Содержание
Points & Rectangles
Surprisingly, I haven’t been able to find a single Python module providing such primitive support.
WxPython supports wxPoint and wxRect, but it lacks many basic functions (such as, say, adding two points together to produce a third point. ) (See: wxPyWiki:wx.Rect)
This code is lacking a zillion essential features (but interpoint distance can now be calculated). I only put in the ones I needed immediately. Please add, refactor, optimize, rename stuff to be more standard, etc., as you see fit.
If there’s an actual, accessible, easy-to-include Python module, not tied to a graphics library, that does this stuff already, please write about it here! No sense in reinventing the wheel. I’ve looked, but haven’t found one. Hence this.
1 """Point and Rectangle classes. 2 3 This code is in the public domain. 4 5 Point -- point with (x,y) coordinates 6 Rect -- two points, forming a rectangle 7 """ 8 9 import math 10 11 12 class Point: 13 14 """A point identified by (x,y) coordinates. 15 16 supports: +, -, *, /, str, repr 17 18 length -- calculate length of vector to point from origin 19 distance_to -- calculate distance between two points 20 as_tuple -- construct tuple (x,y) 21 clone -- construct a duplicate 22 integerize -- convert x & y to integers 23 floatize -- convert x & y to floats 24 move_to -- reset x & y 25 slide -- move (in place) +dx, +dy, as spec'd by point 26 slide_xy -- move (in place) +dx, +dy 27 rotate -- rotate around the origin 28 rotate_about -- rotate around another point 29 """ 30 31 def __init__(self, x=0.0, y=0.0): 32 self.x = x 33 self.y = y 34 35 def __add__(self, p): 36 """Point(x1+x2, y1+y2)""" 37 return Point(self.x+p.x, self.y+p.y) 38 39 def __sub__(self, p): 40 """Point(x1-x2, y1-y2)""" 41 return Point(self.x-p.x, self.y-p.y) 42 43 def __mul__( self, scalar ): 44 """Point(x1*x2, y1*y2)""" 45 return Point(self.x*scalar, self.y*scalar) 46 47 def __div__(self, scalar): 48 """Point(x1/x2, y1/y2)""" 49 return Point(self.x/scalar, self.y/scalar) 50 51 def __str__(self): 52 return "(%s, %s)" % (self.x, self.y) 53 54 def __repr__(self): 55 return "%s(%r, %r)" % (self.__class__.__name__, self.x, self.y) 56 57 def length(self): 58 return math.sqrt(self.x**2 + self.y**2) 59 60 def distance_to(self, p): 61 """Calculate the distance between two points.""" 62 return (self - p).length() 63 64 def as_tuple(self): 65 """(x, y)""" 66 return (self.x, self.y) 67 68 def clone(self): 69 """Return a full copy of this point.""" 70 return Point(self.x, self.y) 71 72 def integerize(self): 73 """Convert co-ordinate values to integers.""" 74 self.x = int(self.x) 75 self.y = int(self.y) 76 77 def floatize(self): 78 """Convert co-ordinate values to floats.""" 79 self.x = float(self.x) 80 self.y = float(self.y) 81 82 def move_to(self, x, y): 83 """Reset x & y coordinates.""" 84 self.x = x 85 self.y = y 86 87 def slide(self, p): 88 '''Move to new (x+dx,y+dy). 89 90 Can anyone think up a better name for this function? 91 slide? shift? delta? move_by? 92 ''' 93 self.x = self.x + p.x 94 self.y = self.y + p.y 95 96 def slide_xy(self, dx, dy): 97 '''Move to new (x+dx,y+dy). 98 99 Can anyone think up a better name for this function? 100 slide? shift? delta? move_by? 101 ''' 102 self.x = self.x + dx 103 self.y = self.y + dy 104 105 def rotate(self, rad): 106 """Rotate counter-clockwise by rad radians. 107 108 Positive y goes *up,* as in traditional mathematics. 109 110 Interestingly, you can use this in y-down computer graphics, if 111 you just remember that it turns clockwise, rather than 112 counter-clockwise. 113 114 The new position is returned as a new Point. 115 """ 116 s, c = [f(rad) for f in (math.sin, math.cos)] 117 x, y = (c*self.x - s*self.y, s*self.x + c*self.y) 118 return Point(x,y) 119 120 def rotate_about(self, p, theta): 121 """Rotate counter-clockwise around a point, by theta degrees. 122 123 Positive y goes *up,* as in traditional mathematics. 124 125 The new position is returned as a new Point. 126 """ 127 result = self.clone() 128 result.slide(-p.x, -p.y) 129 result.rotate(theta) 130 result.slide(p.x, p.y) 131 return result 132 133 134 class Rect: 135 136 """A rectangle identified by two points. 137 138 The rectangle stores left, top, right, and bottom values. 139 140 Coordinates are based on screen coordinates. 141 142 origin top 143 +-----> x increases | 144 | left -+- right 145 v | 146 y increases bottom 147 148 set_points -- reset rectangle coordinates 149 contains -- is a point inside? 150 overlaps -- does a rectangle overlap? 151 top_left -- get top-left corner 152 bottom_right -- get bottom-right corner 153 expanded_by -- grow (or shrink) 154 """ 155 156 def __init__(self, pt1, pt2): 157 """Initialize a rectangle from two points.""" 158 self.set_points(pt1, pt2) 159 160 def set_points(self, pt1, pt2): 161 """Reset the rectangle coordinates.""" 162 (x1, y1) = pt1.as_tuple() 163 (x2, y2) = pt2.as_tuple() 164 self.left = min(x1, x2) 165 self.top = min(y1, y2) 166 self.right = max(x1, x2) 167 self.bottom = max(y1, y2) 168 169 def contains(self, pt): 170 """Return true if a point is inside the rectangle.""" 171 x,y = pt.as_tuple() 172 return (self.left x self.right and 173 self.top y self.bottom) 174 175 def overlaps(self, other): 176 """Return true if a rectangle overlaps this rectangle.""" 177 return (self.right > other.left and self.left < other.right and 178 self.top < other.bottom and self.bottom > other.top) 179 180 def top_left(self): 181 """Return the top-left corner as a Point.""" 182 return Point(self.left, self.top) 183 184 def bottom_right(self): 185 """Return the bottom-right corner as a Point.""" 186 return Point(self.right, self.bottom) 187 188 def expanded_by(self, n): 189 """Return a rectangle with extended borders. 190 191 Create a new rectangle that is wider and taller than the 192 immediate one. All sides are extended by "n" points. 193 """ 194 p1 = Point(self.left-n, self.top-n) 195 p2 = Point(self.right+n, self.bottom+n) 196 return Rect(p1, p2) 197 198 def __str__( self ): 199 return "%s,%s)-(%s,%s)>" % (self.left,self.top, 200 self.right,self.bottom) 201 202 def __repr__(self): 203 return "%s(%r, %r)" % (self.__class__.__name__, 204 Point(self.left, self.top), 205 Point(self.right, self.bottom))
Historical Note
See Also
PointsAndRectangles (last edited 2008-11-15 13:59:40 by localhost )