
191 gst_text_render_class_init (GstTextRenderClass * klass)
193 GObjectClass *gobject_class;
194 PangoFontMap *fontmap;
196 gobject_class = (GObjectClass *) klass;
198 parent_class = g_type_class_peek_parent (klass);
200 gobject_class->finalize = gst_text_render_finalize;
201 gobject_class->set_property = gst_text_render_set_property;
202 gobject_class->get_property = gst_text_render_get_property;
204 fontmap = pango_cairo_font_map_get_default ();
205 klass->pango_context =
206 pango_cairo_font_map_create_context (PANGO_CAIRO_FONT_MAP (fontmap));
207 g_object_class_install_property (G_OBJECT_CLASS (klass), PROP_FONT_DESC,
208 g_param_spec_string ("font-desc", "font description",
209 "Pango font description of font "
210 "to be used for rendering. "
211 "See documentation of "
212 "pango_font_description_from_string"
213 " for syntax.", "", G_PARAM_WRITABLE | G_PARAM_STATIC_STRINGS));
214 g_object_class_install_property (G_OBJECT_CLASS (klass), PROP_VALIGNMENT,
215 g_param_spec_enum ("valignment", "vertical alignment",
216 "Vertical alignment of the text", GST_TYPE_TEXT_RENDER_VALIGN,
217 DEFAULT_PROP_VALIGNMENT, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
218 g_object_class_install_property (G_OBJECT_CLASS (klass), PROP_HALIGNMENT,
219 g_param_spec_enum ("halignment", "horizontal alignment",
220 "Horizontal alignment of the text", GST_TYPE_TEXT_RENDER_HALIGN,
221 DEFAULT_PROP_HALIGNMENT, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
222 g_object_class_install_property (G_OBJECT_CLASS (klass), PROP_XPAD,
223 g_param_spec_int ("xpad", "horizontal paddding",
224 "Horizontal paddding when using left/right alignment", 0, G_MAXINT,
225 DEFAULT_PROP_XPAD, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
226 g_object_class_install_property (G_OBJECT_CLASS (klass), PROP_YPAD,
227 g_param_spec_int ("ypad", "vertical padding",
228 "Vertical padding when using top/bottom alignment", 0, G_MAXINT,
229 DEFAULT_PROP_YPAD, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
230 g_object_class_install_property (G_OBJECT_CLASS (klass), PROP_LINE_ALIGNMENT,
231 g_param_spec_enum ("line-alignment", "line alignment",
232 "Alignment of text lines relative to each other.",
233 GST_TYPE_TEXT_RENDER_LINE_ALIGN, DEFAULT_PROP_LINE_ALIGNMENT,
234 G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
238 gst_text_render_adjust_values_with_fontdesc (GstTextRender * render,
239 PangoFontDescription * desc)
241 gint font_size = pango_font_description_get_size (desc) / PANGO_SCALE;
243 render->shadow_offset = (double) (font_size) / 13.0;
244 render->outline_offset = (double) (font_size) / 15.0;
245 if (render->outline_offset < MINIMUM_OUTLINE_OFFSET)
246 render->outline_offset = MINIMUM_OUTLINE_OFFSET;
250 gst_text_render_render_pangocairo (GstTextRender * render)
253 cairo_surface_t *surface;
255 cairo_surface_t *surface_shadow;
256 PangoRectangle ink_rect, logical_rect;
259 pango_layout_get_pixel_extents (render->layout, &ink_rect, &logical_rect);
261 width = logical_rect.width + render->shadow_offset;
262 height = logical_rect.height + logical_rect.y + render->shadow_offset;
264 surface_shadow = cairo_image_surface_create (CAIRO_FORMAT_A8, width, height);
265 cr_shadow = cairo_create (surface_shadow);
267 /* clear shadow surface */
268 cairo_set_operator (cr_shadow, CAIRO_OPERATOR_CLEAR);
269 cairo_paint (cr_shadow);
270 cairo_set_operator (cr_shadow, CAIRO_OPERATOR_OVER);
272 /* draw shadow text */
273 cairo_save (cr_shadow);
274 cairo_set_source_rgba (cr_shadow, 0.0, 0.0, 0.0, 0.5);
275 cairo_translate (cr_shadow, render->shadow_offset, render->shadow_offset);
276 pango_cairo_show_layout (cr_shadow, render->layout);
277 cairo_restore (cr_shadow);
279 /* draw outline text */
280 cairo_save (cr_shadow);
281 cairo_set_source_rgb (cr_shadow, 0.0, 0.0, 0.0);
282 cairo_set_line_width (cr_shadow, render->outline_offset);
283 pango_cairo_layout_path (cr_shadow, render->layout);
284 cairo_stroke (cr_shadow);
285 cairo_restore (cr_shadow);
287 cairo_destroy (cr_shadow);
289 render->text_image = g_realloc (render->text_image, 4 * width * height);
291 surface = cairo_image_surface_create_for_data (render->text_image,
292 CAIRO_FORMAT_ARGB32, width, height, width * 4);
293 cr = cairo_create (surface);
294 cairo_set_operator (cr, CAIRO_OPERATOR_CLEAR);
296 cairo_set_operator (cr, CAIRO_OPERATOR_OVER);
298 /* set default color */
299 cairo_set_source_rgb (cr, 1.0, 1.0, 1.0);
303 pango_cairo_show_layout (cr, render->layout);
306 /* composite shadow with offset */
307 cairo_set_operator (cr, CAIRO_OPERATOR_DEST_OVER);
308 cairo_set_source_surface (cr, surface_shadow, 0.0, 0.0);
312 cairo_surface_destroy (surface_shadow);
313 cairo_surface_destroy (surface);
314 render->image_width = width;
315 render->image_height = height;
319 gst_text_render_check_argb (GstTextRender * render)
322 peer_caps = gst_pad_get_allowed_caps (render->srcpad);
323 if (G_LIKELY (peer_caps)) {
326 n = gst_caps_get_size (peer_caps);
327 GST_DEBUG_OBJECT (render, "peer allowed caps (%u structure(s)) are %"
328 GST_PTR_FORMAT, n, peer_caps);
330 /* Check if AYUV or ARGB is first */
331 for (i = 0; i < n; i++) {
332 GstStructure *s = gst_caps_get_structure (peer_caps, i);
333 if (gst_structure_has_name (s, "video/x-raw-rgb") &&
334 gst_structure_has_field (s, "alpha_mask")) {
335 render->use_ARGB = TRUE;
337 } else if (gst_structure_has_name (s, "video/x-raw-yuv")) {
339 if (gst_structure_get_fourcc (s, "format", &fourcc) &&
340 fourcc == GST_MAKE_FOURCC ('A', 'Y', 'U', 'V')) {
341 render->use_ARGB = FALSE;
346 gst_caps_unref (peer_caps);
351 gst_text_render_setcaps (GstPad * pad, GstCaps * caps)
353 GstTextRender *render = GST_TEXT_RENDER (gst_pad_get_parent (pad));
354 GstStructure *structure;
355 gboolean ret = FALSE;
356 gint width = 0, height = 0;
358 structure = gst_caps_get_structure (caps, 0);
359 gst_structure_get_int (structure, "width", &width);
360 gst_structure_get_int (structure, "height", &height);
362 GST_DEBUG ("Got caps %" GST_PTR_FORMAT, caps);
364 if (width >= render->image_width && height >= render->image_height) {
365 render->width = width;
366 render->height = height;
370 gst_text_render_check_argb (render);
372 gst_object_unref (render);
377 gst_text_render_fixate_caps (GstPad * pad, GstCaps * caps)
379 GstTextRender *render = GST_TEXT_RENDER (gst_pad_get_parent (pad));
380 GstStructure *s = gst_caps_get_structure (caps, 0);
382 GST_DEBUG ("Fixating caps %" GST_PTR_FORMAT, caps);
383 gst_structure_fixate_field_nearest_int (s, "width", MAX (render->image_width,
384 DEFAULT_RENDER_WIDTH));
385 gst_structure_fixate_field_nearest_int (s, "height",
386 MAX (render->image_height + render->ypad, DEFAULT_RENDER_HEIGHT));
387 GST_DEBUG ("Fixated to %" GST_PTR_FORMAT, caps);
389 gst_object_unref (render);
392 #define CAIRO_UNPREMULTIPLY(a,r,g,b) G_STMT_START { \
393 b = (a > 0) ? MIN ((b * 255 + a / 2) / a, 255) : 0; \
394 g = (a > 0) ? MIN ((g * 255 + a / 2) / a, 255) : 0; \
395 r = (a > 0) ? MIN ((r * 255 + a / 2) / a, 255) : 0; \
399 gst_text_renderer_image_to_ayuv (GstTextRender * render, guchar * pixbuf,
400 int xpos, int ypos, int stride)
402 int y; /* text bitmap coordinates */
407 width = render->image_width;
408 height = render->image_height;
410 for (y = 0; y < height && ypos + y < render->height; y++) {
412 p = pixbuf + (ypos + y) * stride + xpos * 4;
413 bitp = render->text_image + y * width * 4;
414 for (n = 0; n < width && n < render->width; n++) {
415 b = bitp[CAIRO_ARGB_B];
416 g = bitp[CAIRO_ARGB_G];
417 r = bitp[CAIRO_ARGB_R];
418 a = bitp[CAIRO_ARGB_A];
421 /* Cairo uses pre-multiplied ARGB, unpremultiply it */
422 CAIRO_UNPREMULTIPLY (a, r, g, b);
425 *p++ = CLAMP ((int) (((19595 * r) >> 16) + ((38470 * g) >> 16) +
426 ((7471 * b) >> 16)), 0, 255);
427 *p++ = CLAMP ((int) (-((11059 * r) >> 16) - ((21709 * g) >> 16) +
428 ((32768 * b) >> 16) + 128), 0, 255);
429 *p++ = CLAMP ((int) (((32768 * r) >> 16) - ((27439 * g) >> 16) -
430 ((5329 * b) >> 16) + 128), 0, 255);
436 gst_text_renderer_image_to_argb (GstTextRender * render, guchar * pixbuf,
437 int xpos, int ypos, int stride)
443 width = render->image_width;
444 height = render->image_height;
446 for (i = 0; i < height && ypos + i < render->height; i++) {
447 p = pixbuf + (ypos + i) * stride + xpos * 4;
448 bitp = render->text_image + i * width * 4;
449 for (j = 0; j < width && j < render->width; j++) {
450 p[0] = bitp[CAIRO_ARGB_A];
451 p[1] = bitp[CAIRO_ARGB_R];
452 p[2] = bitp[CAIRO_ARGB_G];
453 p[3] = bitp[CAIRO_ARGB_B];
455 /* Cairo uses pre-multiplied ARGB, unpremultiply it */
456 CAIRO_UNPREMULTIPLY (p[0], p[1], p[2], p[3]);
465 gst_text_render_chain (GstPad * pad, GstBuffer * inbuf)
467 GstTextRender *render;
470 GstCaps *caps = NULL, *padcaps, *peercaps;
471 guint8 *data = GST_BUFFER_DATA (inbuf);
472 guint size = GST_BUFFER_SIZE (inbuf);
476 render = GST_TEXT_RENDER (gst_pad_get_parent (pad));
478 /* somehow pango barfs over "\0" buffers... */
480 (data[size - 1] == '\r' ||
481 data[size - 1] == '\n' || data[size - 1] == '\0')) {
486 GST_DEBUG ("rendering '%*s'", size, data);
487 pango_layout_set_markup (render->layout, (gchar *) data, size);
488 gst_text_render_render_pangocairo (render);
490 gst_text_render_check_argb (render);
492 peercaps = gst_pad_peer_get_caps (render->srcpad);
493 padcaps = gst_pad_get_caps (render->srcpad);
494 caps = gst_caps_intersect (padcaps, peercaps);
495 gst_caps_unref (padcaps);
496 gst_caps_unref (peercaps);
498 if (!caps || gst_caps_is_empty (caps)) {
499 GST_ELEMENT_ERROR (render, CORE, NEGOTIATION, (NULL), (NULL));
500 ret = GST_FLOW_ERROR;
504 gst_caps_truncate (caps);
505 gst_pad_fixate_caps (render->srcpad, caps);
507 if (!gst_pad_set_caps (render->srcpad, caps)) {
508 GST_ELEMENT_ERROR (render, CORE, NEGOTIATION, (NULL), (NULL));
509 ret = GST_FLOW_ERROR;
513 GST_DEBUG ("Allocating buffer WxH = %dx%d", render->width, render->height);
515 gst_pad_alloc_buffer_and_set_caps (render->srcpad, GST_BUFFER_OFFSET_NONE,
516 render->width * render->height * 4, caps, &outbuf);
518 if (ret != GST_FLOW_OK)
521 gst_buffer_copy_metadata (outbuf, inbuf, GST_BUFFER_COPY_TIMESTAMPS);
522 data = GST_BUFFER_DATA (outbuf);
524 if (render->use_ARGB) {
525 memset (data, 0, render->width * render->height * 4);
527 for (n = 0; n < render->width * render->height; n++) {
528 data[n * 4] = data[n * 4 + 1] = 0;
529 data[n * 4 + 2] = data[n * 4 + 3] = 128;
533 switch (render->halign) {
534 case GST_TEXT_RENDER_HALIGN_LEFT:
537 case GST_TEXT_RENDER_HALIGN_CENTER:
538 xpos = (render->width - render->image_width) / 2;
540 case GST_TEXT_RENDER_HALIGN_RIGHT:
541 xpos = render->width - render->image_width - render->xpad;
547 switch (render->valign) {
548 case GST_TEXT_RENDER_VALIGN_BOTTOM:
549 ypos = render->height - render->image_height - render->ypad;
551 case GST_TEXT_RENDER_VALIGN_BASELINE:
552 ypos = render->height - (render->image_height + render->ypad);
554 case GST_TEXT_RENDER_VALIGN_TOP:
562 if (render->text_image) {
563 if (render->use_ARGB) {
564 gst_text_renderer_image_to_argb (render, data, xpos, ypos,
567 gst_text_renderer_image_to_ayuv (render, data, xpos, ypos,
572 ret = gst_pad_push (render->srcpad, outbuf);
576 gst_caps_unref (caps);
577 gst_buffer_unref (inbuf);
578 gst_object_unref (render);
583 gst_text_render_finalize (GObject * object)
585 GstTextRender *render = GST_TEXT_RENDER (object);
587 g_free (render->text_image);
590 g_object_unref (render->layout);
592 G_OBJECT_CLASS (parent_class)->finalize (object);
596 gst_text_render_init (GstTextRender * render, GstTextRenderClass * klass)
598 GstPadTemplate *template;
601 template = gst_static_pad_template_get (&sink_template_factory);
602 render->sinkpad = gst_pad_new_from_template (template, "sink");
603 gst_object_unref (template);
604 gst_pad_set_chain_function (render->sinkpad,
605 GST_DEBUG_FUNCPTR (gst_text_render_chain));
606 gst_element_add_pad (GST_ELEMENT (render), render->sinkpad);
609 template = gst_static_pad_template_get (&src_template_factory);
610 render->srcpad = gst_pad_new_from_template (template, "src");
611 gst_object_unref (template);
612 gst_pad_set_fixatecaps_function (render->srcpad,
613 GST_DEBUG_FUNCPTR (gst_text_render_fixate_caps));
614 gst_pad_set_setcaps_function (render->srcpad,
615 GST_DEBUG_FUNCPTR (gst_text_render_setcaps));
617 gst_element_add_pad (GST_ELEMENT (render), render->srcpad);
619 render->line_align = DEFAULT_PROP_LINE_ALIGNMENT;
621 pango_layout_new (GST_TEXT_RENDER_GET_CLASS (render)->pango_context);
622 pango_layout_set_alignment (render->layout,
623 (PangoAlignment) render->line_align);
625 render->halign = DEFAULT_PROP_HALIGNMENT;
626 render->valign = DEFAULT_PROP_VALIGNMENT;
627 render->xpad = DEFAULT_PROP_XPAD;
628 render->ypad = DEFAULT_PROP_YPAD;
630 render->width = DEFAULT_RENDER_WIDTH;
631 render->height = DEFAULT_RENDER_HEIGHT;
633 render->use_ARGB = FALSE;
637 gst_text_render_set_property (GObject * object, guint prop_id,
638 const GValue * value, GParamSpec * pspec)
640 GstTextRender *render = GST_TEXT_RENDER (object);
643 case PROP_VALIGNMENT:
644 render->valign = g_value_get_enum (value);
646 case PROP_HALIGNMENT:
647 render->halign = g_value_get_enum (value);
649 case PROP_LINE_ALIGNMENT:
650 render->line_align = g_value_get_enum (value);
651 pango_layout_set_alignment (render->layout,
652 (PangoAlignment) render->line_align);
655 render->xpad = g_value_get_int (value);
658 render->ypad = g_value_get_int (value);
662 PangoFontDescription *desc;
664 desc = pango_font_description_from_string (g_value_get_string (value));
666 GST_LOG ("font description set: %s", g_value_get_string (value));
667 GST_OBJECT_LOCK (render);
668 pango_layout_set_font_description (render->layout, desc);
669 gst_text_render_adjust_values_with_fontdesc (render, desc);
670 pango_font_description_free (desc);
671 gst_text_render_render_pangocairo (render);
672 GST_OBJECT_UNLOCK (render);
674 GST_WARNING ("font description parse failed: %s",
675 g_value_get_string (value));
686 gst_text_render_get_property (GObject * object, guint prop_id,
687 GValue * value, GParamSpec * pspec)
689 GstTextRender *render = GST_TEXT_RENDER (object);
692 case PROP_VALIGNMENT:
693 g_value_set_enum (value, render->valign);
695 case PROP_HALIGNMENT:
696 g_value_set_enum (value, render->halign);
698 case PROP_LINE_ALIGNMENT:
699 g_value_set_enum (value, render->line_align);
702 g_value_set_int (value, render->xpad);
705 g_value_set_int (value, render->ypad);
708 G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);