[SciPy-dev] Re: DisplayPDF for Cross-platform GUI Widgets

M. Evans datafeed at SoftHome.net
Thu Nov 21 16:07:42 CST 2002


sdrsn>     ME> Now the idea: Use DisplayPDF to create a
sdrsn>     ME> resolution-independent, cross-platform device context API in
sdrsn>     ME> which to draw user widgets themselves.  The idea resembles
sdrsn>     ME> Chaco,

sdrsn> You might want to take a look at Fresco and Berlin
sdrsn> IIRC they have a similar idea.

sdrsn> cheers,
sdrsn> prabhu

Fresco and Mac OS X may be the only two systems that use such a
concept.  I already knew about Fresco, but it is only for Linux.
It is not cross-platform.

My question revolves around the cross-platform aspect of the idea.
I've never done DisplayPDF, and wanted a bit of feedback about
this idea of different "back ends" for a DisplayPDF cross-platform
graphics layer.

There are many cross-platform widget toolkits.  Some take a layered
approach and some an emulating approach.  The layered approach uses
native OS widgets and tries to wrap them with a cross-platform API.
An example would be wxWindows (not wxUniversal).  The emulating
approach draws its own widgets in a cross-platform device context.
An example of that would be Qt.

That is the approach which interests me, with the major difference
that I want a vector-based device context, not a pixel-based context.

It has to be more than just a graphics layer, since it must also track
mouse and keyboard events, i.e. things like mouse dragging to enlarge a
rectangle.

What do you think about DisplayPDF's suitability for this purpose?
Evidently Apple thinks highly of it, but then again, the Chaco pages
explain that DisplayPDF has no real standard, so it takes some work to
figure out.

Mark




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