Re: [Gimp-user] Installing new script ?

[Steve Kinney <admin pilobilus net>]

On 01/09/2012 05:15 PM, Ronald F. Guilmette wrote:
> When I go to save the fixed image, I am getting a warning message saying:
>
>      You are about to save a layer mask as JPEG.
>      This will not save the visible layers.
>
> I have no idea what this means.  Should I be worried?  Do I have to do
> some other magic before I save the fixed image?

Hey Ronald,

That means that your image in progress includes a layer mask, most
likely added by the script you ran against it.  That layer mask is
the "current selection."

So you need to find the Layers tab in your Tool Options dock.  Left
click on the "image" part of any layer there - that would be any
thumbnail that is in the left column - to select it.  Now your image
will save as JPG without complaint.

> P.S.  This seems rather odd to me, but apparently Darla's defringer will
> not allow itself to be applied twice, successively, to an image.  Once
> you have defringed using the script, you can't get the script to re-run
> on the same image, however...
>
> If you save the defringed image to a file, exit gimp, and then run gimp
> again on the defringed .JPG, then you can get the defringer to run anew.

That's the same problem again:  After running the plugin, it
apparently leaves a layer mask selected.  Many scripts won't run
with a layer mask selected, or at all on a layer with a mask.

The same filter can't run against the "finished result" you see in
the main image edit window, because what you are looking at is the
base layer, with its appearance changed by the masked layer the
script left above it.  It may be possible to select the base layer
in the Layers tab of your tool options dock, and run the filter
against that layer.  If this works it will give you an "additive"
effect from both sets of new layers + masks created by the filter.

Or you can do Edit > Copy Visible followed by Edit > Paste, and
click on the "CReate a new layer" button in the Layers tab of your
dock window, to get what you see as one layer.   You can re-run your
filter against that layer.

Or you can do the quick and dirty version:  Do Image > Flatten
Image.  That will get you a one layer image, where the base layer
looks exactly like what your multi-layer image did moments before. 
Your filter will run against that for sure.

> I did that, and actually, yes, the specific image I'm working with seems to
> have benefitted from having the defringer run on it twice.  Here's the image
> after ONE and then TWO defringing steps:
>
>      ftp://ftp.tristatelogic.com/private/gimp/squirrel-c.jpg
>      ftp://ftp.tristatelogic.com/private/gimp/squirrel-d.jpg

As a general rule, it's not a good idea to edit, save, open, and
re-edit a .jpg image.  The .jpg format is a "lossy" compressed
format:  It sacrifices a small amount of detail to make the saved
image a much smaller file. How much detail you lose can be adjusted
during save with the "Quality" slider in the GIMP, but even 100%
involves some loss:  Every time a .jpg is opened and re-saved as
.jpg, some loss of resolution happens.  Just doing this once, while
saving with a high "quality" setting, does not usually have a
noticeable effect, but multiple cycles of save - close - reopen -
save can add up to a messed up image, and it gets worse faster, the
more you compress the image (= the lower the quality setting).

It is better to save your finished image in .xcf then as .jpg, and
if you need to work on it some more, start with the saved .xcf
file.  The .xcf format uses lossless compression, so you can save it
as many times over as required without any problems.

I understand the next generation of the GIMP will have separate Save
and Export commands, where Save creates an .xcf file and Export
creates the other format of your choice.

:o)

Steve