ImageMath.py 7.1 KB

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  1. #
  2. # The Python Imaging Library
  3. # $Id$
  4. #
  5. # a simple math add-on for the Python Imaging Library
  6. #
  7. # History:
  8. # 1999-02-15 fl Original PIL Plus release
  9. # 2005-05-05 fl Simplified and cleaned up for PIL 1.1.6
  10. # 2005-09-12 fl Fixed int() and float() for Python 2.4.1
  11. #
  12. # Copyright (c) 1999-2005 by Secret Labs AB
  13. # Copyright (c) 2005 by Fredrik Lundh
  14. #
  15. # See the README file for information on usage and redistribution.
  16. #
  17. import builtins
  18. from . import Image, _imagingmath
  19. def _isconstant(v):
  20. return isinstance(v, (int, float))
  21. class _Operand:
  22. """Wraps an image operand, providing standard operators"""
  23. def __init__(self, im):
  24. self.im = im
  25. def __fixup(self, im1):
  26. # convert image to suitable mode
  27. if isinstance(im1, _Operand):
  28. # argument was an image.
  29. if im1.im.mode in ("1", "L"):
  30. return im1.im.convert("I")
  31. elif im1.im.mode in ("I", "F"):
  32. return im1.im
  33. else:
  34. raise ValueError(f"unsupported mode: {im1.im.mode}")
  35. else:
  36. # argument was a constant
  37. if _isconstant(im1) and self.im.mode in ("1", "L", "I"):
  38. return Image.new("I", self.im.size, im1)
  39. else:
  40. return Image.new("F", self.im.size, im1)
  41. def apply(self, op, im1, im2=None, mode=None):
  42. im1 = self.__fixup(im1)
  43. if im2 is None:
  44. # unary operation
  45. out = Image.new(mode or im1.mode, im1.size, None)
  46. im1.load()
  47. try:
  48. op = getattr(_imagingmath, op + "_" + im1.mode)
  49. except AttributeError as e:
  50. raise TypeError(f"bad operand type for '{op}'") from e
  51. _imagingmath.unop(op, out.im.id, im1.im.id)
  52. else:
  53. # binary operation
  54. im2 = self.__fixup(im2)
  55. if im1.mode != im2.mode:
  56. # convert both arguments to floating point
  57. if im1.mode != "F":
  58. im1 = im1.convert("F")
  59. if im2.mode != "F":
  60. im2 = im2.convert("F")
  61. if im1.size != im2.size:
  62. # crop both arguments to a common size
  63. size = (min(im1.size[0], im2.size[0]), min(im1.size[1], im2.size[1]))
  64. if im1.size != size:
  65. im1 = im1.crop((0, 0) + size)
  66. if im2.size != size:
  67. im2 = im2.crop((0, 0) + size)
  68. out = Image.new(mode or im1.mode, im1.size, None)
  69. im1.load()
  70. im2.load()
  71. try:
  72. op = getattr(_imagingmath, op + "_" + im1.mode)
  73. except AttributeError as e:
  74. raise TypeError(f"bad operand type for '{op}'") from e
  75. _imagingmath.binop(op, out.im.id, im1.im.id, im2.im.id)
  76. return _Operand(out)
  77. # unary operators
  78. def __bool__(self):
  79. # an image is "true" if it contains at least one non-zero pixel
  80. return self.im.getbbox() is not None
  81. def __abs__(self):
  82. return self.apply("abs", self)
  83. def __pos__(self):
  84. return self
  85. def __neg__(self):
  86. return self.apply("neg", self)
  87. # binary operators
  88. def __add__(self, other):
  89. return self.apply("add", self, other)
  90. def __radd__(self, other):
  91. return self.apply("add", other, self)
  92. def __sub__(self, other):
  93. return self.apply("sub", self, other)
  94. def __rsub__(self, other):
  95. return self.apply("sub", other, self)
  96. def __mul__(self, other):
  97. return self.apply("mul", self, other)
  98. def __rmul__(self, other):
  99. return self.apply("mul", other, self)
  100. def __truediv__(self, other):
  101. return self.apply("div", self, other)
  102. def __rtruediv__(self, other):
  103. return self.apply("div", other, self)
  104. def __mod__(self, other):
  105. return self.apply("mod", self, other)
  106. def __rmod__(self, other):
  107. return self.apply("mod", other, self)
  108. def __pow__(self, other):
  109. return self.apply("pow", self, other)
  110. def __rpow__(self, other):
  111. return self.apply("pow", other, self)
  112. # bitwise
  113. def __invert__(self):
  114. return self.apply("invert", self)
  115. def __and__(self, other):
  116. return self.apply("and", self, other)
  117. def __rand__(self, other):
  118. return self.apply("and", other, self)
  119. def __or__(self, other):
  120. return self.apply("or", self, other)
  121. def __ror__(self, other):
  122. return self.apply("or", other, self)
  123. def __xor__(self, other):
  124. return self.apply("xor", self, other)
  125. def __rxor__(self, other):
  126. return self.apply("xor", other, self)
  127. def __lshift__(self, other):
  128. return self.apply("lshift", self, other)
  129. def __rshift__(self, other):
  130. return self.apply("rshift", self, other)
  131. # logical
  132. def __eq__(self, other):
  133. return self.apply("eq", self, other)
  134. def __ne__(self, other):
  135. return self.apply("ne", self, other)
  136. def __lt__(self, other):
  137. return self.apply("lt", self, other)
  138. def __le__(self, other):
  139. return self.apply("le", self, other)
  140. def __gt__(self, other):
  141. return self.apply("gt", self, other)
  142. def __ge__(self, other):
  143. return self.apply("ge", self, other)
  144. # conversions
  145. def imagemath_int(self):
  146. return _Operand(self.im.convert("I"))
  147. def imagemath_float(self):
  148. return _Operand(self.im.convert("F"))
  149. # logical
  150. def imagemath_equal(self, other):
  151. return self.apply("eq", self, other, mode="I")
  152. def imagemath_notequal(self, other):
  153. return self.apply("ne", self, other, mode="I")
  154. def imagemath_min(self, other):
  155. return self.apply("min", self, other)
  156. def imagemath_max(self, other):
  157. return self.apply("max", self, other)
  158. def imagemath_convert(self, mode):
  159. return _Operand(self.im.convert(mode))
  160. ops = {}
  161. for k, v in list(globals().items()):
  162. if k[:10] == "imagemath_":
  163. ops[k[10:]] = v
  164. def eval(expression, _dict={}, **kw):
  165. """
  166. Evaluates an image expression.
  167. :param expression: A string containing a Python-style expression.
  168. :param options: Values to add to the evaluation context. You
  169. can either use a dictionary, or one or more keyword
  170. arguments.
  171. :return: The evaluated expression. This is usually an image object, but can
  172. also be an integer, a floating point value, or a pixel tuple,
  173. depending on the expression.
  174. """
  175. # build execution namespace
  176. args = ops.copy()
  177. args.update(_dict)
  178. args.update(kw)
  179. for k, v in list(args.items()):
  180. if hasattr(v, "im"):
  181. args[k] = _Operand(v)
  182. compiled_code = compile(expression, "<string>", "eval")
  183. def scan(code):
  184. for const in code.co_consts:
  185. if type(const) == type(compiled_code):
  186. scan(const)
  187. for name in code.co_names:
  188. if name not in args and name != "abs":
  189. raise ValueError(f"'{name}' not allowed")
  190. scan(compiled_code)
  191. out = builtins.eval(expression, {"__builtins": {"abs": abs}}, args)
  192. try:
  193. return out.im
  194. except AttributeError:
  195. return out