Enrico Forestieri wrote:
> Hi all!
>
> For some reason the dvipng distributed with miktex (at least the one I
> have installed) fails to generate the instant preview images:
>
> $ python /path/to/lyxpreview2bitmap.py png 0lyxpreview.tex 128 000000
> f0f0f0 makepk: METAFONT failed on "cmmi12".
You need to refresh the MikTeX databases. It's some obvious entry in the
package manager's menus. If you can't find it then this is a FAQ on the
MikTeX list.
(Sorry I can't be less vague :()
> So, I tried to force using the legacy_lyxpreview2ppm.py script only to
> discover that it can only generate ppm images (as its name implies ;-)).
What would be *clever* would be to use pvipng if it exists and to parse its
error stream for any "unable to handle PostScript special" type messages,
falling back on the dvips->ppm/png conversion route.
> I propose the patch at the bottom to also allow png generation in the
> legacy script. The patch also addresses the problem that when "ascent" or
> "descent" are zero, then the generated image is not correctly aligned on
> its baseline with the surrounding text.
>
> Another problem I faced is the following. When not specifying a
> \preview_scale_factor in preferences, the instant-preview inlined
> equations are perfectly aligned on the baseline, but specifying, for
> example, "\preview_scale_factor 1.02" causes the inlined images to be
> shifted down by a noticeable amount.
>
> I obviated to this by hardcoding in the conversion script "frac =
> 1.02*frac", after frac is evaluated in extract_metrics_info(), where 1.02
> matches my \preview_scale_factor. I think that this should be done in the
> LyX sources but I didn't had a look at it.
Hmmmmm. But we already pass preview_scale_factor to the script in the form
of the dpi variable. Why do we need to use it twice?
The patch looks good to me but I guess that this block in
legacy_lyxpreview2bitmap.py (renamed ;-)) will need to be specialised for
ppm files only...
# Crop the images
if pnmcrop != None:
crop_files(pnmcrop, latex_file_re.sub("", latex_file))
I guess that's there's going to be some interaction between this cropping
and the veracity of the metric info...
--
Angus
