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authorLars Knoll <lars.knoll@nokia.com>2009-03-23 09:18:55 (GMT)
committerSimon Hausmann <simon.hausmann@nokia.com>2009-03-23 09:18:55 (GMT)
commite5fcad302d86d316390c6b0f62759a067313e8a9 (patch)
treec2afbf6f1066b6ce261f14341cf6d310e5595bc1 /tests/auto/qtessellator/utils.cpp
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Long live Qt 4.5!
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+/****************************************************************************
+**
+** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
+** Contact: Qt Software Information (qt-info@nokia.com)
+**
+** This file is part of the test suite of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the either Technology Preview License Agreement or the
+** Beta Release License Agreement.
+**
+** 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, Nokia gives you certain
+** additional rights. These rights are described in the Nokia Qt LGPL
+** Exception version 1.0, 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.
+**
+** If you are unsure which license is appropriate for your use, please
+** contact the sales department at qt-sales@nokia.com.
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+#include "utils.h"
+
+#include <assert.h>
+#include <qglobal.h>
+
+#include <qnum.h>
+
+#define FloatToXFixed(i) (int)((i) * 65536)
+#define IntToXFixed(i) ((i) << 16)
+
+static double compute_x_at(XFixed y, XPointFixed p1, XPointFixed p2)
+{
+ double d = XFixedToDouble(p2.x - p1.x);
+ return
+ XFixedToDouble(p1.x) + d*XFixedToDouble(y - p1.y)/XFixedToDouble(p2.y - p1.y);
+}
+
+double compute_area(XTrapezoid *trap)
+{
+ double x1 = compute_x_at(trap->top, trap->left.p1, trap->left.p2);
+ double x2 = compute_x_at(trap->top, trap->right.p1, trap->right.p2);
+ double x3 = compute_x_at(trap->bottom, trap->left.p1, trap->left.p2);
+ double x4 = compute_x_at(trap->bottom, trap->right.p1, trap->right.p2);
+
+ double top = XFixedToDouble(trap->top);
+ double bottom = XFixedToDouble(trap->bottom);
+ double h = bottom - top;
+
+ double top_base = x2 - x1;
+ double bottom_base = x4 - x3;
+
+ if ((top_base < 0 && bottom_base > 0)
+ || (top_base > 0 && bottom_base < 0)) {
+ double y0 = top_base*h/(top_base - bottom_base) + top;
+ double area = qAbs(top_base * (y0 - top) / 2.);
+ area += qAbs(bottom_base * (bottom - y0) /2.);
+ return area;
+ }
+
+
+ return 0.5 * h * qAbs(top_base + bottom_base);
+}
+
+double compute_area_for_x(const QVector<XTrapezoid> &traps)
+{
+ double area = 0;
+
+ for (int i = 0; i < traps.size(); ++i) {
+ XTrapezoid trap = traps[i];
+ area += compute_area(&trap);
+ }
+ return area;
+}