diff options
Diffstat (limited to 'Master/texmf-dist/tex/generic/pgf/graphdrawing/lua/pgf/gd/lib/Transform.lua')
-rw-r--r-- | Master/texmf-dist/tex/generic/pgf/graphdrawing/lua/pgf/gd/lib/Transform.lua | 18 |
1 files changed, 17 insertions, 1 deletions
diff --git a/Master/texmf-dist/tex/generic/pgf/graphdrawing/lua/pgf/gd/lib/Transform.lua b/Master/texmf-dist/tex/generic/pgf/graphdrawing/lua/pgf/gd/lib/Transform.lua index 88ffd6446a4..d477c682f60 100644 --- a/Master/texmf-dist/tex/generic/pgf/graphdrawing/lua/pgf/gd/lib/Transform.lua +++ b/Master/texmf-dist/tex/generic/pgf/graphdrawing/lua/pgf/gd/lib/Transform.lua @@ -7,7 +7,7 @@ -- -- See the file doc/generic/pgf/licenses/LICENSE for more information --- @release $Header: /cvsroot/pgf/pgf/generic/pgf/graphdrawing/lua/pgf/gd/lib/Transform.lua,v 1.1 2012/11/27 17:24:26 tantau Exp $ +-- @release $Header: /cvsroot/pgf/pgf/generic/pgf/graphdrawing/lua/pgf/gd/lib/Transform.lua,v 1.2 2014/02/24 10:40:32 tantau Exp $ --- @@ -99,6 +99,22 @@ function Transform.concat(a,b) end + +--- +-- Inverts a transformation matrix. +-- +-- @param t The transformation. +-- +-- @return The inverted transformation +-- +function Transform.invert(t) + local t1, t2, t3, t4 = t[1], t[2], t[3], t[4] + local idet = 1/(t1*t4 - t2*t3) + + return { t4*idet, -t2*idet, -t3*idet, t1*idet, -t[5], -t[6] } +end + + -- Done return Transform
\ No newline at end of file |