AutoSizeBitmap.py

#!/usr/bin/env python

"""
AutoSizeBitmap.py

Example for how to have a bitmap autosize itself in wxPython
"""
import math
import wx

KEEP_ASPECT_RATIO = True


class AutoSizeFrame(wx.Frame):
 def __init__(self, image, *args, **kwargs):
 wx.Frame.__init__(self, *args, **kwargs)

 self.aspect_ratio = float(image.Width) / float(image.Height)
 self.canvas = AutoSizeBitmap(image, self)
 self.canvas.SetSize((300, 400))

 self.Bind(wx.EVT_SIZE, self.OnSize)

 self.Fit()
 self.Show()

 def OnSize(self, evt=None):
 size = self.Size
 if (size[0] > 0 and size[1] > 0):
 width, height = size
 if KEEP_ASPECT_RATIO:
 total_size = width * height
 height = int(math.sqrt(total_size / self.aspect_ratio))
 width = int(total_size / height)
 # resize window on the fly to keep the aspect ratio
 self.SetSize((width, height))
 self.canvas.SetSize((width, height))


class AutoSizeBitmap(wx.Window):
 """
 A subclass of wx.Window that will hold an image (much like a StaticBitmap),
 but re-size it to fit the current size of the Window
 """
 def __init__(self, image, *args, **kwargs):
 """
 initialize an AutoSizeBitmap

 :param parent: parent Window for this window
 :param image: a wx.Image that you want to display
 """
 wx.Window.__init__(self, *args, **kwargs)

 self.orig_image = image
 self.bitmap = None
 self.prev_size = self.Size

 self.Bind(wx.EVT_SIZE, self.OnSize)
 self.Bind(wx.EVT_PAINT, self.OnPaint)

 def OnSize(self, evt=None):
 size = self.Size
 if size[0] > 0 and size[1] > 0:
 img = self.orig_image.Copy()
 img.Rescale(*size)
 self.bitmap = wx.BitmapFromImage(img)
 self.Refresh()

 def OnPaint(self, evt=None):
 dc = wx.PaintDC(self)
 try:
 dc.DrawBitmap(self.bitmap, 0, 0)
 except ValueError: # in case bitmap has not yet been initialized
 pass

if __name__ == "__main__":
 import sys

 try:
 filename = sys.argv[1]
 except:
 filename = "Images/cute_close_up.jpg"
 App = wx.App(False)
 img = wx.Image(filename)
 f = AutoSizeFrame(img, None, size=(400, 600))
 App.MainLoop()