Re: [Tracker] Updated To do for next version

["Edward Duffy" <eduffy gmail com>]

On 10/3/06, Jamie McCracken <jamiemcc blueyonder co uk> wrote:
> René Stadler wrote:
> > Am Dienstag, den 03.10.2006, 12:50 +0100 schrieb Jamie McCracken:
> > [...]
> >> I think for image files (gif, tiff and others) we might want to use
> >> imageMagick's identify command to get the dimensions (especially if
> >> libexif and libpng are not present as we can fallback on this too)
> >>
> >> EG
> >>
> >> identify -format "%wx%h"   sample.jpg
> >> 2112x2720
> >>
> >>
> >> this will allow us to get the Image.Width and Image.Height by parsing
> >> stdout. We also dont need a hard dependency on ImageMagicks stuff.
> >>
> >> It can also be used to get comments embedded and other stuff like
> >> resolutions in image :
> >>
> >> identify -format "%c"   sample.jpg
> >>
> > [...]
> >
> > Using identify might be a bad idea.  Last time I checked, it had the bad
> > habit of performing all of its extraction and analysis capabilities
> > (counting colors etc.) even if you just request things as simple as the
> > geometry or the embedded comment (which should become available after
> > just parsing a few bytes of most image formats).  That is, it is very
> > slow/wastes CPU cycles.  For getting the geometry, I found that it is
> > much faster and efficient to use a GdkPixbufLoader and connect to the
> > "size-prepared" signal.  Not that I think this is the perfect solution
> > either (I think GdkPixbuf has already allocated memory to hold the
> > complete decoded image when it emits the signal), but it tells about the
> > deficiencies of Imagemagick.
> >
>
> yes you might be right there (identify does seem a little slow on large
> images)

It's not slow if you use the "-ping" parameter.  Just a quick test
with over 200 images, it took over 1 minute to run identify all images
(most around 2MB), and 5 seconds with the -ping parameter.

Shouldn't take me long to do this.
> We cant depend on GDK either.
>
> I only suggested it as a fallback for images not supported by libexif or
> libpng (which means stuff like tiff, gif, xpm et all). If we have time
> we can extract libextractor's plugins for these other formats which
> should be more efficient.
>
> --
> Mr Jamie McCracken
> http://jamiemcc.livejournal.com/