I am creating a custom wxpython widget and it seems to work well on Windows (no errors), but when it is run on MacOs (python 3.9 and the latest wxpython) it has a RecursionError:
This is the minimal code with a demo window:
import wx
from wx.lib.newevent import NewCommandEvent
numberfield_cmd_event, EVT_NUMBERFIELD = NewCommandEvent()
numberfield_change_cmd_event, EVT_NUMBERFIELD_CHANGE = NewCommandEvent()
def GetTextExtent(text):
tdc = wx.WindowDC(wx.GetApp().GetTopWindow())
w, h = tdc.GetTextExtent(text)
return w, h
class NumberField(wx.Control):
def __init__(self, parent, _id=wx.ID_ANY, label="", default_value=0, min_value=0,
max_value=10, suffix="px", show_p=True, scroll_horz=True, size=wx.DefaultSize):
wx.Control.__init__(self, parent, _id, pos=wx.DefaultPosition,
size=size, style=wx.NO_BORDER)
self.parent = parent
self.focused = False
self.mouse_in = False
self.control_size = wx.DefaultSize
self.show_p = show_p
self.buffer = None
if scroll_horz is True:
self.scroll_dir = 0
else:
self.scroll_dir = 1
self.cur_value = default_value
self.min_value = min_value
self.max_value = max_value
self.change_rate = .5
self.change_value = 0
self.suffix = suffix
self.value_range = [i for i in range(min_value, max_value)]
self.label = label
self.padding_x = 20
self.padding_y = 10
# Flag that is true if a drag is happening after a left click
self.changing_value = False
# Keep track of last sent event
self.last_sent_event = None
# The point in which the cursor gets anchored to during the drag event
self.anchor_point = (0, 0)
self.Bind(wx.EVT_PAINT, self.OnPaint)
self.Bind(wx.EVT_ERASE_BACKGROUND, lambda x: None)
self.Bind(wx.EVT_MOTION, self.OnMouseMotion)
self.Bind(wx.EVT_LEFT_DOWN, self.OnLeftDown, self)
self.Bind(wx.EVT_LEFT_UP, self.OnLeftUp, self)
self.Bind(wx.EVT_SET_FOCUS, self.OnSetFocus)
self.Bind(wx.EVT_KILL_FOCUS, self.OnKillFocus)
self.Bind(wx.EVT_LEAVE_WINDOW, self.OnMouseLeave)
self.Bind(wx.EVT_ENTER_WINDOW, self.OnMouseEnter)
self.Bind(wx.EVT_SIZE, self.OnSize)
def OnPaint(self, event):
wx.BufferedPaintDC(self, self.buffer)
def OnSize(self, event):
size = self.GetClientSize()
# Make sure size is at least 1px to avoid
# strange "invalid bitmap size" errors.
if size[0] < 1:
size = (1, 1)
self.buffer = wx.Bitmap(*size)
self.UpdateDrawing()
def UpdateDrawing(self):
dc = wx.MemoryDC()
dc.SelectObject(self.buffer)
dc = wx.GCDC(dc)
self.OnDrawBackground(dc)
self.OnDrawWidget(dc)
del dc # need to get rid of the MemoryDC before Update() is called.
self.Refresh()
self.Update()
def OnDrawBackground(self, dc):
dc.SetBackground(wx.Brush(self.parent.GetBackgroundColour()))
dc.Clear()
def OnDrawWidget(self, dc):
fnt = self.parent.GetFont()
dc.SetFont(fnt)
dc.SetPen(wx.TRANSPARENT_PEN)
full_val_lbl = str(self.cur_value)+self.suffix
width = self.Size[0]
height = self.Size[1]
one_val = width / self.max_value
self.p_val = round((self.cur_value*one_val))
if self.mouse_in:
dc.SetTextForeground("#ffffff")
dc.SetBrush(wx.Brush(wx.Colour("#4c4c4c")))
else:
dc.SetTextForeground("#e9e9e9")
dc.SetBrush(wx.Brush(wx.Colour("#333333")))
dc.DrawRoundedRectangle(0, 0, width, height, 4)
if self.show_p is True:
dc.SetBrush(wx.Brush(wx.Colour("#5680C2")))
dc.DrawRoundedRectangle(0, 0, self.p_val, height, 4)
if self.p_val < width-4 and self.p_val > 4:
dc.DrawRectangle((self.p_val)-4, 0, 4, height)
lbl_w, lbl_h = GetTextExtent(self.label)
val_w, val_h = GetTextExtent(full_val_lbl)
dc.DrawText(self.label, self.padding_x, int((height/2) - (lbl_h/2)))
dc.DrawText(full_val_lbl, (width-self.padding_x) - (val_w), int((height/2) - (val_h/2)))
def OnMouseMotion(self, event):
# Changes the cursor
if self.changing_value:
self.SetCursor(wx.Cursor(wx.CURSOR_BLANK))
else:
self.SetCursor(wx.Cursor(wx.CURSOR_SIZEWE))
# Calculate the change in mouse position
cur_point = event.GetPosition()
self.delta = cur_point[self.scroll_dir] - self.anchor_point[self.scroll_dir]
# If the cursor is being moved and dragged left or right
if self.delta != 0 and event.Dragging() and self.changing_value:
self.UpdateWidget()
self.UpdateDrawing()
if event.Dragging() and self.changing_value:
self.SetCursor(wx.Cursor(wx.CURSOR_BLANK))
# Set the cursor back to the original point so it doesn't run away
self.WarpPointer(int(self.anchor_point[0]), int(self.anchor_point[1]))
# Case where the mouse is moving over the control, but has no
# intent to actually change the value
if self.changing_value and not event.Dragging():
self.changing_value = False
self.parent.SetDoubleBuffered(False)
def SendSliderEvent(self):
wx.PostEvent(self, numberfield_cmd_event(id=self.GetId(), value=self.cur_value))
def SendChangeEvent(self):
# Implement a debounce system where only one event is
# sent only if the value actually changed.
if self.cur_value != self.last_sent_event:
wx.PostEvent(self, numberfield_change_cmd_event(
id=self.GetId(), value=self.cur_value))
self.last_sent_event = self.cur_value
def Increasing(self):
if self.delta > 0:
return True
else:
return False
def Decreasing(self):
if self.delta < 0:
return True
else:
return False
def OnLeftUp(self, event):
self.changing_value = False
self.parent.SetDoubleBuffered(False)
self.SetCursor(wx.Cursor(wx.CURSOR_SIZEWE))
self.SendSliderEvent()
def OnLeftDown(self, event):
pos = event.GetPosition()
self.anchor_point = (pos[0], pos[1])
self.changing_value = True
self.parent.SetDoubleBuffered(True)
self.UpdateDrawing()
def OnSetFocus(self, event):
self.focused = True
self.Refresh()
def OnKillFocus(self, event):
self.focused = False
self.Refresh()
def OnMouseEnter(self, event):
self.mouse_in = True
self.Refresh()
self.UpdateDrawing()
def OnMouseLeave(self, event):
if self.changing_value:
self.WarpPointer(self.anchor_point[0], self.anchor_point[1])
self.mouse_in = False
self.Refresh()
self.UpdateDrawing()
def AcceptsFocusFromKeyboard(self):
return True
def AcceptsFocus(self):
return True
def HasFocus(self):
return self.focused
def GetValue(self):
return self.cur_value
def SetValue(self, value):
self.cur_value = value
def SetLabel(self, label):
self.label = label
def UpdateWidget(self):
self.change_value += self.change_rate/2.0
if self.change_value >= 1:
if self.Increasing():
if self.cur_value < self.max_value:
self.cur_value += 1
else:
if (self.cur_value - 1) >= 0:
if self.cur_value > self.min_value:
self.cur_value -= 1
# Reset the change value since the value was just changed.
self.change_value = 0
self.SendChangeEvent()
def DoGetBestSize(self):
normal_label = self.label
value_label = str(self.cur_value) + self.suffix
font = wx.SystemSettings.GetFont(wx.SYS_DEFAULT_GUI_FONT)
dc = wx.ClientDC(self)
dc.SetFont(font)
# Measure our labels
lbl_text_w, lbl_text_h = dc.GetTextExtent(normal_label)
val_text_w, val_text_h = dc.GetTextExtent(value_label)
totalwidth = lbl_text_w + val_text_w + self.padding_x + 76
# To avoid issues with drawing the control properly, we
# always make sure the width is an even number.
if totalwidth % 2:
totalwidth -= 1
totalheight = lbl_text_h + self.padding_y
best = wx.Size(totalwidth, totalheight)
# Cache the best size so it doesn't need to be calculated again,
# at least until some properties of the window change
self.CacheBestSize(best)
return best
class TestAppFrame(wx.Frame):
def __init__(self, *args, **kwds):
wx.Frame.__init__(self, *args, **kwds)
self.SetSize((600, 300))
self.SetBackgroundColour(wx.Colour("#464646"))
sz = wx.BoxSizer(wx.VERTICAL)
ctrl1 = NumberField(self, default_value=10, label="Resolution",
min_value=0, max_value=225, suffix="px")
sz.Add(ctrl1, flag=wx.EXPAND | wx.ALL, border=6)
self.SetSizer(sz)
self.Bind(EVT_NUMBERFIELD_CHANGE, self.OnFieldChange, ctrl1)
self.Bind(EVT_NUMBERFIELD, self.OnFieldChange, ctrl1)
def OnFieldChange(self, event):
print("->", event.value)
if __name__ == "__main__":
app = wx.App(False)
frame = TestAppFrame(None, wx.ID_ANY, "wxpython")
app.SetTopWindow(frame)
frame.Show()
app.MainLoop()
Interestingly, if print statements are added as follows, it works on MacOs (but flickers on Windows):
if self.delta != 0 and event.Dragging() and self.changing_value:
self.UpdateWidget()
self.UpdateDrawing()
print("a")
if event.Dragging() and self.changing_value:
self.SetCursor(wx.Cursor(wx.CURSOR_SIZEWE))
# Set the cursor back to the original point so it doesn't run away
self.WarpPointer(int(self.anchor_point[0]), int(self.anchor_point[1]))
print("b")
# Case where the mouse is moving over the control, but has no
# intent to actually change the value
elif self.changing_value and not event.Dragging():
self.changing_value = False
self.parent.SetDoubleBuffered(False)
print("c")
Any help is appreciated as I am really not sure where the problem is and I don’t see anywhere where it would be creating a recursion. 
