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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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3 if (strcmp (nm, "voronoi")) |
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4 rand("state",9); |
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5 x = rand(10,1); |
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6 y = rand(10,1); |
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7 tri = delaunay (x, y); |
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8 [vx, vy] = voronoi (x, y, tri); |
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9 triplot (tri, x, y, "b"); |
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10 hold on; |
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11 plot (vx, vy, "r"); |
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12 [r, c] = tri2circ (tri(end,:), x, y); |
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13 pc = [-1:0.01:1]; |
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14 xc = r * sin(pi*pc) + c(1); |
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15 yc = r * cos(pi*pc) + c(2); |
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16 plot (xc, yc, "g-", "LineWidth", 3); |
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17 axis([0, 1, 0, 1]); |
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18 legend ("Delaunay Triangulation", "Voronoi Diagram"); |
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19 print (strcat (nm, ".", typ), strcat ("-d", typ)) |
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20 elseif (strcmp (nm, "triplot")) |
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21 rand ("state", 2) |
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22 x = rand (20, 1); |
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23 y = rand (20, 1); |
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24 tri = delaunay (x, y); |
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25 triplot (tri, x, y); |
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26 print (strcat (nm, ".", typ), strcat ("-d", typ)) |
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27 elseif (strcmp (nm, "griddata")) |
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28 rand("state",1); |
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29 x=2*rand(1000,1)-1; |
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30 y=2*rand(size(x))-1; |
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31 z=sin(2*(x.^2+y.^2)); |
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32 [xx,yy]=meshgrid(linspace(-1,1,32)); |
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33 griddata(x,y,z,xx,yy); |
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34 print (strcat (nm, ".", typ), strcat ("-d", typ)) |
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35 elseif (strcmp (nm, "convhull")) |
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36 x = -3:0.05:3; |
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37 y = abs (sin (x)); |
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38 k = convhull (x, y); |
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39 plot (x(k),y(k),'r-',x,y,'b+'); |
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40 axis ([-3.05, 3.05, -0.05, 1.05]); |
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41 print (strcat (nm, ".", typ), strcat ("-d", typ)) |
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42 elseif (strcmp (nm, "delaunay")) |
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43 rand ("state", 1); |
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6847
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44 x = rand (1, 10); |
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45 y = rand (1, 10); |
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6832
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46 T = delaunay (x, y); |
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47 X = [ x(T(:,1)); x(T(:,2)); x(T(:,3)); x(T(:,1)) ]; |
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48 Y = [ y(T(:,1)); y(T(:,2)); y(T(:,3)); y(T(:,1)) ]; |
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49 axis ([0, 1, 0, 1]); |
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50 plot(X, Y, "b", x, y, "r*"); |
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51 print (strcat (nm, ".", typ), strcat ("-d", typ)) |
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6847
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52 elseif (strcmp (nm, "inpolygon")) |
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53 randn ("state", 2); |
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54 x = randn (100, 1); |
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55 y = randn (100, 1); |
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56 vx = cos (pi * [-1 : 0.1: 1]); |
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57 vy = sin (pi * [-1 : 0.1 : 1]); |
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58 in = inpolygon (x, y, vx, vy); |
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59 plot(vx, vy, x(in), y(in), "r+", x(!in), y(!in), "bo"); |
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60 axis ([-2, 2, -2, 2]); |
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61 print (strcat (nm, ".", typ), strcat ("-d", typ)) |
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6832
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62 else |
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63 error ("unrecognized plot requested"); |
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64 endif |
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65 bury_output (); |
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66 endfunction |
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67 |
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68 function [r, c] = tri2circ (tri, xx, yy) |
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69 x = xx(tri); |
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70 y = yy(tri); |
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71 m = (y(1:end-1) - y(2:end)) ./ (x(1:end-1) - x(2:end)); |
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72 xc = (prod(m) .* (y(1) - y(end)) + m(end)*(x(1)+x(2)) - m(1)*(x(2)+x(3))) ... |
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73 ./ (2 * (m(end) - m(1))); |
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74 yc = - (xc - (x(2) + x(3))./2) ./ m(end) + (y(2) + y(3)) / 2; |
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75 c = [xc, yc]; |
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76 r = sqrt ((xc - x(1)).^2 + (yc - y(1)).^2); |
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77 endfunction |
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78 |
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79 ## Use this function before plotting commands and after every call to |
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80 ## print since print() resets output to stdout (unfortunately, gnpulot |
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81 ## can't pop output as it can the terminal type). |
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82 function bury_output () |
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83 f = figure (1); |
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84 set (f, "visible", "off"); |
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85 endfunction |
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86 function geometryimages (nm, typ) |
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87 bury_output (); |
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88 if (strcmp (nm, "voronoi")) |
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89 rand("state",9); |
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90 x = rand(10,1); |
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91 y = rand(10,1); |
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92 tri = delaunay (x, y); |
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93 [vx, vy] = voronoi (x, y, tri); |
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94 triplot (tri, x, y, "b"); |
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95 hold on; |
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96 plot (vx, vy, "r"); |
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97 [r, c] = tri2circ (tri(end,:), x, y); |
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98 pc = [-1:0.01:1]; |
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99 xc = r * sin(pi*pc) + c(1); |
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100 yc = r * cos(pi*pc) + c(2); |
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101 plot (xc, yc, "g-", "LineWidth", 3); |
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102 axis([0, 1, 0, 1]); |
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103 legend ("Delaunay Triangulation", "Voronoi Diagram"); |
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104 print (strcat (nm, ".", typ), strcat ("-d", typ)) |
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105 elseif (strcmp (nm, "triplot")) |
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106 rand ("state", 2) |
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107 x = rand (20, 1); |
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108 y = rand (20, 1); |
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109 tri = delaunay (x, y); |
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110 triplot (tri, x, y); |
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111 print (strcat (nm, ".", typ), strcat ("-d", typ)) |
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112 elseif (strcmp (nm, "griddata")) |
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113 rand("state",1); |
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114 x=2*rand(1000,1)-1; |
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115 y=2*rand(size(x))-1; |
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116 z=sin(2*(x.^2+y.^2)); |
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117 [xx,yy]=meshgrid(linspace(-1,1,32)); |
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118 griddata(x,y,z,xx,yy); |
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119 print (strcat (nm, ".", typ), strcat ("-d", typ)) |
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120 else |
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121 error ("unrecognized plot requested"); |
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122 endif |
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123 bury_output (); |
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124 endfunction |
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125 |
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126 function [r, c] = tri2circ (tri, xx, yy) |
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127 x = xx(tri); |
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128 y = yy(tri); |
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129 m = (y(1:end-1) - y(2:end)) ./ (x(1:end-1) - x(2:end)); |
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130 xc = (prod(m) .* (y(1) - y(end)) + m(end)*(x(1)+x(2)) - m(1)*(x(2)+x(3))) ... |
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131 ./ (2 * (m(end) - m(1))); |
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132 yc = - (xc - (x(2) + x(3))./2) ./ m(end) + (y(2) + y(3)) / 2; |
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133 c = [xc, yc]; |
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134 r = sqrt ((xc - x(1)).^2 + (yc - y(1)).^2); |
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135 endfunction |
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136 |
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137 ## Use this function before plotting commands and after every call to |
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138 ## print since print() resets output to stdout (unfortunately, gnpulot |
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139 ## can't pop output as it can the terminal type). |
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140 function bury_output () |
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141 f = figure (1); |
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142 set (f, "visible", "off"); |
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143 endfunction |
