[Plplot-devel] Further to your recent comment for wxwidgets gradient bug 173

[Alan W. I. <ir...@be...>]

Hi Phil:

In response to your remarks on the bug tracker for bug 173, I would like to
discuss this a bit more on plplot-devel with you, and once I get a full
education on this wxwidgets gradient subject from you I might add a
further comment to bug 173 on the bug tracker for future reference
(if anybody brings up this subject again).

Apparently the wxDC class (documented at
<http://docs.wxwidgets.org/3.1/classwx_d_c.html>) supports arbitrary
affine transformations (including rotations) now.  So it seems to me
that rotation of results from wxDC::GradientFillLinear could be used
to provide at least an arbitrarily rotated rectangular gradient result
to plgradient. That still leave the problem of dealing with the more
general case where the gradient was required for a non-rectangular
(arbitrary) polygon, but could that be handled by natively masking the
(possibly rotated) rectangular area with that polygon?  Or is such
native masking not available with the wxDC class?

Another possibility is wxGraphicsContext::CreateLinearGradientBrush
(documented at
<http://docs.wxwidgets.org/3.1/classwx_graphics_context.html>). I
don't understand how such a gradient brush would be applied, but
apparently there are no rectangular restrictions on it. Or is this
possibility completely shot down because the new wxwidgets code only
inherits from wxDC and not wxGraphicsContext so we have no access to
the CreateLinearGradientBrush method?

My final question is a general C++ one.  What syntax do I need to look
for to tell what wxWidgets library classes we inherit from?  I am pretty sure,
for example that

class wxPLDevice : public PlDevice

means our wxPLDevice class inherits from our PLDevice class.  But I
cannot find any equivalent syntax for what wxWidgets library classes
(such as wxDC or wxGraphicsContext above) we inherit from.

I would appreciate an answer to this question since that should allow
me to always know in the future exactly what wxWidgets library methods
are available to us.

Alan
__________________________
Alan W. Irwin

Astronomical research affiliation with Department of Physics and Astronomy,
University of Victoria (astrowww.phys.uvic.ca).

Programming affiliations with the FreeEOS equation-of-state
implementation for stellar interiors (freeeos.sf.net); the Time
Ephemerides project (timeephem.sf.net); PLplot scientific plotting
software package (plplot.sf.net); the libLASi project
(unifont.org/lasi); the Loads of Linux Links project (loll.sf.net);
and the Linux Brochure Project (lbproject.sf.net).
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