Add BitmapFromBuffer demo

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@40763 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

wxPython/demo/BitmapFromBuffer.py

@@ -0,0 +1,163 @@
+
+import wx
+import array
+
+#----------------------------------------------------------------------
+
+class TestPanel(wx.Panel):
+    def __init__(self, parent, log):
+        self.log = log
+        wx.Panel.__init__(self, parent, -1)
+        self.Bind(wx.EVT_PAINT, self.OnPaint)
+        self.width, self.height = 120,120
+        
+        self.MakeBitmapRGB(self.width, self.height)
+        self.MakeBitmapRGBA(self.width, self.height)
+        self.MakeBitmapRGBpA(self.width, self.height)
+
+    def GetRGB(self, x, y, bpp):
+        # calculate some colour values for this sample based on x,y position
+        r = g = b = 0
+        if y < self.height/3:                           r = 255
+        if y >= self.height/3 and y <= 2*self.height/3: g = 255
+        if y > 2*self.height/3:                         b = 255
+
+        if bpp == 4:
+            a = int(x * 255.0 / self.width)
+            return r, g, b, a
+        else:
+            return r, g, b
+
+
+    def MakeBitmapRGB(self, width, height):
+        # Make a bitmap using an array of RGB bytes
+        bpp = 3  # bytes per pixel
+        bytes = array.array('B', [0] * width*height*bpp)
+
+        def offset(x, y):
+            # return the offset into the bytes array for the start of
+            # the x,y pixel
+            return y*width*bpp + x*bpp
+
+        for y in xrange(height):
+            for x in xrange(width):
+                r,g,b = self.GetRGB(x, y, bpp)
+                bytes[offset(x, y) + 0] = r
+                bytes[offset(x, y) + 1] = g
+                bytes[offset(x, y) + 2] = b
+                ##print (x, y), offset(x, y), (r, g, b)
+
+        self.rgbBmp = wx.BitmapFromBuffer(width, height, bytes)
+        
+
+
+    def MakeBitmapRGBA(self, width, height):
+        # Make a bitmap using an array of RGBA bytes
+        bpp = 4  # bytes per pixel
+        bytes = array.array('B', [0] * width*height*bpp)
+
+        def offset(x, y):
+            # return the offset into the bytes array for the start of
+            # the x,y pixel
+            return y*width*bpp + x*bpp
+
+        for y in xrange(height):
+            for x in xrange(width):
+                r,g,b,a = self.GetRGB(x, y, bpp)
+                bytes[offset(x, y) + 0] = r
+                bytes[offset(x, y) + 1] = g
+                bytes[offset(x, y) + 2] = b
+                bytes[offset(x, y) + 3] = a
+                ##print (x, y), offset(x, y), (r, g, b, a)
+
+        self.rgbaBmp = wx.BitmapFromBufferRGBA(width, height, bytes)
+
+
+    def MakeBitmapRGBpA(self, width, height):
+        # Make a bitmap using an array of RGB bytes plus a separate
+        # buffer for the alpha channel
+        bpp = 3  # bytes per pixel
+        bytes = array.array('B', [1,2,3] * width*height)#*bpp)
+
+        def offset(x, y):
+            # return the offset into the bytes array for the start of
+            # the x,y pixel
+            return y*width*bpp + x*bpp
+
+        for y in xrange(height):
+            for x in xrange(width):
+                r,g,b = self.GetRGB(x, y, bpp)
+                bytes[offset(x, y) + 0] = r
+                bytes[offset(x, y) + 1] = g
+                bytes[offset(x, y) + 2] = b
+                ##print (x, y), offset(x, y), (r, g, b)
+
+        # just use an alpha buffer with a constant alpha value for all
+        # pixels for this example, it could just as easily have
+        # varying alpha values like the other sample.
+        alpha = array.array('B', [128]*width*height)
+        self.rgbaBmp2 = wx.BitmapFromBuffer(width, height, bytes, alpha)
+
+
+    def DrawBitmapAndMessage(self, dc, bmp, msg, x_, y_):
+        x, y = x_, y_
+
+        # draw some text to help show the alpha
+        dc.SetFont(self.GetFont())
+        while y < y_ + self.height + 2*dc.GetCharHeight():
+            dc.DrawText(msg, x,y)
+            y += dc.GetCharHeight() + 5
+
+        # draw the bitmap over the text
+        dc.DrawBitmap(bmp, x+15,y_+15, True)
+
+        
+    def OnPaint(self, evt):
+        dc = wx.PaintDC(self)
+        self.DrawBitmapAndMessage(dc, self.rgbBmp,  "No alpha channel in this image", 30,35)
+        self.DrawBitmapAndMessage(dc, self.rgbaBmp, "This image has some alpha", 325,35)
+        self.DrawBitmapAndMessage(dc, self.rgbaBmp2,"This one made with RGB+A", 180,220)
+
+
+        
+        
+        
+#----------------------------------------------------------------------
+
+def runTest(frame, nb, log):
+    win = TestPanel(nb, log)
+    return win
+
+#----------------------------------------------------------------------
+
+
+
+overview = """<html><body>
+<h2><center>BitmapFromBuffer</center></h2>
+
+Two new wx.Bitmap factory functions allow you to create a wx.Bitmap
+directly from a data buffer.  The the buffer can be any Python object
+that implements the buffer interface, or is convertable to a buffer,
+such as a string or an array.  The new functions are: <ul>
+
+<li><b>wx.BitmapFromBuffer</b>(width, height, dataBuffer, alphaBuffer=None):
+Creates the bitmap from a buffer of RGB bytes, optionally with a separate
+buffer of alpha bytes.
+
+<li><b>wx.BitmapFromBufferRGBA</b>(width, height, dataBuffer): Creates
+the bitmap from a buffer containing RGBA bytes.
+
+</ul>
+
+
+
+</body></html>
+"""
+
+
+
+if __name__ == '__main__':
+    import sys,os
+    import run
+    run.main(['', os.path.basename(sys.argv[0])] + sys.argv[1:])
+