1STREAM(3NCARG) NCAR GRAPHICS STREAM(3NCARG)
2
6 STREAM - Plots a streamline representation of field flow data, based on
7 conditions established by STINIT and the current values of a set of
8 user-modifiable internal parameters associated with the Streamlines
9 utility.
10
12 CALL STREAM (U,V,P,IAM,STUMSL,WRK)
13
15 #include <ncarg/ncargC.h>
16 void c_stream(float *u, float *v, float *p, int *iam,
18 int (*stumsl_)( float *xcs, float *ycs,
19 int *ncs, int *iai, int *iag, int *nai),
20 float *wrk)
21
23 U (REAL 2 dimensional array, dimensioned as specified in last
24 call to STINIT, input): By default, assumed to contain the
25 first dimensional axis components of the vector field.
26 However, if PLR is non-zero, it is treated as containing
27 the vector magnitudes.
28 V (REAL 2 dimensional array, dimensioned as specified in last
30 call to STINIT, input): By default, assumed to contain the
31 second dimensional axis components of the vector field.
32 However, if PLR is non-zero, it is treated as containing
33 the vector angles.
34 P (REAL, input, DUMMY): This argument is currently ignored.
36 May be assigned a dummy value.
37 IAM (INTEGER array, unknown dimension, input): Area map array
39 previously established by calls to routines in the Areas
40 utility. It is checked to see that the number of area
41 groups is within the limits allowed by Streamlines, then
42 simply passed through to an Areas routine for further
43 processing. Required only if MSK is set to a non-zero
44 value; otherwise it is ignored and may be assigned a dummy
45 value.
46 STUMSL (EXTERNAL subroutine, input): User-definable masked drawing
48 subroutine. Required only if MSK is set to a non-zero
49 value; otherwise it is ignored and may be assigned a dummy
50 value.
51 WRK (REAL array, dimensioned as specified in last call to
53 STINIT, input/output): Work array used to store normalized
54 values of the U and V vector components while the
55 streamlines are calculated. It also holds bit flags
56 indicating whether a grid location is eligible for starting
57 a streamline or placing a directional arrowhead.
58
60 The C-binding argument descriptions are the same as the FORTRAN
61 argument descriptions.
62
64 A call to STINIT must precede the first call to STREAM, and is again
65 required any time the vector array data changes or any of the
66 coordinate space control parameters are modified. However, you may
67 modify certain rendering control parameters between multiple
68 invocations of STREAM. See the streamlines_params man page for more
69 information.
70 Arguments to STINIT establish the sizes of the vector component arrays
72 and the WRK array. STINIT places these values into common block
73 variables where they become available to STREAM. Therefore no size
74 arguments need appear in the STREAM argument list. When area masking
75 is not enabled, the third, fourth and fifth arguments to STREAM may all
76 have dummy values and the invocation would be something like:
77 CALL STREAM(U,V,IDM,IDM,IDM,WRK)
79 where IDM is an arbitrary variable that need not have been initialized.
81 The masking capability supported by Streamlines allows you to overlay
83 streamlines on graphics produced by other utilities, such as Conpack
84 contour plots, without encroaching on areas, like label boxes, that
85 should appear in the foreground. Normally the area map should be
86 generated and used in the normal way (as described in the Areas and
87 Conpack documentation) before calling any routines in the Streamlines
88 utility. When the parameter MSK has a non-zero value, masking is
89 enabled and a previously created area map must be passed to STREAM.
90 STREAM examines the map, returning an error if the map appears to be
91 invalid or the number of area groups is beyond the range it can handle
92 (currently 64). Otherwise, it only uses the map as an argument to the
93 Areas utility subroutine, ARDRLN. The user must also pass in a user-
94 definable masked drawing subroutine. A simple version of this
95 subroutine, named (like the argument) STUMSL, is supplied with the
96 Streamlines utility, and may suffice for basic masked drawing
97 operations. See the stumsl man page for more information.
98 The P array argument is intended for future enhancement of the
100 Streamlines utility and is not currently used or examined in any way.
101 You may pass it an uninitialized dummy argument.
102
104 Use the ncargex command to see the following relevant examples: ffex00,
105 ffex01, ffex03, ffex04, fstream, stex01, stex02, stex03, stex03.
106
108 To use STREAM or c_stream, load the NCAR Graphics libraries ncarg,
109 ncarg_gks, and ncarg_c, preferably in that order.
110
112 See the streamlines man page for a description of all Streamlines error
113 messages and/or informational messages.
114
116 Online: stgetc, stgeti, stgetr, stinit, streamlines,
117 streamlines_params, strset, stsetc, stseti, stsetr, stuixy, stumsl,
118 stumta, stumxy, ncarg_cbind.
119 Hardcopy: NCAR Graphics Fundamentals, UNIX Version
121
123 Copyright (C) 1987-2009
124 University Corporation for Atmospheric Research
125 The use of this Software is governed by a License Agreement.
126UNIX April 1993 STREAM(3NCARG)