wxWidgets/wxPython/demo/ImageAlpha.py

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import wx # This module uses the new wx namespace
from Main import opj
#----------------------------------------------------------------------
msg = "Some text will appear mixed in the image's shadow..."
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)
def OnPaint(self, evt):
dc = wx.PaintDC(self)
dc.SetBackground(wx.Brush("WHITE"))
dc.Clear()
dc.SetFont(wx.Font(16, wx.SWISS, wx.NORMAL, wx.BOLD, True))
dc.DrawText("Bitmap alpha blending (on all ports but gtk+ 1.2)",
25,25)
bmp = wx.Bitmap(opj('bitmaps/toucan.png'))
if "gtk1" in wx.PlatformInfo:
# Try to make up for lack of alpha support in wxGTK (gtk+
# 1.2) by converting the alpha blending into a
# transparency mask.
# first convert to a wx.Image
img = bmp.ConvertToImage()
# Then convert the alpha channel to a mask, specifying the
# threshold below which alpha will be made fully
# transparent
img.ConvertAlphaToMask(220)
# convert back to a wx.Bitmap
bmp = img.ConvertToBitmap()
dc.DrawBitmap(bmp, 25,100, True)
dc.SetFont(self.GetFont())
y = 75
for line in range(10):
y += dc.GetCharHeight() + 5
dc.DrawText(msg, 200, y)
dc.DrawBitmap(bmp, 250,100, True)
#----------------------------------------------------------------------
def runTest(frame, nb, log):
win = TestPanel(nb, log)
return win
#----------------------------------------------------------------------
overview = """<html><body>
<h2><center>Images with Alpha</center></h2>
wxMSW and wxMac now support alpha channels of supported image
types, and will properly blend that channel when drawing a
bitmap. It is not supported yet on wxGTK, (if you would like to
change that please submit a patch!)
<p>On wxGTK this demo turns the alpha channel into a 1-bit mask, so
yes, it looks like crap. Please help us fix it!
</body></html>
"""
if __name__ == '__main__':
import sys,os
import run
run.main(['', os.path.basename(sys.argv[0])] + sys.argv[1:])