attachment:ImgConv.py of PILwxImageWxBitmapAlphaConversion

   1 # ImgConv.py
   2 
   3 """
   4 Based on pyWiki 'Working With Images' @  http://wiki.wxpython.org/index.cgi/WorkingWithImages
   5 Modified to properly copy, create or remove any alpha in all conversion permutations.
   6 
   7 Note:  The terms "plane", "band", "layer" and "channel" are used interchangibly.
   8 
   9 Tested on Win7 64-bit (6.1.7600) and Win XP SP3 (5.1.2600) using Python 32-bit.
  10 
  11 Platform  Windows 6.1.7600
  12 Python    2.5.4 (r254:67916, Dec 23 2008, 15:10:54) [MSC v.1310 32 bit (Intel) (x86)]
  13 Python wx 2.8.10.1
  14 Pil       1.1.7
  15 
  16 Ray Pasco      
  17 pascor(at)verizon(dot)net
  18 
  19 Last modification:      2011-04-02
  20 
  21 This code may be modified and distributed for any purpose whatsoever.
  22 
  23 """
  24 
  25 import sys
  26 
  27 import wx       # WxBmap <==> wxImage
  28 import Image    # wxImage <==> PilImage.  Used whenf converting to or from Pil images.
  29 
  30 #------------------------------------------------------------------------------
  31 
  32 #   image type         image type       image type
  33 #       1                  2                3
  34 #   wx.Bitmap   <==>   wx.Image  <==>   pilImage
  35 
  36 #----------------------------
  37 
  38 def WxBitmapFromPilImage( pilImage, addAlphaLayer=False, delAlphaLayer=False ) :
  39     """
  40     3 ==> 1
  41     
  42     The default parameter valuess preserve any existing transparency, 
  43       but do not add one if none exists.
  44     
  45     If the given pilImage mode is RGB, optionally create a new wxImage 
  46       alpha transparency plane by calling with addAlphaLayer=True.
  47       
  48     If the given pilImage mode is RGBA, optionally create a new wxImage 
  49       and delete any transparency plane by calling with delAlphaLayer=True.
  50       
  51     If given *both* addAlphaLayer=True *and* delAlphaLayer=True, 
  52       addAlphaLayer=True will take precidence.
  53       
  54     """
  55     
  56     # Pass on the given parameters.
  57     wxImage = WxImageFromPilImage( pilImage, addAlphaLayer, delAlphaLayer )
  58     wxBitmap = wxImage.ConvertToBitmap()
  59     
  60     return wxBitmap
  61 #end def
  62 
  63 #----------------------------
  64 
  65 def WxImageFromPilImage( pilImage, addAlphaLayer=False, delAlphaLayer=False ) :
  66     """
  67     3 ==> 2
  68     
  69     The default parameter values preserve any existing transparency, 
  70       but do not add one if it none exists in the source image.
  71     
  72     If the given source has no alpha, a new image with alpha transparency 
  73       can be returned by calling with addAlphaLayer=True.
  74       
  75     If the given source image has alpha, a new image without alpha
  76       can be returned by calling with delAlphaLayer=True.
  77       
  78     """
  79     
  80     wxImage = wx.EmptyImage( *pilImage.size  )      # Has no transparency plane.
  81     
  82     pilMode = pilImage.mode
  83     hasAlpha = pilImage.mode[-1] == 'A'
  84     
  85     if hasAlpha or (not hasAlpha and addAlphaLayer) :
  86         
  87         pilImageRGBA = pilImage.copy()  # Image mode might now be RGB, not RGBA.
  88         if pilImage.mode != 'RGBA' :
  89             pilImageRGBA = pilImageRGBA.convert( 'RGBA' )
  90         #end if
  91         # The image mode is now gauranteed to be RGBA.
  92         
  93         pilImageStr = pilImageRGBA.tostring()    # Convert all 4 image planes.
  94         
  95         # Extract just the RGB data
  96         pilRgbStr = pilImageRGBA.copy().convert( 'RGB').tostring()
  97         wxImage.SetData( pilRgbStr )
  98         
  99         # Extract just the existing pilImage alpha plane data.
 100         pilAlphaStr = pilImageStr[3::4]      # start at index 3 with a stride (skip) of 4.
 101         wxImage.SetAlphaData( pilAlphaStr )
 102         
 103     elif delAlphaLayer or ((not hasAlpha) and (not addAlphaLayer)) :
 104         
 105         pilImageRGB = pilImage.copy().convert( 'RGB' )
 106         
 107         wxImage.SetData( pilImageRGB.tostring() )     
 108         
 109     else :      # All undecoded parameter permutations.  This is for DEBUG.
 110         
 111         print '####  ERROR:  ImgConv:WxImageFromPilImage():   Undecoded Parameter Combination.'
 112         sys.exit(1)
 113         
 114     #end if
 115     
 116     return wxImage
 117     
 118 #end def
 119 
 120 #----------------------------
 121 
 122 def WxBitmapFromWxImage( wxImage, threshold=128 ) :    
 123     """
 124     2 ==> 1
 125     
 126     Any transparency mask or alpha transparency will be copied, to0.
 127     """
 128     
 129     wxBmap = wxImage.ConvertToBitmap()
 130     
 131     return wxBmap
 132     
 133 #end def
 134 
 135 #----------------------------
 136 
 137 def WxImageFromWxBitmap( wxBmap ) :              
 138     """
 139     1 ==> 2
 140     
 141     Any transparency mask or alpha transparency will be copied, to0.
 142     """
 143     return wx.ImageFromBitmap( wxBmap )
 144 #end def
 145 
 146 #------------------------------------------------------------------------------
 147 
 148 def PilImageFromWxBitmap( wxBmap, keepTransp=True, createTransp=False, debug=False ) :
 149     """
 150     1 ==> 3
 151     
 152     The default parameter values preserve any existing transparency, 
 153       but do not add one if it none exists in the source image.
 154     
 155     If the given source has no alpha, a new image with alpha transparency 
 156       can be returned by calling with addAlphaLayer=True.
 157       
 158     If the given source image has alpha, a new image without alpha
 159       can be returned by calling with delAlphaLayer=True.
 160       
 161     """
 162     
 163     wxImage = WxImageFromWxBitmap( wxBmap )
 164     
 165     return PilImageFromWxImage( wxImage )   # Always preserves any transparency.
 166 #end def
 167 
 168 #----------------------------
 169 
 170 def PilImageFromWxImage( wxImage, keepTransp=True, createTransp=False, debug=False ) :
 171     """
 172     2 ==> 3  
 173     
 174     Default preserves any transparency.
 175     """
 176     
 177     # These can never be simultaneous.
 178     hasMask  = wxImage.HasMask()
 179     hasAlpha = wxImage.HasAlpha()
 180     if debug :
 181         print '>>>>  PilImageFromWxImage():  Input Image has Alpha'
 182     
 183     # Always convert a mask into an aplha layer.
 184     # Deal with keeping or discarding this alpha later on.
 185     if hasMask :    # Is always mutually exclusive with hasAlpha.
 186         
 187         if debug :
 188             print '>>>>  PilImageFromWxImage():  Converting Input Image Mask to Alpha'
 189         
 190         wxImage.InitAlpha()     # Covert the separate mask to a 4th alpha layer.
 191         hasAlpha = True
 192             
 193     #end if 
 194     
 195     image_size = wxImage.GetSize()      # All images here have the same size.
 196     
 197     # Create an RGB pilImage and stuff it with RGB data from the wxImage.
 198     pilImage = Image.new( 'RGB', image_size )
 199     pilImage.fromstring( wxImage.GetData() )
 200     
 201     # May need the separated planes if an RGBA image is needed. later.
 202     r_pilImage, g_pilImage, b_pilImage = pilImage.split()
 203         
 204     if hasAlpha :
 205         
 206         if keepTransp : # Ignore createTransp - has no meaning
 207             
 208             if debug :
 209                 print '>>>>  PilImageFromWxImage():  Keeping Transparency'
 210 
 211             # Must recompose the pilImage from 4 layers.
 212             r_pilImage, g_pilImage, b_pilImage = pilImage.split()
 213 
 214             # Create a Black L pilImage and stuff it with the alpha data 
 215             #   extracted from the alpha layer of the wxImage.
 216             pilImage_L = Image.new( 'L', image_size )
 217             pilImage_L.fromstring( wxImage.GetAlphaData() )
 218 
 219             # Create an RGBA PIL image from the 4 layers.
 220             pilImage = Image.merge( 'RGBA', (r_pilImage, g_pilImage, b_pilImage, pilImage_L) )
 221         
 222         elif (not keepTransp) :
 223             
 224             # The RGB pilImage can be returned as it is now.
 225             if debug :
 226                 print '>>>>  PilImageFromWxImage():  Returning an RGB PIL Image.'
 227             
 228         #end if
 229         
 230     elif (not hasAlpha) and createTransp :      # Ignore keepTransp - has no meaning
 231         
 232         if debug :
 233             print '>>>>  PilImageFromWxImage():  Creating a New Transparency Layer'
 234         
 235         # Create a Black L mode pilImage. The resulting image will still
 236         #  look the same, but will allow future transparency modification.
 237         pilImage_L = Image.new( 'L', image_size )
 238         
 239         # Create an RGBA pil image from the 4 bands.
 240         pilImage = Image.merge( 'RGBA', (r_pilImage, g_pilImage, b_pilImage, pilImage_L) )
 241         
 242     #end if
 243     
 244     return pilImage
 245     
 246 #end PilImageFromWxImage def
 247 
 248 #------------------------------------------------------------------------------