1 | /* |
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2 | * $Id: LinearTransform.java,v 1.10 2003/08/22 23:02:32 dwd Exp $ |
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3 | * |
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4 | * This software is provided by NOAA for full, free and open release. It is |
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5 | * understood by the recipient/user that NOAA assumes no liability for any |
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6 | * errors contained in the code. Although this software is released without |
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7 | * conditions or restrictions in its use, it is expected that appropriate |
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8 | * credit be given to its author and to the National Oceanic and Atmospheric |
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9 | * Administration should the software be included by the recipient as an |
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10 | * element in other product development. |
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11 | */ |
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12 | |
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13 | package gov.noaa.pmel.sgt; |
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14 | |
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15 | import gov.noaa.pmel.util.Range2D; |
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16 | import gov.noaa.pmel.util.GeoDate; |
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17 | import gov.noaa.pmel.util.TimeRange; |
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18 | import gov.noaa.pmel.util.SoTValue; |
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19 | import gov.noaa.pmel.util.SoTRange; |
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20 | |
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21 | /** |
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22 | * Performs a linear transformation on cartesian axes. If the |
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23 | * transformtion is for space the equation is phys = a*user + b |
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24 | * and if time is phys = at*time + bt. |
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25 | * |
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26 | * @author Donald Denbo |
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27 | * @version $Revision: 1.10 $, $Date: 2003/08/22 23:02:32 $ |
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28 | * @since 1.0 |
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29 | */ |
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30 | public class LinearTransform extends AxisTransform implements Cloneable { |
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31 | double at_; |
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32 | double bt_; |
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33 | double a_; |
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34 | double b_; |
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35 | /** |
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36 | * Default constructor. Creates a transform with arguments |
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37 | * <code>Transform(0.0, 1.0, 0.0, 1.0)</code>. |
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38 | **/ |
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39 | public LinearTransform() { |
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40 | super(); |
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41 | } |
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42 | /** |
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43 | * <code>LinearTransform</code> constructor. |
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44 | * This constructor is used to define |
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45 | * transforms that use double user values. |
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46 | * |
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47 | * @param p1 minimum value, physical coordinates |
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48 | * @param p2 maximum value, physical coordinates |
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49 | * @param u1 minimum value, user coordinates |
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50 | * @param u2 maximum value, user coordinates |
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51 | **/ |
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52 | public LinearTransform(double p1,double p2,double u1,double u2) { |
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53 | super(p1, p2, u1, u2); |
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54 | } |
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55 | /** |
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56 | * <code>LinearTransform</code> constructor. This constructor is used to define |
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57 | * transforms that use double user values. |
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58 | * |
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59 | * @param pr physical coordinate range |
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60 | * @param ur user coordinate range |
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61 | * @see Range2D |
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62 | **/ |
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63 | public LinearTransform(Range2D pr,Range2D ur) { |
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64 | super(pr, ur); |
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65 | } |
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66 | /** |
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67 | * <code>LinearTransform</code> constructor. This constructor is used to define |
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68 | * transforms that use <code>GeoDate</code> user values. |
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69 | * |
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70 | * @param p1 minimum value, physical coordinates |
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71 | * @param p2 maximum value, physical coordinates |
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72 | * @param t1 minimum time |
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73 | * @param t2 maximum time |
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74 | * @see GeoDate |
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75 | **/ |
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76 | public LinearTransform(double p1,double p2,GeoDate t1,GeoDate t2) { |
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77 | super(p1, p2, t1, t2); |
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78 | } |
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79 | /** |
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80 | * <code>LinearTransform</code> constructor. This constructor is used to define |
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81 | * transforms that use <code>GeoDate</code> user values. |
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82 | * |
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83 | * @param pr physical coordinates range |
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84 | * @param tr time range |
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85 | * @see Range2D |
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86 | * @see TimeRange |
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87 | * @see GeoDate |
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88 | **/ |
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89 | public LinearTransform(Range2D pr,TimeRange tr) { |
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90 | super(pr, tr); |
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91 | } |
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92 | /** |
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93 | * <code>LinearTransform</code> constructor. This constructor is used to define |
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94 | * transforms that use <code>SoTRange</code> user values. |
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95 | * |
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96 | * @since 2.0 |
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97 | * @param pr physical coordinates range |
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98 | * @param str space or time range |
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99 | * @see SoTRange |
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100 | * @see Range2D |
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101 | **/ |
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102 | public LinearTransform(Range2D pr, SoTRange str) { |
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103 | super(pr, str); |
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104 | } |
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105 | /** |
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106 | * Transform from user to physical coordinates. |
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107 | * |
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108 | * @param u user value |
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109 | * @return physical value |
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110 | */ |
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111 | public double getTransP(double u) { |
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112 | return a_*u + b_; |
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113 | } |
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114 | /** |
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115 | * Create a copy of the <code>LinearTransform</code>. |
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116 | * |
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117 | * @return the copy |
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118 | */ |
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119 | public AxisTransform copy() { |
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120 | LinearTransform newTransform; |
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121 | try { |
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122 | newTransform = (LinearTransform)clone(); |
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123 | } catch (CloneNotSupportedException e) { |
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124 | newTransform = new LinearTransform(); |
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125 | } |
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126 | return (AxisTransform)newTransform; |
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127 | } |
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128 | // |
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129 | /** |
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130 | * Transform from time to physical coordinates. |
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131 | * |
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132 | * @param t time |
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133 | * @return user value |
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134 | */ |
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135 | public double getTransP(GeoDate t) { |
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136 | return (double)(at_*t.getTime() + bt_); |
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137 | } |
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138 | public double getTransP(SoTValue v) { |
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139 | if(v.isTime()) { |
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140 | long t = v.getLongTime(); |
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141 | return (double)at_*t + bt_; |
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142 | } else { |
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143 | double u = ((SoTValue.Double)v).getValue(); |
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144 | return a_*u + b_; |
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145 | } |
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146 | } |
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147 | /** |
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148 | * Transform from <code>long</code> representation of time |
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149 | * to physical coordinates. |
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150 | * |
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151 | * @since 3.0 |
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152 | */ |
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153 | public double getTransP(long t) { |
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154 | return (double)at_*t + bt_; |
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155 | } |
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156 | /** |
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157 | * Transform from physical to user coordinates. |
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158 | * |
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159 | * @param p physical value |
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160 | * @return user value |
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161 | */ |
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162 | public double getTransU(double p) { |
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163 | return (p - b_)/a_; |
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164 | } |
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165 | /** |
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166 | * Transform from physical coordinates to time. |
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167 | * |
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168 | * @param p physical value |
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169 | * @return time value |
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170 | */ |
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171 | public GeoDate getTimeTransU(double p) { |
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172 | return new GeoDate((long)((p - bt_)/at_)); |
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173 | } |
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174 | /** |
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175 | * Transform from physical coordinates to <code>long</code> |
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176 | * representation of time. |
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177 | * |
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178 | * @since 3.0 |
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179 | * @param p physical value |
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180 | * @return milliseconds since 1970-01-01 |
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181 | */ |
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182 | public long getLongTimeTransU(double p) { |
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183 | return (long)((p - bt_)/at_); |
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184 | } |
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185 | |
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186 | public SoTValue getSoTTransU(double p) { |
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187 | if(!space_) { |
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188 | return new SoTValue.Time((long)((p - bt_)/at_)); |
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189 | } else { |
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190 | return new SoTValue.Double((p - b_)/a_); |
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191 | } |
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192 | } |
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193 | |
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194 | // |
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195 | void computeTransform() { |
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196 | if(space_) { |
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197 | double denom; |
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198 | denom = u1_ - u2_; |
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199 | if(denom == 0) { |
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200 | a_ = 1.0f; |
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201 | b_ = 0.0f; |
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202 | } else { |
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203 | a_ = (p1_ - p2_)/denom; |
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204 | b_ = p1_ - a_*u1_; |
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205 | } |
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206 | } else { |
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207 | double denom; |
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208 | denom = t1_ - t2_; |
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209 | if(denom == 0) { |
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210 | at_ = 1.0; |
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211 | bt_ = 0.0; |
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212 | } else { |
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213 | at_ = (p1_ - p2_)/denom; |
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214 | bt_ = p1_ - at_*t1_; |
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215 | } |
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216 | } |
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217 | } |
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218 | |
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219 | public String toString() { |
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220 | return "LinearTransform: " + a_ + ", " + b_ + "; " + at_ + ", " + bt_; |
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221 | } |
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222 | } |
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