Changing the image size dynamically when the sizer's size changes in wxPython

Question

I am working with python v2.7 and wxPython v3.0 on Windows 8 OS. In the code snippet provided below simply creates a frame which has a vertical sizer that contains an image and an other horizontal sizer that in turn contains two panels.

Question : When I resize the frame by dragging the border, the panels resize automatically. Unlike the panels the image doesn't resize? How can I make my image to behave like panels for the case of resizing?

Code: The image file used can be downloaded from here: green.bmp

import wx

class Frame(wx.Frame):
    def __init__(self, parent, id, title):
        wx.Frame.__init__(self, parent, id, title, style=wx.DEFAULT_FRAME_STYLE)
        panelA = wx.Panel(self,-1)
        imageFile = wx.Image('greenbig.bmp', wx.BITMAP_TYPE_ANY).ConvertToBitmap()
        myBitmap = wx.StaticBitmap(panelA, -1, imageFile)

        panel1 = wx.Panel(self, -1,style=wx.SIMPLE_BORDER)
        panel2 = wx.Panel(self, -1, style=wx.SIMPLE_BORDER)
        panelSizer = wx.BoxSizer(wx.HORIZONTAL)
        panelSizer.Add(panel1, 1, wx.ALL|wx.EXPAND, 0)
        panelSizer.Add(panel2, 1, wx.ALL|wx.EXPAND, 0)

        sizer = wx.BoxSizer(wx.VERTICAL)
        sizer.Add(panelA, 1, wx.ALL|wx.EXPAND, 0)
        sizer.Add(panelSizer,  1, wx.ALL|wx.EXPAND, 0)
        self.SetSizer(sizer)

        self.Show(True)

app = wx.App()
frame = Frame(None, wx.ID_ANY, 'Image')
app.MainLoop()

Thank you for your time!

Answer 1

(eight years later) I was struggling to show an image that was dynamically resized with the window frame. These days, I'm using Python 3 with wxPython version 4 . I pieced this solution from a lot of reading of the documentation and tips on how best to use sizers. I then whittled my code down to the absolute minimum required to accomplish this narrow use case.

Notice that I don't ever call Frame.Layout() or Panel.Layout() because I rely on the initial size of the Frame and the fact that a single Panel in a Frame will be automatically resized with the Frame . Also, any call to Fit() was unnecessary. The sizer containing the ImagePanel does need the EXPAND flag, but the ImagePanel does not need a sizer itself.

Note: you'll have to supply your own example image to load.

import wx


class ImagePanel(wx.Panel):
    def __init__(self, parent):
        super().__init__(parent)
        self.img = wx.Image(width=1, height=1)
        self.ctrl = wx.StaticBitmap(self, bitmap=self.img.ConvertToBitmap())
        self.Bind(wx.EVT_SIZE, self.on_resize)

    def load_image(self):
        with open('image.png', 'rb') as fin:
            self.img = wx.Image(fin)
        self.update_bitmap()

    def update_bitmap(self):
        w, h = self.GetSize()
        self.ctrl.SetBitmap(self.img.Scale(w, h).ConvertToBitmap())

    def on_resize(self, evt):
        self.update_bitmap()


class MainWindow(wx.Frame):
    def __init__(self):
        initial_size = wx.Size(width=480, height=480)
        super().__init__(None, wx.ID_ANY, title='Main Window Title', size=initial_size)
        self.panel = wx.Panel(self)
        self.image = ImagePanel(self.panel)

        vbox = wx.BoxSizer(wx.VERTICAL)
        vbox.Add(self.image, proportion=1, flag=wx.EXPAND)
        self.panel.SetSizer(vbox)


if __name__ == '__main__':
    app = wx.App()
    win = MainWindow()
    win.Show()
    win.image.load_image()
    app.MainLoop()

Answer 2

The image will never be resized automatically. If you want this behaviour, you need to handle wxEVT_SIZE and do it yourself in its handler.