Re: [Pythoncard-users] colored rectangles

[Alex T. <al...@tw...>]

Kevin Altis wrote:

> IIRC, z-order and overlapping widgets is going to be a problem on the 
> Mac in the foreseeable future. wx doesn't really support overlapping 
> widgets anyway, it is just that there are certain situations you can 
> get away with them on Windows and Linux.

Oh boy, am I glad you said that now. I was just about to set off on a 
project that would have utterly failed because it was completely 
dependent on reliable z-order and overlapping components. And of course 
I'd have been developing on Win, so it would probably have worked *most* 
of the time - leaving me baffled why sometimes I didn't get away with 
it. And eventually, I'd have put it on a Mac and discovered I'd wasted a 
lot of time.
So I'm really glad you said that now - thanks Kevin.

> Another possibility might be to use a background image which has the 
> rectangles you want and will be drawn instead of the normal background 
> window pattern; see the proof sample for an example of the use of a 
> background image. The downside is that the background image you create 
> will need to be tweaked as your layout changes, window grows, etc. but 
> it should work on all platforms.

Using an image and adjusting it for changes sounds like a nuisance, so I 
kept looking ....

Brad,

Another approach (not quite so simple, I'm afraid) would be to define 
your own background handler (this idea and code stolen from the 
resourceEditor's way of doing gridlines). This works fine (as far as I 
can tell) on Windows - and should, I hope, work on other systems as well 
(assuming the resourceEditor's gridlines work)

For this demo, I just defined Image components called "colouredArea1", 
"colouredArea2", etc. and defined their fore & backgroundColor (remember 
they're not going to be actually visible, so shouldn't be any 
platform-specific issues) - but doing this let me see in the 
resourceEditor how it should look. And using simple components like this 
means that you can use them in sizers, or adjust their size in your own 
geometry handlers. 

class MyBackground(model.Background):

    def on_initialize(self, event):
        # if you have any initialization
        # including sizer setup, do it here
        for comp in self.components.itervalues():
            if comp.name[:12] == "colouredArea":
                comp.visible = False
        self.panel.Bind(wx.EVT_ERASE_BACKGROUND, self.drawBackgroundAreas)
        self.panel.Refresh()
        pass
       
    def on_close(self, event):
        # Not sure why this is needed - resourceEditor doesn't appear to 
have an equivalent
        # but without this, we get attempts to use "dead" C++ objects
        self.panel.Unbind(wx.EVT_ERASE_BACKGROUND)
        event.skip()

    def drawBackgroundAreas(self, event):
        dc = event.GetDC()
        if not dc :
            dc = wx.ClientDC(self.panel)
            r = self.panel.GetUpdateRegion().GetBox()
            dc.SetClippingRegion(r.x, r.y, r.width, r.height)
        # need to set the background color to the default panel color
        brush = dc.GetBackground()
        brush.SetColour(self.panel.GetBackgroundColour())
        dc.SetBackground(brush)
        dc.Clear()
        for comp in self.components.itervalues():
            if comp.name[:12] == "colouredArea":
                dc.SetPen(wx.Pen(comp.backgroundColor, 1, wx.SOLID))
                dc.SetBrush(wx.Brush(comp.backgroundColor, wx.SOLID))
                x,y = comp.position
                sx,sy = comp.size
                dc.DrawRectangle(x,y, sx,sy)
       




Good luck ...

-- 
Alex Tweedly       http://www.tweedly.net



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