1GEVTM(3NCARG)                    NCAR GRAPHICS                   GEVTM(3NCARG)
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NAME

6       GEVTM  (Evaluate  transformation  matrix)  -  Constructs  a GKS segment
7       transformation matrix starting from a given point, a  shift  vector,  a
8       rotation angle, and X and Y scale factors.
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SYNOPSIS

11       CALL GEVTM(X0,Y0,DX,DY,PHI,FX,FY,SW,MOUT)
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C-BINDING SYNOPSIS

14       #include <ncarg/gks.h>
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16       void  geval_tran_matrix(const Gpoint *point, const Gvec *shift, Gdouble
17       angle, const  Gvec  *scale,  Gcoord_switch  coord_switch,  Gtran_matrix
18       tran_matrix);
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DESCRIPTION

21       X0          (Real,  Input) - An X coordinate value for a fixed point to
22                   be used for the scaling and rotation parts  of  the  output
23                   transformation.   X  is either in world coordinates or nor‐
24                   malized device coordinates depending on the setting of  the
25                   argument SW described below.
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27       Y0          (Real,  Input)  - A Y coordinate value for a fixed point to
28                   be used for the scaling and rotation parts  of  the  output
29                   transformation.   Y  is either in world coordinates or nor‐
30                   malized device coordinates depending on the setting of  the
31                   argument SW described below.
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33       DX          (Real,  Input)  -  The  X component of a shift vector to be
34                   used for the scaling part of the output transformation.  DX
35                   is either in world coordinates or normalized device coordi‐
36                   nates depending on the setting of the argument SW described
37                   below.
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39       DY          (Real,  Input)  -  The  Y component of a shift vector to be
40                   used for the scaling part of the output transformation.  DY
41                   is either in world coordinates or normalized device coordi‐
42                   nates depending on the setting of the argument SW described
43                   below.
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45       PHI         (Real,  Input) - The rotation angle, in radians, to be used
46                   for the rotation part of the output transformation.
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48       FX          (Real, Input) - An X coordinate scale factor to be used  in
49                   the scaling part of the output transformation.
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51       FY          (Real,  Input)  - A Y coordinate scale factor to be used in
52                   the scaling part of the output transformation.
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54       SW          (Integer, Input) - A coordinate switch to indicate  whether
55                   the  values for the arguments X0, Y0, DX, and DY (described
56                   above) are in world coordinates or normalized device  coor‐
57                   dinates.   SW=0  indicates world coordinates and SW=1 indi‐
58                   cates normalized device coordinates.
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60       MOUT        (Real, Output) - A 2x3 array that contains the  GKS  trans‐
61                   formation  matrix  in  a  form that can be used as input to
62                   other GKS functions such as GSSGT.
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USAGE

65       If world coordinates are used, the shift vector and the fixed point are
66       transformed by the current normalization transformation.
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68       The  order  of  the  transformation operations as built into the output
69       matrix is: scale (relative to the fixed point); rotate (relative to the
70       fixed point; shift.
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72       Elements  MOUT(1,3)  and MOUT(2,3) are in normalized device coordinates
73       and the other elements of MOUT are unitless.
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EXAMPLE

76       The following code
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79             PI = 3.1415926
80             CALL GEVTM(.5,.5,.25,0.,45.*PI/180.,.5,1.5,0,TM)
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82       would produce a transformation matrix in TM that  would:  scale  the  X
83       coordinates  by  .5,  scale  the  Y coordinates by 1.5 (relative to the
84       fixed point of (.5,.5) ); rotate by 45 degrees (relative to  the  fixed
85       point  (.5,.5)  ); and shift by .25 in X and 0. in Y.  The input values
86       for the fixed point and shift vector are in world coordintes.
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ACCESS

89       To use GKS routines, load the NCAR GKS-0A library ncarg_gks.
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SEE ALSO

92       Online: gactm, gclsg, gcrsg,  gcsgwk,  gdsg,  gqopsg,  gqsgus,  gssgt.,
93       geval_tran_matrix
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95       Hardcopy: "User's Guide for NCAR GKS-0A Graphics"
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98       Copyright (C) 1987-2007
99       University Corporation for Atmospheric Research
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101       This  documentation  is  free  software; you can redistribute it and/or
102       modify it under the terms of the GNU General  Public  License  as  pub‐
103       lished  by  the  Free  Software  Foundation;  either  version  2 of the
104       License, or (at your option) any later version.
105
106       This software is distributed in the hope that it will  be  useful,  but
107       WITHOUT  ANY  WARRANTY;  without  even  the  implied  warranty  of MER‐
108       CHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU  General
109       Public License for more details.
110
111       You should have received a copy of the GNU General Public License along
112       with this software; if not, write  to  the  Free  Software  Foundation,
113       Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
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117UNIX                              March 1993                     GEVTM(3NCARG)
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