94 lines
2.9 KiB
C++
94 lines
2.9 KiB
C++
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/****************************************************************************
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**
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** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
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** All rights reserved.
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** Contact: Nokia Corporation (qt-info@nokia.com)
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**
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** This file is part of the test suite of the Qt Toolkit.
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**
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** $QT_BEGIN_LICENSE:LGPL$
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** No Commercial Usage
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** This file contains pre-release code and may not be distributed.
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** You may use this file in accordance with the terms and conditions
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** contained in the Technology Preview License Agreement accompanying
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** this package.
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**
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** GNU Lesser General Public License Usage
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** Alternatively, this file may be used under the terms of the GNU Lesser
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** General Public License version 2.1 as published by the Free Software
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** Foundation and appearing in the file LICENSE.LGPL included in the
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** packaging of this file. Please review the following information to
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** ensure the GNU Lesser General Public License version 2.1 requirements
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** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
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**
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** In addition, as a special exception, Nokia gives you certain additional
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** rights. These rights are described in the Nokia Qt LGPL Exception
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** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
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**
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** If you have questions regarding the use of this file, please contact
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** Nokia at qt-info@nokia.com.
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**
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**
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**
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**
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**
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**
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**
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**
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** $QT_END_LICENSE$
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**
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****************************************************************************/
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#include "utils.h"
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#include <assert.h>
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#include <qglobal.h>
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#include "qnum.h"
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#define FloatToXFixed(i) (int)((i) * 65536)
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#define IntToXFixed(i) ((i) << 16)
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static double compute_x_at(XFixed y, XPointFixed p1, XPointFixed p2)
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{
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double d = XFixedToDouble(p2.x - p1.x);
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return
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XFixedToDouble(p1.x) + d*XFixedToDouble(y - p1.y)/XFixedToDouble(p2.y - p1.y);
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}
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double compute_area(XTrapezoid *trap)
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{
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double x1 = compute_x_at(trap->top, trap->left.p1, trap->left.p2);
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double x2 = compute_x_at(trap->top, trap->right.p1, trap->right.p2);
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double x3 = compute_x_at(trap->bottom, trap->left.p1, trap->left.p2);
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double x4 = compute_x_at(trap->bottom, trap->right.p1, trap->right.p2);
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double top = XFixedToDouble(trap->top);
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double bottom = XFixedToDouble(trap->bottom);
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double h = bottom - top;
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double top_base = x2 - x1;
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double bottom_base = x4 - x3;
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if ((top_base < 0 && bottom_base > 0)
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|| (top_base > 0 && bottom_base < 0)) {
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double y0 = top_base*h/(top_base - bottom_base) + top;
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double area = qAbs(top_base * (y0 - top) / 2.);
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area += qAbs(bottom_base * (bottom - y0) /2.);
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return area;
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}
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return 0.5 * h * qAbs(top_base + bottom_base);
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}
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double compute_area_for_x(const QVector<XTrapezoid> &traps)
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{
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double area = 0;
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for (int i = 0; i < traps.size(); ++i) {
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XTrapezoid trap = traps[i];
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area += compute_area(&trap);
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}
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return area;
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}
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