Question on SetClippingRegion before Blit

chacabuco · June 14, 2023, 9:54am

Hello,

I would like to know for which purpose one would call the SetClippingRegion before the blit method when the Blit method already defines a rect. such in the following lines:

github.com

wxWidgets/Phoenix/blob/f4db521a37149d13621a82589fcda0e08f822aed/demo/agw/UltimateReportDemo.py#L220


    else:
        mdc.SetBackground(wx.Brush(wx.SystemSettings.GetColour(wx.SYS_COLOUR_WINDOW)))
    mdc.Clear()
    self.DrawProgressBar(mdc, 0, 0, rect.width, rect.height, self.progressValue)
    mdc.SetFont(wx.Font(8, wx.FONTFAMILY_SWISS, wx.FONTSTYLE_NORMAL, wx.FONTWEIGHT_BOLD))
    text = "%d Mb"%self.progressValue
    textWidth, dummy = mdc.GetTextExtent(text)
    mdc.DrawText(text, rect.width//2 - textWidth//2, rect.height//2 - dummy//2)
    dc.SetClippingRegion(rect.x, rect.y, rect.width, rect.height)
    dc.Blit(rect.x+3, rect.y, rect.width-6, rect.height, mdc, 0, 0)
    dc.DestroyClippingRegion()
def GetLineHeight(self):
    return PIPE_HEIGHT + 6
def GetSubItemWidth(self):

Is it to speed it up?