Topic: How to get the dpi of an image?

[guohq]

I want to get the dpi of an image with lisp. How can I do?

[Hedgehog]

I want to get the dpi of an image with lisp. How can I do?

Impossible without knowing what size the end product is to be printed at... it annoys me when files such as jpg's contain a value that pretends to be the dpi even though it has no physical reference size... it's dots per inch!

[guohq]

I can see the information of an image in property dialogue when I rigth click the image. So I think there is a way to get the dpi of the image use lisp perhaps.

[VovKa]

Code: [Select]

(mapcar
     (function (lambda (r) (/ (CVUNIT 1 "INCH" "MM") r)))
     (reverse
       (cdr
(reverse
   (cdr
     (assoc 11
    (entget (cdr (assoc 340 (entget (car (entsel "\nSelect image: "))))))
     )
   )
)
       )
     )
   )


[deegeecees]

Great stuff Vovka! Another piece of my personal puzzle is solved!

[guohq]

You are great!

 Thks a lot!

[Hedgehog]

I can see the information of an image in property dialogue when I rigth click the image. So I think there is a way to get the dpi of the image use lisp perhaps.

So what are you going to use this information for?  ... as I said before, it's a useless non-figure... meaningless without a print size... the pixel count is far more useful & enables you to calc the correct dpi for the image you're printing.