1GEVTM(3NCARG) NCAR GRAPHICS GEVTM(3NCARG)
2
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.
9
11 CALL GEVTM(X0,Y0,DX,DY,PHI,FX,FY,SW,MOUT)
12
14 #include <ncarg/gks.h>
15 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);
19
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.
26 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.
32 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.
38 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.
44 PHI (Real, Input) - The rotation angle, in radians, to be used
46 for the rotation part of the output transformation.
47 FX (Real, Input) - An X coordinate scale factor to be used in
49 the scaling part of the output transformation.
50 FY (Real, Input) - A Y coordinate scale factor to be used in
52 the scaling part of the output transformation.
53 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.
59 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.
63
65 If world coordinates are used, the shift vector and the fixed point are
66 transformed by the current normalization transformation.
67 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.
71 Elements MOUT(1,3) and MOUT(2,3) are in normalized device coordinates
73 and the other elements of MOUT are unitless.
74
76 The following code
77 PI = 3.1415926
80 CALL GEVTM(.5,.5,.25,0.,45.*PI/180.,.5,1.5,0,TM)
81 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.
87
89 To use GKS routines, load the NCAR GKS-0A library ncarg_gks.
90
92 Online: gactm, gclsg, gcrsg, gcsgwk, gdsg, gqopsg, gqsgus, gssgt.,
93 geval_tran_matrix
94 Hardcopy: "User's Guide for NCAR GKS-0A Graphics"
96
98 Copyright (C) 1987-2009
99 University Corporation for Atmospheric Research
100 The use of this Software is governed by a License Agreement.
101UNIX March 1993 GEVTM(3NCARG)