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/*
Copyright (C) 2014-2015 Carl Hetherington <cth@carlh.net>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include "render_subtitles.h"
#include "types.h"
#include "image.h"
#include <cairomm/cairomm.h>
#include <pangomm.h>
#include <boost/foreach.hpp>
using std::list;
using std::cout;
using std::string;
using std::min;
using std::max;
using std::pair;
using boost::shared_ptr;
using boost::optional;
static PositionImage
render_subtitle (dcp::SubtitleString const & subtitle, dcp::Size target)
{
/* Calculate x and y scale factors. These are only used to stretch
the font away from its normal aspect ratio.
*/
float xscale = 1;
float yscale = 1;
if (fabs (subtitle.aspect_adjust() - 1.0) > dcp::ASPECT_ADJUST_EPSILON) {
if (subtitle.aspect_adjust() < 1) {
xscale = max (0.25f, subtitle.aspect_adjust ());
yscale = 1;
} else {
xscale = 1;
yscale = 1 / min (4.0f, subtitle.aspect_adjust ());
}
}
/* Make an empty bitmap as wide as target and at
least tall enough for this subtitle.
*/
/* Basic guess on height... */
int height = subtitle.size() * target.height / (11 * 72);
/* ...scaled... */
height *= yscale;
/* ...and add a bit more for luck */
height += target.height / 11;
shared_ptr<Image> image (new Image (PIX_FMT_RGBA, dcp::Size (target.width, height), false));
image->make_black ();
Cairo::RefPtr<Cairo::ImageSurface> surface = Cairo::ImageSurface::create (
image->data()[0],
Cairo::FORMAT_ARGB32,
image->size().width,
image->size().height,
Cairo::ImageSurface::format_stride_for_width (Cairo::FORMAT_ARGB32, image->size().width)
);
Cairo::RefPtr<Cairo::Context> context = Cairo::Context::create (surface);
Glib::RefPtr<Pango::Layout> layout = Pango::Layout::create (context);
layout->set_alignment (Pango::ALIGN_LEFT);
context->set_line_width (1);
/* Render the subtitle at the top left-hand corner of image */
Pango::FontDescription font (subtitle.font().get_value_or ("Arial"));
font.set_absolute_size (subtitle.size_in_pixels (target.height) * PANGO_SCALE);
if (subtitle.italic ()) {
font.set_style (Pango::STYLE_ITALIC);
}
layout->set_font_description (font);
layout->set_text (subtitle.text ());
/* Compute fade factor */
/* XXX */
float fade_factor = 1;
layout->update_from_cairo_context (context);
context->scale (xscale, yscale);
if (subtitle.effect() == dcp::SHADOW) {
/* Drop-shadow effect */
dcp::Colour const ec = subtitle.effect_colour ();
context->set_source_rgba (float(ec.r) / 255, float(ec.g) / 255, float(ec.b) / 255, fade_factor);
context->move_to (4, 4);
layout->add_to_cairo_context (context);
context->fill ();
}
/* The actual subtitle */
dcp::Colour const c = subtitle.colour ();
context->set_source_rgba (float(c.r) / 255, float(c.g) / 255, float(c.b) / 255, fade_factor);
context->move_to (0, 0);
layout->add_to_cairo_context (context);
context->fill ();
if (subtitle.effect() == dcp::BORDER) {
/* Border effect */
dcp::Colour ec = subtitle.effect_colour ();
context->set_source_rgba (float(ec.r) / 255, float(ec.g) / 255, float(ec.b) / 255, fade_factor);
context->move_to (0, 0);
layout->add_to_cairo_context (context);
context->stroke ();
}
int layout_width;
int layout_height;
layout->get_size (layout_width, layout_height);
int x = 0;
switch (subtitle.h_align ()) {
case dcp::HALIGN_LEFT:
/* h_position is distance between left of frame and left of subtitle */
x = subtitle.h_position() * target.width;
break;
case dcp::HALIGN_CENTER:
/* h_position is distance between centre of frame and centre of subtitle */
x = (0.5 + subtitle.h_position()) * target.width - layout_width / (PANGO_SCALE * 2);
break;
case dcp::HALIGN_RIGHT:
/* h_position is distance between right of frame and right of subtitle */
x = (1.0 - subtitle.h_position()) * target.width - layout_width / PANGO_SCALE;
break;
}
int y = 0;
switch (subtitle.v_align ()) {
case dcp::VALIGN_TOP:
/* v_position is distance between top of frame and top of subtitle */
y = subtitle.v_position() * target.height;
break;
case dcp::VALIGN_CENTER:
/* v_position is distance between centre of frame and centre of subtitle */
y = (0.5 + subtitle.v_position()) * target.height - layout_height / (PANGO_SCALE * 2);
break;
case dcp::VALIGN_BOTTOM:
/* v_position is distance between bottom of frame and bottom of subtitle */
y = (1.0 - subtitle.v_position()) * target.height - layout_height / PANGO_SCALE;
break;
}
return PositionImage (image, Position<int> (x, y));
}
list<PositionImage>
render_subtitles (list<dcp::SubtitleString> subtitles, dcp::Size target)
{
list<PositionImage> images;
BOOST_FOREACH (dcp::SubtitleString const & i, subtitles) {
images.push_back (render_subtitle (i, target));
}
return images;
}
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