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1 /**************************************************************************** |
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2 ** |
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3 ** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies). |
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4 ** All rights reserved. |
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5 ** Contact: Nokia Corporation (qt-info@nokia.com) |
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6 ** |
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7 ** This file is part of the test suite of the Qt Toolkit. |
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8 ** |
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9 ** $QT_BEGIN_LICENSE:LGPL$ |
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10 ** No Commercial Usage |
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11 ** This file contains pre-release code and may not be distributed. |
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12 ** You may use this file in accordance with the terms and conditions |
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13 ** contained in the Technology Preview License Agreement accompanying |
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14 ** this package. |
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15 ** |
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16 ** GNU Lesser General Public License Usage |
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17 ** Alternatively, this file may be used under the terms of the GNU Lesser |
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18 ** General Public License version 2.1 as published by the Free Software |
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19 ** Foundation and appearing in the file LICENSE.LGPL included in the |
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20 ** packaging of this file. Please review the following information to |
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21 ** ensure the GNU Lesser General Public License version 2.1 requirements |
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22 ** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html. |
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23 ** |
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24 ** In addition, as a special exception, Nokia gives you certain additional |
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25 ** rights. These rights are described in the Nokia Qt LGPL Exception |
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26 ** version 1.1, included in the file LGPL_EXCEPTION.txt in this package. |
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27 ** |
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28 ** If you have questions regarding the use of this file, please contact |
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29 ** Nokia at qt-info@nokia.com. |
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30 ** |
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31 ** |
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32 ** |
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33 ** |
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34 ** |
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35 ** |
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36 ** |
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37 ** |
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38 ** $QT_END_LICENSE$ |
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39 ** |
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40 ****************************************************************************/ |
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41 #include "utils.h" |
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42 |
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43 #include <assert.h> |
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44 #include <qglobal.h> |
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45 |
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46 #include "qnum.h" |
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47 |
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48 #define FloatToXFixed(i) (int)((i) * 65536) |
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49 #define IntToXFixed(i) ((i) << 16) |
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50 |
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51 static double compute_x_at(XFixed y, XPointFixed p1, XPointFixed p2) |
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52 { |
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53 double d = XFixedToDouble(p2.x - p1.x); |
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54 return |
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55 XFixedToDouble(p1.x) + d*XFixedToDouble(y - p1.y)/XFixedToDouble(p2.y - p1.y); |
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56 } |
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57 |
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58 double compute_area(XTrapezoid *trap) |
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59 { |
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60 double x1 = compute_x_at(trap->top, trap->left.p1, trap->left.p2); |
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61 double x2 = compute_x_at(trap->top, trap->right.p1, trap->right.p2); |
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62 double x3 = compute_x_at(trap->bottom, trap->left.p1, trap->left.p2); |
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63 double x4 = compute_x_at(trap->bottom, trap->right.p1, trap->right.p2); |
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64 |
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65 double top = XFixedToDouble(trap->top); |
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66 double bottom = XFixedToDouble(trap->bottom); |
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67 double h = bottom - top; |
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68 |
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69 double top_base = x2 - x1; |
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70 double bottom_base = x4 - x3; |
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71 |
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72 if ((top_base < 0 && bottom_base > 0) |
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73 || (top_base > 0 && bottom_base < 0)) { |
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74 double y0 = top_base*h/(top_base - bottom_base) + top; |
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75 double area = qAbs(top_base * (y0 - top) / 2.); |
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76 area += qAbs(bottom_base * (bottom - y0) /2.); |
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77 return area; |
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78 } |
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79 |
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80 |
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81 return 0.5 * h * qAbs(top_base + bottom_base); |
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82 } |
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83 |
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84 double compute_area_for_x(const QVector<XTrapezoid> &traps) |
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85 { |
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86 double area = 0; |
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87 |
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88 for (int i = 0; i < traps.size(); ++i) { |
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89 XTrapezoid trap = traps[i]; |
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90 area += compute_area(&trap); |
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91 } |
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92 return area; |
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93 } |