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From: ads@cs.qmc.ac.uk (Adam Billyard)
Newsgroups: comp.windows.news
Subject: Re: Moving child canvases
Message-ID: <1016@sequent.cs.qmc.ac.uk>
Date: 26 May 89 10:22:02 GMT
References: <1523@murtoa.cs.mu.oz.au>
Reply-To: ads@cs.qmc.ac.uk (Adam Billyard)
Organization: Computer Science Dept, Queen Mary College, University of London, UK.
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In article <1523@murtoa.cs.mu.oz.au> mwp@cs.mu.oz.au (Michael Paddon) writes:
>I have an application which basically consists of a window (canvas)
>with lots of objects (child canvases) in it. I want to scroll around
>the object space represented by the window.
>
>Unfortunately, it seems that NeWS won't let a child canvas extend
>beyond the top and left edges of its parent.
>
>Two questions...
>       (i) Why is it so?
>       (ii) How do I get around it?

This is an old documented bug of the underlying Pixrect library
that NeWS ultimately uses for rendering. There is no way around
this problem short of some pretty hairy reshaping for canvases
on the left and top edges. My solution was to drop the use of
child canvases and build some path classes to allow me to have
hierarchies of paths - these obviously aren't affected by this
bug.

        Adam.

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