Hi
On 7/12/2011 9:34 a.m., Zack Weinberg wrote:
Is there a hook that allows a graphics device to apply transformations
to plotmath expressions *before* they are rendered? If there isn't
one yet, would it be feasible to add one?
No such hook exists. Plotmath expression get split off before the
graphics engine (in 'graphics' and 'grid').
One possibility might be to add a device flag that says the device wants
to handle plotmath, plus a new device call, DEV_math() say, so that
'graphics' and 'grid' can send plotmath unaltered to the device. But
there are likely to be complications. For example, both 'graphics' and
'grid' can ask for metric information about text, so there would be more
work to ensure that metric information corresponded to what the device
would draw for plotmath expressions.
Paul
The motivation for this hook is graphic devices that feed into
something that already has support for math layout, such as the
tikzDevice package (which has TeX downstream). Given
text(x, y, expression(alpha+beta+gamma+delta))
it would be ideal (in terms of output quality) if tikzDevice could
process that as if
text(x, y, "$\\alpha+\\beta+\\gamma+\\delta$")
had been written instead. This would also be easier to *implement*,
from the device side, than a back-conversion from Adobe-Symbol glyph
requests to TeX math symbol macros.
(Users of tikzDevice can of course write all their TeX math
expressions directly, but this may be a great deal of conversion work,
and is also inconvenient for someone tweaking their plots in one of
the interactive graphics devices before saving them permanently.)
Thanks in advance,
zw
p.s. I am not subscribed to this list, please cc: me on replies.
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Dr Paul Murrell
Department of Statistics
The University of Auckland
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