[XeTeX] XeTeX, XeTeXpicfile, and transparency

[Zdenek Wagner]

2012/3/16 Jonathan Kew <jfkthame at googlemail.com>:
> On 16 Mar 2012, at 12:32, Philip TAYLOR wrote:
>
>>
>> Universe of discourse : Plain XeTeX.
>>
>> I know that XeTeX has some support for transparency,
>> but the TeX Live documentation for XeTeXpicfile has
>> nothing to say on the subject :
>>
>>> \XeTeXpdffile ‹filename› [ page ‹int› ] [ crop | media | bleed | trim | art ]
>>> [ scaled ‹int› | xscaled ‹int› | yscaled ‹int› | width ‹dimen› |
>>> height ‹dimen› | rotated ‹decimal› ]
>>> Insert (pages of) a . See below for explanation of optional arguments
>>
>> If I were to want to insert an image with (say) 90% transparency
>> (i.e., 10% opacity), how might I best go about this ?
>
> This would depend on the output driver's capabilities - xetex doesn't have any built-in magic to do this, but I wouldn't be surprised if xdvipdfmx supports \special{}s that can achieve it. Possibly a \special before the \XeTeXpdffile command to set up transparency, and another afterwards to restore it. I'd suggest checking the dvipdfmx documentation for anything that looks promising.
>
xdvipdfmx --help says that option -V is used to set the PDF minor
version and the default is 4. I read the manual a few months ago and
there seem to be no \special allowing to change the minor version from
the TeX code. I do not remember exactly which version of PDF supports
transparency, maybe 1.5 and higher. If this is the case, you would
have to create first the xdv file and then run xdvipdfmx with -V 5.
Maybe the default can be set in a configuration file.

> JK
>
>
>
>
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-- 
Zdeněk Wagner
http://hroch486.icpf.cas.cz/wagner/
http://icebearsoft.euweb.cz