Alan, Hazen,
I certainly can figure out how to build the library, but it would *really* be
nice to have it in the plplot9-driver-cairo package. Never hurts to ask :)
However, it turns out not to be magic fix, as the memory layout is ARGB vs.
RGBA:
/* Malloc memory the way cairo likes it. Aligned on the stride computed by
cairo_format_stride_for_width
* and in the RGB24 format (from
http://cairographics.org/manual/cairo-Image-Surfaces.html):
* Each pixel is a 32-bit quantity, with the upper 8 bits unused.
* Red, Green, and Blue are stored in the remaining 24 bits in that order */
I need to read up on Pharo, what it calls Rome, and Cairo. If Pharo has or
grows a Cairo interface, then the above become a non-problem.
Thanks!
Bill
________________________________________
From: Alan W. Irwin [ir...@beluga.phys.uvic.ca]
Sent: Tuesday, September 21, 2010 11:24 AM
To: Schwab,Wilhelm K; Hazen Babcock
Cc: plplot-devel@lists.sourceforge.net
Subject: Re: [Plplot-devel] plsmem(), RGB+alpha vs. RGB?
On 2010-09-21 10:43-0400 Schwab,Wilhelm K wrote:
> Hazen,
>
> Ideally, I would prefer a cross-platform solution, but the reality is that I
> work on Linux. Cairo appears to have installed vai apt-get; I have yet to do
> anything with it.
>
> Where should I look for the memcairo driver?
Hi Bill:
First, make sure our cairo device driver (that contains all sorts of
devices including memcairo) works. If your list of devices in the
cmake output includes any device with "cairo" in the name, then that
means our build system has found the development version pango/cairo
libraries needed by our cairo device driver. Otherwise,
look for any WARNING messages in your cmake output having to do with
pango/cairo and deal with them (normally by installing the developer version
of pango and cairo, cleaning out your build tree, and trying again).
Once some "*cairo" devices are available, then make the memcairo
device available using the cmake option -DPLD_memcairo=ON.
Hi Hazen:
The rest of this is directed to you. There is a note in
cmake/modules/drivers-init.cmake that says "memcairo does not work so
turn it off by default". Does memcairo actually work now? If so, you
should remove that note, and turn memcairo on by default just like our
other cairo devices so that users don't have to use -DPLD_memcairo=ON
to access it.
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); PLplot scientific plotting software
package (plplot.org); 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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