with negative size draw GCDC/DC DrawRoundedRectangle different.

[yiyunzhi]

Operating system: Win10 wxPython version & source: v4.1.1 Python version & source: v3.8

Description of the problem: Hi, anyone found this difference?

with paintDC size=(100,-100):

class TestPanel(wx.Panel):
    def __init__(self, parent, wx_id=wx.ID_ANY, style=0):
        wx.Panel.__init__(self, parent, wx_id, style=style)
        # bind event
        self.Bind(wx.EVT_PAINT, self.on_paint)

    def on_paint(self, evt):
        _dc = wx.PaintDC(self)
        _dc .SetPen(wx.BLACK_PEN)
        _dc .DrawRoundedRectangle(200, 200, 100, -100, 10)

result looks like: with GCDC size=(100,-100):

class TestPanel(wx.Panel):
    def __init__(self, parent, wx_id=wx.ID_ANY, style=0):
        wx.Panel.__init__(self, parent, wx_id, style=style)
        # bind event
        self.Bind(wx.EVT_PAINT, self.on_paint)

    def on_paint(self, evt):
        _dc = wx.PaintDC(self)
        _dc = wx.GCDC(_dc)
        _dc .SetPen(wx.BLACK_PEN)
        _dc .DrawRoundedRectangle(200, 200, 100, -100, 10)

[DietmarSchwertberger]

The documentation does not mention negative sizes. I would say, it's not supported and I don't see the motivation why anyone would like to use negative sizes. It's definitely a wxWidgets behaviour. I have compiled the wxWidgets "drawing" sample and it behaves the same. Whether you use GCDC or not you are using different graphics implementations which obviously behave differently.

[yiyunzhi]

Thanks for replying. 1: the mention of negative Size actually exist in the docu, but for DrawRectangle only. https://wxpython.org/Phoenix/docs/html/wx.DC.html?highlight=setlayoutdirection#wx.DC.DrawRectangle 2: the motivation. firstly I think also no neccesary to using the negative size, until I read the sourcecode of Floatcanvas. They need a transformvector (ScaleWorldToPixel()) and the to transforming the coordinate. Then the negative size was out given. ps: N is numpy.

 self.TransformVector = N.array( (1,-1), N.float)

[DietmarSchwertberger]

Coordinate transformations are doing exactly this: they transform coordinates. They do not transform widths or heights. They do not necessarily preserve angles. So transforming coordinates for a rectangle is pointless. You need a polygon and draw it yourself after the transformation. Anyway, this is a bug tracker, not a discussion forum. For this there is discuss.wxpython.org.