I was referred to this forum for my
request for a change in Gimp's behavior while using the Free Select
tool.  Ref Bugzilla Bug 456277.

Performing selections on a complex
shape is one of the most labor intensive and time consuming tasks in
Gimp (probably in any other editor as well).  Whether the task is
meticulous or tedious work is influenced by how many times you have
to use the “undo” before you complete the task.  The current
behavior of the Free Select while Adding or Subtracting to an already
selected region is the single largest cause of my use of the undo
function.  I am assuming that other users run into this as well.

To illustrate the problem I am having,
imagine that you had a picture in which you wanted to select a bridge
with a superstructure and separate it from the background.  If you
select the outline of the bridge, you cannot use the freehand select
to cut the regions where the background shows through the
superstructure out of the selection without cutting out hunks of the
superstructure that you wanted to keep.  The current behavior of Gimp
switches from the User Selected Mode of “Free Select – Subtract
from the Current Selection” to “Move Floating Section” making
it impossible to simply cut a hole in a selected area.

Philosophically, it seems like you
should be able to use a “subtract from the current selection” to
cut a hole in a selected area.  It seems like the tool should honor
the settings made by the user, and if there is an automated mode
change due to cursor location, the user should have the ability to
turn it off.

I obviously don't have to select around
that many pictures of bridges, where the mode selection problem is
most prevalent is when you use the freehand select to trim a
selection in a tight area.  If you inadvertently start the small
circle that you want to add in or cut off over the already selected
area, the whole thing moves, requiring an undo to get back on track. 
The freehand select is actually a really good tool for trimming a
selection other than this behavior switch.  The response is fast, the
visual feedback is very good, and the results are what you often want
a selected region with the same edge feathering for the external and
internal boundaries.

The mouse is an inherently clumsy
drawing tool, particularly when you try to use it to describe a large
and complicated area.  From a control point of view it is more like a
sculptor's chisel than a painter's brush.  It works better when you
tap with it than when you give it a big smack.  I use the freehand
select a lot, and a fairly high zoom level to trim (add and subtract)
a region with lots of small incremental add subtract regions.

If you could modify the freehand select
to stay in the user selected mode, or provide a way that I could
globally override the current behavior switch based on cursor
location, it would make the Freehand Select Tool even more useful.

Since this request is already pretty
long (felt I had to make a detailed plea to change the intended
behavior / spec), I would like to float a second request for general
Selection behavior.  My second request is for a “Selection Stack”.
 The reason for this request is there is no one selection tool or
mode that will always be best for all pictures.  In fact many times
the most effective selections are made with a combination of
selection tools, for example, using the freehand select to isolate a
region and then using the “Select by Color” to Subtract or
Intersect within the selected region.  You can be a lot more precise
with the Threshold adjustment within a specific region.  Being able
to push a selection onto a stack and then combine / merge the stacked
selections using either Add / Subtract / or Intersect modes.  

Let me throw out another hypothetical
example to illustrate.  I have a picture of a couple and I want to
select them out from the background.  Lets assume the background is
non-uniform so simply selecting by color does not produce a real
useful result.  I would like to be able to Freehand Select around her
blond hair and differentiate it from the background using Select by
Color intersect and put the results on a selection stack.  I would
then like to Freehand select around his dark brown hair,
differentiate it from the background based on color and put that on
the stack as well.  Continuing with faces, shirts, etc. you would
merge / assemble the puzzle pieces of the selection using Add,
Subtract, or Intersect according to what works best for the image.

In a sense, the current implementation
has a single level stack allowing one Selection tool, then another
Selection tool and mode of merging the results.  I would like to be
able to push the selections on a deeper stack so I could merge
different regions with different merge modes and then combine the
resulting regions.

I have tried a work around with the
current implementation of the tool, selecting regions, floating them
to layers and merging the layers, but this doesn't work as well as I
had hoped for the following reasons:

1) It is real hard to see and control
what is going on, the visual feedback is awkward.

2) The merging of layers only gives you
and “Add” mode.

3) The Feathering of edges can create
unintended voids in the selection.  You would almost always want the
Feathering to be on the border (perimeter and holes you might cut) of
the resultant selection, not within the selection itself.

Anyway thanks in advance for
considering my request.  I understand that you have to weigh these
request to create the best usage for the entire user community and
even though I feel these changes would make a better and more usable
tool, that is really for you to decide.


Stephen Kiel

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