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
89 #define VIDEO_FORMATS "{ AYUV, ARGB } "
91 static GstStaticPadTemplate src_template_factory =
92 GST_STATIC_PAD_TEMPLATE ("src",
95 GST_STATIC_CAPS (GST_VIDEO_CAPS_MAKE (VIDEO_FORMATS))
98 static GstStaticPadTemplate sink_template_factory =
99 GST_STATIC_PAD_TEMPLATE ("sink",
102 GST_STATIC_CAPS ("text/x-pango-markup; text/plain")
105 #define GST_TYPE_TEXT_RENDER_VALIGN (gst_text_render_valign_get_type())
107 gst_text_render_valign_get_type (void)
109 static GType text_render_valign_type = 0;
110 static const GEnumValue text_render_valign[] = {
111 {GST_TEXT_RENDER_VALIGN_BASELINE, "baseline", "baseline"},
112 {GST_TEXT_RENDER_VALIGN_BOTTOM, "bottom", "bottom"},
113 {GST_TEXT_RENDER_VALIGN_TOP, "top", "top"},
117 if (!text_render_valign_type) {
118 text_render_valign_type =
119 g_enum_register_static ("GstTextRenderVAlign", text_render_valign);
121 return text_render_valign_type;
124 #define GST_TYPE_TEXT_RENDER_HALIGN (gst_text_render_halign_get_type())
126 gst_text_render_halign_get_type (void)
128 static GType text_render_halign_type = 0;
129 static const GEnumValue text_render_halign[] = {
130 {GST_TEXT_RENDER_HALIGN_LEFT, "left", "left"},
131 {GST_TEXT_RENDER_HALIGN_CENTER, "center", "center"},
132 {GST_TEXT_RENDER_HALIGN_RIGHT, "right", "right"},
136 if (!text_render_halign_type) {
137 text_render_halign_type =
138 g_enum_register_static ("GstTextRenderHAlign", text_render_halign);
140 return text_render_halign_type;
143 #define GST_TYPE_TEXT_RENDER_LINE_ALIGN (gst_text_render_line_align_get_type())
145 gst_text_render_line_align_get_type (void)
147 static GType text_render_line_align_type = 0;
148 static const GEnumValue text_render_line_align[] = {
149 {GST_TEXT_RENDER_LINE_ALIGN_LEFT, "left", "left"},
150 {GST_TEXT_RENDER_LINE_ALIGN_CENTER, "center", "center"},
151 {GST_TEXT_RENDER_LINE_ALIGN_RIGHT, "right", "right"},
155 if (!text_render_line_align_type) {
156 text_render_line_align_type =
157 g_enum_register_static ("GstTextRenderLineAlign",
158 text_render_line_align);
160 return text_render_line_align_type;
163 static void gst_text_render_adjust_values_with_fontdesc (GstTextRender *
164 render, PangoFontDescription * desc);
166 #define gst_text_render_parent_class parent_class
167 G_DEFINE_TYPE (GstTextRender, gst_text_render, GST_TYPE_ELEMENT);
169 static void gst_text_render_finalize (GObject * object);
170 static void gst_text_render_set_property (GObject * object,
171 guint prop_id, const GValue * value, GParamSpec * pspec);
172 static void gst_text_render_get_property (GObject * object,
173 guint prop_id, GValue * value, GParamSpec * pspec);
176 gst_text_render_class_init (GstTextRenderClass * klass)
178 GObjectClass *gobject_class;
179 GstElementClass *gstelement_class;
180 PangoFontMap *fontmap;
182 gobject_class = (GObjectClass *) klass;
183 gstelement_class = (GstElementClass *) klass;
185 parent_class = g_type_class_peek_parent (klass);
187 gobject_class->finalize = gst_text_render_finalize;
188 gobject_class->set_property = gst_text_render_set_property;
189 gobject_class->get_property = gst_text_render_get_property;
191 gst_element_class_add_pad_template (gstelement_class,
192 gst_static_pad_template_get (&src_template_factory));
193 gst_element_class_add_pad_template (gstelement_class,
194 gst_static_pad_template_get (&sink_template_factory));
196 gst_element_class_set_details_simple (gstelement_class, "Text renderer",
197 "Filter/Editor/Video",
198 "Renders a text string to an image bitmap",
199 "David Schleef <ds@schleef.org>, "
200 "GStreamer maintainers <gstreamer-devel@lists.sourceforge.net>");
202 fontmap = pango_cairo_font_map_get_default ();
203 klass->pango_context =
204 pango_cairo_font_map_create_context (PANGO_CAIRO_FONT_MAP (fontmap));
205 g_object_class_install_property (G_OBJECT_CLASS (klass), PROP_FONT_DESC,
206 g_param_spec_string ("font-desc", "font description",
207 "Pango font description of font "
208 "to be used for rendering. "
209 "See documentation of "
210 "pango_font_description_from_string"
211 " for syntax.", "", G_PARAM_WRITABLE | G_PARAM_STATIC_STRINGS));
212 g_object_class_install_property (G_OBJECT_CLASS (klass), PROP_VALIGNMENT,
213 g_param_spec_enum ("valignment", "vertical alignment",
214 "Vertical alignment of the text", GST_TYPE_TEXT_RENDER_VALIGN,
215 DEFAULT_PROP_VALIGNMENT, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
216 g_object_class_install_property (G_OBJECT_CLASS (klass), PROP_HALIGNMENT,
217 g_param_spec_enum ("halignment", "horizontal alignment",
218 "Horizontal alignment of the text", GST_TYPE_TEXT_RENDER_HALIGN,
219 DEFAULT_PROP_HALIGNMENT, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
220 g_object_class_install_property (G_OBJECT_CLASS (klass), PROP_XPAD,
221 g_param_spec_int ("xpad", "horizontal paddding",
222 "Horizontal paddding when using left/right alignment", 0, G_MAXINT,
223 DEFAULT_PROP_XPAD, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
224 g_object_class_install_property (G_OBJECT_CLASS (klass), PROP_YPAD,
225 g_param_spec_int ("ypad", "vertical padding",
226 "Vertical padding when using top/bottom alignment", 0, G_MAXINT,
227 DEFAULT_PROP_YPAD, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
228 g_object_class_install_property (G_OBJECT_CLASS (klass), PROP_LINE_ALIGNMENT,
229 g_param_spec_enum ("line-alignment", "line alignment",
230 "Alignment of text lines relative to each other.",
231 GST_TYPE_TEXT_RENDER_LINE_ALIGN, DEFAULT_PROP_LINE_ALIGNMENT,
232 G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
236 gst_text_render_adjust_values_with_fontdesc (GstTextRender * render,
237 PangoFontDescription * desc)
239 gint font_size = pango_font_description_get_size (desc) / PANGO_SCALE;
241 render->shadow_offset = (double) (font_size) / 13.0;
242 render->outline_offset = (double) (font_size) / 15.0;
243 if (render->outline_offset < MINIMUM_OUTLINE_OFFSET)
244 render->outline_offset = MINIMUM_OUTLINE_OFFSET;
248 gst_text_render_render_pangocairo (GstTextRender * render)
251 cairo_surface_t *surface;
253 cairo_surface_t *surface_shadow;
254 PangoRectangle ink_rect, logical_rect;
257 pango_layout_get_pixel_extents (render->layout, &ink_rect, &logical_rect);
259 width = logical_rect.width + render->shadow_offset;
260 height = logical_rect.height + logical_rect.y + render->shadow_offset;
262 surface_shadow = cairo_image_surface_create (CAIRO_FORMAT_A8, width, height);
263 cr_shadow = cairo_create (surface_shadow);
265 /* clear shadow surface */
266 cairo_set_operator (cr_shadow, CAIRO_OPERATOR_CLEAR);
267 cairo_paint (cr_shadow);
268 cairo_set_operator (cr_shadow, CAIRO_OPERATOR_OVER);
270 /* draw shadow text */
271 cairo_save (cr_shadow);
272 cairo_set_source_rgba (cr_shadow, 0.0, 0.0, 0.0, 0.5);
273 cairo_translate (cr_shadow, render->shadow_offset, render->shadow_offset);
274 pango_cairo_show_layout (cr_shadow, render->layout);
275 cairo_restore (cr_shadow);
277 /* draw outline text */
278 cairo_save (cr_shadow);
279 cairo_set_source_rgb (cr_shadow, 0.0, 0.0, 0.0);
280 cairo_set_line_width (cr_shadow, render->outline_offset);
281 pango_cairo_layout_path (cr_shadow, render->layout);
282 cairo_stroke (cr_shadow);
283 cairo_restore (cr_shadow);
285 cairo_destroy (cr_shadow);
287 render->text_image = g_realloc (render->text_image, 4 * width * height);
289 surface = cairo_image_surface_create_for_data (render->text_image,
290 CAIRO_FORMAT_ARGB32, width, height, width * 4);
291 cr = cairo_create (surface);
292 cairo_set_operator (cr, CAIRO_OPERATOR_CLEAR);
294 cairo_set_operator (cr, CAIRO_OPERATOR_OVER);
296 /* set default color */
297 cairo_set_source_rgb (cr, 1.0, 1.0, 1.0);
301 pango_cairo_show_layout (cr, render->layout);
304 /* composite shadow with offset */
305 cairo_set_operator (cr, CAIRO_OPERATOR_DEST_OVER);
306 cairo_set_source_surface (cr, surface_shadow, 0.0, 0.0);
310 cairo_surface_destroy (surface_shadow);
311 cairo_surface_destroy (surface);
312 render->image_width = width;
313 render->image_height = height;
317 gst_text_render_check_argb (GstTextRender * render)
320 peer_caps = gst_pad_get_allowed_caps (render->srcpad);
321 if (G_LIKELY (peer_caps)) {
324 n = gst_caps_get_size (peer_caps);
325 GST_DEBUG_OBJECT (render, "peer allowed caps (%u structure(s)) are %"
326 GST_PTR_FORMAT, n, peer_caps);
328 /* Check if AYUV or ARGB is first */
329 for (i = 0; i < n; i++) {
331 GstVideoFormat vformat;
334 s = gst_caps_get_structure (peer_caps, i);
335 if (!gst_structure_has_name (s, "video/x-raw"))
338 fmt = gst_structure_get_string (s, "format");
342 vformat = gst_video_format_from_string (fmt);
343 render->use_ARGB = gst_video_format_has_alpha (vformat);
345 gst_caps_unref (peer_caps);
350 gst_text_render_src_setcaps (GstTextRender * render, GstCaps * caps)
352 GstStructure *structure;
354 gint width = 0, height = 0;
356 structure = gst_caps_get_structure (caps, 0);
357 gst_structure_get_int (structure, "width", &width);
358 gst_structure_get_int (structure, "height", &height);
360 GST_DEBUG_OBJECT (render, "Got caps %" GST_PTR_FORMAT, caps);
362 if (width >= render->image_width && height >= render->image_height) {
363 render->width = width;
364 render->height = height;
367 gst_text_render_check_argb (render);
369 ret = gst_pad_push_event (render->srcpad, gst_event_new_caps (caps));
375 gst_text_render_fixate_caps (GstPad * pad, GstCaps * caps)
377 GstTextRender *render = GST_TEXT_RENDER (gst_pad_get_parent (pad));
378 GstStructure *s = gst_caps_get_structure (caps, 0);
380 GST_DEBUG ("Fixating caps %" GST_PTR_FORMAT, caps);
381 gst_structure_fixate_field_nearest_int (s, "width", MAX (render->image_width,
382 DEFAULT_RENDER_WIDTH));
383 gst_structure_fixate_field_nearest_int (s, "height",
384 MAX (render->image_height + render->ypad, DEFAULT_RENDER_HEIGHT));
385 GST_DEBUG ("Fixated to %" GST_PTR_FORMAT, caps);
387 gst_object_unref (render);
390 #define CAIRO_UNPREMULTIPLY(a,r,g,b) G_STMT_START { \
391 b = (a > 0) ? MIN ((b * 255 + a / 2) / a, 255) : 0; \
392 g = (a > 0) ? MIN ((g * 255 + a / 2) / a, 255) : 0; \
393 r = (a > 0) ? MIN ((r * 255 + a / 2) / a, 255) : 0; \
397 gst_text_renderer_image_to_ayuv (GstTextRender * render, guchar * pixbuf,
398 int xpos, int ypos, int stride)
400 int y; /* text bitmap coordinates */
405 width = render->image_width;
406 height = render->image_height;
408 for (y = 0; y < height && ypos + y < render->height; y++) {
410 p = pixbuf + (ypos + y) * stride + xpos * 4;
411 bitp = render->text_image + y * width * 4;
412 for (n = 0; n < width && n < render->width; n++) {
413 b = bitp[CAIRO_ARGB_B];
414 g = bitp[CAIRO_ARGB_G];
415 r = bitp[CAIRO_ARGB_R];
416 a = bitp[CAIRO_ARGB_A];
419 /* Cairo uses pre-multiplied ARGB, unpremultiply it */
420 CAIRO_UNPREMULTIPLY (a, r, g, b);
423 *p++ = CLAMP ((int) (((19595 * r) >> 16) + ((38470 * g) >> 16) +
424 ((7471 * b) >> 16)), 0, 255);
425 *p++ = CLAMP ((int) (-((11059 * r) >> 16) - ((21709 * g) >> 16) +
426 ((32768 * b) >> 16) + 128), 0, 255);
427 *p++ = CLAMP ((int) (((32768 * r) >> 16) - ((27439 * g) >> 16) -
428 ((5329 * b) >> 16) + 128), 0, 255);
434 gst_text_renderer_image_to_argb (GstTextRender * render, guchar * pixbuf,
435 int xpos, int ypos, int stride)
441 width = render->image_width;
442 height = render->image_height;
444 for (i = 0; i < height && ypos + i < render->height; i++) {
445 p = pixbuf + (ypos + i) * stride + xpos * 4;
446 bitp = render->text_image + i * width * 4;
447 for (j = 0; j < width && j < render->width; j++) {
448 p[0] = bitp[CAIRO_ARGB_A];
449 p[1] = bitp[CAIRO_ARGB_R];
450 p[2] = bitp[CAIRO_ARGB_G];
451 p[3] = bitp[CAIRO_ARGB_B];
453 /* Cairo uses pre-multiplied ARGB, unpremultiply it */
454 CAIRO_UNPREMULTIPLY (p[0], p[1], p[2], p[3]);
463 gst_text_render_chain (GstPad * pad, GstBuffer * inbuf)
465 GstTextRender *render;
468 GstCaps *caps = NULL, *padcaps;
474 render = GST_TEXT_RENDER (gst_pad_get_parent (pad));
476 data = gst_buffer_map (inbuf, &size, NULL, GST_MAP_READ);
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);
489 gst_buffer_unmap (inbuf, data, size);
491 gst_text_render_check_argb (render);
493 padcaps = gst_pad_get_caps (render->srcpad, NULL);
494 caps = gst_pad_peer_get_caps (render->srcpad, padcaps);
495 gst_caps_unref (padcaps);
497 if (!caps || gst_caps_is_empty (caps)) {
498 GST_ELEMENT_ERROR (render, CORE, NEGOTIATION, (NULL), (NULL));
499 ret = GST_FLOW_ERROR;
503 gst_caps_truncate (caps);
504 gst_pad_fixate_caps (render->srcpad, caps);
506 if (!gst_text_render_src_setcaps (render, caps)) {
507 GST_ELEMENT_ERROR (render, CORE, NEGOTIATION, (NULL), (NULL));
508 ret = GST_FLOW_ERROR;
512 GST_DEBUG ("Allocating buffer WxH = %dx%d", render->width, render->height);
513 outbuf = gst_buffer_new_and_alloc (render->width * render->height * 4);
515 gst_buffer_copy_into (outbuf, inbuf, GST_BUFFER_COPY_TIMESTAMPS, 0, -1);
516 data = gst_buffer_map (outbuf, &size, NULL, GST_MAP_WRITE);
518 if (render->use_ARGB) {
519 memset (data, 0, render->width * render->height * 4);
521 for (n = 0; n < render->width * render->height; n++) {
522 data[n * 4] = data[n * 4 + 1] = 0;
523 data[n * 4 + 2] = data[n * 4 + 3] = 128;
527 switch (render->halign) {
528 case GST_TEXT_RENDER_HALIGN_LEFT:
531 case GST_TEXT_RENDER_HALIGN_CENTER:
532 xpos = (render->width - render->image_width) / 2;
534 case GST_TEXT_RENDER_HALIGN_RIGHT:
535 xpos = render->width - render->image_width - render->xpad;
541 switch (render->valign) {
542 case GST_TEXT_RENDER_VALIGN_BOTTOM:
543 ypos = render->height - render->image_height - render->ypad;
545 case GST_TEXT_RENDER_VALIGN_BASELINE:
546 ypos = render->height - (render->image_height + render->ypad);
548 case GST_TEXT_RENDER_VALIGN_TOP:
556 if (render->text_image) {
557 if (render->use_ARGB) {
558 gst_text_renderer_image_to_argb (render, data, xpos, ypos,
561 gst_text_renderer_image_to_ayuv (render, data, xpos, ypos,
565 gst_buffer_unmap (outbuf, data, size);
567 ret = gst_pad_push (render->srcpad, outbuf);
571 gst_caps_unref (caps);
572 gst_buffer_unref (inbuf);
573 gst_object_unref (render);
578 gst_text_render_finalize (GObject * object)
580 GstTextRender *render = GST_TEXT_RENDER (object);
582 g_free (render->text_image);
585 g_object_unref (render->layout);
587 G_OBJECT_CLASS (parent_class)->finalize (object);
591 gst_text_render_init (GstTextRender * render)
593 GstPadTemplate *template;
596 template = gst_static_pad_template_get (&sink_template_factory);
597 render->sinkpad = gst_pad_new_from_template (template, "sink");
598 gst_object_unref (template);
599 gst_pad_set_chain_function (render->sinkpad,
600 GST_DEBUG_FUNCPTR (gst_text_render_chain));
601 gst_element_add_pad (GST_ELEMENT (render), render->sinkpad);
604 template = gst_static_pad_template_get (&src_template_factory);
605 render->srcpad = gst_pad_new_from_template (template, "src");
606 gst_object_unref (template);
607 gst_pad_set_fixatecaps_function (render->srcpad,
608 GST_DEBUG_FUNCPTR (gst_text_render_fixate_caps));
610 gst_element_add_pad (GST_ELEMENT (render), render->srcpad);
612 render->line_align = DEFAULT_PROP_LINE_ALIGNMENT;
614 pango_layout_new (GST_TEXT_RENDER_GET_CLASS (render)->pango_context);
615 pango_layout_set_alignment (render->layout,
616 (PangoAlignment) render->line_align);
618 render->halign = DEFAULT_PROP_HALIGNMENT;
619 render->valign = DEFAULT_PROP_VALIGNMENT;
620 render->xpad = DEFAULT_PROP_XPAD;
621 render->ypad = DEFAULT_PROP_YPAD;
623 render->width = DEFAULT_RENDER_WIDTH;
624 render->height = DEFAULT_RENDER_HEIGHT;
626 render->use_ARGB = FALSE;
630 gst_text_render_set_property (GObject * object, guint prop_id,
631 const GValue * value, GParamSpec * pspec)
633 GstTextRender *render = GST_TEXT_RENDER (object);
636 case PROP_VALIGNMENT:
637 render->valign = g_value_get_enum (value);
639 case PROP_HALIGNMENT:
640 render->halign = g_value_get_enum (value);
642 case PROP_LINE_ALIGNMENT:
643 render->line_align = g_value_get_enum (value);
644 pango_layout_set_alignment (render->layout,
645 (PangoAlignment) render->line_align);
648 render->xpad = g_value_get_int (value);
651 render->ypad = g_value_get_int (value);
655 PangoFontDescription *desc;
657 desc = pango_font_description_from_string (g_value_get_string (value));
659 GST_LOG ("font description set: %s", g_value_get_string (value));
660 GST_OBJECT_LOCK (render);
661 pango_layout_set_font_description (render->layout, desc);
662 gst_text_render_adjust_values_with_fontdesc (render, desc);
663 pango_font_description_free (desc);
664 gst_text_render_render_pangocairo (render);
665 GST_OBJECT_UNLOCK (render);
667 GST_WARNING ("font description parse failed: %s",
668 g_value_get_string (value));
679 gst_text_render_get_property (GObject * object, guint prop_id,
680 GValue * value, GParamSpec * pspec)
682 GstTextRender *render = GST_TEXT_RENDER (object);
685 case PROP_VALIGNMENT:
686 g_value_set_enum (value, render->valign);
688 case PROP_HALIGNMENT:
689 g_value_set_enum (value, render->halign);
691 case PROP_LINE_ALIGNMENT:
692 g_value_set_enum (value, render->line_align);
695 g_value_set_int (value, render->xpad);
698 g_value_set_int (value, render->ypad);
701 G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);