[GEM-dev] image quality when saving

IOhannes m zmoelnig zmoelnig at iem.at
Tue Jun 21 09:53:20 CEST 2011


-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

On 2011-06-20 18:15, cyrille henry wrote:
> hello,
> 
> using pix_write, pix_writer, or pix_buffer to save a jpeg image, i
> always got the same result whatever quality asked.
>  
> using quality 1 or 100 gives the same image : a good quality, but not
> perfect.
> 
> This is a regression, i think it use to work. Iohannes : is this related
> to the huge work you did recently?

yes, it definitely is.

> 
> also, will you also add plugins support for image export?
> (png export would be nice).

yes, theoretically it's there already :-)
(but see the PS)

both your questions are tightly related (for me), as they involve a more
generic way to select and parameterize the image saving plugins.

the framework is basically there, but it's currently unused :-(

the main idea is to have the same "properties" system as we already have
for pix_video and pix_record.
i guess, the easiest way to specify image formats explicitely, would be
using mimetypes (a pre-defined property "mimetype", which you could set
to "image/vogel" to save images in vgl-format)
for compatibility (and usability) reasons, there should be an auto-mode
to automatically select the mime-type based on the filename.

and then of course, plugins would need to specify "how good" they could
saving of a certain filename/property combination
e.g. the imageTIFF plugin is very good at exporting "TIFF" files, but
less so at exporting JPEGs (which it cannot do at all, but at least it
would save the image to disk in some format, which might be better than
nothing); nevertheless imageMAGICK might be even better at exporting
TIFFs, as it could support adding some special tags to the image, the
user might want to have included in the image.



fmgasdr
IOhannes

PS: though i'm not entirely sure what you mean by "image export" in
contrast to what pix_buffer and friends already do.
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.11 (GNU/Linux)
Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/

iEYEARECAAYFAk4ATewACgkQkX2Xpv6ydvRU/QCcCpuGHoW5FXl0sMiKIgZsrjiv
jTkAnjUAhpWGqA3W2oR0HDqXgUud2LE3
=lMMs
-----END PGP SIGNATURE-----

-------------- next part --------------
A non-text attachment was scrubbed...
Name: smime.p7s
Type: application/pkcs7-signature
Size: 3636 bytes
Desc: S/MIME Cryptographic Signature
URL: <http://lists.puredata.info/pipermail/gem-dev/attachments/20110621/373e4287/attachment-0001.bin>


More information about the GEM-dev mailing list