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livetrax/libs/gtkmm2ext/emscale.cc

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/*
* Copyright (C) 2014-2016 Paul Davis <paul@linuxaudiosystems.com>
*
* 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.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include <algorithm>
#include <gdk/gdk.h>
#include <pangomm/layout.h>
#include "gtkmm2ext/emscale.h"
#include "pbd/i18n.h"
using namespace Gtkmm2ext;
std::map<std::string,EmScale> EmScale::_emscales;
EmScale::EmScale (const Pango::FontDescription& fd)
: _font (fd)
, _char_pixel_width (-1)
, _char_pixel_height (-1)
, _char_avg_pixel_width (-1)
{
}
void
EmScale::recalc_char_pixel_geometry ()
{
if (_char_pixel_height > 0 && _char_pixel_width > 0) {
return;
}
Glib::RefPtr<Pango::Context> pc = Glib::wrap (gdk_pango_context_get_for_screen (gdk_screen_get_default()));
Glib::RefPtr<Pango::Layout> layout = Pango::Layout::create (pc);
layout->set_font_description (_font);
int w, h;
std::string x = _("ABCDEFGHIJLKMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789");
layout->set_text (x);
layout->get_pixel_size (w, h);
_char_pixel_height = std::max(4, h);
// number of actual chars in the string (not bytes)
// Glib to the rescue.
Glib::ustring gx(x);
_char_avg_pixel_width = w / (float)gx.size();
_char_pixel_width = std::max(4, (int) ceil (_char_avg_pixel_width));
}
EmScale&
EmScale::by_font (const Pango::FontDescription& fd)
{
std::map<std::string,EmScale>::iterator i = _emscales.find (fd.to_string());
if (i == _emscales.end()) {
i = _emscales.insert (std::make_pair (fd.to_string(), EmScale (fd))).first;
}
return i->second;
}