wxPython - PaintDC not refreshing_问答_开发者_运维开发者技术经验分享

开发者 https://www.devze.com 2022-12-19 22:45 出处：网络

import wx class TestDraw(wx.Panel): def __init__(self,parent=None,id=-1): wx.Panel.__init__(self,parent,id)



import wx

class TestDraw(wx.Panel):
    def __init__(self,parent=None,id=-1):
        wx.Panel.__init__(self,parent,id)
        self.SetBackgroundColour("#FFFFFF")
        self.Bind(wx.EVT_PAINT,self.onPaint)
    def onPaint(self, event):
        event.Skip()

        dc=wx.PaintDC(self)
        dc.BeginDrawing()
        width=dc.GetSize()[0]
        height=dc.GetSize()[1]
        if height<width:
            self.drawTestRects(dc)
        else:
            dc.Clear()
        dc.EndDrawing()

    def drawTestRects(self,dc):
        dc.SetBrush(wx.Brush("#000000",style=wx.SOLID))
        dc.DrawRectangle(50,50,50,50)
        dc.DrawRectangle(100,100,100,100)

class TestFrame(wx.Frame):
    def __init__(self, parent, title):
        wx.Frame.__init__(self, parent, title=title, size=(640,480))
        self.mainPanel=TestDraw(self,-1)

        self.Show(True)


app = wx.App(False)
frame = TestFrame(None,"Test App")
app.MainLoop()

This code should draw the test recta开发者_StackOverflow中文版ngles only when the height is less than the width, and otherwise the window should remain clear. However, if you mess with resizing the window, the panel isn't actually redrawn unless it is moved off the window. What am I doing wrong?

You can bind a method to handle wx.EVT_SIZE or the panel and invalidate it there. Alternatively simply use the wx.FULL_REPAINT_ON_RESIZE for the panel.

The documentation for a SizeEvent claims that there may be some complications when drawing depends on the dimensions of the window. I do not know exactly what is going on behind the scenes. I followed the suggestion on the link and added the call self.Refresh() to the top of onPaint() and this seems to give the desired behavior. See mghie's answer for a more efficient example of working code.