[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Texmacs-dev] [TeXmacs] New experimental Pdf export facility
From: |
Joris van der Hoeven |
Subject: |
Re: [Texmacs-dev] [TeXmacs] New experimental Pdf export facility |
Date: |
Wed, 13 Nov 2013 10:18:10 +0100 |
User-agent: |
Mutt/1.5.20 (2009-06-14) |
On Tue, Nov 12, 2013 at 11:22:40PM +0100, Massimiliano Gubinelli wrote:
> > As to pure image formats (jpg, png, tiff, svg, etc.), I would like to avoid
> > depending on too many libraries. Ideally, Qt should be able to do them
> > all for us. If not, Qt in combination with a tool such as ImageMagick
> > which supports many different formats. I agree that it is best to touch
> > images files as little as possible when including them in Pdf output.
> > Is there a way to include them in some kind of verbatim/escaped fashion?
>
> > I still don't understand why libpng and the jpeg library would be necessary.
>
> I was looking to how pdftex handle the problem. If I understand well their
> code they can include directly jpg images without any external support (and
> without uncompressing the jpg stream). For png they rely on libpng to read
> the files. I think I can use Qt to read the actual bits and obtain enough
> information (DPI, color depth, color map, to reconstruct a faithful
> representation of the png data inside the pdf).
I still don't understand something.
How exactly are png and jpg images stored in Pdf files?
If they are compressed in the standard png/jpg way,
then I would expect the images to be included in
a verbatim/escaped way. If they are compressed in
an ad hoc Pdf way, then why would we need libpng,
except for obtaining the pixmaps (which Qt can give us)?
> The point is that ideally one should keep (lossy and lossless) compressed
> formats compressed. Qt can read all the formats but give back only the
> uncompressed bits, so this is almost useless if you want to put the image
> into a compressed file format like PDF. The point is to try to maintain the
> data compressed without wasting time in uncompressing it and then
> recompressing it (in necessarily unoptimal ways).
I agree that compressed images should not be touched.
But if we do not want to touch them, why do we need libpng?
> > There is also the question of producing image files directly from TeXmacs,
> > for instance when exporting mathematical formulas to Html. What exactly
> > does Qt provide for the manipulation of image _files_?
>
> Qt can produce images (especially raster) to any common format (png, maybe
> jpg, pdf and eps) so I think there are no problem producing them.
Does Qt also perform the corresponding compression?
Best wishes, --Joris
- Re: [Texmacs-dev] [TeXmacs] New experimental Pdf export facility, (continued)
- Re: [Texmacs-dev] [TeXmacs] New experimental Pdf export facility, Massimiliano Gubinelli, 2013/11/09
- Re: [Texmacs-dev] [TeXmacs] New experimental Pdf export facility, Joris van der Hoeven, 2013/11/11
- Re: [Texmacs-dev] [TeXmacs] New experimental Pdf export facility, Massimiliano Gubinelli, 2013/11/11
- Re: [Texmacs-dev] [TeXmacs] New experimental Pdf export facility, Joris van der Hoeven, 2013/11/12
- Re: [Texmacs-dev] [TeXmacs] New experimental Pdf export facility, Massimiliano Gubinelli, 2013/11/12
- Re: [Texmacs-dev] [TeXmacs] New experimental Pdf export facility, François Poulain, 2013/11/13
- Re: [Texmacs-dev] [TeXmacs] New experimental Pdf export facility, Andrey G. Grozin, 2013/11/13
- Re: [Texmacs-dev] [TeXmacs] New experimental Pdf export facility, Michael Lachmann, 2013/11/13
- Re: [Texmacs-dev] [TeXmacs] New experimental Pdf export facility, Massimiliano Gubinelli, 2013/11/13
- Re: [Texmacs-dev] [TeXmacs] New experimental Pdf export facility, David E. Miller, 2013/11/13
- Re: [Texmacs-dev] [TeXmacs] New experimental Pdf export facility,
Joris van der Hoeven <=
- Re: [Texmacs-dev] [TeXmacs] New experimental Pdf export facility, Massimiliano Gubinelli, 2013/11/13
- Re: [Texmacs-dev] [TeXmacs] New experimental Pdf export facility, Joris van der Hoeven, 2013/11/13
- Re: [Texmacs-dev] [TeXmacs] New experimental Pdf export facility, Massimiliano Gubinelli, 2013/11/13
- Re: [Texmacs-dev] [TeXmacs] New experimental Pdf export facility, Michael Lachmann, 2013/11/13