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无闪烁可绘制滚动窗口

scrolledwindow flicker wxpython python

3

Joril · 技术社区 · 14 年前

我试图建立一个滚动窗口,你可以用鼠标绘制,它也工作,但我得到一个恶劣的闪烁,当用户在窗口上绘制,而滚动条不在“主页”的位置。。

import wx

class MainFrame(wx.Frame):
    """ Just a frame with a DrawPane """

    def __init__(self, *args, **kw):
        wx.Frame.__init__(self, *args, **kw)
        s = wx.BoxSizer(wx.VERTICAL)
        s.Add(DrawPane(self), 1, wx.EXPAND)
        self.SetSizer(s)

########################################################################
class DrawPane(wx.PyScrolledWindow):
    """ A PyScrolledWindow with a 1000x1000 drawable area """

    VSIZE = (1000, 1000)

    def __init__(self, *args, **kw):
        wx.PyScrolledWindow.__init__(self, *args, **kw)
        self.SetScrollbars(10, 10, 100, 100)
        self.prepare_buffer()

        self.Bind(wx.EVT_PAINT, self.on_paint)
        self.Bind(wx.EVT_LEFT_DOWN, self.on_mouse_down)
        self.Bind(wx.EVT_MOTION, self.on_motion)

    def prepare_buffer(self):
        self.buffer = wx.EmptyBitmap(*DrawPane.VSIZE)
        dc = wx.BufferedDC(None, self.buffer)
        dc.Clear()
        dc.DrawLine(0, 0, 999, 999) # Draw something to better show the flicker problem

    def on_paint(self, evt):
        dc = wx.BufferedPaintDC(self, self.buffer, wx.BUFFER_VIRTUAL_AREA)

    def on_mouse_down(self, evt):
        self.mouse_pos = self.CalcUnscrolledPosition(evt.GetPosition()).Get()

    def on_motion(self, evt):
        if evt.Dragging() and evt.LeftIsDown():
            dc = wx.BufferedDC(wx.ClientDC(self), self.buffer)
            newpos = self.CalcUnscrolledPosition(evt.GetPosition()).Get()
            coords = self.mouse_pos + newpos
            dc.DrawLine(*coords)
            self.mouse_pos = newpos
            self.Refresh()

if __name__ == "__main__":
    app = wx.PySimpleApp()
    wx.InitAllImageHandlers()
    MainFrame(None).Show()
    app.MainLoop()

我试过用 SetBackgroundStyle(wx.BG_STYLE_CUSTOM) ,或绑定 EVT_ERASE_BACKGROUND ,或使用 RefreshRect Refresh ,但闪烁仍然存在。。你知道我下一步要做什么吗?

我的环境:Xubuntu 9.04,wxPython 2.8.9.1

2 回复 | 直到 7 年前

1

5

Joril 14 年前

首先,一个 Refresh() 绘制事件(尽管设置 BG样式或捕捉擦除事件会处理好的。)The 这个案子的问题是 on_motion 你不是吗通过滚动偏移ClientDC 偏移量,只是你在画一条线段位于。所以当缓冲区虚拟(0,0)。换言之你看到的闪烁来自在错误的位置绘制缓冲区然后它马上就被画出来了再次在正确的位置 on_paint 刷新() .

你应该可以通过打电话 PrepareDC 在使用之前,像这样:
    cdc = wx.CLientDC(self)
    self.PrepareDC(cdc)
    dc = wx.BufferedDC(cdc, self.buffer)
但是既然你在做 Refresh RefreshRect 不管怎样, 不需要使用客户机DC 在这里,就让水冲出来吧屏幕的缓冲区将在
    dc = wx.BufferedDC(None, self.buffer)

2

laurent 14 年前

使用Joril recomendations和removing Refresh(),不再闪烁(甚至放大帧)。

import wx


class MainFrame(wx.Frame):
    """ Just a frame with a DrawPane """

    def __init__(self, *args, **kw):
        wx.Frame.__init__(self, *args, **kw)
        s = wx.BoxSizer(wx.VERTICAL)
        s.Add(DrawPane(self), 1, wx.EXPAND)
        self.SetSizer(s)

########################################################################
class DrawPane(wx.PyScrolledWindow):
    """ A PyScrolledWindow with a 1000x1000 drawable area """

    VSIZE = (1000, 1000)

    def __init__(self, *args, **kw):
        wx.PyScrolledWindow.__init__(self, *args, **kw)
        self.SetScrollbars(10, 10, 100, 100)
        self.prepare_buffer()
        cdc = wx.ClientDC(self)
        self.PrepareDC(cdc)
        dc = wx.BufferedDC(cdc, self.buffer)

        self.Bind(wx.EVT_PAINT, self.on_paint)
        self.Bind(wx.EVT_LEFT_DOWN, self.on_mouse_down)
        self.Bind(wx.EVT_MOTION, self.on_motion)

    def prepare_buffer(self):
        self.buffer = wx.EmptyBitmap(*DrawPane.VSIZE)
        cdc = wx.ClientDC(self)
        self.PrepareDC(cdc)
        dc = wx.BufferedDC(cdc, self.buffer)
        dc.Clear()
        dc.DrawLine(0, 0, 999, 999) # Draw something to better show the flicker problem


    def on_paint(self, evt):
        dc = wx.BufferedPaintDC(self, self.buffer, wx.BUFFER_VIRTUAL_AREA)

    def on_mouse_down(self, evt):
        self.mouse_pos = self.CalcUnscrolledPosition(evt.GetPosition()).Get()

    def on_motion(self, evt):
        if evt.Dragging() and evt.LeftIsDown():
            newpos = self.CalcUnscrolledPosition(evt.GetPosition()).Get()
            coords = self.mouse_pos + newpos
            cdc = wx.ClientDC(self)
            self.PrepareDC(cdc)
            dc = wx.BufferedDC(cdc, self.buffer)
            dc.DrawLine(*coords)
            self.mouse_pos = newpos

if __name__ == "__main__":
    app = wx.PySimpleApp()
    wx.InitAllImageHandlers()
    MainFrame(None).Show()
    app.MainLoop()