Ignoring pdftex primitives

[Robert Howlett]

David Carlisle wrote:
> 
> > \pdfimage height 3 cm imagefile.png
> 
> I can't say I like the syntax either, but it is probably the `TeX way'.
> It is just that Knuth's decision to give TeX primitives a syntax that
> is totally alien to the TeX macro syntax was simply wrong:-)
> 
> In practice I am not sure it would help much in this case. Even if the
> syntax were slightly more helpful you would probably never be able to
> totally fake a non expandable primitive with a macro. In this case
> probably you should just use some macro and document that it be used for
> both tex and pdftex. For latex this would just be
> 
> \includegraphics{imagefile}
> 
> (being a macro it can do other checks, like deciding which extension to
> use depending on what tex version and drivers are specified)
> Context no doubt has similar image inclusion macros which again give a
> consistent interface. For plain tex you could either provide just a
> basic wrapper around \special and \pdfimage, or you could use the
> latex interface (which does work with plain tex).
> 
> > Incidentally, with the syntax as it is, I notice that I can't
> > include an image file with a name like depthcharge.png.
> 
> If you know there is no depth you can always use depth 0pt, can't you?
> so that \pdfimage has seen a depth and doesn't look for another. (not
> tried)
> 

No, things like
\pdfimage height 3 cm height 2 cm depth 1cm height 5cm picture.png
are perfectly valid (as with \hrule and \vrule in ordinary TeX),
the later ones overriding the earlier ones.

Bob