在不触发 EVT_SIZE 的情况下调整 wxPython 面板的大小

Question

编辑当我用下面的编辑更新这个时，我在测试期间意识到python的回溯功能似乎有问题。我将发布一个新问题

编辑：更新以使问题更简单

问题

问题是当在 EVT_SIZE 事件处理程序中调用一个函数时，无论出于何种原因必须调整面板大小，它将变成一个无限循环，导致递归错误。

这个使用被解决（在 2.8 中）使用一个布尔值 true/false 变量来判断函数是否在 EVT_SIZE 处理程序中。然而，这在 2.9 中不起作用，因为似乎事件已经变得异步（或者至少在某些方面意味着允许返回 SetSize 调用，重置标志，然后调用事件处理程序）。

情况示例

默认（不以任何方式处理它

import wx


class TestPanel(wx.Panel):

    def __init__(self, parent):
        wx.Panel.__init__(self, parent, -1)
        self.Bind(wx.EVT_SIZE, self.OnSize, self)

        wx.CallLater(10000, self.ResizeThing)

    def ResizeThing(self):
        print "Doing our resize thing...."
        # calculate whatever we need to calculate
        # seems we got to change it in some way
        self.SetSize(self.GetSize() + (30, 30))
        return "whatever we'd return"

    def OnSize(self, event):
        print "Size event got to resize"
        self.ResizeThing()


if __name__ == '__main__':
    app = wx.App(False)
    f = wx.Frame(None, -1)
    TestPanel(f)
    f.Show()
    app.MainLoop()

2.8 使用布尔标志的解决方案

有没有办法在不触发 evt size 事件的情况下调整面板的大小，因为这样做会导致无限循环（由于某种原因，在 2.9 上而不是 2.8 上）。

值得注意的代码

    def __init__(...):
        ..... other stuff....
        self.Bind(wx.EVT_SIZE, self.OnSize, self)

    def OnSize(self, event):
        # if we didn't have it we would have a infinite recursion going evt_size -> update -> evt_size -> update -> evt_size -> update... forever
        if not self.setting_size:
            # update current size and set artwork
            print self.GetSize()
            print self.current_size
            print "OnSize"
            self.current_size = self.GetSize()
            print self.current_size
            self.UpdateArtwork(self.current_img)


        else:
            event.Skip()



    def UpdateArtwork(self, img):
        ... get scaled image and set the bitmap
        img = self.scale(img)
        self.SetBitmap(img.ConvertToBitmap())

    def scale(self, img):
        print "Calling Scale"
        # size the window to the correct dimensions
        # get the size the sizer thinks is best

        wW = self.GetBestVirtualSize()[0] # the width that the sizer reccomends
        wH = self.GetBestVirtualSize()[1] # the height the sizer recommends
        W = img.GetWidth()
        H = img.GetHeight()

        # modifiy the sizer recommendations to fit the image aspect ratio
        # use bigger side as the base
        if wW > wH:
            # round to nearest integer value sense we are using future division
            # get the new wH base on the image aspect ratio
            wH = round(H/W * wW) # H/W how many H pixels per one W
        else:
            wW = round(W/H * wH) # W/H how many W pixels per one H

        ... this is SUPPOSE to prevent a loop by flagging it
        self.setting_size = True
        print time.time()
        print "Setting size in scale..."
        self.current_size = (wW, wH)
        print self.current_size
        self.SetSize((wW, wH))
        print time.time()
        self.setting_size = False
        print time.time()
        # then scale the image based on the panel size
        return img.Scale(wW, wH)

但是这不起作用，因为 EVT 是非同步的，因此它会在将其重置为 false 后触发，然后导致无限循环！

完整代码

# for proper scaling calculations (such things as .6451 going becoming 0)
from __future__ import division
import time

import wx

from twisted.web import client
from twisted.python import log

try:
    import cStringIO as StringIO
except ImportError:
    import StringIO

class URLImage(wx.StaticBitmap):
    '''Allows a easy mechanism for setting url images'''
    def __init__(self, parent, default_image):
        wx.StaticBitmap.__init__(self, parent, -1)

        self.current_img = None
        self.current_url = None
        self.current_size = self.GetSize()

        self.di_d = default_image
        self.default_image = wx.Image(default_image, wx.BITMAP_TYPE_ANY)
        self.current_img = self.default_image
        self.SetArtwork(self.default_image)

        self.Bind(wx.EVT_SIZE, self.OnSize, self)

    def OnSize(self, event):
        # if we didn't have it we would have a infinite recursion going evt_size -> update -> evt_size -> update -> evt_size -> update... forever
        if not self.current_size == self.GetSize():
            # update current size and set artwork
            print self.GetSize()
            print self.current_size
            print "OnSize"
            self.current_size = self.GetSize()
            print self.current_size
            self.UpdateArtwork(self.current_img)


        else:
            event.Skip()

    def SetArtwork(self, img):
        # for bitmaps (use corresponding method for urls)
        self.current_url = None # the current artwork isn't a url, it is a bitmap
        print "SetArtwork Updating Artwork"
        self.UpdateArtwork(img)


    def SetDefaultImage(self):
        # this is to change the image to the default
        # NOT to change the default image to some other one
        # ^(like Text SetLabel changes the Label)
        # similiar to SetArtwork
        self.current_url = None
        print "SetDefault Updating Artwork"
        self.UpdateArtwork(self.default_image)


    def SetArtworkFromURL(self, url = None):

        if url == self.current_url:
            print "[URLImage] Duplicate URL"
            return

        else:
            # set back the defualt art
            print "Defaulting for URL loading"
            self.UpdateArtwork(self.default_image)
            # update current_url
            self.current_url = url

        if url == None:
            return

        d = client.getPage(url.encode("ascii"), method = "GET", agent = 'Mozilla/5.0 (Windows; U; Windows NT 5.1; fr; rv:1.9.2b4) Gecko/20091124 Firefox/3.6b4 (.NET CLR 3.5.30729)')
        d.addCallback(lambda data: self.UpdateArtwork(wx.ImageFromStream(StringIO.StringIO(data))))
        d.addErrback(self.error)

    def UpdateArtwork(self, img):
        # ALBUM ART
        # From: http://www.blog.pythonlibrary.org/2010/03/26/creating-a-simple-photo-viewer-with-wxpython/
        # scale the image, preserving the aspect ratio
        self.current_img = img
        print "Update Artwork"
        img = self.scale(img)
        self.SetBitmap(img.ConvertToBitmap())

    def scale(self, img):
        print "Calling Scale"
        # size the window to the correct dimensions
        # get the size the sizer thinks is best

        wW = self.GetBestVirtualSize()[0] # the width that the sizer reccomends
        wH = self.GetBestVirtualSize()[1] # the height the sizer recommends
        W = img.GetWidth()
        H = img.GetHeight()

        # modifiy the sizer recommendations to fit the image aspect ratio
        # use bigger side as the base
        if wW > wH:
            # round to nearest integer value sense we are using future division
            # get the new wH base on the image aspect ratio
            wH = round(H/W * wW) # H/W how many H pixels per one W
        else:
            wW = round(W/H * wH) # W/H how many W pixels per one H

        self.setting_size = True
        print time.time()
        print "Setting size in scale..."
        self.current_size = (wW, wH)
        print self.current_size
        self.SetSize((wW, wH))
        print time.time()
        self.setting_size = False
        print time.time()
        # then scale the image based on the panel size
        return img.Scale(wW, wH)


    def error(self, err_):
        ''' Error callback for fetching the album art'''
        self.current_url = None# no current (succesful) url artwork set
        self.SetArtwork(self.default_image)
        log.msg("Error getting Album Artwork")
        log.err(err_)

Answer 1

怎么样

    print "Setting size in scale..."
    #unbind Size Event
    self.UnBind(wx.EVT_SIZE)

    self.current_size = (wW, wH)
    print self.current_size
    self.SetSize((wW, wH))
    print time.time()
    self.Update() #force update so it does not trigger after rebind
    #rebind Size Event
    self.Bind(wx.EVT_SIZE, self.OnSize, self)