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From: Reece Dunn (msclrhd_at_[hidden])
Date: 2004-09-15 06:34:00


Andy Little wrote:
>Recent discussions on boost have talked about GUI's in quite technical
>terms, windowing etc. Another part of the abstraction is simply that of
>providing an area for drawing on. The code below is a simple example of
>what
>I mean. The "drawFunction" is meant to be like a graphics version of a
>main() function .( Note that there should ideally be no DeviceHandle
>visible
>to the "drawFunction". The DeviceHandle should be wrapped in the GX object,
>passed to the function so some of the impl is poking through here in form
>of
>the gx.line_to etc functions 'hdc' argument. Its early days.)

Your code looks good, but here are a few comments:
[1] The general impression from users of a GUI library is that they are
against using a template-based library.

[2] The DeviceHandle should be hidden via an interface and have an
implementation for *nix, mac, Windows and others.

[3] I strongly recommend that the graphical side (devices, pens, brushes,
images, fonts, etc.) be separate from the GUI (windows/widgets, events,
etc.). The GUI framework will make use of the graphics framework for drawing
to a window's client area.

[4] I like how you specify independant coordinates. Is this customizable
(i.e. can you change between pixels, cm, inches, etc.) and can you convert
between coordinate systems (e.g. when implementing a web browser, CSS units
can be percentages, cm, pc, pt, etc.)?

[5] Can you get the width and height of the drawing rectangle? Is it
possible to create a scrolling view of a larger drawing area?

Regards,
Reece

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