pylib/gp_codegen/pixeltype.py

   1 #
   2 #  gfxprim.pixeltype - Module with PixelType descrition class
   3 #
   4 # 2011 - Tomas Gavenciak <gavento@ucw.cz>
   5 # 2013   Cyril Hrubis <metan@ucw.cz>
   6 #
   7
   8 import re
   9 from .pixelsize import PixelSize
  10
  11 class PixelChannel(list):
  12   def __init__(self, triplet, idx):
  13     (name, offset, size) = triplet
  14     # Create the list -> backward compatibility with triplets
  15     self.append(name)
  16     self.append(offset)
  17     self.append(size)
  18     # Add index (position in pixel from left)
  19     self.idx = idx
  20     # Add some convinience variables
  21     self.name = name
  22     self.off = offset
  23     self.size = size
  24     # Shift ready to used in C
  25     self.C_shift = " << " + hex(offset)
  26     # Maximal channel value as an integer
  27     self.max = 2 ** size - 1
  28     # Maximal value as a C string
  29     self.C_max = hex(self.max)
  30     # Chanel bitmask as int
  31     self.mask = self.max * (2 ** offset)
  32     # Channel bitmas as hex string
  33     self.C_mask = hex(self.mask)
  34
  35 class PixelType(object):
  36   """Representation of one GP_PixelType"""
  37
  38   def __init__(self, name, pixelsize, chanslist):
  39     """`name` must be a valid C identifier
  40     `pixelsize` is an instance of PixelSize
  41     `chanslist` is a list of triplets describing individual channels as
  42       [ (`chan_name`, `bit_offset`, `bit_size`) ]
  43       where `chan_name` is usually one of: R, G, B,
  44       V (value, used for grayscale), A (opacity)
  45     """
  46     assert re.match('\A[A-Za-z][A-Za-z0-9_]*\Z', name)
  47     self.name = name
  48     # Create channel list with convinience variables
  49     new_chanslist = []
  50     idx = 0
  51     for i in chanslist:
  52       new_chanslist.append(PixelChannel(i, idx))
  53       idx = idx + 1
  54     self.chanslist = new_chanslist
  55     self.chans = dict() # { chan_name: (offset, size) }
  56     self.pixelsize = pixelsize
  57     # C enum as defined in GP_Pixel.gen.h
  58     self.C_type = "GP_PIXEL_" + self.name
  59
  60     # Verify channel bits for overlaps
  61     # also builds a bit-map of the PixelType
  62     self.bits = ['x'] * pixelsize.size
  63     for c in new_chanslist:
  64       assert c[0] not in self.chans.keys()
  65       self.chans[c[0]] = c
  66       for i in range(c[1], c[1] + c[2]):
  67         assert(i < self.pixelsize.size)
  68         assert(self.bits[i] == 'x')
  69         self.bits[i] = c[0]
  70
  71   def valid_for_config(self, config):
  72     "Check PixelType compatibility with given GfxPrimConfig."
  73
  74     # all types except UNKNOWN must have one of these sizes
  75     if not self.is_unknown():
  76       assert(self.pixelsize in config.pixelsizes)
  77
  78   def __str__(self):
  79     return "<PixelType " + self.name + ">"
  80
  81   def is_palette(self):
  82     return ('P' in self.chans)
  83
  84   def is_unknown(self):
  85     return (self.name == "UNKNOWN")
  86
  87   def is_rgb(self):
  88     for i in 'RGB':
  89       if i not in self.chans: return False
  90     return True
  91
  92   def is_gray(self):
  93     return ('V' in self.chans)
  94
  95   def is_cmyk(self):
  96     for i in 'CMYK':
  97       if i not in self.chans: return False
  98     return True
  99
 100   def is_alpha(self):
 101     return ('A' in self.chans)
 102