Dear Norwid,
On Wed, Mar 05, 2025 at 06:29:32PM +0100, Norwid Behrnd wrote:
> Dear Hans
>
> I'm able to locally replicate and compile the examples shared by you. Are the
> names of the bond types preliminary only?
Yes they are. Maybe a mere descriptive name would be more appropiate:
- dashed for what's now called `racemic'
- wdashed for what's now called 'back' (and leave back unaltered, see comment
below)
- rwdashed for what's now called 'rback'
What would you prefer?
> For instance `racemic` for a bond
> which is `down` (relative to an other marked as `up`, but in absence of R/S
> assignments) could be improved.
I think that it is up to the user to use bonds as see fit.
It would complicate matters to supply rules on when and how a bond is used.
> However, CSTR 122 uses `down` already as an
> alternative to indicate an angle of 180 degrees -- using the same string twice
> as keywords in different spot might derail chem or groff.
The only thing that is added are macro's for new bonds (which are modifications
of existings bond macro's). So the use of `down' is not altered.
> Why a `back` and an
> additional `rback`?
Mere practical reasons: sometimes it is easier to start with the substituent:
Cl
rback 45
C
and so on.
In the "test star pattterns", is `Y` meant to be a
> representative of the stereogenic centre, and `X` a substituent?
Yes. Just to show how a certain bond looks under a certain angle.
(Which is still far from being perfect as you rightly observe.)
> Is the > overarching aim to modernize both chem as well as CSTR 122/its
> documentation
> further?
No, I just started tinkering with chem and chem.pic because I needed a wedged
dashed bond.
I think there's even a more simple solution, which gives the individual user the
possibility to create his own bonds to his liking.
Changing this line:
if ($Words[0] =~ /^(double|triple|front|back)$/ &&
in chem into:
if ($Words[0] =~ /^[a-z]/ &&
would give the opportunity to source your own bonds and leave chem.pic
unaltered.
>
> Prior to the addition of new features, depending an either horizontal, or
> diagonal alignment, the bonds lengths in the six-pointed stars vary. The
> wider width of the wedged bonds vary, too. What defines the start / end point
> of a wavy bond seems to differ in comparison with plain single bonds; at
> times,
> the resulting depiction appears "off centred". This is both surprising, and
> unexpected.
Yes, you're right. This has to be adressed.
>From what I see, the two main reasons why this happens are:
1. A bond is connected to one of the eight compass points.
The distance from the compass points to the text of the atom or group
differs somewhat from point to point;
2. The way dashed and wavy bonds are drawn / calculated.
I don't have a solution for it yet, but I'm pondering over it.
Suggestions are more then welcome.
>
> Can the bold bond's use be edited to the result of a more "hugging" connection
> with a ring, i.e. without a gap this much noticeable?
I will take a look at this.
> In the .zip archive is
> an example how e.g., ChemDraw presents such a structure.
>
> Kind regards,
>
> Norwid
Kind regards,
Hans
