wxpython双缓冲_双缓冲类里的OnPaint与OnSize，以及构造函数的关系

亦凉 2022-10-26 14:13 6阅读 0赞

\#----------------------------------------------------------------------\#BUFFERENDWINDOW Class\#This Class Has Been Taken From The wxPython Wiki, And Slightly\#Adapted To Fill My Needs. See:\#

\#http://wiki.wxpython.org/index.cgi/DoubleBufferedDrawing\#

\#For More Info About DC And Double Buffered Drawing.\#----------------------------------------------------------------------

classBufferedWindow(wx.Window):"""A Buffered window class.

To use it, subclass it and define a \`Draw(dc)\` method that takes a \`dc\`

to draw to. In that method, put the code needed to draw the picture

you want. The window will automatically be double buffered, and the

screen will be automatically updated when a Paint event is received.

When the drawing needs to change, you app needs to call the

L\{BufferedWindow.UpdateDrawing\} method. Since the drawing is stored in a bitmap, you

can also save the drawing to file by calling the

\`SaveToFile(self, file\_name, file\_type)\` method."""

def \_\_init\_\_(self, parent, id=wx.ID\_ANY, pos=wx.DefaultPosition, size=wx.DefaultSize,

style=wx.NO\_FULL\_REPAINT\_ON\_RESIZE, agwStyle=KC\_BUFFERED\_DC):"""Default class constructor.

:param \`style\`: the window style;

:param \`agwStyle\`: if set to \`\`KC\_BUFFERED\_DC\`\`, double-buffering will

be used."""wx.Window.\_\_init\_\_(self, parent, id, pos, size, style)

self.Bind(wx.EVT\_PAINT, self.OnPaint)

self.Bind(wx.EVT\_SIZE, self.OnSize)

self.Bind(wx.EVT\_ERASE\_BACKGROUND,lambdax: None)\#OnSize called to make sure the buffer is initialized.

\#This might result in OnSize getting called twice on some

\#platforms at initialization, but little harm done.

self.OnSize(None)defDraw(self, dc):"""This method should be overridden when sub-classed.

:param \`dc\`: an instance of \`wx.DC\`."""

pass

defOnPaint(self, event): \# 需要使用的时候，才会被系统自动调用，否则也不会执行到这里来"""Handles the \`\`wx.EVT\_PAINT\`\` event for L\{BufferedWindow\}.

:param \`event\`: a \`wx.PaintEvent\` event to be processed."""

print "OnPaint"

\#All that is needed here is to draw the buffer to screen

if self.\_agwStyle ==KC\_BUFFERED\_DC: \# 如果是双缓冲

dc=wx.BufferedPaintDC(self, self.\_Buffer) \# 从已经准备好的双缓冲中直接得到DC指针并显示else: \# 如果不是双缓冲

dc=wx.PaintDC(self) \# 那就直接申请新的PaintDC，无法从双缓冲处直接获得DC

dc.DrawBitmap(self.\_Buffer,0,0) \# 也可以用新的DC读取相关数据，现场读数据也许慢，且很多数据的话会闪烁？defOnSize(self,event):"""Handles the \`\`wx.EVT\_SIZE\`\` event for L\{BufferedWindow\}.

:param \`event\`: a \`wx.SizeEvent\` event to be processed."""

\#The Buffer init is done here, to make sure the buffer is always

\#the same size as the Window

self.Width, self.Height =self.GetClientSizeTuple()print "OnSize"

\#Make new off screen bitmap: this bitmap will always have the

\#current drawing in it, so it can be used to save the image to

\#a file, or whatever.

\#This seems required on MacOS, it doesn't like wx.EmptyBitmap with

\#size = (0, 0)

\#Thanks to Gerard Grazzini

if "\_\_WXMAC\_\_" inwx.Platform:if self.Width ==0:

self.Width= 1