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+/****************************************************************************
+**
+** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the QtGui module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and Digia.  For licensing terms and
+** conditions see http://qt.digia.com/licensing.  For further information
+** use the contact form at http://qt.digia.com/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Digia gives you certain additional
+** rights.  These rights are described in the Digia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3.0 as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU General Public License version 3.0 requirements will be
+** met: http://www.gnu.org/copyleft/gpl.html.
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QHIGHDPISCALING_P_H
+#define QHIGHDPISCALING_P_H
+
+#include <QtCore/qglobal.h>
+#include <QtCore/qmargins.h>
+#include <QtCore/qrect.h>
+#include <QtCore/qvector.h>
+#include <QtGui/qregion.h>
+
+// This file implmements utility functions for high-dpi scaling on operating
+// systems that do not provide native scaling support.
+//
+// The functions support creating a logical device-independent
+// coordinate system which is related to the device pixel coordinate
+// through a scaling factor. The scaling factor is set by the
+// QT_HIGHDPI_SCALE_FACTOR environment variable.
+//
+// With these functions in use  most of the Qt API will then operate in
+// the device-independent coordinate system. For example, setting
+// the scale factor to 2.0 will make Qt see half of the "device"
+// window geometry. Desktop and event geometry will be scaled
+// to match.
+//
+// Integer scaling factors work best. Glitch-free graphics at non-integer
+// scaling factors can not be guaranteed.
+
+QT_BEGIN_NAMESPACE
+
+class Q_GUI_EXPORT QHighDpiScaling {
+public:
+    static bool isActive() { return m_active; }
+    static qreal factor()  { return m_factor; }
+    static void setFactor(qreal factor);
+
+private:
+    static qreal m_factor;
+    static bool m_active;
+};
+
+// Coordinate system conversion functions:
+// qHighDpiToDeviceIndependentPixels   : from physical(screen/backing) to logical pixels
+// qHighDpiToDevicePixels              : from logical to physical pixels
+inline QRect qHighDpiToDeviceIndependentPixels(const QRect &pixelRect)
+{
+    const qreal scaleFactor = QHighDpiScaling::factor();
+    return QRect(pixelRect.topLeft() / scaleFactor, pixelRect.size() / scaleFactor);
+}
+
+inline QRect qHighDpiToDevicePixels(const QRect &pointRect)
+{
+    const qreal scaleFactor = QHighDpiScaling::factor();
+    return QRect(pointRect.topLeft() * scaleFactor, pointRect.size() * scaleFactor);
+}
+
+inline QRectF qHighDpiToDeviceIndependentPixels(const QRectF &pixelRect)
+{
+    const qreal scaleFactor = QHighDpiScaling::factor();
+    return QRectF(pixelRect.topLeft() / scaleFactor, pixelRect.size() / scaleFactor);
+}
+
+inline QRectF qHighDpiToDevicePixels(const QRectF &pointRect)
+{
+   const qreal scaleFactor = QHighDpiScaling::factor();
+   return QRectF(pointRect.topLeft() * scaleFactor, pointRect.size() * scaleFactor);
+}
+
+inline QSize qHighDpiToDeviceIndependentPixels(const QSize &pixelSize)
+{
+    return pixelSize / QHighDpiScaling::factor();
+}
+
+// For converting minimum/maximum sizes of QWindow, limits to 0..QWINDOWSIZE_MAX
+Q_GUI_EXPORT QSize qHighDpiToDevicePixelsConstrained(const QSize &size);
+
+inline QSize qHighDpiToDevicePixels(const QSize &pointSize)
+{
+    return pointSize * QHighDpiScaling::factor();
+}
+
+inline QSizeF qHighDpiToDeviceIndependentPixels(const QSizeF &pixelSize)
+{
+    return pixelSize / QHighDpiScaling::factor();
+}
+
+inline QSizeF qHighDpiToDevicePixels(const QSizeF &pointSize)
+{
+    return pointSize * QHighDpiScaling::factor();
+}
+
+inline QPoint qHighDpiToDeviceIndependentPixels(const QPoint &pixelPoint)
+{
+    return pixelPoint / QHighDpiScaling::factor();
+}
+
+inline QPoint qHighDpiToDevicePixels(const QPoint &pointPoint)
+{
+    return pointPoint * QHighDpiScaling::factor();
+}
+
+inline QPointF qHighDpiToDeviceIndependentPixels(const QPointF &pixelPoint)
+{
+    return pixelPoint / QHighDpiScaling::factor();
+}
+
+inline QPointF qHighDpiToDevicePixels(const QPointF &pointPoint)
+{
+    return pointPoint * QHighDpiScaling::factor();
+}
+
+inline QMargins qHighDpiToDeviceIndependentPixels(const QMargins &pixelMargins)
+{
+    const qreal scaleFactor = QHighDpiScaling::factor();
+    return QMargins(pixelMargins.left() / scaleFactor, pixelMargins.top() / scaleFactor,
+                    pixelMargins.right() / scaleFactor, pixelMargins.bottom() / scaleFactor);
+}
+
+inline QMargins qHighDpiToDevicePixels(const QMargins &pointMargins)
+{
+    const qreal scaleFactor = QHighDpiScaling::factor();
+    return QMargins(pointMargins.left() * scaleFactor, pointMargins.top() * scaleFactor,
+                    pointMargins.right() * scaleFactor, pointMargins.bottom() * scaleFactor);
+}
+
+inline QRegion qHighDpiToDeviceIndependentPixels(const QRegion &pixelRegion)
+{
+    if (!QHighDpiScaling::isActive())
+        return pixelRegion;
+
+    QRegion pointRegion;
+    foreach (const QRect &rect, pixelRegion.rects())
+        pointRegion += qHighDpiToDeviceIndependentPixels(rect);
+    return pointRegion;
+}
+
+inline QRegion qHighDpiToDevicePixels(const QRegion &pointRegion)
+{
+    if (!QHighDpiScaling::isActive())
+        return pointRegion;
+
+    QRegion pixelRegon;
+    foreach (const QRect &rect, pointRegion.rects())
+        pixelRegon += qHighDpiToDevicePixels(rect);
+    return pixelRegon;
+}
+
+// Any T that has operator/()
+template <typename T>
+T qHighDpiToDeviceIndependentPixels(const T &pixelValue)
+{
+    if (!QHighDpiScaling::isActive())
+        return pixelValue;
+
+    return pixelValue / QHighDpiScaling::factor();
+
+}
+
+// Any T that has operator*()
+template <typename T>
+T qHighDpiToDevicePixels(const T &pointValue)
+{
+    if (!QHighDpiScaling::isActive())
+        return pointValue;
+
+    return pointValue * QHighDpiScaling::factor();
+}
+
+// Any QVector<T> where T has operator/()
+template <typename T>
+QVector<T> qHighDpiToDeviceIndependentPixels(const QVector<T> &pixelValues)
+{
+    if (!QHighDpiScaling::isActive())
+        return pixelValues;
+
+    QVector<T> pointValues;
+    foreach (const T& pixelValue, pixelValues)
+        pointValues.append(pixelValue / QHighDpiScaling::factor());
+    return pointValues;
+}
+
+// Any QVector<T> where T has operator*()
+template <typename T>
+QVector<T> qHighDpiToDevicePixels(const QVector<T> &pointValues)
+{
+    if (!QHighDpiScaling::isActive())
+        return pointValues;
+
+    QVector<T> pixelValues;
+    foreach (const T& pointValue, pointValues)
+        pixelValues.append(pointValue * QHighDpiScaling::factor());
+    return pixelValues;
+}
+
+
+// Any QPair<T, U> where T and U has operator/()
+template <typename T, typename U>
+QPair<T, U> qHighDpiToDeviceIndependentPixels(const QPair<T, U> &pixelPair)
+{
+    return qMakePair(qHighDpiToDeviceIndependentPixels(pixelPair.first), qHighDpiToDeviceIndependentPixels(pixelPair.second));
+}
+
+// Any QPair<T, U> where T and U has operator*()
+template <typename T, typename U>
+QPair<T, U> qHighDpiToDevicePixels(const QPair<T, U> &pointPair)
+{
+    return qMakePair(qHighDpiToDevicePixels(pointPair.first), qHighDpiToDevicePixels(pointPair.second));
+}
+
+QT_END_NAMESPACE
+
+#endif