On Tue, Feb 21, 2012 at 1:50 AM, Christopher Howard wrote:
> I think the fundamental problem is that PDF isn't an image format, it
> is a portable document format that stores images. Consequently, the
Not to be disputatious, but this is an oversimplification. One of the
things PDF can do is store images, yes, but PDF is essentially a
portable version of PostScript, which is a page description language.
If you're talking about scanned faxes, then yes, it will be bitmap
images you are dealing with, but if you're talking about output from
TeX or InDesign or a virtual PDF printer, then you may be dealing just
as much with vectors and text layout.
> PDF viewer code base isn't going to be focused on getting the fastest
> possible document -> image -> rendering. To really get that speed you
> are looking for, the software would presumably need be running
> multi-threaded handling of images chunks and utilizing all the
> relevant multimedia instructions or acceleration pipelines to handle
> resizing and layout. PDF viewers aren't made for this.
Why would a reader not optimize for speed? What else would it be
optimizing for? (Think FoxIt, which optimizes for 'omit unnecessary
plugins') However, I do believe that not all viewers are made with
this in mind. However, like Joshua, I am fairly certain that Adobe's
viewer uses 2D acceleration when available. At least it does so on
Windows and Mac OS X. Not sure how performance compares across those
platforms; OS X is based on a version of Display PostScript, which is
essentially PostScript -> OpenGL, if I'm not oversimplifying=85 I have
noticed that for certain document types, Apple's Preview [image
viewer] is faster than Adobe, and for others, Adobe seems faster.
The builtin PDF viewer on iOS, for instance, handles resizing fairly
snappily per CPU cycle, at least compared to Android, I think. There's
interesting magic with rapid bitmap rescaling/re-rendering vectors
behind the scenes.
fwiw
jermudgeon
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Received on Tue Feb 21 09:52:02 2012
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