Re: [docbook-apps] excluding image format according to output

["Paul A. Hoadley" <paulh at logicsquad dot net>]

Hi Dave,

On Sat, Apr 16, 2005 at 09:13:37AM +0100, Dave Pawson wrote:

> Generalising the question then (for my education if no one else's),
> Are there 'quality ladders' that are common?  and I guess I'd better
> caveat that as for either being html and PDF.
> 
> What are peoples preferences? Which ones do you avoid, always
> choose?  What are the considerations.

To keep it simple, I'll stick with line drawing diagrams as the type
of image, since the considerations are probably different for
different image types (such as photographs, screenshots, and so on).
If the output format can handle it, you are certainly better off using
a vector format for the image (EPS, SVG, PDF).  The main issue is
scaling.  Say your printer can print 600x600 DPI, and you have a 2
inch square region on your page for a diagram.  An EPS image will be
rasterised into a 1200x1200 bitmap to be placed in that region.  Now,
if you had a 1200x1200 PNG of your diagram, the output would be
essentially the same.  But what if you don't?  As soon as you start
scaling _the bitmap_, there is the potential for degradation of the
image.  A vector graphic will always produce output at the maximum
capability of the device.


-- 
Paul.

w  http://logicsquad.net/
h  http://paul.hoadley.name/

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