Hi John,
On Sun, 12 Jan 2003 14:18:53 -0800 (PST), John Vertegaal wrote:
> Ron Clarke wrote:
>> I have found that "re-sizing" the graphic to the exact size specified
>> in the web page will do the trick best. It will give you exactly the
>> right size graphic for ther way you want it shown. PictView will do
>> that nicely (freeware), as will many others.
> But either that's exactly what I did Ron, or I don't understand what you
> mean. After cropping a 1840x.... (med. res.) jpeg obtained from CD down
> to its bare essentials, a 1173x.... (same res.) jpeg results. The later
> resized by PictView to 150x..., when called up as such, gives a terrible
> blotchy result on my 640x480 screen.
No, resize the original first. This will give you a smaller version
of the original, but with the same quality resolution.
If you need to remove some of the outside picture, then crop it after
re-sizing.
Then, and this is also important, write your HTML to display the
picture at its ACTUAL size, i.e. no resizing up or down. This will make
the picture display as is, and will not be affected by differing monitor
resolutions.
I have sometimes found that even this can give a poor result, and I
have used an alternative method to reduce file size without losing
quality - convert the graphic to a GIF, using PictView or Compushow 2000.
This will reduce the colours from 16 million to 256, and greatly reduce
file size. With a good dithering converter, it is hard to spot any loss of
detail.
> Perhaps PictView allows alternate parameters for resizing, but they
> aren't obvious to me.
PictView is highly configurable.
> So the safest is to keep the src at about 640x...
> when spec'd at about 160x.... Correct?
I guess it is a case of suck it and see. Trying a few different
methods should give an idea of what will work. It may vary according to
what you start with.
> The bottom two, spec'd at 150x100 were sourced at about 1200x...., that's
> why the page took so long to load and hence you original criticism. That
> 1200x.... was never enlarged from a smaller res. picture and looks sharp
> enough when viewed as such, and thus brings up another question. Could
> the reason my thumbnails look kind of crappy be, because the step from
> 1200 down to 150 is too great? As you said before, a 640 src viewed at
> 160 looks sharp.
Rather than think of screen resolutions, I work with actual pixel
numbers when re-sizing or writing HTML sizes. That way, you can keep a
closer control and also ensure that a graphic is kept in the same
scaling (width x height).
> I'm limited to use whatever jpegs are supplied by my source and/or
> conversion software. I really have no idea, but it looks to me that
> "invalid SOS parameters" and not "sequential" is the malefactor here.
> Steve's recoding of the jpegs rendered them fine again. But PictView
> doesn't seem to be able to rectify the miscoding of ftcolor's output;
> it reads them fine, without giving the "error" message. That's why I'd
> like to get hold of a different cropping program than ftcolor, so the
> problem doesn't come up in the first place.
Have you tried CompuShow 2000 ? Shareware, wont print, but one of
the best converters I have used. Needs enough RAM, so a 2 MB 386 won't
run at all fast, but it will use disk-swap if RAM is limited.
I can ZIP and email.
Regards,
Ron
Ron Clarke
http://homepages.valylink.net.au/~ausreg/index.html
http://tadpole.aus.as
-- This mail was written by user of The Arachne Browser - http://arachne.cz/
