wxpython用鼠标移动绘制点

Question

我现在正在使用 wxpython 做一些图像处理工作。我想用鼠标左键向下绘制一个点，然后用鼠标移动绘制的点。

以下是我的代码。按下左键绘制点没问题，但是当我移动鼠标时，之前绘制的点也会显示，这不符合我的预期。

当我移动鼠标时如何隐藏上一个点，让我看起来像是在移动点？

# -*- coding: utf-8 -*- 

import wx

class MyFrame(wx.Frame):
    isLeftDown = False

    def __init__(self, parent):
        wx.Frame.__init__(self, parent, id=wx.ID_ANY, size=wx.Size(500, 500))
        bSizer1 = wx.BoxSizer(wx.VERTICAL)

        self.m_panel = wx.Panel(self, wx.ID_ANY, wx.DefaultPosition, 
                                wx.DefaultSize, wx.TAB_TRAVERSAL)
        bSizer1.Add(self.m_panel, 3, wx.EXPAND | wx.ALL, 5)

        bmp = wx.EmptyBitmap(500, 500)
        self.staticBMP = wx.StaticBitmap(self.m_panel, wx.ID_ANY, bmp)

        self.SetSizer(bSizer1)

        # bind event
        self.staticBMP.Bind(wx.EVT_LEFT_DOWN, self.OnLeftDown)
        self.staticBMP.Bind(wx.EVT_LEFT_UP, self.OnLeftUp)
        self.staticBMP.Bind(wx.EVT_MOTION, self.OnMove)

    def OnLeftDown(self, event):
        pos = event.GetPositionTuple()
        dc = wx.ClientDC(self.staticBMP)
        dc.DrawCircle(pos[0], pos[1], 5)
        self.isLeftDown = True

    def OnLeftUp(self, event):
        self.isLeftDown = False

    def OnMove(self, event):
        if self.isLeftDown:
            pos = event.GetPositionTuple()
            dc = wx.ClientDC(self.staticBMP)
            dc.DrawCircle(pos[0], pos[1], 3)


if __name__ == '__main__':
    app = wx.App()
    frame = MyFrame(None)
    frame.Show(True)
    app.MainLoop()

Answer 1

您不想绘制一个新圆，而是通过更新参数列表来移动现有圆。

import wx

WHITE_COLOR = (255,255,255)

class MoveCircle():

    def __init__(self, parent): 
        self.parent=parent
        self.parameters = [36,36,30]
        self.advance=3
        self.parent.Bind(wx.EVT_PAINT, self.on_paint)
        self.timer = wx.Timer(self.parent)
        self.parent.Bind(wx.EVT_TIMER, self.on_timer, self.timer)
        self.timer.Start(100)

    def on_paint(self, event=None):
        dc = wx.PaintDC(self.parent)
        dc.SetBrush(wx.Brush("blue"))
        dc.DrawCircle(*self.parameters)

    def on_timer(self, event):
        self.parameters[0] += self.advance
        print self.parameters
        if self.parameters[0] < 36 or self.parameters[0] > 210:
            self.advance *= -1
        self.parent.Refresh()


if __name__ == "__main__":
    app = wx.App()
    title = "Circle"
    frame = wx.Frame(None, wx.ID_ANY, title, size=(250, 200))
    MoveCircle(frame)
    frame.Show(True)
    app.MainLoop()

Answer 2

我用脏方法实现了这个效果。但我不知道它是否是属性方法。如果方法错误，请告诉我，我将更新或删除此答案。这是我的代码：

# -*- coding: utf-8 -*- 

import wx

class MyFrame(wx.Frame):
    isLeftDown = False

    def __init__(self, parent):
        wx.Frame.__init__(self, parent, id=wx.ID_ANY, size=wx.Size(500, 500))
        bSizer1 = wx.BoxSizer(wx.VERTICAL)

        self.m_panel = wx.Panel(self, wx.ID_ANY)
        bSizer1.Add(self.m_panel, 3, wx.EXPAND | wx.ALL, 5)

        self.bmp = wx.EmptyBitmap(500, 500)
        self.staticBMP = wx.StaticBitmap(self.m_panel, wx.ID_ANY, self.bmp)

        self.SetSizer(bSizer1)

        # bind event
        self.staticBMP.Bind(wx.EVT_LEFT_DOWN, self.OnLeftDown)
        self.staticBMP.Bind(wx.EVT_LEFT_UP, self.OnLeftUp)
        self.staticBMP.Bind(wx.EVT_MOTION, self.OnMove)

    def OnLeftDown(self, event):
        pos = event.GetPositionTuple()
        dc = wx.ClientDC(self.staticBMP)
        dc.DrawCircle(pos[0], pos[1], 5)
        self.isLeftDown = True

    def OnLeftUp(self, event):
        self.isLeftDown = False

    def OnMove(self, event):
        if self.isLeftDown:
            pos = event.GetPositionTuple()
            dc = wx.ClientDC(self.staticBMP)
            dc.DrawBitmap(self.bmp, 0, 0)
            dc.DrawCircle(pos[0], pos[1], 5)


if __name__ == '__main__':
    app = wx.App()
    frame = MyFrame(None)
    frame.Show(True)
    app.MainLoop()