Re: [docbook-apps] DPI in FOP for images

[Bob Stayton <bobs@sco.com>]

On Tue, May 06, 2003 at 06:25:27PM -0400, Mike Mascari wrote:
> Bob Stayton wrote:
> 
> > On Tue, May 06, 2003 at 04:48:26PM -0400, Mike Mascari wrote:
> > 
> >>I know I've seen this before, but I cannot seem to find the style
> >>sheet variable to tweak. Perhaps I'm remembering openjade options for
> >>PostScript output. When FOP generates PDF with in-lined GIF images, it
> >>assumes a DPI of 72. Is there any way to change this value for an
> >>entire document without specifying the scaling values for each
> >><imagedata> element?
> > 
> > 
> > You are thinking of the 'pixels.per.inch' parameter, but
> > that is only used by the HTML stylesheets, not the FO stylesheet.
> > 
> > What exactly is the problem you are trying to solve?
> 
> I have documentation which includes screen shots as GIFs of various
> GUI elements of an application. I'd like to take the documentation and
> generate a PDF from the XML source. The HTML and HTML Help look fine,
> but the resultant PDF has pages composed largely of images where the
> associated text is pushed onto the next page. A long, long time ago, I
> had generated Postscript from the equivalent SGML source and ran into
> the same problem. Adjusting the DPI assumptions made by the renderer
> (I think it was openjade, I can't recall) allowed the images to be
> rendered properly on the Postscript device. What I don't want to do is
> scale the bitmaps themselves down (causing a loss of information) and
> then have the bitmaps scaled back up by the PDF renderer.
> 
> In a nutshell:
> 
> I want a 300 x 300 pixel image to be rendered in the PDF output as
> 2.08" wide instead of 4.16" wide.

Well, the "correct" solution would be to put a contentwidth="2.08in"
attribute in each imagedata element, and then set the
'ignore.image.scaling' parameter to 1 to turn it off for
HTML output.  If you have been following docbook-apps, though,
you will have noticed the discussion about the bug in the
HTML stylesheets that prevents it from working.  There was
a workaround for that in another message (disabling the
process.image.attributes template).  The workaround would
only be needed until the bug gets fixed.

If you are asking if there is a way to globally scale the
images for FO output without using the scaling attributes,
I don't think so.

-- 

Bob Stayton                                 400 Encinal Street
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Technical Publications                      voice: (831) 427-7796
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                                            email: bobs@sco.com