Provided by: libncarg-dev_6.6.2.dfsg.1-4_amd64 bug

NAME

       geval_tran_matrix - Connstruct GKS segment by evaluating a transform matrix

DESCRIPTION

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

SYNOPSIS

       #include <ncarg/gks.h>

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

DESCRIPTION

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

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

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

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

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

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

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

       coord_switch
                   (Input) - A coordinate switch to indicate whether the values for the arguments
                   shift and scale (described above)  are  in  world  coordinates  or  normalized
                   device coordinates.  Possible values include:

                   GCOORD_WC
                          World coordinates

                   GCOORD_NDC
                          Normalized device coordinates

                   tran_matrix (Gfloat,   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 gset_seg_tran.

USAGE

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

       The order of the transformation operations as built  into  the  output  matrix  is:  scale
       (relative to the fixed point); rotate (relative to the fixed point; shift.

       Elements  tran_matrix[0][2] and tran_matrix[1][2] are in normalized device coordinates and
       the other elements of tran_matrix are unitless.

EXAMPLE

       The following code

             pi = 3.1415926;
             point.x = point.y = 0.5;
             shift.delta_x = 0.25;
             shift.delta_y = 0.;
             scale.delta_x = 0.5;
             scale.delta_y = 1.5;
             geval_tran_matrix(&point,&shift,45.*pi/180.,&scale,GCOORD_WC,tm);

       would produce a transformation matrix in tm that would: scale the  X  coordinates  by  .5,
       scale  the  Y  coordinates  by 1.5 (relative to the fixed point of (.5,.5) ); rotate by 45
       degrees (relative to the fixed point (.5,.5) ); and shift by .25 in X and 0.  in  Y.   The
       input values for the fixed point and shift vector are in world coordintes.

ACCESS

       To use the GKS C-binding routines, load the ncarg_gks and ncarg_c libraries.

SEE ALSO

       Online:      gaccum_tran_matrix(3NCARG),      gclose_seg(3NCARG),     gcreate_seg(3NCARG),
       gcopy_seg_ws(3NCARG),            gdel_seg(3NCARG),             ginq_name_open_seg(3NCARG),
       ginq_set_seg_names(3NCARG), gset_seg_tran(3NCARG), gks(3NCARG), ncarg_gks_cbind(3NCARG)

       Hardcopy: User's Guide for NCAR GKS-0A Graphics; NCAR Graphics Fundamentals, UNIX Version

COPYRIGHT

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