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gstreamer/ext/cairo/gsttextoverlay.c

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/* GStreamer
* Copyright (C) <1999> Erik Walthinsen <omega@cse.ogi.edu>
* Copyright (C) <2003> David Schleef <ds@schleef.org>
*
* 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-cairotextoverlay
*
* cairotextoverlay renders the text on top of the video frames.
*
* <refsect2>
* <title>Example launch line</title>
* |[
* gst-launch videotestsrc ! cairotextoverlay text="hello" ! autovideosink
* ]|
* </refsect2>
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <string.h>
#include <gst/video/video.h>
#include "gsttextoverlay.h"
#include <cairo.h>
/* FIXME:
* - calculating the position of the shading rectangle is
* not really right (try with text "L"), to say the least.
* Seems to work at least with latin script though.
* - check final x/y position and text width/height so that
* we don't do out-of-memory access when blitting the text.
* Also, we do not want to blit over the right or left margin.
* - what about text with newline characters? Cairo doesn't deal
* with that (we'd need to fix text_height usage for that as well)
* - upstream caps renegotiation, ie. when video window gets resized
*/
GST_DEBUG_CATEGORY_EXTERN (cairo_debug);
#define GST_CAT_DEFAULT cairo_debug
enum
{
ARG_0,
ARG_TEXT,
ARG_SHADING,
ARG_VALIGN,
ARG_HALIGN,
ARG_XPAD,
ARG_YPAD,
ARG_DELTAX,
ARG_DELTAY,
ARG_FONT_DESC
};
#define DEFAULT_YPAD 25
#define DEFAULT_XPAD 25
#define DEFAULT_FONT "sans"
#define GST_CAIRO_TEXT_OVERLAY_DEFAULT_SCALE 20.0
static GstStaticPadTemplate cairo_text_overlay_src_template_factory =
GST_STATIC_PAD_TEMPLATE ("src",
GST_PAD_SRC,
GST_PAD_ALWAYS,
GST_STATIC_CAPS (GST_VIDEO_CAPS_YUV ("I420"))
);
static GstStaticPadTemplate video_sink_template_factory =
GST_STATIC_PAD_TEMPLATE ("video_sink",
GST_PAD_SINK,
GST_PAD_ALWAYS,
GST_STATIC_CAPS (GST_VIDEO_CAPS_YUV ("I420"))
);
static GstStaticPadTemplate text_sink_template_factory =
GST_STATIC_PAD_TEMPLATE ("text_sink",
GST_PAD_SINK,
GST_PAD_ALWAYS,
GST_STATIC_CAPS ("text/plain")
);
static void gst_text_overlay_set_property (GObject * object,
guint prop_id, const GValue * value, GParamSpec * pspec);
static GstStateChangeReturn gst_text_overlay_change_state (GstElement * element,
GstStateChange transition);
static GstCaps *gst_text_overlay_getcaps (GstPad * pad);
static gboolean gst_text_overlay_setcaps (GstPad * pad, GstCaps * caps);
static GstPadLinkReturn gst_text_overlay_text_pad_linked (GstPad * pad,
GstPad * peer);
static void gst_text_overlay_text_pad_unlinked (GstPad * pad);
static GstFlowReturn gst_text_overlay_collected (GstCollectPads * pads,
gpointer data);
static void gst_text_overlay_finalize (GObject * object);
static void gst_text_overlay_font_init (GstCairoTextOverlay * overlay);
/* These macros are adapted from videotestsrc.c */
#define I420_Y_ROWSTRIDE(width) (GST_ROUND_UP_4(width))
#define I420_U_ROWSTRIDE(width) (GST_ROUND_UP_8(width)/2)
#define I420_V_ROWSTRIDE(width) ((GST_ROUND_UP_8(I420_Y_ROWSTRIDE(width)))/2)
#define I420_Y_OFFSET(w,h) (0)
#define I420_U_OFFSET(w,h) (I420_Y_OFFSET(w,h)+(I420_Y_ROWSTRIDE(w)*GST_ROUND_UP_2(h)))
#define I420_V_OFFSET(w,h) (I420_U_OFFSET(w,h)+(I420_U_ROWSTRIDE(w)*GST_ROUND_UP_2(h)/2))
#define I420_SIZE(w,h) (I420_V_OFFSET(w,h)+(I420_V_ROWSTRIDE(w)*GST_ROUND_UP_2(h)/2))
GST_BOILERPLATE (GstCairoTextOverlay, gst_text_overlay, GstElement,
GST_TYPE_ELEMENT);
static void
gst_text_overlay_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 (&cairo_text_overlay_src_template_factory));
gst_element_class_add_pad_template (element_class,
gst_static_pad_template_get (&video_sink_template_factory));
gst_element_class_add_pad_template (element_class,
gst_static_pad_template_get (&text_sink_template_factory));
gst_element_class_set_details_simple (element_class, "Text overlay",
"Filter/Editor/Video",
"Adds text strings on top of a video buffer",
"David Schleef <ds@schleef.org>");
}
static void
gst_text_overlay_class_init (GstCairoTextOverlayClass * klass)
{
GObjectClass *gobject_class;
GstElementClass *gstelement_class;
gobject_class = (GObjectClass *) klass;
gstelement_class = (GstElementClass *) klass;
gobject_class->finalize = gst_text_overlay_finalize;
gobject_class->set_property = gst_text_overlay_set_property;
gstelement_class->change_state =
GST_DEBUG_FUNCPTR (gst_text_overlay_change_state);
g_object_class_install_property (G_OBJECT_CLASS (klass), ARG_TEXT,
g_param_spec_string ("text", "text",
"Text to be display.", "",
G_PARAM_WRITABLE | G_PARAM_STATIC_STRINGS));
g_object_class_install_property (G_OBJECT_CLASS (klass), ARG_SHADING,
g_param_spec_boolean ("shaded-background", "shaded background",
"Whether to shade the background under the text area", FALSE,
G_PARAM_WRITABLE | G_PARAM_STATIC_STRINGS));
g_object_class_install_property (G_OBJECT_CLASS (klass), ARG_VALIGN,
g_param_spec_string ("valign", "vertical alignment",
"Vertical alignment of the text. "
"Can be either 'baseline', 'bottom', or 'top'",
"baseline", G_PARAM_WRITABLE | G_PARAM_STATIC_STRINGS));
g_object_class_install_property (G_OBJECT_CLASS (klass), ARG_HALIGN,
g_param_spec_string ("halign", "horizontal alignment",
"Horizontal alignment of the text. "
"Can be either 'left', 'right', or 'center'",
"center", G_PARAM_WRITABLE | G_PARAM_STATIC_STRINGS));
g_object_class_install_property (G_OBJECT_CLASS (klass), ARG_XPAD,
g_param_spec_int ("xpad", "horizontal paddding",
"Horizontal paddding when using left/right alignment",
G_MININT, G_MAXINT, DEFAULT_XPAD,
G_PARAM_WRITABLE | G_PARAM_STATIC_STRINGS));
g_object_class_install_property (G_OBJECT_CLASS (klass), ARG_YPAD,
g_param_spec_int ("ypad", "vertical padding",
"Vertical padding when using top/bottom alignment",
G_MININT, G_MAXINT, DEFAULT_YPAD,
G_PARAM_WRITABLE | G_PARAM_STATIC_STRINGS));
g_object_class_install_property (G_OBJECT_CLASS (klass), ARG_DELTAX,
g_param_spec_int ("deltax", "X position modifier",
"Shift X position to the left or to the right. Unit is pixels.",
G_MININT, G_MAXINT, 0, G_PARAM_WRITABLE | G_PARAM_STATIC_STRINGS));
g_object_class_install_property (G_OBJECT_CLASS (klass), ARG_DELTAY,
g_param_spec_int ("deltay", "Y position modifier",
"Shift Y position up or down. Unit is pixels.",
G_MININT, G_MAXINT, 0, G_PARAM_WRITABLE | G_PARAM_STATIC_STRINGS));
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 | G_PARAM_STATIC_STRINGS));
}
static void
gst_text_overlay_finalize (GObject * object)
{
GstCairoTextOverlay *overlay = GST_CAIRO_TEXT_OVERLAY (object);
gst_collect_pads_stop (overlay->collect);
gst_object_unref (overlay->collect);
g_free (overlay->text_fill_image);
g_free (overlay->text_outline_image);
g_free (overlay->default_text);
g_free (overlay->font);
G_OBJECT_CLASS (parent_class)->finalize (object);
}
static void
gst_text_overlay_init (GstCairoTextOverlay * overlay,
GstCairoTextOverlayClass * klass)
{
/* video sink */
overlay->video_sinkpad =
gst_pad_new_from_static_template (&video_sink_template_factory,
"video_sink");
gst_pad_set_getcaps_function (overlay->video_sinkpad,
GST_DEBUG_FUNCPTR (gst_text_overlay_getcaps));
gst_pad_set_setcaps_function (overlay->video_sinkpad,
GST_DEBUG_FUNCPTR (gst_text_overlay_setcaps));
gst_element_add_pad (GST_ELEMENT (overlay), overlay->video_sinkpad);
/* text sink */
overlay->text_sinkpad =
gst_pad_new_from_static_template (&text_sink_template_factory,
"text_sink");
gst_pad_set_link_function (overlay->text_sinkpad,
GST_DEBUG_FUNCPTR (gst_text_overlay_text_pad_linked));
gst_pad_set_unlink_function (overlay->text_sinkpad,
GST_DEBUG_FUNCPTR (gst_text_overlay_text_pad_unlinked));
gst_element_add_pad (GST_ELEMENT (overlay), overlay->text_sinkpad);
/* (video) source */
overlay->srcpad =
gst_pad_new_from_static_template
(&cairo_text_overlay_src_template_factory, "src");
gst_pad_set_getcaps_function (overlay->srcpad,
GST_DEBUG_FUNCPTR (gst_text_overlay_getcaps));
gst_element_add_pad (GST_ELEMENT (overlay), overlay->srcpad);
overlay->halign = GST_CAIRO_TEXT_OVERLAY_HALIGN_CENTER;
overlay->valign = GST_CAIRO_TEXT_OVERLAY_VALIGN_BASELINE;
overlay->xpad = DEFAULT_XPAD;
overlay->ypad = DEFAULT_YPAD;
overlay->deltax = 0;
overlay->deltay = 0;
overlay->default_text = g_strdup ("");
overlay->need_render = TRUE;
overlay->font = g_strdup (DEFAULT_FONT);
gst_text_overlay_font_init (overlay);
overlay->fps_n = 0;
overlay->fps_d = 1;
overlay->collect = gst_collect_pads_new ();
gst_collect_pads_set_function (overlay->collect,
GST_DEBUG_FUNCPTR (gst_text_overlay_collected), overlay);
overlay->video_collect_data = gst_collect_pads_add_pad (overlay->collect,
overlay->video_sinkpad, sizeof (GstCollectData));
/* text pad will be added when it is linked */
overlay->text_collect_data = NULL;
}
static void
gst_text_overlay_font_init (GstCairoTextOverlay * overlay)
{
cairo_font_extents_t font_extents;
cairo_surface_t *surface;
cairo_t *cr;
gchar *font_desc, *sep;
font_desc = g_ascii_strdown (overlay->font, -1);
/* cairo_select_font_face() does not parse the size at the end, so we have
* to do that ourselves; same for slate and weight */
sep = MAX (strrchr (font_desc, ' '), strrchr (font_desc, ','));
if (sep != NULL && g_strtod (sep, NULL) > 0.0) {
/* there may be a suffix such as 'px', but we just ignore that for now */
overlay->scale = g_strtod (sep, NULL);
} else {
overlay->scale = GST_CAIRO_TEXT_OVERLAY_DEFAULT_SCALE;
}
if (strstr (font_desc, "bold"))
overlay->weight = CAIRO_FONT_WEIGHT_BOLD;
else
overlay->weight = CAIRO_FONT_WEIGHT_NORMAL;
if (strstr (font_desc, "italic"))
overlay->slant = CAIRO_FONT_SLANT_ITALIC;
else if (strstr (font_desc, "oblique"))
overlay->slant = CAIRO_FONT_SLANT_OBLIQUE;
else
overlay->slant = CAIRO_FONT_SLANT_NORMAL;
GST_LOG_OBJECT (overlay, "Font desc: '%s', scale=%f, weight=%d, slant=%d",
overlay->font, overlay->scale, overlay->weight, overlay->slant);
surface = cairo_image_surface_create (CAIRO_FORMAT_ARGB32, 256, 256);
cr = cairo_create (surface);
cairo_select_font_face (cr, overlay->font, overlay->slant, overlay->weight);
cairo_set_font_size (cr, overlay->scale);
/* this has a static leak:
* http://lists.freedesktop.org/archives/cairo/2007-May/010623.html
*/
cairo_font_extents (cr, &font_extents);
overlay->font_height = GST_ROUND_UP_2 ((guint) font_extents.height);
overlay->need_render = TRUE;
cairo_destroy (cr);
cairo_surface_destroy (surface);
g_free (font_desc);
}
static void
gst_text_overlay_set_property (GObject * object, guint prop_id,
const GValue * value, GParamSpec * pspec)
{
GstCairoTextOverlay *overlay = GST_CAIRO_TEXT_OVERLAY (object);
GST_OBJECT_LOCK (overlay);
switch (prop_id) {
case ARG_TEXT:{
g_free (overlay->default_text);
overlay->default_text = g_value_dup_string (value);
break;
}
case ARG_SHADING:{
overlay->want_shading = g_value_get_boolean (value);
break;
}
case ARG_VALIGN:{
const gchar *s = g_value_get_string (value);
if (g_ascii_strcasecmp (s, "baseline") == 0)
overlay->valign = GST_CAIRO_TEXT_OVERLAY_VALIGN_BASELINE;
else if (g_ascii_strcasecmp (s, "bottom") == 0)
overlay->valign = GST_CAIRO_TEXT_OVERLAY_VALIGN_BOTTOM;
else if (g_ascii_strcasecmp (s, "top") == 0)
overlay->valign = GST_CAIRO_TEXT_OVERLAY_VALIGN_TOP;
else
g_warning ("Invalid 'valign' property value: %s", s);
break;
}
case ARG_HALIGN:{
const gchar *s = g_value_get_string (value);
if (g_ascii_strcasecmp (s, "left") == 0)
overlay->halign = GST_CAIRO_TEXT_OVERLAY_HALIGN_LEFT;
else if (g_ascii_strcasecmp (s, "right") == 0)
overlay->halign = GST_CAIRO_TEXT_OVERLAY_HALIGN_RIGHT;
else if (g_ascii_strcasecmp (s, "center") == 0)
overlay->halign = GST_CAIRO_TEXT_OVERLAY_HALIGN_CENTER;
else
g_warning ("Invalid 'halign' property value: %s", s);
break;
}
case ARG_XPAD:{
overlay->xpad = g_value_get_int (value);
break;
}
case ARG_YPAD:{
overlay->ypad = g_value_get_int (value);
break;
}
case ARG_DELTAX:{
overlay->deltax = g_value_get_int (value);
break;
}
case ARG_DELTAY:{
overlay->deltay = g_value_get_int (value);
break;
}
case ARG_FONT_DESC:{
g_free (overlay->font);
overlay->font = g_value_dup_string (value);
if (overlay->font == NULL)
overlay->font = g_strdup (DEFAULT_FONT);
gst_text_overlay_font_init (overlay);
break;
}
default:{
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
overlay->need_render = TRUE;
GST_OBJECT_UNLOCK (overlay);
}
static void
gst_text_overlay_render_text (GstCairoTextOverlay * overlay,
const gchar * text, gint textlen)
{
cairo_text_extents_t extents;
cairo_surface_t *surface;
cairo_t *cr;
gchar *string;
double x, y;
if (textlen < 0)
textlen = strlen (text);
if (!overlay->need_render) {
GST_DEBUG ("Using previously rendered text.");
g_return_if_fail (overlay->text_fill_image != NULL);
g_return_if_fail (overlay->text_outline_image != NULL);
return;
}
string = g_strndup (text, textlen);
GST_DEBUG ("Rendering text '%s' on cairo RGBA surface", string);
overlay->text_fill_image =
g_realloc (overlay->text_fill_image,
4 * overlay->width * overlay->font_height);
surface = cairo_image_surface_create_for_data (overlay->text_fill_image,
CAIRO_FORMAT_ARGB32, overlay->width, overlay->font_height,
overlay->width * 4);
cr = cairo_create (surface);
cairo_select_font_face (cr, overlay->font, overlay->slant, overlay->weight);
cairo_set_font_size (cr, overlay->scale);
cairo_save (cr);
cairo_rectangle (cr, 0, 0, overlay->width, overlay->font_height);
cairo_set_source_rgba (cr, 0, 0, 0, 1.0);
cairo_set_operator (cr, CAIRO_OPERATOR_SOURCE);
cairo_fill (cr);
cairo_restore (cr);
cairo_save (cr);
cairo_text_extents (cr, string, &extents);
cairo_set_source_rgba (cr, 1, 1, 1, 1.0);
switch (overlay->halign) {
case GST_CAIRO_TEXT_OVERLAY_HALIGN_LEFT:
x = overlay->xpad;
break;
case GST_CAIRO_TEXT_OVERLAY_HALIGN_CENTER:
x = (overlay->width - extents.width) / 2;
break;
case GST_CAIRO_TEXT_OVERLAY_HALIGN_RIGHT:
x = overlay->width - extents.width - overlay->xpad;
break;
default:
x = 0;
}
x += overlay->deltax;
overlay->text_x0 = x;
overlay->text_x1 = x + extents.x_advance;
overlay->text_dy = (extents.height + extents.y_bearing);
y = overlay->font_height - overlay->text_dy;
cairo_move_to (cr, x, y);
cairo_show_text (cr, string);
cairo_restore (cr);
cairo_destroy (cr);
cairo_surface_destroy (surface);
/* ----------- */
overlay->text_outline_image =
g_realloc (overlay->text_outline_image,
4 * overlay->width * overlay->font_height);
surface = cairo_image_surface_create_for_data (overlay->text_outline_image,
CAIRO_FORMAT_ARGB32, overlay->width, overlay->font_height,
overlay->width * 4);
cr = cairo_create (surface);
cairo_select_font_face (cr, overlay->font, overlay->slant, overlay->weight);
cairo_set_font_size (cr, overlay->scale);
cairo_save (cr);
cairo_rectangle (cr, 0, 0, overlay->width, overlay->font_height);
cairo_set_source_rgba (cr, 0, 0, 0, 1.0);
cairo_set_operator (cr, CAIRO_OPERATOR_SOURCE);
cairo_fill (cr);
cairo_restore (cr);
cairo_save (cr);
cairo_move_to (cr, x, y);
cairo_set_source_rgba (cr, 1, 1, 1, 1.0);
cairo_set_line_width (cr, 1.0);
cairo_text_path (cr, string);
cairo_stroke (cr);
cairo_restore (cr);
g_free (string);
cairo_destroy (cr);
cairo_surface_destroy (surface);
overlay->need_render = FALSE;
}
static GstCaps *
gst_text_overlay_getcaps (GstPad * pad)
{
GstCairoTextOverlay *overlay;
GstPad *otherpad;
GstCaps *caps;
overlay = GST_CAIRO_TEXT_OVERLAY (gst_pad_get_parent (pad));
if (pad == overlay->srcpad)
otherpad = overlay->video_sinkpad;
else
otherpad = overlay->srcpad;
/* we can do what the peer can */
caps = gst_pad_peer_get_caps (otherpad);
if (caps) {
GstCaps *temp;
const GstCaps *templ;
GST_DEBUG_OBJECT (pad, "peer caps %" GST_PTR_FORMAT, caps);
/* filtered against our padtemplate */
templ = gst_pad_get_pad_template_caps (otherpad);
GST_DEBUG_OBJECT (pad, "our template %" GST_PTR_FORMAT, templ);
temp = gst_caps_intersect (caps, templ);
GST_DEBUG_OBJECT (pad, "intersected %" GST_PTR_FORMAT, temp);
gst_caps_unref (caps);
/* this is what we can do */
caps = temp;
} else {
/* no peer, our padtemplate is enough then */
caps = gst_caps_copy (gst_pad_get_pad_template_caps (pad));
}
GST_DEBUG_OBJECT (overlay, "returning %" GST_PTR_FORMAT, caps);
gst_object_unref (overlay);
return caps;
}
/* FIXME: upstream nego (e.g. when the video window is resized) */
static gboolean
gst_text_overlay_setcaps (GstPad * pad, GstCaps * caps)
{
GstCairoTextOverlay *overlay;
GstStructure *structure;
gboolean ret = FALSE;
const GValue *fps;
if (!GST_PAD_IS_SINK (pad))
return TRUE;
g_return_val_if_fail (gst_caps_is_fixed (caps), FALSE);
overlay = GST_CAIRO_TEXT_OVERLAY (gst_pad_get_parent (pad));
overlay->width = 0;
overlay->height = 0;
structure = gst_caps_get_structure (caps, 0);
fps = gst_structure_get_value (structure, "framerate");
if (gst_structure_get_int (structure, "width", &overlay->width) &&
gst_structure_get_int (structure, "height", &overlay->height) &&
fps != NULL) {
ret = gst_pad_set_caps (overlay->srcpad, caps);
}
overlay->fps_n = gst_value_get_fraction_numerator (fps);
overlay->fps_d = gst_value_get_fraction_denominator (fps);
gst_object_unref (overlay);
return ret;
}
static GstPadLinkReturn
gst_text_overlay_text_pad_linked (GstPad * pad, GstPad * peer)
{
GstCairoTextOverlay *overlay;
overlay = GST_CAIRO_TEXT_OVERLAY (GST_PAD_PARENT (pad));
GST_DEBUG_OBJECT (overlay, "Text pad linked");
if (overlay->text_collect_data == NULL) {
overlay->text_collect_data = gst_collect_pads_add_pad (overlay->collect,
overlay->text_sinkpad, sizeof (GstCollectData));
}
overlay->need_render = TRUE;
return GST_PAD_LINK_OK;
}
static void
gst_text_overlay_text_pad_unlinked (GstPad * pad)
{
GstCairoTextOverlay *overlay;
/* don't use gst_pad_get_parent() here, will deadlock */
overlay = GST_CAIRO_TEXT_OVERLAY (GST_PAD_PARENT (pad));
GST_DEBUG_OBJECT (overlay, "Text pad unlinked");
if (overlay->text_collect_data) {
gst_collect_pads_remove_pad (overlay->collect, overlay->text_sinkpad);
overlay->text_collect_data = NULL;
}
overlay->need_render = TRUE;
}
#define BOX_SHADING_VAL -80
#define BOX_XPAD 6
#define BOX_YPAD 6
static inline void
gst_text_overlay_shade_y (GstCairoTextOverlay * overlay, guchar * dest,
guint dest_stride, gint y0, gint y1)
{
gint i, j, x0, x1;
x0 = CLAMP (overlay->text_x0 - BOX_XPAD, 0, overlay->width);
x1 = CLAMP (overlay->text_x1 + BOX_XPAD, 0, overlay->width);
y0 = CLAMP (y0 - BOX_YPAD, 0, overlay->height);
y1 = CLAMP (y1 + BOX_YPAD, 0, overlay->height);
for (i = y0; i < y1; ++i) {
for (j = x0; j < x1; ++j) {
gint y = dest[(i * dest_stride) + j] + BOX_SHADING_VAL;
dest[(i * dest_stride) + j] = CLAMP (y, 0, 255);
}
}
}
static inline void
gst_text_overlay_blit_1 (GstCairoTextOverlay * overlay, guchar * dest,
guchar * text_image, gint val, guint dest_stride, gint y0)
{
gint i, j;
gint x, a, y;
gint y1;
y = val;
y0 = MIN (y0, overlay->height);
y1 = MIN (y0 + overlay->font_height, overlay->height);
for (i = y0; i < y1; i++) {
for (j = 0; j < overlay->width; j++) {
x = dest[i * dest_stride + j];
a = text_image[4 * ((i - y0) * overlay->width + j) + 1];
dest[i * dest_stride + j] = (y * a + x * (255 - a)) / 255;
}
}
}
static inline void
gst_text_overlay_blit_sub2x2 (GstCairoTextOverlay * overlay, guchar * dest,
guchar * text_image, gint val, guint dest_stride, gint y0)
{
gint i, j;
gint x, a, y;
gint y1;
y0 = MIN (y0, overlay->height);
y1 = MIN (y0 + overlay->font_height, overlay->height);
y = val;
for (i = y0; i < y1; i += 2) {
for (j = 0; j < overlay->width; j += 2) {
x = dest[(i / 2) * dest_stride + j / 2];
a = (text_image[4 * ((i - y0) * overlay->width + j) + 1] +
text_image[4 * ((i - y0) * overlay->width + j + 1) + 1] +
text_image[4 * ((i - y0 + 1) * overlay->width + j) + 1] +
text_image[4 * ((i - y0 + 1) * overlay->width + j + 1) + 1] + 2) / 4;
dest[(i / 2) * dest_stride + j / 2] = (y * a + x * (255 - a)) / 255;
}
}
}
static GstFlowReturn
gst_text_overlay_push_frame (GstCairoTextOverlay * overlay,
GstBuffer * video_frame)
{
guchar *y, *u, *v;
gint ypos;
video_frame = gst_buffer_make_writable (video_frame);
switch (overlay->valign) {
case GST_CAIRO_TEXT_OVERLAY_VALIGN_BOTTOM:
ypos = overlay->height - overlay->font_height - overlay->ypad;
break;
case GST_CAIRO_TEXT_OVERLAY_VALIGN_BASELINE:
ypos = overlay->height - (overlay->font_height - overlay->text_dy)
- overlay->ypad;
break;
case GST_CAIRO_TEXT_OVERLAY_VALIGN_TOP:
ypos = overlay->ypad;
break;
default:
ypos = overlay->ypad;
break;
}
ypos += overlay->deltay;
y = GST_BUFFER_DATA (video_frame);
u = y + I420_U_OFFSET (overlay->width, overlay->height);
v = y + I420_V_OFFSET (overlay->width, overlay->height);
/* shaded background box */
if (overlay->want_shading) {
gst_text_overlay_shade_y (overlay,
y, I420_Y_ROWSTRIDE (overlay->width),
ypos + overlay->text_dy, ypos + overlay->font_height);
}
/* blit outline text on video image */
gst_text_overlay_blit_1 (overlay,
y,
overlay->text_outline_image, 0, I420_Y_ROWSTRIDE (overlay->width), ypos);
gst_text_overlay_blit_sub2x2 (overlay,
u,
overlay->text_outline_image, 128, I420_U_ROWSTRIDE (overlay->width),
ypos);
gst_text_overlay_blit_sub2x2 (overlay, v, overlay->text_outline_image, 128,
I420_V_ROWSTRIDE (overlay->width), ypos);
/* blit text on video image */
gst_text_overlay_blit_1 (overlay,
y,
overlay->text_fill_image, 255, I420_Y_ROWSTRIDE (overlay->width), ypos);
gst_text_overlay_blit_sub2x2 (overlay,
u,
overlay->text_fill_image, 128, I420_U_ROWSTRIDE (overlay->width), ypos);
gst_text_overlay_blit_sub2x2 (overlay,
v,
overlay->text_fill_image, 128, I420_V_ROWSTRIDE (overlay->width), ypos);
return gst_pad_push (overlay->srcpad, video_frame);
}
static void
gst_text_overlay_pop_video (GstCairoTextOverlay * overlay)
{
GstBuffer *buf;
buf = gst_collect_pads_pop (overlay->collect, overlay->video_collect_data);
g_return_if_fail (buf != NULL);
gst_buffer_unref (buf);
}
static void
gst_text_overlay_pop_text (GstCairoTextOverlay * overlay)
{
GstBuffer *buf;
if (overlay->text_collect_data) {
buf = gst_collect_pads_pop (overlay->collect, overlay->text_collect_data);
g_return_if_fail (buf != NULL);
gst_buffer_unref (buf);
}
overlay->need_render = TRUE;
}
/* This function is called when there is data on all pads */
static GstFlowReturn
gst_text_overlay_collected (GstCollectPads * pads, gpointer data)
{
GstCairoTextOverlay *overlay;
GstFlowReturn ret = GST_FLOW_OK;
GstClockTime now, txt_end, frame_end;
GstBuffer *video_frame = NULL;
GstBuffer *text_buf = NULL;
gchar *text;
gint text_len;
overlay = GST_CAIRO_TEXT_OVERLAY (data);
GST_DEBUG ("Collecting");
video_frame = gst_collect_pads_peek (overlay->collect,
overlay->video_collect_data);
/* send EOS if video stream EOSed regardless of text stream */
if (video_frame == NULL) {
GST_DEBUG ("Video stream at EOS");
if (overlay->text_collect_data) {
text_buf = gst_collect_pads_pop (overlay->collect,
overlay->text_collect_data);
}
gst_pad_push_event (overlay->srcpad, gst_event_new_eos ());
ret = GST_FLOW_UNEXPECTED;
goto done;
}
if (GST_BUFFER_TIMESTAMP (video_frame) == GST_CLOCK_TIME_NONE) {
g_warning ("%s: video frame has invalid timestamp", G_STRLOC);
}
now = GST_BUFFER_TIMESTAMP (video_frame);
if (GST_BUFFER_DURATION (video_frame) != GST_CLOCK_TIME_NONE) {
frame_end = now + GST_BUFFER_DURATION (video_frame);
} else if (overlay->fps_n > 0) {
frame_end = now + gst_util_uint64_scale_int (GST_SECOND,
overlay->fps_d, overlay->fps_n);
} else {
/* magic value, does not really matter since texts
* tend to span quite a few frames in practice anyway */
frame_end = now + GST_SECOND / 25;
}
GST_DEBUG ("Got video frame: %" GST_TIME_FORMAT " - %" GST_TIME_FORMAT,
GST_TIME_ARGS (now), GST_TIME_ARGS (frame_end));
/* text pad not linked? */
if (overlay->text_collect_data == NULL) {
GST_DEBUG ("Text pad not linked, rendering default text: '%s'",
GST_STR_NULL (overlay->default_text));
if (overlay->default_text && *overlay->default_text != '\0') {
gst_text_overlay_render_text (overlay, overlay->default_text, -1);
ret = gst_text_overlay_push_frame (overlay, video_frame);
} else {
ret = gst_pad_push (overlay->srcpad, video_frame);
}
gst_text_overlay_pop_video (overlay);
video_frame = NULL;
goto done;
}
text_buf = gst_collect_pads_peek (overlay->collect,
overlay->text_collect_data);
/* just push the video frame if the text stream has EOSed */
if (text_buf == NULL) {
GST_DEBUG ("Text pad EOSed, just pushing video frame as is");
ret = gst_pad_push (overlay->srcpad, video_frame);
gst_text_overlay_pop_video (overlay);
video_frame = NULL;
goto done;
}
/* if the text buffer isn't stamped right, pop it off the
* queue and display it for the current video frame only */
if (GST_BUFFER_TIMESTAMP (text_buf) == GST_CLOCK_TIME_NONE ||
GST_BUFFER_DURATION (text_buf) == GST_CLOCK_TIME_NONE) {
GST_WARNING ("Got text buffer with invalid time stamp or duration");
gst_text_overlay_pop_text (overlay);
GST_BUFFER_TIMESTAMP (text_buf) = now;
GST_BUFFER_DURATION (text_buf) = frame_end - now;
}
txt_end = GST_BUFFER_TIMESTAMP (text_buf) + GST_BUFFER_DURATION (text_buf);
GST_DEBUG ("Got text buffer: %" GST_TIME_FORMAT " - %" GST_TIME_FORMAT,
GST_TIME_ARGS (GST_BUFFER_TIMESTAMP (text_buf)), GST_TIME_ARGS (txt_end));
/* if the text buffer is too old, pop it off the
* queue and return so we get a new one next time */
if (txt_end < now) {
GST_DEBUG ("Text buffer too old, popping off the queue");
gst_text_overlay_pop_text (overlay);
ret = GST_FLOW_OK;
goto done;
}
/* if the video frame ends before the text even starts,
* just push it out as is and pop it off the queue */
if (frame_end < GST_BUFFER_TIMESTAMP (text_buf)) {
GST_DEBUG ("Video buffer before text, pushing out and popping off queue");
ret = gst_pad_push (overlay->srcpad, video_frame);
gst_text_overlay_pop_video (overlay);
video_frame = NULL;
goto done;
}
/* text duration overlaps video frame duration */
text = g_strndup ((gchar *) GST_BUFFER_DATA (text_buf),
GST_BUFFER_SIZE (text_buf));
g_strdelimit (text, "\n\r\t", ' ');
text_len = strlen (text);
if (text_len > 0) {
GST_DEBUG ("Rendering text '%*s'", text_len, text);;
gst_text_overlay_render_text (overlay, text, text_len);
} else {
GST_DEBUG ("No text to render (empty buffer)");
gst_text_overlay_render_text (overlay, " ", 1);
}
g_free (text);
gst_text_overlay_pop_video (overlay);
ret = gst_text_overlay_push_frame (overlay, video_frame);
video_frame = NULL;
goto done;
done:
{
if (text_buf)
gst_buffer_unref (text_buf);
if (video_frame)
gst_buffer_unref (video_frame);
return ret;
}
}
static GstStateChangeReturn
gst_text_overlay_change_state (GstElement * element, GstStateChange transition)
{
GstStateChangeReturn ret = GST_STATE_CHANGE_SUCCESS;
GstCairoTextOverlay *overlay = GST_CAIRO_TEXT_OVERLAY (element);
switch (transition) {
case GST_STATE_CHANGE_READY_TO_PAUSED:
gst_collect_pads_start (overlay->collect);
break;
case GST_STATE_CHANGE_PAUSED_TO_READY:
/* need to unblock the collectpads before calling the
* parent change_state so that streaming can finish */
gst_collect_pads_stop (overlay->collect);
break;
default:
break;
}
ret = parent_class->change_state (element, transition);
if (ret == GST_STATE_CHANGE_FAILURE)
return ret;
switch (transition) {
default:
break;
}
return ret;
}
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