python - 在小部件上使用 Overlay？

Question

我在这个橡皮筋示例中创建了一个按钮。橡皮筋没有出现在按钮上方，我希望橡皮筋出现在按钮上方。

import wx
print wx.version()

class TestPanel(wx.Panel):
     def __init__(self, *args, **kw):
         wx.Panel.__init__(self, *args, **kw)

         self.Bind(wx.EVT_PAINT, self.OnPaint)
         self.Bind(wx.EVT_LEFT_DOWN, self.OnLeftDown)
         self.Bind(wx.EVT_LEFT_UP, self.OnLeftUp)
         self.Bind(wx.EVT_MOTION, self.OnMouseMove)

         self.startPos = None
         self.overlay = wx.Overlay()
         self.b=wx.Button(self)

     def OnPaint(self, evt):
         # Just some simple stuff to paint in the window for an example
         dc = wx.PaintDC(self)
         coords = ((40,40),(200,220),(210,120),(120,300))
         dc.SetBackground(wx.Brush("sky blue"))
         dc.Clear()
         dc.SetPen(wx.Pen("red", 2))
         dc.SetBrush(wx.CYAN_BRUSH)
         dc.DrawPolygon(coords)
         dc.DrawLabel("Drag the mouse across this window to see \n"
                     "a rubber-band effect using wx.Overlay",
                     (140, 50, -1, -1))

     def OnLeftDown(self, evt):
         # Capture the mouse and save the starting posiiton for the
         # rubber-band
         self.CaptureMouse()
         self.startPos = evt.GetPosition()

     def OnMouseMove(self, evt):
         if evt.Dragging() and evt.LeftIsDown():
             rect = wx.RectPP(self.startPos, evt.GetPosition())

             # Draw the rubber-band rectangle using an overlay so it
             # will manage keeping the rectangle and the former window
             # contents separate.
             dc = wx.ClientDC(self)

             #***  This won't work because wx.GCDC is not a wx.WindowDC
             #dc = wx.GCDC(dc)

             odc = wx.DCOverlay(self.overlay, dc)
             odc.Clear()

             #***  This crashes on wxMac

             #dc = wx.GCDC(dc)

             dc.SetPen(wx.Pen("black", 2))
             if 'wxMac' in wx.PlatformInfo:
                 dc.SetBrush(wx.Brush(wx.Colour(0xC0, 0xC0, 0xC0, 0x80)))
             else:
                 dc.SetBrush(wx.TRANSPARENT_BRUSH)
             dc.DrawRectangleRect(rect)

             del odc # work around a bug in the Python wrappers to make
                     # sure the odc is destroyed before the dc is.

     def OnLeftUp(self, evt):
         if self.HasCapture():
             self.ReleaseMouse()
         self.startPos = None

         # When the mouse is released we reset the overlay and it
         # restores the former content to the window.
         dc = wx.ClientDC(self)
         odc = wx.DCOverlay(self.overlay, dc)
         odc.Clear()
         del odc
         self.overlay.Reset()

app = wx.App(redirect=False)
frm = wx.Frame(None, title="wx.Overlay Test", size=(450,450))
pnl = TestPanel(frm)
frm.Show()
app.MainLoop()

Answer 1

我认为目前它只能在 wx.Overlay 是真正的覆盖对象的 OSX 上完成。在其他平台上，它们只是使用 wx.ClientDC 进行模拟，这意味着对覆盖层所做的绘图只能发送到为其创建 DC 的窗口。