special Chemical letters
lazarus / 21-General

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flori · 2021-03-12 14:16

Hi!
Does anyone know how can I write in label or edit special chemical
characters? (atomic weight and atomic number)
for example:
H+, Ca2+
Thank u

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balazsszekely · 2021-03-12 14:24

@flori
QuoteDoes anyone know how can I write in label or edit special
chemical characters? (atomic weight and atomic number)
for example:
H+, Ca2+Did you try ChemText from OPM? After package install, open the
chemdemo application. You will see something like in the attachment.

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paweld · 2021-03-12 14:33

or DzHTMLText - html label component: https://github.com/digao-
dalpiaz/DzHTMLText
and sup and sub html tags

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Handoko · 2021-03-12 14:49

Sub and super scripts can be done easily even without using any third
party component. For example:
https://forum.lazarus.freepascal.org/index.php/topic,46775.msg333936.h
tml#msg333936

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Kays · 2021-03-12 14:54

Quote from: paweld on March 12, 2021, 03:33:27 pm[…] sup and sub html
tagsI’m afraid this won’t be of much use if sub- and supscript is to
be rendered. E.g. 0nX2+ shows a horizontal displacement between sub-
and supscripts, but it’s supposed to like in the attached picture:

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wp · 2021-03-12 15:39

No, Handoko's code works exactly for this. You only must keep track of
the horizontal painting position and restore it to that of the
previous character when needed. Of course, you must do all the
painting yourself - AFAIK there is not ready-made component for this
complex index stuff.

I do think, though, that ChemText can be extended to support this. The
most difficult part is to conceive a reasonable syntax. How about such
a syntax to define your symbol:
Code: [Select]'$^0|_nX$_2|^+''$' ... store current horizontal
position'|' ... return to stored painting position'^' ... superscript
next character'_' ... subscript next characterThe painting occurs in
procedure ChemTextOut of unit chemtext.pas, and measuring the text
extent is done in ChemTextExtent. I think the parser is pretty
straightforward. If you submit a patch I'd be glad to appy it.

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Handoko · 2021-03-12 16:13

Interesting, I like this challenge. Unfortunately I'm busy at this
weekend, I'll pass.

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flori · 2021-03-12 16:35

thank you

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winni · 2021-03-12 18:30

Hi!

This is a try with UTF-8 glyphs from subscript and superscript
codeblock.
If that is satisfying you don't need additional software:


⁰    ⁺
  X
ₙ    ₂


Winni

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wp · 2021-03-12 18:56

Quote from: wp on March 12, 2021, 04:39:40 pmHow about such a syntax
to define your symbol:
Code: [Select]'$^0|_nX$_2|^2''$' ... store current horizontal
position'|' ... return to stored painting position'^' ... superscript
next character'_' ... subscript next character
Couldn't resist and implemented it myself. To get the new version
either install the snapshot from https://sourceforge.net/p/lazarus-
ccr/svn/HEAD/tree/components/chemtext/ or install from OPM and replace
the file chemtext.pas by this version:
https://sourceforge.net/p/lazarus-
ccr/svn/HEAD/tree/components/chemtext/source/chemtext.pas

Usage: like in the cited text (except for '$' which has been replaced
by '@')
The ChemLabel's Caption for the formula mentioned a few posts higher
is:
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i  
ChemLabel1.Caption := '@^0|_nX@_2|^+';
See also: https://wiki.lazarus.freepascal.org/ChemText