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1 " |
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2 COPYRIGHT (c) 1989-93 by Claus Gittinger |
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3 All Rights Reserved |
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4 |
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5 This software is furnished under a license and may be used |
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6 only in accordance with the terms of that license and with the |
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7 inclusion of the above copyright notice. This software may not |
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8 be provided or otherwise made available to, or used by, any |
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9 other person. No title to or ownership of the software is |
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10 hereby transferred. |
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11 " |
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12 |
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13 ArithmeticValue subclass:#Point |
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14 instanceVariableNames:'x y' |
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15 classVariableNames:'PointZero PointOne' |
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16 poolDictionaries:'' |
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17 category:'Graphics-Primitives' |
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18 ! |
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19 |
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20 Point comment:' |
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21 |
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22 COPYRIGHT (c) 1989-93 by Claus Gittinger |
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23 All Rights Reserved |
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24 |
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25 I represent a point in 2D space. Or I can be used to represent |
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26 an extent (of a rectangle for example), in which case my x-coordinate |
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27 represents the width, and y-coordinate the height of something. |
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28 |
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29 The x and y coordinate are usually numbers. |
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30 |
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31 Instance variables: |
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32 |
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33 x <Number> the x-coordinate of myself |
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34 y <Number> the y-coordinate of myself |
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35 |
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36 %W% %E% |
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37 written 89 by claus |
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38 '! |
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39 |
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40 !Point class methodsFor:'initialization'! |
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41 |
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42 initialize |
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43 PointZero := 0 @ 0. |
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44 PointOne := 1 @ 1 |
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45 ! ! |
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46 |
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47 !Point class methodsFor:'constants'! |
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48 |
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49 zero |
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50 ^ PointZero |
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51 ! |
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52 |
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53 unity |
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54 ^ PointOne |
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55 ! ! |
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56 |
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57 !Point class methodsFor:'instance creation'! |
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58 |
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59 x:newX y:newY |
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60 "create and return a new point with coordinates newX and newY" |
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61 |
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62 %{ /* NOCONTEXT */ |
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63 extern char *newNextPtr, *newEndPtr; |
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64 |
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65 if (self == Point) { |
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66 if (_CanDoQuickNew(sizeof(struct point))) { |
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67 OBJ newPoint; |
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68 |
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69 _qCheckedAlignedNew(newPoint, sizeof(struct point), __context); |
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70 _InstPtr(newPoint)->o_class = Point; |
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71 _PointInstPtr(newPoint)->p_x = newX; |
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72 _PointInstPtr(newPoint)->p_y = newY; |
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73 /* no store check needed - its definitely in newSpace */ |
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74 RETURN ( newPoint ); |
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75 } |
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76 } |
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77 %} |
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78 . |
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79 ^ (self basicNew) x:newX y:newY |
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80 ! |
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81 |
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82 readFrom:aStream |
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83 "return the next Point from the (character-)stream aStream; |
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84 skipping all whitespace first; return nil if no point" |
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85 |
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86 |newX newY| |
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87 |
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88 newX := Number readFrom:aStream. |
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89 newX isNil ifTrue:[^ nil]. |
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90 (aStream skipSeparators ~~ $@) ifTrue:[^nil]. |
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91 aStream next. |
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92 newY := Number readFrom:aStream. |
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93 newY isNil ifTrue:[^ nil]. |
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94 ^ (self basicNew) x:newX y:newY |
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95 ! ! |
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96 |
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97 !Point methodsFor:'accessing'! |
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98 |
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99 x |
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100 "return the x coordinate" |
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101 |
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102 ^x |
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103 ! |
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104 |
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105 y |
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106 "return the y coordinate" |
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107 |
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108 ^y |
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109 ! |
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110 |
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111 x:newX |
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112 "set the x coordinate to be the argument, aNumber" |
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113 |
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114 x := newX |
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115 ! |
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116 |
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117 y:newY |
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118 "set the y coordinate to be the argument, aNumber" |
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119 |
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120 y := newY |
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121 ! |
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122 |
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123 x:newX y:newY |
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124 "set both the x and y coordinates" |
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125 |
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126 x := newX. |
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127 y := newY |
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128 ! ! |
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129 |
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130 !Point methodsFor:'comparing'! |
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131 |
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132 hash |
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133 "return a number for hashing" |
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134 |
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135 ^ (x hash) bitXor:(y hash) |
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136 ! |
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137 |
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138 < aPoint |
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139 "return true if the receiver is above and to the left |
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140 of the argument, aPoint" |
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141 |
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142 |p| |
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143 |
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144 p := aPoint asPoint. |
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145 x >= (p x) ifTrue:[^ false]. |
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146 y >= (p y) ifTrue:[^ false]. |
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147 ^ true |
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148 ! |
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149 |
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150 > aPoint |
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151 "return true if the receiver is below and to the right |
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152 of the argument, aPoint" |
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153 |
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154 |p| |
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155 |
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156 p := aPoint asPoint. |
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157 x <= (p x) ifTrue:[^ false]. |
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158 y <= (p y) ifTrue:[^ false]. |
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159 ^ true |
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160 ! |
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161 |
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162 = aPoint |
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163 "return true if the receiver represents the same point as |
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164 the argument, aPoint" |
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165 |
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166 |p| |
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167 |
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168 (aPoint isMemberOf:Point) ifTrue:[ |
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169 x ~~ (aPoint x) ifTrue:[^ false]. |
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170 y ~~ (aPoint y) ifTrue:[^ false]. |
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171 ^ true |
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172 ]. |
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173 aPoint respondsToArithmetic ifFalse:[ ^ false]. |
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174 p := aPoint asPoint. |
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175 x ~~ (p x) ifTrue:[^ false]. |
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176 y ~~ (p y) ifTrue:[^ false]. |
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177 ^ true |
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178 ! |
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179 |
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180 max:aPoint |
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181 "return the lower right corner of the rectangle uniquely defined by |
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182 the receiver and the argument, aPoint" |
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183 |
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184 |p maxX maxY| |
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185 |
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186 p := aPoint asPoint. |
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187 maxX := x max:(p x). |
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188 maxY := y max:(p y). |
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189 ^ maxX @ maxY |
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190 ! |
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191 |
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192 min:aPoint |
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193 "return the upper left corner of the rectangle uniquely defined by |
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194 the receiver and the argument, aPoint" |
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195 |
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196 |p minX minY| |
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197 |
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198 p := aPoint asPoint. |
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199 minX := x min:(p x). |
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200 minY := y min:(p y). |
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201 ^ minX @ minY |
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202 ! ! |
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203 |
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204 !Point methodsFor:'converting'! |
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205 |
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206 generality |
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207 ^ 120 |
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208 ! |
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209 |
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210 coerce:anObject |
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211 ^ anObject asPoint |
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212 ! |
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213 |
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214 asPoint |
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215 "return the receiver as Point - this is the receiver" |
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216 |
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217 ^ self |
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218 ! |
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219 |
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220 asRectangle |
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221 "return a zero-width rectangle consisting of origin |
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222 and corner beeing the receiver" |
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223 |
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224 ^ self corner:self |
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225 ! ! |
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226 |
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227 !Point methodsFor:'creating rectangles'! |
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228 |
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229 corner:aPoint |
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230 "return a rectangle whose origin is self and corner is aPoint" |
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231 |
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232 ^ Rectangle origin:self corner:aPoint |
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233 ! |
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234 |
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235 extent:aPoint |
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236 "return a rectangle whose origin is self and extent is aPoint" |
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237 |
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238 ^ Rectangle origin:self extent:aPoint |
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239 ! ! |
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240 |
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241 !Point methodsFor:'transformations'! |
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242 |
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243 + scale |
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244 "Return a new Point that is the sum of the |
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245 receiver and scale (which is a Point or Number)." |
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246 |
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247 |scalePoint| |
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248 |
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249 scalePoint := scale asPoint. |
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250 ^ (x + scalePoint x) @ (y + scalePoint y) |
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251 ! |
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252 |
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253 - scale |
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254 "Return a new Point that is the difference of the |
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255 receiver and scale (which is a Point or Number)." |
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256 |
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257 |scalePoint| |
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258 |
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259 scalePoint := scale asPoint. |
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260 ^ (x - scalePoint x) @ (y - scalePoint y) |
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261 ! |
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262 |
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263 * scale |
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264 "Return a new Point that is the product of the |
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265 receiver and scale (which is a Point or Number)." |
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266 |
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267 |scalePoint| |
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268 |
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269 scalePoint := scale asPoint. |
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270 ^ (x * scalePoint x) @ (y * scalePoint y) |
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271 ! |
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272 |
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273 / scale |
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274 "Return a new Point that is the integer quotient of the |
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275 receiver and scale (which is a Point or Number)." |
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276 |
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277 |scalePoint| |
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278 |
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279 scalePoint := scale asPoint. |
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280 ^ (x / scalePoint x) @ (y / scalePoint y) |
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281 ! |
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282 |
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283 // scale |
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284 "Return a new Point that is the quotient of the |
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285 receiver and scale (which is a Point or Number)." |
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286 |
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287 |scalePoint| |
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288 |
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289 scalePoint := scale asPoint. |
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290 ^ (x // scalePoint x) @ (y // scalePoint y) |
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291 ! |
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292 |
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293 reciprocal |
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294 "return a new point where the coordinates are |
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295 the reciproce of mine" |
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296 |
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297 ^ (1 / x) @ (1 / y) |
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298 ! |
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299 |
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300 negated |
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301 "return a new point with my coordinates negated i.e. |
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302 the receiver mirrored at the origin" |
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303 |
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304 ^ (x negated) @ (y negated) |
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305 ! |
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306 |
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307 scaleBy:aScale |
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308 "Return a new Point that is the product of the |
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309 receiver and scale (which is a Point or Number)." |
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310 |
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311 ^ self * aScale |
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312 ! |
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313 |
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314 translateBy:anOffset |
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315 "Return a new Point that is the sum of the |
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316 receiver and scale (which is a Point or Number)." |
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317 |
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318 ^ self + anOffset |
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319 ! ! |
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320 |
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321 !Point methodsFor:'misc'! |
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322 |
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323 dist:aPoint |
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324 "return the distance between aPoint and the receiver." |
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325 |
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326 ^ (aPoint - self) r |
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327 ! |
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328 |
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329 dotProduct:aPoint |
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330 "return a Number that is the dot product of the receiver and |
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331 the argument, aPoint. That is, the two points are |
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332 multipled and the coordinates of the result summed." |
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333 |
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334 |temp| |
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335 |
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336 temp := self * aPoint. |
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337 ^ temp x abs + temp y abs |
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338 ! |
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339 |
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340 r |
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341 "return the receiver's radius in polar coordinate system." |
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342 |
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343 ^ (self dotProduct:self) sqrt |
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344 ! |
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345 |
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346 abs |
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347 "return a new point with my coordinates taken from the absolute values" |
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348 |
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349 ^ (x abs) @ (y abs) |
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350 ! |
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351 |
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352 truncated |
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353 "return a new point with my coordinates truncated as integer" |
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354 |
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355 ^ (x truncated) @ (y truncated) |
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356 ! |
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357 |
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358 rounded |
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359 "return a new point with my coordinates rounded to the next integer |
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360 coordinated (use for gridding)" |
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361 |
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362 ^ (x rounded) @ (y rounded) |
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363 ! |
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364 |
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365 grid:gridPoint |
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366 "return a new point with coordinates grided (i.e. rounded to the |
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367 nearest point on the grid)" |
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368 |
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369 |newX newY gridX gridY| |
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370 |
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371 gridX := gridPoint x. |
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372 (gridX <= 1) ifTrue:[ |
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373 newX := x asInteger |
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374 ] ifFalse:[ |
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375 newX := ((x + (gridX // 2)) // gridX) * gridX |
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376 ]. |
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377 gridY := gridPoint y. |
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378 (gridY <= 1) ifTrue:[ |
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379 newY := y asInteger |
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380 ] ifFalse:[ |
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381 newY := ((y + (gridY // 2)) // gridY) * gridY |
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382 ]. |
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383 ^ newX @ newY |
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384 ! ! |
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385 |
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386 !Point methodsFor:'printing & storing'! |
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387 |
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388 printString |
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389 "return my printString" |
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390 |
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391 ^ x printString , '@' , y printString |
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392 ! |
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393 |
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394 storeString |
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395 "return my storeString" |
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396 |
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397 ^ self printString |
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398 ! ! |