[udig-devel] dpi issues

[andrea antonello]

Hmmm, I never noticed that thread before.

May I ask how the dpi are dealth with?
As long as I know, iText creates pdfs only in 72 dpi mode. There is no
way to create a higher resolutions PDF. Am I wrong?

>From the itext mailinglist, explaining why it makes no sense to talk
about dpi in pdf:
"Because the default "transformation matrix" in a PDF is 72
USER UNITS to an inch, but that's not an actual "dots per inch" (dpi)
since vector and textual data have no "dots".

         When placing an image, unless you specify a transform, the
pixels in the image are assumed to be in user units (so there would
be 72 of them to an inch, which would be logically equivalent to
72dpi).  If you wish to adjust the relationship of pixels to user
units for this particular image, then you apply a transform when you
place the image."

Full thread here:
http://www.mail-archive.com/itext-questions@lists.sourceforge.net/msg24474.html

For high resolution stuff there is the need for something more
graphics related, like http://www.jibble.org/epsgraphics/ or so.

So what is supposed to happen when the dpi are changed? I believe that
the scale is no more accurate, that is in fact the proper behaviour,
do you agree?

Ciao
Andrea





On Wed, Mar 26, 2008 at 12:37 PM, Vince Darley
<vince.darley at eurobios.com> wrote:
> I notice from the mailing list that Jody wrote this in December:
>
>  >As we cranked up the DPI on our PDF export functions the text, and the
>  >scalebar started getting smaller and smaller.
>  >
>  >I have added a couple of methods to ViewportGraphics interface:
>  >- getDPI()
>  >- setFont( font )
>  >
>  >The font provided is an AWT Font; with getSize() expressed in "points"
>  >(according to the the javadocs that is assumed to be 72 dpi).
>
>  is this supposed to have fixed the "the text, and the scalebar
>  started getting smaller and smaller." problem?  I still see that same
>  problem when I adjust the dpi.  (I'm using ApplicationGIS.drawMap()).
>
>  regards,
>  Vince.
>
>
>
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