man Gridall (3): Allows one to draw backgrounds for

SYNOPSIS

Each of the routines GRID, GRIDL, HALFAX, PERIM, PERIML, and GRIDAL draws a background of some sort within the part of the plotter frame occupied by the current GKS viewport, as follows:

GRID draws an unlabeled grid.
GRIDL draws a labeled grid.
HALFAX draws a pair of intersecting axes.
PERIM draws an unlabeled perimeter.
PERIML draws a labeled perimeter.
GRIDAL draws any of the above.

The positioning of ticks and grid lines is determined partly by the arguments of these routines and partly by the nature of the current mapping from the "user" coordinate system to the "fractional" coordinate system, as determined by the current definitions of the GKS viewport and window and by the values of two internal parameters of the package SPPS: 'LS' and 'MI'. Numeric labels reflect values in the "user" coordinate system.
Note: Calling the SPPS routine SET defines the GKS viewport and window and the values of the parameters 'LS' and 'MI'. The parameter 'LS' determines whether the mappings of user coordinates to fractional coordinates are linear or logarithmic and the parameter 'MI' determines whether the mappings are mirror-imaged or not.
Each of the internal parameters of Gridall has a three-character mnemonic name of the form 'xxx'. Each of the routines GAGETC, GAGETI, GAGETR, GASETC, GASETI, and GASETR is intended either to retrieve the value of a specific internal parameter of Gridall or to give a new value to it, as follows:

GAGETC is called with the name of an internal parameter of type CHARACTER and a character variable in which the value of the parameter is to be returned.
GAGETI is called with the name of an internal parameter of type INTEGER or REAL and an integer variable in which the integer equivalent of the value of the parameter is to be returned.
GAGETR is called with the name of an internal parameter of type INTEGER or REAL and a real variable in which the real equivalent of the value of the parameter is to be returned.
GASETC is called with the name of an internal parameter of type CHARACTER and a character expression that is to become the new value of the parameter.
GASETI is called with the name of an internal parameter of type INTEGER or REAL and an integer expression that is to become the new value of the parameter.
GASETR is called with the name of an internal parameter of type INTEGER or REAL and a real expression that is to become the new value of the parameter.

These six routines allow one to access all of the internal parameters of Gridall in a manner consistent with other NCAR Graphics utilities and are intended to replace some older routines, each of which allows access to a limited subset of the internal parameters. However, the older routines are still available and will remain so for the foreseeable future:

GACOLR sets the value of internal parameters that control the color of various parts of the background.
LABMOD sets the value of internal parameters that affect the appearance of labels.
TICKS and TICK4 set the value of internal parameters that determine the length and direction of ticks.

C-BINDING SYNOPSIS

c_grid
c_gridl
c_halfax
c_perim
c_periml
c_gridal
c_gagetc
c_gageti
c_gagetr
c_gasetc
c_gaseti
c_gasetr
c_gacolr
c_labmod
c_ticks
c_tick4

USER-MODIFIABLE INTERNAL ROUTINES

None.

ACCESS

To use Gridall C or Fortran routines, load the NCAR Graphics libraries ncarg, ncarg_gks, and ncarg_c, preferably in that order.

MESSAGES

Various error conditions can occur in Gridall. Each of these results in a call to the error-handling routine SETER, with a final argument indicating that the error is recoverable; by default, an error message is printed and execution is terminated, but, if you turn on error recovery (as described in the "man" page for "error_handling"), you can get control back.

The error messages are as follows; all should be more or less self-explanatory.

GACOLR - UNCLEARED PRIOR ERROR
GAGETC - UNCLEARED PRIOR ERROR
GAGETC - UNRECOGNIZED PARAMETER NAME
GAGETI - UNCLEARED PRIOR ERROR
GAGETR - UNCLEARED PRIOR ERROR
GAGETR - UNRECOGNIZED PARAMETER NAME
GASETC - UNCLEARED PRIOR ERROR
GASETC - UNRECOGNIZED PARAMETER NAME
GASETI - UNCLEARED PRIOR ERROR
GASETR - UNCLEARED PRIOR ERROR
GASETR - UNRECOGNIZED PARAMETER NAME
GRID - UNCLEARED PRIOR ERROR
GRIDAL - ERROR EXIT FROM GQCLIP
GRIDAL - ERROR EXIT FROM GQLWSC
GRIDAL - ERROR EXIT FROM GQPLCI
GRIDAL - ERROR EXIT FROM GQTXCI
GRIDAL - UNCLEARED PRIOR ERROR
GRIDL - UNCLEARED PRIOR ERROR
HALFAX - UNCLEARED PRIOR ERROR
LABMOD - UNCLEARED PRIOR ERROR
PERIM - UNCLEARED PRIOR ERROR
PERIML - UNCLEARED PRIOR ERROR
TICK4 - UNCLEARED PRIOR ERROR
TICKS - UNCLEARED PRIOR ERROR

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