wxPython - 使用DC绘制不填充的矩形

Question

dc.SetPen(wx.Pen(wx.BLACK, 0))
dc.SetBrush(wx.Brush("C0C0C0"))
dc.DrawRectangle(50,50,50,50)

这是我尽力画一个50x50的灰色方块，没有边框。不过，把笔的宽度设置为0似乎没什么用，而设置画刷只会把填充颜色从纯白变成纯黑。

这里是它在一个面板中的样子，可能这也是问题的一部分：

class DrawRect(wx.Panel):
     def __init__(self,parent=None,id=-1,pos=(-1,-1),size=(-1,-1),style=0):
         wx.Panel.__init__(self,parent,id,size,pos,style)
         self.SetBackgroundColour("#D18B47")
         self.Bind(wx.EVT_PAINT,self.onPaint)

     def onPaint(self, event):
         event.Skip()
         dc = wx.PaintDC(event.GetEventObject())
         self.drawRect(dc)

     def drawRect(self,dc):
         dc.SetPen(wx.Pen("FFCE8A", 0))
         dc.SetBrush(wx.Brush("C0C0C0"))
         dc.DrawRectangle(50,50,50,50)

Answer 1

要画一个没有填充颜色的矩形，你需要把画刷设置为透明，因为画刷负责填充颜色，而笔则用来画轮廓。下面的例子展示了一个蓝色的没有填充的矩形和一个红色的填充矩形。

import wx

class MyPanel(wx.Panel):
    """ class MyPanel creates a panel to draw on, inherits wx.Panel """

    def __init__(self, parent, id):
        wx.Panel.__init__(self, parent, id)

        self.SetBackgroundColour("white")
        self.Bind(wx.EVT_PAINT, self.OnPaint)

    def OnPaint(self, event):
        """set up the device context (DC) for painting"""
        dc = wx.PaintDC(self)

        #blue non-filled rectangle
        dc.SetPen(wx.Pen("blue"))
        dc.SetBrush(wx.Brush("blue", wx.TRANSPARENT)) #set brush transparent for non-filled rectangle
        dc.DrawRectangle(10,10,200,200)

        #red filled rectangle
        dc.SetPen(wx.Pen("red"))
        dc.SetBrush(wx.Brush("red"))
        dc.DrawRectangle(220,10,200,200)

app = wx.App()
frame = wx.Frame(None, -1, "Drawing A Rectangle...", size=(460, 300))
MyPanel(frame,-1)
frame.Show()        
frame.Centre()
app.MainLoop()

Answer 2

这段代码会生成一个灰色的矩形：

import wx

class MyPanel(wx.Panel):
    """ class MyPanel creates a panel to draw on, inherits wx.Panel """
    def __init__(self, parent, id):
        # create a panel
        wx.Panel.__init__(self, parent, id)
        self.SetBackgroundColour("white")
        self.Bind(wx.EVT_PAINT, self.OnPaint)

    def OnPaint(self, evt):
        """set up the device context (DC) for painting"""
        self.dc = wx.PaintDC(self)
        self.dc.BeginDrawing()
        self.dc.SetPen(wx.Pen("grey",style=wx.TRANSPARENT))
        self.dc.SetBrush(wx.Brush("grey", wx.SOLID))
        # set x, y, w, h for rectangle
        self.dc.DrawRectangle(250,250,50, 50)
        self.dc.EndDrawing()
        del self.dc

app = wx.PySimpleApp()
# create a window/frame, no parent, -1 is default ID
frame = wx.Frame(None, -1, "Drawing A Rectangle...", size = (500, 500))
# call the derived class, -1 is default ID
MyPanel(frame,-1)
# show the frame
frame.Show(True)
# start the event loop
app.MainLoop()