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-rw-r--r--Master/texmf-dist/metapost/context/base/mp-chem.mpiv34
1 files changed, 26 insertions, 8 deletions
diff --git a/Master/texmf-dist/metapost/context/base/mp-chem.mpiv b/Master/texmf-dist/metapost/context/base/mp-chem.mpiv
index a316a1a30cb..b861d3f123e 100644
--- a/Master/texmf-dist/metapost/context/base/mp-chem.mpiv
+++ b/Master/texmf-dist/metapost/context/base/mp-chem.mpiv
@@ -11,7 +11,8 @@
%C therefore copyrighted by \PRAGMA. See licen-en.pdf for
%C details.
-%D This module is incomplete and experimental.
+%D This module is incomplete and experimental. Okay, it's not that bad but we do need
+%D some disclaimer.
% either consistent setting or not
@@ -131,6 +132,8 @@ vardef chem_init_some (suffix $) (expr e) =
fi
if not chem_star[$] :
scaled (.5/(sind .5chem_num1))
+ % carbon-carbon benzene bond length
+ scaled (1.4/1.54)
fi ;
fi ;
@@ -300,7 +303,6 @@ enddef ;
chem_init_all ; % WHY does this not work unless defined and then called?
-
% Like most often in ConTeXt, we will trap but then silently ignore mistaken use,
% unless of course the error be too harmful...
@@ -529,6 +531,17 @@ vardef chem_set (suffix $) =
% This is a fairly complicated optimization and ajustement. It took some
% thinking to get right, so beware!
+ % And then even more time fixing a bug of a rotation +- half the symmetry
+ % angle of a structure depending on the scale and/or the font size
+ % (through chem_b_length).
+
+ % first save the symmetry angle of the structure (as in chem_rot):
+ chem_num0 := if chem_stacked[$] : 3 else : 0 fi ;
+ chem_num9 := if chem_tetra[$] : 360 else :
+ abs(angle(point 0+chem_num0 of chem_b_path[$]) -
+ angle(point 1+chem_num0 of chem_b_path[$]))
+ fi ;
+
if (chem_adjacent<>0) and chem_star[P] and chem_star[$] :
% nop
chem_adjacent := 0 ;
@@ -581,7 +594,8 @@ vardef chem_set (suffix $) =
-((point (chem_adjacent-1) of chem_b_path[P]) chem_transformed(P)) ;
fi
% adjust the bond angles
- chem_rotation := (chem_rotation + angle(chem_pair1)-angle(chem_pair3)) mod 360 ;
+ chem_num4 := (angle(chem_pair1)-angle(chem_pair3)) zmod chem_num9 ;
+ chem_rotation := chem_rotation + chem_num4 ;
if not chem_star[$] :
chem_pair4 :=
if chem_star[P] :
@@ -666,7 +680,8 @@ vardef chem_set (suffix $) =
fi
endfor
if not chem_front[$] : % adjust rotation
- chem_rotation := (chem_rotation + angle(chem_pair1)-angle(chem_pair3)) mod 360 ;
+ chem_num4 := angle(chem_pair1)-angle(chem_pair3) ;
+ chem_rotation := (chem_rotation + chem_num4) mod 360 ;
fi ;
chem_t := identity chem_transformed($) ;
chem_pair4 := (point chem_num3 of chem_b_path[$]) transformed chem_t ;
@@ -674,6 +689,9 @@ vardef chem_set (suffix $) =
currentpicture := currentpicture shifted chem_pair4 ;
chem_origin := chem_origin shifted chem_pair4 ;
fi
+ if not chem_front[$] : % adjust rotation
+ chem_rotation := chem_rotation zmod chem_num9 ;
+ fi
fi
chem_substituent := 0 ;
fi ;
@@ -1571,9 +1589,9 @@ vardef chem_rot (suffix $) (expr d, s) = % ROT
chem_rotation := 0
else :
chem_num0 := if chem_stacked[$] : 3 else : 0 fi ;
- chem_num1 := .5(angle(point d+chem_num0 of chem_b_path[$]) -
+ chem_num1 := .5(angle(point d+chem_num0 of chem_b_path[$]) -
angle(point d+chem_num0-1 of chem_b_path[$])) ;
- chem_rotation := (chem_rotation + s*chem_num1) mod 360 ;
+ chem_rotation := (chem_rotation + s*chem_num1) zmod 360 ;
fi
fi
enddef ;
@@ -1584,7 +1602,7 @@ vardef chem_mir (suffix $) (expr d, s) = % MIR
if not chem_front[$] :
if d=0 : % inversion
if chem_mirror=origin :
- chem_rotation := (chem_rotation + 180*s) mod 360 ;
+ chem_rotation := (chem_rotation + 180*s) zmod 360 ;
else :
chem_mirror := chem_mirror rotated 90 ;
fi
@@ -1600,7 +1618,7 @@ vardef chem_mir (suffix $) (expr d, s) = % MIR
chem_num0 := -360 - chem_num0 ;
fi
chem_num0 := chem_num0 * s ;
- chem_rotation := (chem_rotation + 2chem_num0) mod 360 ;
+ chem_rotation := (chem_rotation + 2chem_num0) zmod 360 ;
chem_mirror := origin ;
fi
fi