94 lines
3.0 KiB
Plaintext
94 lines
3.0 KiB
Plaintext
# macros for chem
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# Source file position: <groff-source>/contrib/chem/chem.pic
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# Installed position: <prefix>/share/groff/<version>/pic
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# Copyright (C) 2006-2014 Free Software Foundation, Inc.
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# Written by Brian Kernighan <http://cm.bell-labs.com/cm/cs/who/bwk>,
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# modified by Bernd Warken <groff-bernd.warken-72@web.de>.
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# This file is part of `chem', which is part of `groff'.
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# `groff' is free software; you can redistribute it and/or modify it
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# under the terms of the GNU General Public License (GPL) version 2 as
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# published by the Free Software Foundation.
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# `groff' is distributed in the hope that it will be useful, but
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# WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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# General Public License for more details.
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# The license text for GPL2 is available in the internet at
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# <http://www.gnu.org/licenses/gpl-2.0.html>.
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########################################################################
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pi = 3.141592654
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deg = 57.29578
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# cr = 0.08 # radius of invis circle at ring vertices (see cr[vh])
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# crh = 0.16; crw = 0.12 # ht & wid of invis ellipse around atoms at ring vertices
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# dav = 0.015 # vertical shift up for atoms in atom macro
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# atom(text, wid, ht, carbon position, crh, crw, dav)
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define atom { [
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T: $1 wid $2 ht $3-2*$7
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C: ellipse invis ht $5 wid $6 at T.w + ($4,$7)
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L: ellipse invis ht $5 wid $6 at T.w + (cwid/2,$7)
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R: ellipse invis ht $5 wid $6 at T.e + (-cwid/2,$7)
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] }
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# bond(length, angle in degrees, whatever)
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define bond {
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line $3 by ($1) * sin(($2)/deg), ($1) * cos(($2)/deg)
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}
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# fancy bonds: r, theta, from/at
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define doublebond {
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line $3 invis by ($1) * sin(($2)/deg), ($1) * cos(($2)/deg)
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V1: last line.start; V2: last line.end; dx = V2.x-V1.x; dy = V2.y-V1.y
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norm = sqrt(dx*dx + dy*dy)
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ny = dx * .02 / norm
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nx = -dy * .02 / norm
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line from V1 + (nx,ny) to V2 + (nx,ny)
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line from V1 - (nx,ny) to V2 - (nx,ny)
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move to V2
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}
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define triplebond {
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line $3 invis by ($1) * sin(($2)/deg), ($1) * cos(($2)/deg)
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V1: last line.start; V2: last line.end; dx = V2.x-V1.x; dy = V2.y-V1.y
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norm = sqrt(dx*dx + dy*dy)
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ny = dx * .025 / norm
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nx = -dy * .025 / norm
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line from V1 + (nx,ny) to V2 + (nx,ny)
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line from V1 - (nx,ny) to V2 - (nx,ny)
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line from V1 to V2
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move to V2
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}
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define backbond {
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line $3 invis by ($1) * sin(($2)/deg), ($1) * cos(($2)/deg)
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V1: last line.start; V2: last line.end; dx = V2.x-V1.x; dy = V2.y-V1.y
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norm = sqrt(dx*dx + dy*dy)
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n = norm / .025
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ny = dx * .02 / norm
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nx = -dy * .02 / norm
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for i = 1 to n-1 do {
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XZ: i/n <V1,V2>
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line from XZ + (nx,ny) to XZ - (nx,ny)
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}
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move to V2
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}
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define frontbond {
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line $3 invis by ($1) * sin(($2)/deg), ($1) * cos(($2)/deg)
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V1: last line.start; V2: last line.end; dx = V2.x-V1.x; dy = V2.y-V1.y
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ah = arrowht; aw = arrowwid; ahead = arrowhead
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arrowht = sqrt(dx*dx + dy*dy)
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arrowwid = 0.05
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arrowhead = 7
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line <- from V1 to V2
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arrowht = ah; arrowwid = aw; arrowhead = ahead
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}
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### Emacs settings
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# Local Variables:
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# mode: Nroff
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# End:
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