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的大小，它将变成一个无限循环，导致递归错误。
这个使用（在 2.8 中）通过一个布尔值 true/false 变量来解决 EVT_SIZE 处理程序中的函数是否存在。但是，这在 2.9 中不起作用，因为似乎事件已经变得异步（或者至少在某种程度上这意味着允许返回 SetSize 调用，重置标志，然后调用事件处理程序）。
情况示例
默认值（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，因为当它触发时会导致无限循环（在 2.9 上但由于某种原因不是 2.8）。
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_)