lossless jpeg rotation

nightowl

is there a possibility (GD, command line utility) to rotate a JPEG lossless on a linux server via PHP ?

Don't think GD supports this, couldn't find info on ImageMagick supporting this so I guess not ... any other tool ?

rurbaniak

Originally posted by nightowl
is there a possibility (GD, command line utility) to rotate a JPEG lossless on a linux server via PHP ?

Don't think GD supports this, couldn't find info on ImageMagick supporting this so I guess not ... any other tool ?

When you say ROTATE, you mean to rotate it 90% to the left or right correct?

rurbaniak

If that's what you meant, the way to do it from PHP with ImageMagick is:

system("convert -rotate '$degree' '$path'/'$rotate' '$path'/'$rotate' 2>&1 &");

To use the system() you'll need either to have safe mode off, or setup a safe directory in the php.ini file for save commands to run.

And with this example, I was allowing user input to determine the degree of rotation.

nightowl

normal rotation for a JPEG results in loss of quality since the file is re-saved. However, it is "possible" to turn a JPEG file 90° lossless with certain programs. IrfanView (windows) supports this. Now, I'm looking for a commandline linux tool which supports this too.

Weedpacket

Originally posted by nightowl
normal rotation for a JPEG results in loss of quality since the file is re-saved. However, it is "possible" to turn a JPEG file 90° lossless with certain programs. IrfanView (windows) supports this. Now, I'm looking for a commandline linux tool which supports this too.

The conventional jpeg library Linux distros usually ship with includes such a tool. Ah, jpegtran.

man jpegtran

jpegtran - lossless transformation of JPEG files
...

nightowl

jpegtran does exactly what I expect. But it's terribly slow on a 2.5Mb image. Works very fast on a 10Kb image (thumbnail) though. How come ? Takes me 7 seconds avg (measured via time) to complete a simple rotation of a 2.5 Mb JPEG ...