在 wxPython 中绘制到框架内的面板 [英] Drawing to Panel inside of Frame in wxPython

问题描述

下面，我在框架内有一个面板.为什么我无法在面板上绘图?我只是得到一个纯白色的屏幕.如果我摆脱面板并直接绘制到框架......它可以工作.任何帮助将不胜感激.

Below, I have a panel inside of a frame. Why am I not able to draw to the panel? I just get a plain white screen. If I get rid of the panel and draw directly to the frame...it works. any help would be appreciated.

import wx

class MyFrame(wx.Frame):
    def __init__(self):
        wx.Frame.__init__(self,None,-1,'window',(200,200),(600,600))
        self.Center()
        self.panel=wx.Panel(self)
        self.panel.SetBackgroundColour('white')
        self.firstpoint=wx.Point(300,300)
        self.secondpoint=wx.Point(400,400)
        self.Bind(wx.EVT_PAINT,self.onPaint)


    def onPaint(self,event):
        dc=wx.PaintDC(self.panel)
        dc.DrawLine(self.firstpoint.x,self.firstpoint.y,
                    self.secondpoint.x,self.secondpoint.y)

推荐答案

尝试将事件绑定到面板，而不是整个框架:

Try binding the event to the panel, not to the whole frame:

self.panel.Bind(wx.EVT_PAINT, self.onPaint)

你的版本对我有用(windows)，但它不断重绘面板，所以它吃掉了整个处理器.

Your version kind-of work for me (windows), but it keeps redrawing the panel so it eats up the whole processor.

来自文档:请注意，在绘制事件处理程序中，应用程序必须始终创建一个 wxPaintDC 对象，即使您不使用它.否则，在 MS Windows 下，刷新此窗口和其他窗口会出错.

在这里，您收到了整个帧的绘制事件，但对面板使用了 dc.

Here, you received the paint event for the whole frame but used the dc for the panel.

这个 http://wiki.wxpython.org/self.Bind%20vs.%20self.button.Bind 很好地解释了为什么这不起作用:

This http://wiki.wxpython.org/self.Bind%20vs.%20self.button.Bind explains quite nicely why this won't work:

self.Bind(wx.EVT_PAINT, self.onPaint, self.panel)

在这种情况下，永远不会调用 onPaint 处理程序.

In this case the onPaint handler is never called.

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