[Techtalk] Website Building Program For Dummies (me)

Sophie sophie at cats.meow.at
Thu Aug 15 21:08:25 EST 2002

On Thu, Aug/15/02 09:56:59AM -0700, Akkana wrote:
> mia at miaridge.com writes:
> > I mean 'reduce jpgs/gifs/pngs to the smallest possible file size while
> > retaining as much image quality as possible'.  
> The gimp has sliders for image quality when I save as a jpeg, so
> I can reduce the file size that way, and it shows me the file size
> right above the slider.  What does photoshop do that's better?

It would be the actual algorthyms used for compression. If I rember correctly, the definitions of jpeg, mpeg etc say very well defined things about what to do with blocks of images once you've found similar sections, but they do not specify a method of finding similar sections in the first place. This is left to the implementor, and thus quality varies across different programs. As far as I understand it, anyway :)

> Adding things to gimp is fairly easy, so if there's something it
> could be doing better, I bet it wouldn't be too difficult.

Indeed, but I know I dont have the time or skill to pitch my energies against Adobe...

> The png save dialog has a slider for compression level, but it doesn't
> show the file size in the dialog.  I wonder if there's a bug filed
> on that already?  I don't know what optimizations are available for
> gif (does gif have a compression option?) but I can save interlaced

Intresting about png not showing the size before you save it. I'd assume that's something somebody didnt get around to imeplemnting, probbaly because it's too tricky for that particular time in the morning.

gif is compressed, but it's not variable. If I rember correctly, it's something like identifying a row of similar colours and saying "repeat this pixel X times" until it hits something differnt. I may, however, be utterly wrong.

> > When you consider that most web developers try to keep the total 'weight'
> > of a page below 50k, image optimisation becomes really important.  

I'm lucky there, my index page comes in at around 20k =)

> Ha, I wish more web developers worried about such things!
> Doesn't seem like it from some of the pages I come across.
> Thank you for caring about it, anyway!

I care. Unfortunaley I am not employed, so I can care all I want, but nobody will benifit...

> > I also find that the Gimp's text handling tools, filters and other tools
> > (auto levels, smudge, etc etc) aren't as configurable as Photoshop's and
> > don't yet produce results with the same quality.

I definatley agree there. Also, this leads onto a subject of much ranting for me; it would seem that very few people in the opensource world care to implement systems with thought to good HCI design. Most of it is pretty awful... the same applies to the "less important" features, as you spot in The Gimp. Oh the other hand, it does excell at doing wierd things I probbaly wouldnt find a use for!

> I highly recommend the gimp-freetype plugin (available at gimp.org). 
> It lets you scale and rotate text, and it can see all your truetype fonts
> even if you haven't set up your X server to see them.  Lots of gimp
> developers like "Dynamic Text" (doubleclick on the T in the toolbox to
> get tool options, and there's a checkbox there for dynamic) but I can't
> say much about it myself because I always end up using gimp-freetype.

I didnt know that existed! I shall have to try that, thank you

> About auto levels: I have a patch submitted in a gimp bug (my first
> submitted gimp patch!) that will make gimp's levels tool more
> configurable than Photoshop's, if I can just persuade one of the
> developers to check it in. :-)  My understanding was that the 
> current gimp dialog looked almost exactly like photoshop's -- no?

Excellent! I shall keep an eye out for this also

- sophie

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