WxPython更改位图按钮形状

Question

你好，我刚开始接触wxPython，还在学习中。我想用一张特定的图片制作一个位图按钮，比如这个样子：http://i.min.us/idk3Uy.png

问题是，我想在按钮中保留图片的原始形状，比如说做成一个圆形按钮，而不是默认的矩形按钮。

我想知道具体该怎么做，或者说这样做是否可能。我看过文档，发现样式常量wx.BU_EXACTFIT可以去掉多余的边框……但按钮的形状还是不是我想要的。

谢谢。

Answer 1

你可能需要自己做一个自定义控件。我之前做过不少自定义的wxPython控件，所以我为你写了一个叫ShapedButton的类。=)

要运行这个演示，你只需要三张图片：

• button-normal.png
• button-pressed.png
• button-disabled.png

这三张图片会根据按钮的状态来使用。其实只需要“正常”状态的图片，但你可能至少想提供“正常”和“按下”状态的图片，这样用户在点击时能有反馈。

这个控件只会在正常图片的非透明区域响应点击。当你点击和释放按钮时，它会正确触发EVT_BUTTON事件。

希望你喜欢！

import wx

class ShapedButton(wx.PyControl):
    def __init__(self, parent, normal, pressed=None, disabled=None):
        super(ShapedButton, self).__init__(parent, -1, style=wx.BORDER_NONE)
        self.normal = normal
        self.pressed = pressed
        self.disabled = disabled
        self.region = wx.RegionFromBitmapColour(normal, wx.Color(0, 0, 0, 0))
        self._clicked = False
        self.SetBackgroundStyle(wx.BG_STYLE_CUSTOM)
        self.Bind(wx.EVT_SIZE, self.on_size)
        self.Bind(wx.EVT_PAINT, self.on_paint)
        self.Bind(wx.EVT_LEFT_DOWN, self.on_left_down)
        self.Bind(wx.EVT_LEFT_DCLICK, self.on_left_dclick)
        self.Bind(wx.EVT_LEFT_UP, self.on_left_up)
        self.Bind(wx.EVT_MOTION, self.on_motion)
        self.Bind(wx.EVT_LEAVE_WINDOW, self.on_leave_window)
    def DoGetBestSize(self):
        return self.normal.GetSize()
    def Enable(self, *args, **kwargs):
        super(ShapedButton, self).Enable(*args, **kwargs)
        self.Refresh()
    def Disable(self, *args, **kwargs):
        super(ShapedButton, self).Disable(*args, **kwargs)
        self.Refresh()
    def post_event(self):
        event = wx.CommandEvent()
        event.SetEventObject(self)
        event.SetEventType(wx.EVT_BUTTON.typeId)
        wx.PostEvent(self, event)
    def on_size(self, event):
        event.Skip()
        self.Refresh()
    def on_paint(self, event):
        dc = wx.AutoBufferedPaintDC(self)
        dc.SetBackground(wx.Brush(self.GetParent().GetBackgroundColour()))
        dc.Clear()
        bitmap = self.normal
        if self.clicked:
            bitmap = self.pressed or bitmap
        if not self.IsEnabled():
            bitmap = self.disabled or bitmap
        dc.DrawBitmap(bitmap, 0, 0)
    def set_clicked(self, clicked):
        if clicked != self._clicked:
            self._clicked = clicked
            self.Refresh()
    def get_clicked(self):
        return self._clicked
    clicked = property(get_clicked, set_clicked)
    def on_left_down(self, event):
        x, y = event.GetPosition()
        if self.region.Contains(x, y):
            self.clicked = True
    def on_left_dclick(self, event):
        self.on_left_down(event)
    def on_left_up(self, event):
        if self.clicked:
            x, y = event.GetPosition()
            if self.region.Contains(x, y):
                self.post_event()
        self.clicked = False
    def on_motion(self, event):
        if self.clicked:
            x, y = event.GetPosition()
            if not self.region.Contains(x, y):
                self.clicked = False
    def on_leave_window(self, event):
        self.clicked = False

def main():
    def on_button(event):
        print 'Button was clicked.'
    app = wx.PySimpleApp()
    frame = wx.Frame(None, -1, 'Shaped Button Demo')
    panel = wx.Panel(frame, -1)
    button = ShapedButton(panel, 
        wx.Bitmap('button-normal.png'), 
        wx.Bitmap('button-pressed.png'), 
        wx.Bitmap('button-disabled.png'))
    button.Bind(wx.EVT_BUTTON, on_button)
    sizer = wx.BoxSizer(wx.VERTICAL)
    sizer.AddStretchSpacer(1)
    sizer.Add(button, 0, wx.ALIGN_CENTER)
    sizer.AddStretchSpacer(1)
    panel.SetSizer(sizer)
    frame.Show()
    app.MainLoop()

if __name__ == '__main__':
    main()