On 5/18/06, Taco Hoekwater
What about a new pdftex primitive: \pdfimagepixel, which would force using a unit. Then the above would be done by \pdfimagepixel=1bp
You can (as always) propose it on the pdftex list, but i personally do not see the point. Bear in mind that the png spec is extremely clear on the use pHYs:
If this ancillary chunk is not present, pixels are assumed to be square, and the physical size of each pixel is unknown.
So the problem was created way before pdftex came into play.
Pdftex's image inclusion should be viewed as a convenience feature
that is nice when it works, but it is no substitute for using good
external software to create good images (preferrably in pdf format so
no conversions are needed). Once you have support for
including images you have to deal with questions of what should be
supported, and to which the only good answer is "any image George's
boss wants to use". By offloading such questions onto the authors of
sam2p, imagemagick, netpbm, gimp, cinepaint, Photoshop, etc. there is
time for more texy questions that those authors won't address.
--
George N. White III