To create a font, you must create a data set that contains font
information. Typically, you use a DATA step to create a SAS data set from
which the GFONT procedure generates the font. The data set is referred to
as the font data set and you can specify it with the DATA= argument.
To produce the font, invoke the GFONT procedure and
specify the data set that contains the font information. In addition you
can include options to modify the design and appearance of the font. For
example, the following statement uses the data set FONTDATA to generate the
font MYLOGO:
proc gfont data=fontdata name=mylogo;
For a demonstration of the font creation process, see Creating Figures for a Symbol Font.
The GFONT
procedure uses three types of data sets:
the font data set, the kern data set, and the space data set. Each type of
data set must contain certain variables and meet certain requirements. The
following sections explain what each data set contains, how it is built, and
what the requirements of the variables are.
The font data set consists of a series of observations that
include the horizontal and vertical coordinate values and line segment numbers
that the GFONT procedure uses to generate each character. In addition, each
observation must include a character code that is associated with the font
character and is used to specify the font character in a text string. The
font data set also determines whether the font is stroked or polygon. A font
data set that generates a polygon font produces an outline font by default.
You can use the FILLED option with the same data set to generate a filled
font.
The variables in the font data set must be assigned certain
names and types. The table below summarizes the characteristics of the variables
which are described further in Font Data Set Variables.
-
CHAR
-
provides a code for the character or figure that you are creating. CHAR is
a character variable with a length of 1 or 2 and is required for all fonts.
- CAUTION:
- Using reserved or undefined hexadecimal codes as CHAR values may
require the use of the NOKEYMAP option.
![[cautend]](../common/images/cautend.gif)
The CHAR variable takes any character as its value,
including characters that you can enter from your keyboard and hexadecimal
values from '00'x to 'FF'x. (If you use hexadecimal values as CHAR values,
your font may not work correctly under a key map that is different from the
one under which the font was created because positions that are not defined
in one key map may be defined in another.)
When you specify the code character in a text string,
the associated font character is drawn. For example, if you create a Roman
alphabet font, typically the characters you specify for CHAR are keyboard
characters that match the character in the font. All of the observations that
build the letter A have a CHAR value of A. When you specify 'A' in a text
string this produces A in the output.
However, if you build a symbol font, the symbols may
not have corresponding keyboard characters. In that case, you select a character
or hexadecimal value to represent each symbol in the font and assign it to
CHAR. For example, in the Special font, the letter G is assigned as the code
for the fleur-de-lis symbol. When you specify the code in a text string,
the associated symbol displays.
If the CODELEN= option is set to 2, the values for CHAR
represent two characters, such as AA, or a four-digit hexadecimal value, such
as '00A5'x.
-
LP
-
tells the GFONT procedure whether the coordinates
of each segment form a line or a polygon. LP is a character variable with
a length of 1. It is required for polygon fonts but optional for stroked fonts.
You can assign the LP variable either of the following values:
Every group
of line segments with an LP value of P is designated
as a polygon; if the observations do not draw a completely closed figure,
the program closes the figure automatically. For example, the following observations
do not contain an LP variable. They produce a shape like the one in Using an LP Value of Line.
Using an LP Value of Line
![[IMAGE]](./images/01215309.gif)
-
LP
(continued)
-
An LP variable with a value of P for all observations added
to the data set produces a complete box like the one in Using an LP Value of Polygon.
Using an LP Value of Polygon
![[IMAGE]](./images/01215310.gif)
-
LP
(continued)
-
The LP variable allows you to mix lines and polygons when you
create characters in a font. For example, the following observations produce
the single figure that is composed of a polygon and a line segment, as shown
in Mixing LP Values of Line and Polygon:
Mixing LP Values of Line and Polygon
![[IMAGE]](./images/01215311.gif)
-
PTYPE
-
tells the GFONT procedure what type of data
are in the observation. PTYPE is a character variable of length 1 that is
optional for both stroked and polygon fonts. For each observation, the PTYPE
variable assigns a characteristic to the point that is determined by the X
and Y values. You can assign the PTYPE variable any of the following values:
If the GFONT procedure encounters the sequence V-C-V
in consecutive observations, it draws an arc that connects the two V points
and has its center at the C point. If a circle cannot be centered at C and
pass through both V points, the results are unpredictable. Arcs are limited
to 106 degrees or less.
If you specify an observation with a PTYPE value of
W, it must always be the first observation for a character. Instead of providing
digitizing data to the procedure, the observation gives the minimum and maximum
X values for the character. Note that in this case, the Y variable observation
actually contains the maximum X value. Usually, these values include a little
extra space for intercharacter spacing. Use a PTYPE of W only if you have
specified CHARSPACETYPE=DATA; otherwise, the points are ignored. See the CHARSPACETYPE=
option description for more information on intercharacter spacing.
If you do not specify a PTYPE variable in the font data
set, all points are assumed to be V-type points.
The following observations illustrate
how the PTYPE variable
is used to draw an arc similar to Using the PTYPE Variable to Create an Arc.
(After the figure was generated, a grid was overlaid on it to show the location
of the points.) A comment following each observation explains its function.
Using the PTYPE Variable to Create an Arc
![[IMAGE]](./images/01215312.gif)
-
Note the following:
The font that contains the figure of the arc was generated
with a PROC GFONT statement like the following:
proc gfont data=arc name=arcfig
charspacetype=data filled;
Note that the GFONT procedure uses the CHARSPACETYPE=
option with a value of DATA to specify that the first observation sets the
width of the character. The FILLED option fills the area of the arc.
-
SEGMENT
numbers the line segments that compose a
character or symbol. SEGMENT is a numeric variable that is required for both
polygon and stroked fonts. All the observations for a given line segment
have the same segment number. The segment number changes when a new line segment
starts.
When the GFONT procedure
draws a stroked character with more than one line segment (for example, the
letter E), or a polygon character with a hole (for example, the letter A),
it needs to know when one line stops and where the next line begins. There
are two ways to do this, as follows:
-
Change the segment number when a new line segment
starts. If the value of LP is L (line), a change in segment numbers tells
the GFONT procedure not to connect the last point in line segment 1 and the
first point in line segment 2. If the value of LP is P (polygon), a change
in segment numbers causes both of the following:
Use this method for characters that are composed of
two polygons, such as a question mark (?). If you draw a polygon with a hole
in it, such as the letter A, use the second method.
-
Keep the same segment number for all lines, but
insert an observation with missing values for X and Y between the observation
that marks the end of the first line and the observation that begins the next
line. For example, if you are drawing the letter O, insert an observation
with a missing value between the line that draws the outer circle and the
beginning of the line that draws the inner circle.
The first method is preferred,
unless you are creating a polygon
character with a hole in it. In this case, you should separate the lines with
a missing value and keep the same segment numbers. (Note that if you use separate
line segments when you create a polygon with a hole, the results may be unpredictable.)
For example, observations such as the following from a data set called BOXES
were used to draw the hollow square in Drawing Nested Polygons. The data points that form the
figure are laid out on a grid shown next to the square.
Note that observation 5, which
has missing values for
X and Y, separates the observations that draw the inner box from those that
draw the outer box and that the segment number is the same for all the observations. Drawing Nested Polygons
was generated with a GFONT statement like the following:
proc gfont data=boxes name=boxes filled;
Note that the FILLED option is included and that only
the space between the two squares is filled.
Drawing Nested Polygons
![[IMAGE]](./images/01215313.gif)
-
X Y
-
specify the horizontal and vertical coordinates
of the points for each character. These variables must be numeric, and they
must be named X and Y for the horizontal and vertical coordinates, respectively.
Their values describe the position of the points on the character. These
values can be in any range that you choose, but both variables must describe
the character in the same scale or font units. In other words, 10 horizontal
units must be the same distance as 10 vertical units. You should define vertical
coordinates for all characters on the same baseline.
Note:
When you specify PTYPE=W, both X and Y contain horizontal coordinate
values.
You can create a font data set by digitizing the shape
of the characters or figures either manually or with special digitizing equipment.
To create a font data set by digitizing the characters manually, follow these
steps:
-
Determine the coordinate points for each line
segment by drawing
the characters on a grid.
-
Lay out the observations for each character.
Each observation describes a move from one point to another along a line segment.
For each line segment, enter the coordinate points in the order in which they
are drawn. For a stroked font, when you start a new line segment, change the
segment number. For a polygon font, when you start a new polygon, change
the line segment number.
If the polygon has a hole in it, as in the letter O,
keep the line segment number and separate the lines with a missing value.
Use the same value for CHAR for all of the observations that describe one
character.
-
Create a SAS data set that contains the variables
CHAR, SEGMENT, X, and Y, and read in the data for each observation. Include
the variables LP and PTYPE if necessary.
-
Sort the data set by CHAR and SEGMENT.
-
Assign the font data set with the
DATA= argument.
This process is illustrated in Creating Figures for a Symbol Font.
The kern data
set consists of observations that specify how much space to add or remove
between any two characters when they appear in combination. This process,
called kerning, increases or decreases space between the characters.
Kerning usually is applied to certain pairs of characters that, because of
their shape, have too much space between them. Reducing the space between
characters may allow part of one character to extend over the body of the
next. Examples of some combinations that should be kerned are AT, AV, AW,
TA, VA, and WA.
You can apply kerning to the intercharacter
spacing that you specify with the CHARSPACETYPE= option (except for uniform
fonts). You can refine the kerning of your characters as little or as much
as you like. You assign the kern data set with the KERNDATA= option.
The kern data set must contain these
variables:
-
CHAR1
-
specifies the first character in the pair
to be kerned. CHAR1 is a character variable with a length of 1.
-
CHAR2
-
specifies the second character in the pair
to be kerned. CHAR2 is a character variable with a length of 1.
-
XADJ
-
specifies the amount of space to add or
remove between the two characters. XADJ is a numeric variable that uses the
same font units as the font data set. The value of XADJ specifies the horizontal
adjustment to be applied to CHAR2 whenever CHAR1 is followed immediately by
CHAR2. Negative numbers decrease the spacing, and positive numbers increase
the spacing.
Each observation in a kern data set names
the pair of characters
to be kerned and the amount of space to be added or deleted between them.
To create a kern data set, follow these steps:
-
Select the pairs of characters to be kerned, and
specify the space adjustment (in font units) for each pair as a positive number
(more space) or negative number (less space).
-
Create a SAS data set that contains the variables
CHAR1, CHAR2, and XADJ; produce one observation for each pair of characters
and the corresponding space adjustment.
data kern1;
input char1 $ char2 $ xadj;
datalines;
A T -4
D A -3
T A -4
;
-
Assign the kern data set with the KERNDATA= option.
proc gfont data=fontdata
name=font2
charspacetype=data
kerndata=kern1
nodisplay;
run;
Comparison of Kerned and Unkerned Text
illustrates how you can use the KERNDATA= option to create a font in which
the space between specified pairs of letters is reduced. The characters A,
D, and T are shown as the word DATA. The first line uses the unkerned font,
FONT1, and the second line uses the kerned font, FONT2. Note that the characters
in FONT2 are spaced more closely than the characters in FONT1.
The following title statements specify the kerned and
unkerned fonts and are used with the GSLIDE procedure to produce Comparison of Kerned and Unkerned Text:
title2 lspace=6 f=font1 h=10 j=l 'DATA';
title3 lspace=4 f=font2 h=10 j=l 'DATA';
Comparison of Kerned and Unkerned Text
![[IMAGE]](./images/01215314.gif)
As the height (point size) of a font increases, less space is required between
letters in relation to their height. If the point size decreases, more space
may be needed. The space data set tells the GFONT procedure how much to increase
or decrease the intercharacter spacing for a given point size. Like kerning,
spacing is added to or subtracted from the intercharacter spacing that is
specified by the CHARSPACETYPE= option. However, kerning applies the adjustment
to specified pairs of characters, while spacing is applied uniformly to all
characters.
Values that are
specified in the space data set are added to the normal intercharacter spacing
and any kerning data. Normal intercharacter spacing is determined by the
CHARSPACETYPE= option.
The space data set must contain these
variables:
-
SIZE
-
specifies the point size of the font. SIZE
is a numeric variable.
-
ADJ
-
specifies the spacing adjustment for the
point size in hundredths (1/100) of a point. (A point is equal to 1/72 of
an inch.) ADJ is a numeric variable. Positive values for the ADJ variable
increase the spacing between characters; negative values reduce the space.
Each observation in a space data set specifies a point size
(SIZE) and the amount of space (ADJ) to be added or subtracted between characters
when a font of that point size is requested. When you specify a point size
that is not in the space data set, the adjustment for the next smaller size
is used. To create a space data set, follow these steps:
-
Determine the amount of adjustment that is required
for typical point sizes; positive numbers increase spacing, and negative numbers
decrease spacing.
-
Create a SAS data set that contains the variables
SIZE and ADJ; produce one observation for each point size and corresponding
space adjustment.
data space1;
input size adj;
datalines;
6 40
12 0
18 -40
24 -90
30 -150
36 -300
42 -620
;
-
Assign the space data
set with the SPACEDATA= option.
proc gfont data=reflib.fontdata
name=font3
charspacetype=data
spacedata=space1
nodisplay;
run;
Comparison of Text with and without Spacing Adjustments
illustrates how to use the SPACEDATA= option to generate a font in which intercharacter
spacing is adjusted according to the height of the characters. The characters
A, D, and T are shown as the word DATA. Each pair of lines displays the word
DATA and at the same size uses first the font with spacing adjustment (FONT3)
and then the original font (FONT1). Note that as the size of the characters
increases, the space between them decreases.
The following title statements are used with the GSLIDE
procedure to produce Comparison of Text with and without Spacing Adjustments:
title2;
title3 f=font3 h=.25in j=l 'DATA'; /* 18 points */
title4 f=font1 h=.25in j=l 'DATA';
title5;
title6 f=font3 h=.50in j=l 'DATA'; /* 36 points */
title7 f=font1 h=.50in j=l 'DATA';
title8;
title9 f=font3 h=1.0in j=l 'DATA'; /* 72 points */
title10 f=font1 h=1.0in j=l 'DATA';
Comparison of Text with and without Spacing Adjustments
![[IMAGE]](./images/01215315.gif)
Copyright © 1999 by SAS Institute Inc., Cary, NC, USA. All rights reserved.
