The order of overlays

[GB, author of iNMR]

The order of the overlays is one of the great mysteries of iNMR. You
probably remember that the Overlay Manager contains two parameters
called "progressive horizontal offset" and "progressive vertical
offset". When you apply them, each overlays is offset by a variable
amount (the progressive amount). The question is: which gets the minor
and which gets the major offset? iNMR remembers the order of creation
of the overlays. The oldest overlay gets the minimal offset; the
newest overlay receives the highest offset. Up to this point the
concept looks simple. The only thing that the program remembers is the
chronological order of creation. You can think at a stack of overlays.
If you add another one, it goes to the top.
When the Overlay Manger is open, however, the reported list of
overlays seldom corresponds to the internal order (the stack). If you
cliick on the "name" header, the overlays are listed alphabetically,
for example. Only if you click on the "ov." header, the visible order
corresponds to the internal order. This approach is efficient if you
remember how it works. Unfortunately it is something very difficult to
remember.
In version 5 I am experimenting a much simpler approach. It is less
efficient, but I hope it is self-explicatory. Just remember: the
"stack" is the internal (chronological) order; the "list" is the table
that appears on the screen, inside the dialog called "Overlay
Manager". When you apply a vertical offset, the stacked plot of
spectra corresponds to the internal stack. The table is ignored.
There are two commands. "stack as listed" copies the visible order
from the table on the creen into the internal logic of the program.
"list as stacked" shows the internal order on the screen. After
executing either command, the stack and the list are equal (in other
words: you get what you see).
Now suppose you want to order the overlays in alphabetical order. In
version 4 you have the single button: "Sort √ Spectra" which does it
all. In version 5 you have to:
- click on the header "name" to sort the table alphabetically;
- select the command "stack as listed".
It's two commands instead of one, hopefully they will be easier to
remember. The new approach offers more flexibility too, because you
can order the overlays into any order, not just an alphabetical one.
You will also notice that in version 4 the table background is white,
while version 5 has alternating stripes. For the opearating system
there's a lot of difference. The former is a Carbon table and the OS
is responsible of sorting it. The latter is a Cocoa table and the
program is responsible of sorting. This is another reason why the
Overlay Manager is so different in the two versions.