wxPython/demo/BitmapFromBuffer.py

   1
   2 import wx
   3 import array
   4
   5 #----------------------------------------------------------------------
   6
   7 class TestPanel(wx.Panel):
   8     def __init__(self, parent, log):
   9         self.log = log
  10         wx.Panel.__init__(self, parent, -1)
  11         self.Bind(wx.EVT_PAINT, self.OnPaint)
  12         self.width, self.height = 120,120
  13
  14         self.MakeBitmapRGB(self.width, self.height)
  15         self.MakeBitmapRGBA(self.width, self.height)
  16         self.MakeBitmapRGBpA(self.width, self.height)
  17
  18     def GetRGB(self, x, y, bpp):
  19         # calculate some colour values for this sample based on x,y position
  20         r = g = b = 0
  21         if y < self.height/3:                           r = 255
  22         if y >= self.height/3 and y <= 2*self.height/3: g = 255
  23         if y > 2*self.height/3:                         b = 255
  24
  25         if bpp == 4:
  26             a = int(x * 255.0 / self.width)
  27             return r, g, b, a
  28         else:
  29             return r, g, b
  30
  31
  32     def MakeBitmapRGB(self, width, height):
  33         # Make a bitmap using an array of RGB bytes
  34         bpp = 3  # bytes per pixel
  35         bytes = array.array('B', [0] * width*height*bpp)
  36
  37         def offset(x, y):
  38             # return the offset into the bytes array for the start of
  39             # the x,y pixel
  40             return y*width*bpp + x*bpp
  41
  42         for y in xrange(height):
  43             for x in xrange(width):
  44                 r,g,b = self.GetRGB(x, y, bpp)
  45                 bytes[offset(x, y) + 0] = r
  46                 bytes[offset(x, y) + 1] = g
  47                 bytes[offset(x, y) + 2] = b
  48                 ##print (x, y), offset(x, y), (r, g, b)
  49
  50         self.rgbBmp = wx.BitmapFromBuffer(width, height, bytes)
  51
  52
  53
  54     def MakeBitmapRGBA(self, width, height):
  55         # Make a bitmap using an array of RGBA bytes
  56         bpp = 4  # bytes per pixel
  57         bytes = array.array('B', [0] * width*height*bpp)
  58
  59         def offset(x, y):
  60             # return the offset into the bytes array for the start of
  61             # the x,y pixel
  62             return y*width*bpp + x*bpp
  63
  64         for y in xrange(height):
  65             for x in xrange(width):
  66                 r,g,b,a = self.GetRGB(x, y, bpp)
  67                 bytes[offset(x, y) + 0] = r
  68                 bytes[offset(x, y) + 1] = g
  69                 bytes[offset(x, y) + 2] = b
  70                 bytes[offset(x, y) + 3] = a
  71                 ##print (x, y), offset(x, y), (r, g, b, a)
  72
  73         self.rgbaBmp = wx.BitmapFromBufferRGBA(width, height, bytes)
  74
  75
  76     def MakeBitmapRGBpA(self, width, height):
  77         # Make a bitmap using an array of RGB bytes plus a separate
  78         # buffer for the alpha channel
  79         bpp = 3  # bytes per pixel
  80         bytes = array.array('B', [1,2,3] * width*height)#*bpp)
  81
  82         def offset(x, y):
  83             # return the offset into the bytes array for the start of
  84             # the x,y pixel
  85             return y*width*bpp + x*bpp
  86
  87         for y in xrange(height):
  88             for x in xrange(width):
  89                 r,g,b = self.GetRGB(x, y, bpp)
  90                 bytes[offset(x, y) + 0] = r
  91                 bytes[offset(x, y) + 1] = g
  92                 bytes[offset(x, y) + 2] = b
  93                 ##print (x, y), offset(x, y), (r, g, b)
  94
  95         # just use an alpha buffer with a constant alpha value for all
  96         # pixels for this example, it could just as easily have
  97         # varying alpha values like the other sample.
  98         alpha = array.array('B', [128]*width*height)
  99         self.rgbaBmp2 = wx.BitmapFromBuffer(width, height, bytes, alpha)
 100
 101
 102     def DrawBitmapAndMessage(self, dc, bmp, msg, x_, y_):
 103         x, y = x_, y_
 104
 105         # draw some text to help show the alpha
 106         dc.SetFont(self.GetFont())
 107         while y < y_ + self.height + 2*dc.GetCharHeight():
 108             dc.DrawText(msg, x,y)
 109             y += dc.GetCharHeight() + 5
 110
 111         # draw the bitmap over the text
 112         dc.DrawBitmap(bmp, x+15,y_+15, True)
 113
 114
 115     def OnPaint(self, evt):
 116         dc = wx.PaintDC(self)
 117         self.DrawBitmapAndMessage(dc, self.rgbBmp,  "No alpha channel in this image", 30,35)
 118         self.DrawBitmapAndMessage(dc, self.rgbaBmp, "This image has some alpha", 325,35)
 119         self.DrawBitmapAndMessage(dc, self.rgbaBmp2,"This one made with RGB+A", 180,220)
 120
 121
 122
 123
 124
 125 #----------------------------------------------------------------------
 126
 127 def runTest(frame, nb, log):
 128     win = TestPanel(nb, log)
 129     return win
 130
 131 #----------------------------------------------------------------------
 132
 133
 134
 135 overview = """<html><body>
 136 <h2><center>BitmapFromBuffer</center></h2>
 137
 138 Two new wx.Bitmap factory functions allow you to create a wx.Bitmap
 139 directly from a data buffer.  The the buffer can be any Python object
 140 that implements the buffer interface, or is convertable to a buffer,
 141 such as a string or an array.  The new functions are: <ul>
 142
 143 <li><b>wx.BitmapFromBuffer</b>(width, height, dataBuffer, alphaBuffer=None):
 144 Creates the bitmap from a buffer of RGB bytes, optionally with a separate
 145 buffer of alpha bytes.
 146
 147 <li><b>wx.BitmapFromBufferRGBA</b>(width, height, dataBuffer): Creates
 148 the bitmap from a buffer containing RGBA bytes.
 149
 150 </ul>
 151
 152
 153
 154 </body></html>
 155 """
 156
 157
 158
 159 if __name__ == '__main__':
 160     import sys,os
 161     import run
 162     run.main(['', os.path.basename(sys.argv[0])] + sys.argv[1:])
 163