pylib/context.py

   1 import gfxprim_core_c as core
   2 import gfxprim_loaders_c as loaders
   3
   4 def extend(cls, name=None):
   5   def decf(method):
   6     funname = name
   7     if not funname:
   8       funname = method.__name__
   9     type.__setattr__(cls, funname, method)
  10     return method
  11   return decf
  12
  13 def add_swig_getmethod(cls, name=None):
  14   def decf(method):
  15     propname = name
  16     if not propname:
  17       propname = method.__name__
  18     cls.__swig_getmethods__[propname] = method
  19   return decf
  20
  21 def add_swig_setmethod(cls, name=None):
  22   def decf(method):
  23     propname = name
  24     if not propname:
  25       propname = method.__name__
  26     cls.__swig_setmethods__[propname] = method
  27   return decf
  28
  29
  30 def extend_context_class(_context_class = core.Context):
  31   """
  32   Extends _context_class class with convenience methods.
  33   Called on module inicialization.
  34   """
  35
  36   # Add "parent" attribute
  37   extend(_context_class, name='parent')(None)
  38
  39   @extend(_context_class, name='__str__')
  40   @extend(_context_class, name='__repr__')
  41   def context_str(self):
  42     return "<Context %dx%d, %dbpp, GP_Context %sowned, %s parent>" % (
  43       self.w, self.h, self._bpp,
  44       "" if self.thisown else "not ",
  45       "with" if self.parent else "no")
  46
  47   @add_swig_getmethod(_context_class)
  48   def w(self):
  49     return core.GP_ContextW(self)
  50
  51   @add_swig_getmethod(_context_class)
  52   def h(self):
  53     return core.GP_ContextH(self)
  54
  55   @extend(_context_class)
  56   def subcontext(self, x, y, w, h):
  57     "Create a subcontext (rectangular view)."
  58     c = core.GP_ContextSubContext(self, None, x, y, w, h)
  59     c.parent = self
  60     return c
  61
  62   @extend(_context_class)
  63   def copy(self, withdata):
  64     "Copy the context to a new context. Pixel data are copie optionally."
  65     flags = core.GP_COPY_WITH_PIXELS if withdata else 0
  66     return core.GP_ContextCopy(self, flags)
  67
  68   @extend(_context_class)
  69   def convert(self, target_type):
  70     """Converts context to a different pixel type, allocates new context.
  71     See GP_ContextConvert() for details."""
  72     pixeltype_no = target_type ## TODO also accept PixelType
  73     return core.GP_ContextConvert(self, pixeltype_no)
  74
  75
  76   @extend(_context_class)
  77   def save(self, filename, format=None):
  78     """Save the image in given format (or guess it from the extension)
  79
  80     Currently, JPG, PNG and P[BGP]M are supported, but not for all
  81     context pixel types.
  82     """
  83     if not format:
  84       format = filename.rsplit('.', 1)[-1]
  85     format = format.lower()
  86     if format == 'jpg':
  87       res = loaders.GP_SaveJPG(filename, self, None)
  88     elif format == 'png':
  89       res = loaders.GP_SavePNG(filename, self, None)
  90     elif format == 'pbm':
  91       res = loaders.GP_SavePBM(filename, self, None)
  92     elif format == 'pgm':
  93       res = loaders.GP_SavePGM(filename, self, None)
  94     elif format == 'ppm':
  95       res = loaders.GP_SavePPM(filename, self, None)
  96     else:
  97       raise Exception("Format %r not supported.", format)
  98     if res != 0:
  99       raise Exception("Error saving %r (code %d)", filename, res)
 100
 101   @extend(_context_class, name='create')
 102   @staticmethod
 103   def create(w, h, pixeltype):
 104     "Allocate a new w*h bitmap of given type."
 105
 106     pixeltype_no = pixeltype if isinstance(pixeltype, int) else 0 # !!!
 107     # TODO: actually accept a PixelType
 108     c = core.GP_ContextAlloc(w, h, pixeltype_no)
 109     return c
 110
 111   @extend(_context_class, name='load')
 112   @staticmethod
 113   def load(filename):
 114     "Load image from given file, guess type."
 115     c = loaders.GP_LoadImage_SWIG(filename)
 116     return c
 117
 118
 119
 120 extend_context_class()
 121