ncl_plchhq (3) - Linux Manuals

NAME

PCHIQU - Draws high quality characters. By default, it uses the same database as the old NCAR Graphics routine PWRITX, but it can also use characters from any of the fontcap-defined databases, it has an improved interface, and it has many more capabilities than PWRITX.

PLCHHQ is an alternate name for the routine PCHIQU.

SYNOPSIS

CALL PCHIQU (XPOS,YPOS,CHRS,SIZE,ANGD,CNTR)

C-BINDING SYNOPSIS

#include <ncarg/ncargC.h>

void c_pchiqu (float xpos, float ypos, char *chrs,
float size, float angd, float cntr)

DESCRIPTION

XPOS,YPOS

(input expressions of type REAL) specify positioning coordinates for the characters to be drawn. If the internal parameter 'MA' has the value 0, these are given in the current user coordinate system; otherwise, they are given in an arbitrary X/Y coordinate system, as implied by the value of 'MA' and the nature of the routine CPMPXY. (For example, if 'MA' has the value 1 and the default version of CPMPXY is being used, then XPOS is a longitude, in degrees, and YPOS is a latitude, in degrees.) The argument CNTR (described below) specifies how the characters are to be positioned relative to the point (XPOS,YPOS).

CHRS

(an input constant or variable of type CHARACTER) specifies the characters to be drawn. The number of characters in CHRS is taken to be LEN(CHRS); to use characters "m" through "n" from a character variable CHRV, use the FORTRAN-77 substring notation "CHRV(m:n)". CHRS may contain characters to be drawn and "function codes", which are used for various purposes. The possible function codes are completely described in the programmer document for Plotchar and are summarized in a later section of this man page.

SIZE

(an input expression of type REAL) specifies the desired character size. If the internal parameter 'MA' is zero, then the following comments apply:

•

If SIZE is less than or equal to zero, its absolute value specifies the size as a multiple of the digitized size. On a 1024x1024 grid, principal-size capitals are about 'PW' units wide by 'PH' units high and the vertical spacing between lines is 'PV' units (by default, 'PW', 'PH', and 'PV' are 16, 21, and 32). Indexical-size capitals are 'IW' units wide by 'IH' units high and the vertical spacing between lines is 'IV' units (by default, 'IW', 'IH', and 'IV' are 12, 13, and 20). Cartographic-size capitals are 'CW' units wide by 'CH' units high and the vertical spacing between lines is 'CV' units (by default, 'CW', 'CH', and 'CV' are 8, 9, and 14).

Example: Using CHRS = 'ABC' and SIZE = -2. will write three characters, each of which is about 32/1024 of the plotter frame in width.

•

If SIZE is greater than zero, but less than one, it specifies the desired approximate width of a principal-size capital as a fraction of the distance across the plotter frame. This is the recommended scheme.

Example: Using CHRS = 'ABC' and SIZE = .05 will write three characters, each of which is about 5 hundredths of the plotter frame in width.

•

If SIZE is greater than or equal to one, it specifies the desired approximate width of a principal-size capital in plotter coordinates, as defined by default or by a user call to the SPPS routine SETI. Note that use of the routine SETI is now discouraged.

Example: Using CHRS = 'ABC' and SIZE = 13. (assuming there have been no calls to the SPPS routine SETI) will write three characters, each of which is about 13/1024 of the plotter frame in width.

If 'MA' is nonzero, then SIZE is the desired approximate width of a principal-size capital as a value in the X/Y coordinate system in which XPOS and YPOS are given.

In most of the databases used by PCHIQU, the character width varies from character to character. Most principal-size capitals will be a little wider than the value specified by SIZE (and a few will be narrower). Thus, a little experimenting may be necessary to get just the size one wants. A rule of thumb that works pretty well when using all capitals is as follows:

SIZE = DLOS / REAL(NCIS)

where "DLOS" is the desired length of the string, in the fractional system, and "NCIS" is the number of characters in the string.

Note: As of version 3.2 of NCAR Graphics, the size of all characters written by PCHIQU has been reduced by a multiplicative factor (the internal parameter 'SA') whose default value is .88888888... The object of this is to make the size of characters written by PCHIQU consistent with the size of characters written by PCMEQU and PCLOQU. If the value of 'SA' is not changed, then the height of principal-size capitals written by PCHIQU and PCMEQU will be 7/6 times the value specified by SIZE. Thus, if the desired character height (CHRH) is known, use "SIZE = 6.*CHRH/7." .

The values of the internal parameters 'PW', 'PH', 'PV', 'IW', 'IH', 'IV', 'CW', 'CH', and 'CV' (as well as two others, 'PS' and 'IS') may be changed by user calls to CPSETR. This can be used to change the effective size and shape of digitized characters in the PWRITX database (the effect is the same as if the characters had been digitized differently at the outset). If, for example, one were to double the value of 'PH', it would make the principal characters twice as tall as they are by default. (In this case, one would probably also want to double the value of 'PV', so as to make the vertical spacing between lines consistent with the character height.) Note that, if one changes the value of 'PW', 'IW', or 'CW', the meaning of a negative value of the argument SIZE may thereby be changed.

ANGD

(an input expression of type REAL) is the angle, in degrees counterclockwise from the positive X axis, at which the character string is to be written. If the internal parameter 'TE' is nonzero (by default, it is zero) and if ANGD is exactly 360., then no characters are drawn by PCHIQU; it just computes the distances, in the fractional coordinate system, from the point (XPOS,YPOS) to the left edge, the right edge, the bottom edge, and the top edge of a box enclosing the string. These are stored as the values of the parameters 'DL', 'DR', 'DB', and 'DT' and may be retrieved by calls to PCGETR.

CNTR

(an input expression of type REAL) is the centering option. If the internal parameter 'CE' is zero (the default), then

•

CNTR = -1. means that (XPOS,YPOS) is the center of the left edge of the first character (if that character is to be written "across" the frame) or the center of the top edge of the first character (if that character is to be written "down" the frame).

•

CNTR = 1. means that (XPOS,YPOS) is the center of the right edge of the last character (if the writing direction at the end of the character string is "across" the frame) or the center of the bottom edge of the last character (if the writing direction at the end of the character string is "down" the frame).

•

CNTR = s, where "s" is any real number, means that (XPOS,YPOS) is a point obtained by linear interpolation along the line joining the two points mentioned above (the first point being associated with the value -1. and the second with the value +1.). The value "0." gives the midpoint of the line.

If 'CE' is nonzero, then the value of CNTR is ignored. Text-extent quantities are computed and used to exactly center the output on the point (XPOS,YPOS). This is useful, among other things, for labeling each of a number of points with a single character; however, it works as desired only when 'QU' is zero.

Upon return from PCHIQU, all arguments are unchanged.

C-BINDING DESCRIPTION

The C-binding argument descriptions are the same as the FORTRAN argument descriptions.

FUNCTION CODES

The function codes that may be used for various purposes in the input character string CHRS are described completely in the programmer document for Plotchar. The material that follows will principally be of use as a memory aid to someone who is already familiar with the use of function codes.

As the characters of CHRS are scanned from left to right, the scanner is always in one of two states: either it is looking for characters to be drawn or it is looking for characters to be interpreted as function codes. Each occurrence of the function-code signal character (defined by the internal parameter 'FC' - a colon by default) flips the state of the scanner. Thus, in the character string 'ABC:L:DEF', "A", "B", and "C" will be treated as characters to be drawn, "L" will be treated as a function code, and "D", "E", and "F" will be treated as characters to be drawn. (In this particular example, since the function code "L" requests lower case, what would be drawn is "ABCdef".) Occasionally, function codes may need to be separated by commas or blanks; this is necessary only when there would otherwise be a syntactical problem.

F

Switch to using the database specified by the value of 'FN'.

F0

Switch to using the PWRITX database.

Fn

Switch to using fontcap-defined font "n".

R

Switch to the "Roman" part of the PWRITX database. If characters are currently being used from a fontcap-defined font, this function code will have no effect.

G

Switch to the "Greek" part of the PWRITX database. If characters are currently being used from a fontcap-defined font, this function code will have no effect.

P

Use characters of principal size from the PWRITX database. If characters are currently being used from a fontcap-defined font, there will be an appropriate shift in size.

I

Use characters of indexical size from the PWRITX database. If characters are currently being used from a fontcap-defined font, there will be an appropriate shift in size.

K

Use characters of cartographic size from the PWRITX database. If characters are currently being used from a fontcap-defined font, there will be an appropriate shift in size.

U

Switch to using upper case letters from the PWRITX database. If characters are currently being used from a fontcap-defined font, this function code will have no effect.

Un

For the next "n" characters, switch to using upper case letters from the PWRITX database and then switch to lower case. If characters are currently being used from a fontcap-defined font, this function code will have no effect.

L

Switch to using lower case letters from the PWRITX database. If characters are currently being used from a fontcap-defined font, this function code will force the use of lower case letters from it.

Ln

For the next "n" characters, switch to using lower case letters from the PWRITX database and then switch to upper case. If characters are currently being used from a fontcap-defined font, this function code will force the use of lower case letters from it.

A

Switch to writing "across" the frame, in the direction ANGD. This is the normal mode.

D

Switch to writing "down" the frame, in the direction ANGD-90. This causes each character to be written beneath the previous one.

B

Switch to subscript level.

Bn

For the next "n" characters, use subscript level and then revert to normal level.

S

Switch to superscript level.

Sn

For the next "n" characters, use superscript level and then revert to normal level.

E

Switch to normal level in such a way as to allow for another sub- or superscript on the base character.

N

Switch to normal level in such a way as not to allow for another sub- or superscript on the base character.

Hn

Offset by "n" digitization units in the direction ANGD.

HnQ

Offset by "n" blank widths in the direction ANGD.

Vn

Offset by "n" digitization units in the direction ANGD+90.

VnQ

Offset by "n" blank heights in the direction ANGD+90.

C

Do a "carriage return".

Xn or XnQ

Zoom character width to "n" percent of normal.

Yn

Zoom character height to "n" percent of normal.

YnQ

Zoom character height to "n" percent of normal and introduce a shift in the direction ANGD+90 sufficient to keep the bases of characters properly aligned.

Zn

Same as "XnYn".

ZnQ

Same as "XnQYnQ".

nnnn

An octal number may be used as a function code to select a particular character from the PWRITX database. The octal number for a given character is the sum of a font index (0 for Roman or 600 for Greek), a size index (0 for Principal, 200 for Indexical, or 400 for Cartographic), a case index (0 for Upper or 100 for Lower), and the octal equivalent of a character index (1-32 for A through Z, 33-44 for 0 through 9, or 45-57 for the individual characters, +, -, *, /, (, ), $, =, blank, comma, or period).

EXAMPLES

Use the ncargex command to see the following relevant examples: cmpit, cmpita, cmptit, cpexcc, elblba, cbex01, coex01, coex02, coex03, cpex10, epltch, sfex02, srex01, tpltch, fcoord1, fcoord2.

ACCESS

To use PCHIQU or c_pchiqu, load the NCAR Graphics libraries ncarg, ncarg_gks, and ncarg_c, preferably in that order.

COPYRIGHT

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