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/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*- vi:set ts=8 sts=4 sw=4: */
/*
Sonic Visualiser
An audio file viewer and annotation editor.
Centre for Digital Music, Queen Mary, University of London.
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. See the file
COPYING included with this distribution for more information.
*/
#ifndef SV_WIDGET_SCALE_H
#define SV_WIDGET_SCALE_H
#include <QFont>
#include <QFontMetrics>
#include "base/Debug.h"
namespace sv {
class WidgetScale
{
public:
/**
* Take a "design pixel" size and scale it for the actual
* display. This is relevant to hi-dpi systems that do not do
* pixel doubling (i.e. Windows and Linux rather than OS/X).
*/
static int scalePixelSize(int pixels) {
static double ratio = 0.0;
if (ratio == 0.0) {
double baseEm;
#ifdef Q_OS_MAC
baseEm = 17.0;
#else
baseEm = 15.0;
#endif
double em = QFontMetrics(QFont()).height();
ratio = em / baseEm;
SVDEBUG << "WidgetScale::scalePixelSize: baseEm = " << baseEm
<< ", platform default font height = " << em
<< ", resulting scale factor = " << ratio << endl;
if (ratio < 1.0) {
SVDEBUG << "WidgetScale::scalePixelSize: rounding up to 1.0"
<< endl;
ratio = 1.0;
}
}
int scaled = int(pixels * ratio + 0.5);
if (pixels != 0 && scaled == 0) scaled = 1;
return scaled;
}
static QSize scaleQSize(QSize size) {
return QSize(scalePixelSize(size.width()),
scalePixelSize(size.height()));
}
};
} // end namespace sv
#endif
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