added aspect ratio preservation to AutoSizeBitmap demo

Author: ChrisBarker-NOAA

AutoSizeBitmap.py

@@ -5,54 +5,83 @@
 
 Example for how to have a bitmap autosize itself in wxPython
 """
-
+import math
 import wx
-print "using wxPython version:", wx.__version__
+
+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, parent, image, *args, **kwargs):
+   """
+    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, parent, *args, **kwargs)
+        """
+        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):
-        img = self.orig_image.Copy()
-        img.Rescale(*self.Size)
-        self.bitmap = wx.BitmapFromImage(img)
-        self.Refresh()
+        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
+            dc.DrawBitmap(self.bitmap, 0, 0)
+        except ValueError:  # in case bitmap has not yet been initialized
             pass
 
 if __name__ == "__main__":
     import sys
-    
-    try: 
+
+    try:
         filename = sys.argv[1]
     except:
         filename = "Images/cute_close_up.jpg"
     App = wx.App(False)
-    f = wx.Frame(None)
     img = wx.Image(filename)
-    b = AutoSizeBitmap(f, img)
-    f.Show()
+    f = AutoSizeFrame(img, None, size=(400, 600))
     App.MainLoop()
 

ScrolledBitmap.py

@@ -1,5 +1,11 @@
 #!/usr/bin/env
 
+"""
+Putting an image in a Scrolled Window
+
+And drawing something over it.
+"""
+
 import wx
 
 # set an image file here