Provided by: libncarg-dev_6.1.2-7_amd64 bug

NAME

       gactm - Accumulate (GKS) transformation matrix

DESCRIPTION

       GACTM  (Accumulate transformation matrix) - Constructs a GKS segment transformation matrix
       by starting with an existing matrix and composing it  with  a  shift  vector,  a  rotation
       angle,  and X and Y scale factors to create a new transformation matrix.  The rotation and
       scaling are done with respect to a user-defined fixed point.

SYNOPSIS

       CALL GACTM(MINP,X0,Y0,DX,DY,PHI,FX,FY,SW,MOUT)

C-BINDING SYNOPSIS

       #include <ncarg/gks.h>

       void gaccum_tran_matrix(const Gtran_matrix  t_matrix,  const  Gpoint  *point,  const  Gvec
       *shift,  Gdouble  angle,  const  Gvec  *scale,  Gcoord_switch  coord_switch,  Gtran_matrix
       tran_matrix);

DESCRIPTION

       MINP        (Real, Input) - A 2x3 GKS transformation matrix.

       X0          (Real, Input) - An X coordinate value for a fixed point to  be  used  for  the
                   scaling and rotation parts of the output transformation.  X is either in world
                   coordinates or normalized device coordinates depending on the setting  of  the
                   argument SW described below.

       Y0          (Real,  Input)  -  A  Y  coordinate value for a fixed point to be used for the
                   scaling and rotation parts of the output transformation.  Y is either in world
                   coordinates  or  normalized device coordinates depending on the setting of the
                   argument SW described below.

       DX          (Real, Input) - The X component of a shift vector to be used for  the  scaling
                   part  of  the  output  transformation.   DX  is either in world coordinates or
                   normalized device coordinates depending on the  setting  of  the  argument  SW
                   described below.

       DY          (Real,  Input)  - The Y component of a shift vector to be used for the scaling
                   part of the output transformation.  DY  is  either  in  world  coordinates  or
                   normalized  device  coordinates  depending  on  the setting of the argument SW
                   described below.

       PHI         (Real, Input) - The rotation angle, in radians, to be used  for  the  rotation
                   part of the output transformation.

       FX          (Real, Input) - An X coordinate scale factor to be used in the scaling part of
                   the output transformation.

       FY          (Real, Input) - A Y coordinate scale factor to be used in the scaling part  of
                   the output transformation.

       SW          (Integer,  Input) - A coordinate switch to indicate whether the values for the
                   arguments X0, Y0, DX, and DY (described above) are  in  world  coordinates  or
                   normalized  device  coordinates.   SW=0  indicates  world coordinates and SW=1
                   indicates normalized device coordinates.

       MOUT        (Real, Output) - A 2x3 array that contains the GKS transformation matrix in  a
                   form  that  can  be  used as input to other GKS functions such as GSSGT.  This
                   matrix is constructed  by  composing  the  scale,  rotate,  and  shift  input,
                   described above, with the original input matrix MINP.

USAGE

       If world coordinates are used, the shift vector and the fixed point are transformed by the
       current normalization transformation.

       The order in which the transformations are applied is: input matrix,  scale,  rotate,  and
       shift.

       Elements  MOUT(1,3)  and  MOUT(2,3)  are  in  normalized  device coordinates and the other
       elements of MOUT are unitless.

       GACTM can be used to construct more general transformation matrices than GEVTM.  The  most
       common usage of GACTM is to change the order in which the operations of scale, rotate, and
       shift are applied (which is fixed in GEVTM).  The example below shows how to  construct  a
       transformation matrix that shifts first and then rotates.

EXAMPLE

       Assuming that the input matrix TIN is initially the identity, the following code

             PI = 3.1415926
             CALL GACTM(TIN,.5,.5,.25,0.,0.,1.,1.,0,TOUT)
             DO 20 I=1,2
               DO 30 J=1,3
                 TIN(I,J) = TOUT(I,J)
          30   CONTINUE
          20 CONTINUE
             CALL GACTM(TIN,.5,.5,0.,0.,45.*PI/180.,1.,1.,0,TOUT)

       would produce a transformation matrix in TOUT that would shift by (.25,0.) first, and then
       rotate by 45 degrees.

ACCESS

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

SEE ALSO

       Online: gevtm, gclsg, gcrsg, gcsgwk, gdsg, gqopsg, gqsgus, gssgt., gaccum_tran_matrix

       Hardcopy: "User's Guide for NCAR GKS-0A Graphics"

COPYRIGHT

       Copyright (C) 1987-2009
       University Corporation for Atmospheric Research
       The use of this Software is governed by a License Agreement.