I would like to request some testing of and comments on a  few changes
I have made to the Cairo output driver.

The first, and hopefully least offensive, is the addition of
right-click support to xcairo.  Advancing to the next page of a plot
using the xcairo driver is now possible using either the keyboard
(enter) or mouse (right-click).  The plot window title is also updated
to let the user know that the window is waiting for this input.  These
changes comes as revisions 9981 and 9982.

The second and much larger change affects how plimage and plimagefr.
Rather than rendering the polygons which make up the image directly to
the plot surface, which is the current default action for both plimage
and plimagefr, the image is rendered to an off-screen surface and then
overlaid on to the plot.  This results in the output of plimage on
vector surfaces (PDF, PS, SVG) being pixel-based (raster) rather than
vector-based.  Aside from greatly speeding up plimage and plimagefr
rendering, this has two main effects:

a) The individual polygons which make up the plimage output are no
longer antialiased when rasterization is in effect.  This can be
changed, but (in my opinion) the output looks much better this way.

b) Vector output for example 20 is around two orders of magnitude smaller:
498652 bytes for x20c-cairo-raster.pdf
871294 bytes for x20c-cairo-raster.ps
12184856 bytes for x20c-cairo-vector.pdf
84609543 bytes for x20c-cairo-vector.ps

Since this is rather significant change to the output generated using
the Cairo drivers and the plimage functions, I have also added a
drvopt command line switch to disable this.  For example:

/x20c -drvopt rasterize_image=0

will run example 20 with rasterization disabled.  In this case, the
output should be no different than it was before this change.

The rasterized plimage change is added as revision 10003.

plimage raster support can be added for other output devices as well.
It should be simpler than the older "dev_fastimg" rendering path
previously used by the xwin driver as it will (hopefully) require less
code on the driver side to implement.

Please test and let me know what you think, particularly for example
20 with the default settings and with "-drvopt rasterize_image=0".  It
works quite well on my system (Ubuntu 9.04 64bit, Cairo 1.8.6) but I
don't have easy access to other version of Cairo or other OSs for
testing.

Thanks,

Hez

-- 
Hezekiah M. Carty
Graduate Research Assistant
University of Maryland
Department of Atmospheric and Oceanic Science

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