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1 /* Contour lines for function evaluated on a grid. |
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2 |
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3 Copyright (C) 2004 Shai Ayal |
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4 |
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5 Adapted to an oct file from the stand alone contourl by Victro Munoz |
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6 Copyright (C) 2004 Victor Munoz |
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7 |
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8 Based on contour plot routine (plcont.c) in PLPlot package |
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9 http://plplot.org/ |
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10 |
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11 Copyright (C) 1995, 2000, 2001 Maurice LeBrun |
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12 Copyright (C) 2000, 2002 Joao Cardoso |
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13 Copyright (C) 2000, 2001, 2002, 2004 Alan W. Irwin |
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14 Copyright (C) 2004 Andrew Ross |
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15 |
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16 This file is part of Octave. |
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17 |
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18 Octave is free software; you can redistribute it and/or modify it |
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19 under the terms of the GNU General Public License as published by the |
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20 Free Software Foundation; either version 3 of the License, or (at your |
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21 option) any later version. |
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22 |
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23 Octave is distributed in the hope that it will be useful, but WITHOUT |
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24 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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25 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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26 for more details. |
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27 |
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28 You should have received a copy of the GNU General Public License |
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29 along with Octave; see the file COPYING. If not, see |
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30 <http://www.gnu.org/licenses/>. |
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31 |
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32 */ |
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33 |
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34 #ifdef HAVE_CONFIG_H |
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35 #include <config.h> |
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36 #endif |
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37 |
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38 #include "quit.h" |
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39 |
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40 #include "defun-dld.h" |
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41 #include "error.h" |
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42 #include "oct-obj.h" |
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43 |
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44 static Matrix this_contour; |
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45 static Matrix contourc; |
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46 static int elem; |
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47 |
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48 // this is the quanta in which we increase this_contour |
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49 #define CONTOUR_QUANT 50 |
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50 |
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51 // cl_add_point(x,y); |
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52 // |
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53 // Add a coordinate point (x,y) to this_contour |
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54 |
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55 static void |
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56 cl_add_point (double x, double y) |
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57 { |
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58 if (elem % CONTOUR_QUANT == 0) |
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59 this_contour = this_contour.append (Matrix (2, CONTOUR_QUANT, 0)); |
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60 |
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61 this_contour (0, elem) = x; |
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62 this_contour (1, elem) = y; |
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63 elem++; |
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64 } |
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65 |
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66 // cl_end_contour(); |
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67 // |
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68 // Adds contents of current contour to contourc. |
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69 // this_contour.cols () - 1; |
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70 |
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71 static void |
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72 cl_end_contour (void) |
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73 { |
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74 if (elem > 2) |
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75 { |
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76 this_contour (1, 0) = elem - 1; |
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77 contourc = contourc.append (this_contour.extract_n (0, 0, 2, elem)); |
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78 } |
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79 this_contour = Matrix (); |
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80 elem = 0; |
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81 } |
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82 |
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83 // cl_start_contour(flev,x,y); |
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84 // |
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85 // Start a new contour, and adds contents of current one to contourc |
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86 |
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87 static void |
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88 cl_start_contour (double flev, double x, double y) |
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89 { |
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90 cl_end_contour (); |
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91 this_contour.resize (2, 0); |
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92 cl_add_point (flev, flev); |
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93 cl_add_point (x, y); |
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94 } |
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95 |
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96 static void |
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97 cl_drawcn (RowVector & X, RowVector & Y, Matrix & Z, double flev, |
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98 int krow, int kcol, double lastx, double lasty, int startedge, |
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99 Matrix & ipts) |
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100 { |
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101 |
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102 int kx = 0, lx = Z.cols () - 1, ky = 0, ly = Z.rows () - 1; |
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103 |
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104 double f[4]; |
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105 double px[4], py[4], locx[4], locy[4]; |
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106 int iedge[4]; |
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107 int num, first, inext, kcolnext, krownext; |
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108 |
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109 px[0] = X (krow + 1); |
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110 px[1] = X (krow); |
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111 px[2] = X (krow); |
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112 px[3] = X (krow + 1); |
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113 py[0] = Y (kcol); |
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114 py[1] = Y (kcol); |
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115 py[2] = Y (kcol + 1); |
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116 py[3] = Y (kcol + 1); |
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117 |
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118 f[0] = Z (krow + 1, kcol) - flev; |
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119 f[1] = Z (krow, kcol) - flev; |
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120 f[2] = Z (krow, kcol + 1) - flev; |
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121 f[3] = Z (krow + 1, kcol + 1) - flev; |
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122 |
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123 for (int i = 0, j = 1; i < 4; i++, j = (j + 1) % 4) |
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124 { |
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125 iedge[i] = (f[i] * f[j] > 0.0) ? -1 : ((f[i] * f[j] < 0.0) ? 1 : 0); |
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126 } |
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127 |
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128 // Mark this square as done |
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129 ipts(krow,kcol) = 1; |
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130 |
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131 // Check if no contour has been crossed i.e. iedge[i] = -1 |
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132 if (iedge[0] == -1 && iedge[1] == -1 && iedge[2] == -1 && iedge[3] == -1) |
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133 return; |
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134 |
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135 // Check if this is a completely flat square - in which case ignore it |
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136 if (f[0] == 0.0 && f[1] == 0.0 && f[2] == 0.0 && f[3] == 0.0) |
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137 return; |
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138 |
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139 // Calculate intersection points |
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140 num = 0; |
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141 if (startedge < 0) |
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142 { |
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143 first = 1; |
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144 } |
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145 else |
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146 { |
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147 locx[num] = lastx; |
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148 locy[num] = lasty; |
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149 num++; |
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150 first = 0; |
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151 } |
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152 |
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153 for (int k = 0, i = (startedge < 0 ? 0 : startedge); k < 4; |
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154 k++, i = (i + 1) % 4) |
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155 { |
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156 if (i == startedge) |
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157 continue; |
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158 |
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159 // If the contour is an edge check it hasn't already been done |
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160 if (f[i] == 0.0 && f[(i + 1) % 4] == 0.0) |
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161 { |
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162 kcolnext = kcol; |
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163 krownext = krow; |
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164 if (i == 0) |
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165 kcolnext--; |
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166 if (i == 1) |
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167 krownext--; |
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168 if (i == 2) |
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169 kcolnext++; |
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170 if (i == 3) |
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171 krownext++; |
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172 if (kcolnext < kx || kcolnext >= lx || krownext < ky |
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173 || krownext >= ly || ipts(krownext,kcolnext) == 1) |
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174 continue; |
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175 } |
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176 if (iedge[i] == 1 || f[i] == 0.0) |
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177 { |
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178 int j = (i + 1) % 4; |
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179 if (f[i] != 0.0) |
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180 { |
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181 locx[num] = |
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182 (px[i] * fabs (f[j]) + px[j] * fabs (f[i])) / fabs (f[j] - |
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183 f[i]); |
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184 locy[num] = |
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185 (py[i] * fabs (f[j]) + py[j] * fabs (f[i])) / fabs (f[j] - |
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186 f[i]); |
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187 } |
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188 else |
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189 { |
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190 locx[num] = px[i]; |
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191 locy[num] = py[i]; |
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192 } |
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193 // If this is the start of the contour then move to the point |
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194 if (first == 1) |
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195 { |
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196 cl_start_contour (flev, locx[num], locy[num]); |
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197 first = 0; |
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198 } |
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199 else |
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200 { |
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201 // Link to the next point on the contour |
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202 cl_add_point (locx[num], locy[num]); |
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203 // Need to follow contour into next grid box |
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204 // Easy case where contour does not pass through corner |
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205 if (f[i] != 0.0) |
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206 { |
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207 kcolnext = kcol; |
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208 krownext = krow; |
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209 inext = (i + 2) % 4; |
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210 if (i == 0) |
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211 kcolnext--; |
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212 if (i == 1) |
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213 krownext--; |
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214 if (i == 2) |
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215 kcolnext++; |
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216 if (i == 3) |
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217 krownext++; |
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218 if (kcolnext >= kx && kcolnext < lx |
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219 && krownext >= ky && krownext < ly |
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220 && ipts(krownext,kcolnext) == 0) |
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221 { |
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222 cl_drawcn (X, Y, Z, flev, krownext, kcolnext, |
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223 locx[num], locy[num], inext, ipts); |
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224 } |
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225 } |
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226 // Hard case where contour passes through corner. This |
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227 // is still not perfect - it may lose the contour which |
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228 // won't upset the contour itself (we can find it again |
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229 // later) but might upset the labelling (which is only |
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230 // relevant for the PLPlot implementation, since we |
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231 // don't worry about labels---for now!) |
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232 else |
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233 { |
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234 kcolnext = kcol; |
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235 krownext = krow; |
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236 inext = (i + 2) % 4; |
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237 if (i == 0) |
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238 { |
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239 kcolnext--; |
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240 krownext++; |
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241 } |
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242 if (i == 1) |
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243 { |
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244 krownext--; |
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245 kcolnext--; |
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246 } |
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247 if (i == 2) |
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248 { |
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249 kcolnext++; |
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250 krownext--; |
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251 } |
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252 if (i == 3) |
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253 { |
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254 krownext++; |
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255 kcolnext++; |
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256 } |
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257 if (kcolnext >= kx && kcolnext < lx |
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258 && krownext >= ky && krownext < ly |
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259 && ipts(krownext,kcolnext) == 0) |
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260 { |
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261 cl_drawcn (X, Y, Z, flev, krownext, kcolnext, |
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262 locx[num], locy[num], inext, ipts); |
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263 } |
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264 |
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265 } |
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266 if (first == 1) |
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267 { |
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268 // Move back to first point |
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269 cl_start_contour (flev, locx[num], locy[num]); |
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270 first = 0; |
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271 } |
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272 else |
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273 { |
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274 first = 1; |
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275 } |
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276 num++; |
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277 } |
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278 } |
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279 } |
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280 } |
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281 |
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282 static void |
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283 cl_cntr (RowVector & X, RowVector & Y, Matrix & Z, double flev) |
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284 { |
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285 Matrix ipts (Z.rows (), Z.cols (), 0); |
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286 |
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287 for (int krow = 0; krow < Z.rows () - 1; krow++) |
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288 { |
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289 for (int kcol = 0; kcol < Z.cols () - 1; kcol++) |
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290 { |
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291 if (ipts(krow,kcol) == 0) |
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292 { |
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293 cl_drawcn (X, Y, Z, flev, krow, kcol, 0.0, 0.0, -2, ipts); |
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294 } |
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295 } |
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296 } |
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297 } |
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298 |
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299 DEFUN_DLD (__contourc__, args, , |
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300 "-*- texinfo -*-\n\ |
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301 @deftypefn {Loadable Function} {} __contourc__ (@var{x}, @var{y}, @var{z}, @var{levels})\n\ |
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302 Undocumented internal function.\n\ |
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303 @end deftypefn") |
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304 { |
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305 octave_value retval; |
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306 |
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307 if (args.length () == 4) |
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308 { |
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309 RowVector X = args (0).row_vector_value (); |
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310 RowVector Y = args (1).row_vector_value (); |
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311 Matrix Z = args (2).matrix_value ().transpose (); |
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312 RowVector L = args (3).row_vector_value (); |
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313 |
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314 if (! error_state) |
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315 { |
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316 contourc.resize (2, 0); |
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317 |
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318 for (int i = 0; i < L.length (); i++) |
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319 cl_cntr (X, Y, Z, L (i)); |
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320 |
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321 cl_end_contour (); |
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322 |
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323 retval = contourc; |
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324 } |
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325 else |
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326 error ("__contourc__: invalid argument values"); |
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327 } |
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328 else |
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329 print_usage (); |
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330 |
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331 return retval; |
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332 } |
