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6832
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1 function geometryimages (nm, typ) |
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2 bury_output (); |
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6878
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3 if (isempty (findstr (octave_config_info ("DEFS"), "HAVE_QHULL")) |
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4 && (strcmp (nm, "voronoi") || strcmp (nm, "griddata") |
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5 || strcmp (nm, "convhull") || strcmp (nm, "delaunay") |
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6 || strcmp (nm, "triplot"))) |
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6855
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7 sombreroimage (nm, typ); |
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8 elseif (strcmp (nm, "voronoi")) |
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6832
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9 rand("state",9); |
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10 x = rand(10,1); |
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11 y = rand(10,1); |
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12 tri = delaunay (x, y); |
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13 [vx, vy] = voronoi (x, y, tri); |
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14 triplot (tri, x, y, "b"); |
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15 hold on; |
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16 plot (vx, vy, "r"); |
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17 [r, c] = tri2circ (tri(end,:), x, y); |
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18 pc = [-1:0.01:1]; |
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19 xc = r * sin(pi*pc) + c(1); |
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20 yc = r * cos(pi*pc) + c(2); |
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21 plot (xc, yc, "g-", "LineWidth", 3); |
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22 axis([0, 1, 0, 1]); |
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23 legend ("Delaunay Triangulation", "Voronoi Diagram"); |
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24 print (strcat (nm, ".", typ), strcat ("-d", typ)) |
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25 elseif (strcmp (nm, "triplot")) |
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26 rand ("state", 2) |
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27 x = rand (20, 1); |
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28 y = rand (20, 1); |
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29 tri = delaunay (x, y); |
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30 triplot (tri, x, y); |
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31 print (strcat (nm, ".", typ), strcat ("-d", typ)) |
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32 elseif (strcmp (nm, "griddata")) |
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33 rand("state",1); |
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34 x=2*rand(1000,1)-1; |
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35 y=2*rand(size(x))-1; |
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36 z=sin(2*(x.^2+y.^2)); |
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37 [xx,yy]=meshgrid(linspace(-1,1,32)); |
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38 griddata(x,y,z,xx,yy); |
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39 print (strcat (nm, ".", typ), strcat ("-d", typ)) |
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40 elseif (strcmp (nm, "convhull")) |
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41 x = -3:0.05:3; |
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42 y = abs (sin (x)); |
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43 k = convhull (x, y); |
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44 plot (x(k),y(k),'r-',x,y,'b+'); |
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45 axis ([-3.05, 3.05, -0.05, 1.05]); |
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46 print (strcat (nm, ".", typ), strcat ("-d", typ)) |
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47 elseif (strcmp (nm, "delaunay")) |
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48 rand ("state", 1); |
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6847
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49 x = rand (1, 10); |
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50 y = rand (1, 10); |
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6832
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51 T = delaunay (x, y); |
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52 X = [ x(T(:,1)); x(T(:,2)); x(T(:,3)); x(T(:,1)) ]; |
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53 Y = [ y(T(:,1)); y(T(:,2)); y(T(:,3)); y(T(:,1)) ]; |
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54 axis ([0, 1, 0, 1]); |
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55 plot(X, Y, "b", x, y, "r*"); |
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56 print (strcat (nm, ".", typ), strcat ("-d", typ)) |
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6847
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57 elseif (strcmp (nm, "inpolygon")) |
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58 randn ("state", 2); |
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59 x = randn (100, 1); |
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60 y = randn (100, 1); |
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61 vx = cos (pi * [-1 : 0.1: 1]); |
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62 vy = sin (pi * [-1 : 0.1 : 1]); |
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63 in = inpolygon (x, y, vx, vy); |
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64 plot(vx, vy, x(in), y(in), "r+", x(!in), y(!in), "bo"); |
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65 axis ([-2, 2, -2, 2]); |
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66 print (strcat (nm, ".", typ), strcat ("-d", typ)) |
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6832
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67 else |
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68 error ("unrecognized plot requested"); |
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69 endif |
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70 bury_output (); |
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71 endfunction |
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72 |
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73 function [r, c] = tri2circ (tri, xx, yy) |
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74 x = xx(tri); |
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75 y = yy(tri); |
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76 m = (y(1:end-1) - y(2:end)) ./ (x(1:end-1) - x(2:end)); |
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77 xc = (prod(m) .* (y(1) - y(end)) + m(end)*(x(1)+x(2)) - m(1)*(x(2)+x(3))) ... |
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78 ./ (2 * (m(end) - m(1))); |
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79 yc = - (xc - (x(2) + x(3))./2) ./ m(end) + (y(2) + y(3)) / 2; |
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80 c = [xc, yc]; |
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81 r = sqrt ((xc - x(1)).^2 + (yc - y(1)).^2); |
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82 endfunction |
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83 |
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84 ## Use this function before plotting commands and after every call to |
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85 ## print since print() resets output to stdout (unfortunately, gnpulot |
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86 ## can't pop output as it can the terminal type). |
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87 function bury_output () |
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88 f = figure (1); |
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89 set (f, "visible", "off"); |
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90 endfunction |
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91 function geometryimages (nm, typ) |
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92 bury_output (); |
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93 if (strcmp (nm, "voronoi")) |
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94 rand("state",9); |
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95 x = rand(10,1); |
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96 y = rand(10,1); |
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97 tri = delaunay (x, y); |
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98 [vx, vy] = voronoi (x, y, tri); |
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99 triplot (tri, x, y, "b"); |
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100 hold on; |
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101 plot (vx, vy, "r"); |
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102 [r, c] = tri2circ (tri(end,:), x, y); |
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103 pc = [-1:0.01:1]; |
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104 xc = r * sin(pi*pc) + c(1); |
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105 yc = r * cos(pi*pc) + c(2); |
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106 plot (xc, yc, "g-", "LineWidth", 3); |
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107 axis([0, 1, 0, 1]); |
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108 legend ("Delaunay Triangulation", "Voronoi Diagram"); |
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109 print (strcat (nm, ".", typ), strcat ("-d", typ)) |
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110 elseif (strcmp (nm, "triplot")) |
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111 rand ("state", 2) |
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112 x = rand (20, 1); |
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113 y = rand (20, 1); |
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114 tri = delaunay (x, y); |
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115 triplot (tri, x, y); |
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116 print (strcat (nm, ".", typ), strcat ("-d", typ)) |
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117 elseif (strcmp (nm, "griddata")) |
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118 rand("state",1); |
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119 x=2*rand(1000,1)-1; |
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120 y=2*rand(size(x))-1; |
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121 z=sin(2*(x.^2+y.^2)); |
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122 [xx,yy]=meshgrid(linspace(-1,1,32)); |
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123 griddata(x,y,z,xx,yy); |
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124 print (strcat (nm, ".", typ), strcat ("-d", typ)) |
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125 else |
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126 error ("unrecognized plot requested"); |
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127 endif |
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128 bury_output (); |
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129 endfunction |
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130 |
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131 function [r, c] = tri2circ (tri, xx, yy) |
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132 x = xx(tri); |
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133 y = yy(tri); |
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134 m = (y(1:end-1) - y(2:end)) ./ (x(1:end-1) - x(2:end)); |
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135 xc = (prod(m) .* (y(1) - y(end)) + m(end)*(x(1)+x(2)) - m(1)*(x(2)+x(3))) ... |
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136 ./ (2 * (m(end) - m(1))); |
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137 yc = - (xc - (x(2) + x(3))./2) ./ m(end) + (y(2) + y(3)) / 2; |
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138 c = [xc, yc]; |
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139 r = sqrt ((xc - x(1)).^2 + (yc - y(1)).^2); |
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140 endfunction |
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141 |
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142 ## Use this function before plotting commands and after every call to |
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143 ## print since print() resets output to stdout (unfortunately, gnpulot |
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144 ## can't pop output as it can the terminal type). |
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145 function bury_output () |
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146 f = figure (1); |
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147 set (f, "visible", "off"); |
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148 endfunction |
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6855
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149 |
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150 function sombreroimage (nm, typ) |
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151 if (strcmp (typ, "txt")) |
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152 fid = fopen (sprintf ("%s.txt", nm), "wt"); |
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153 fputs (fid, "+-----------------------------+\n"); |
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154 fputs (fid, "| Image unavailable because |\n"); |
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155 fputs (fid, "| of a missing QHULL library. |\n"); |
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156 fputs (fid, "+-----------------------------+\n"); |
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157 fclose (fid); |
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158 return; |
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159 else ## if (!strcmp (typ, "txt")) |
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160 |
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161 bury_output (); |
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162 |
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163 x = y = linspace (-8, 8, 41)'; |
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164 [xx, yy] = meshgrid (x, y); |
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165 r = sqrt (xx .^ 2 + yy .^ 2) + eps; |
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166 z = sin (r) ./ r; |
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167 unwind_protect |
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168 mesh (x, y, z); |
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169 title ("Sorry, graphics not available because octave was\\ncompiled without the QHULL library."); |
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170 unwind_protect_cleanup |
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171 print (strcat (nm, ".", typ), strcat ("-d", typ)); |
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172 bury_output (); |
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173 end_unwind_protect |
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174 endif |
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175 endfunction |
