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These buttons modify the internal state of the program by setting some global
variables. These variables affect the execution of all rastering functions in
contrast to the buttons described in the next subsection which only take
influence on the X11 rastering functions. When changing
one of the following parameters nothing seems to happen at first. All
actions are deferred to the time when an action button is
clicked. Here is a list of the dialogs and toggles:
-
This dialog allows to specify the font ID that will be used when
the next action takes place. The allowed IDs range from 0 to
,
where
is the number of fonts declared in the font database
file. If using the default configuration file together with the
default font database file, 8 fonts are declared. If an invalid ID
is specified, the next action generates an error message.
-
Here, the size of the font is specified. The value is interpreted in
bigpoints, the default PostScript unit. If the size specified is
invalid, an appropriate error message is generated at the time of
the next action.
-
A slant factor
may be specified. It is interpreted the following
way. A point described by the coordinate-pair
is transformed
to the point with the coordinates
. For instance,
specifying a slant factor
will generate a font slanted by
. Since version 0.3-beta slanted are nearly fully supported.
For a discussion of the remaining problems see
on page
.
-
Horizontal extension of a font may be realized using this
dialog. The default value is 1 which means the characters are
presented at their natural width. Specification of an invalid value
will generate an error message at the time of the next action.
-
This dialog gives complete Control over the transformation matrix that will
be used in consequent rasterizations. The values have to be specified
separated by commas. A specified rotation is still applied after this
matrix.
-
The resolution of the output device (screen) may be specified in
this dialog. Using the default value of 72 dpi means one bp in size
corresponds to exactly one device pixel.
-
This dialog field allows to setup the penwidth used for stroking
characters. If this field is zero, which is the default, the characters are
filled, unless, the font under consideration is a stroked font, that is, it
has PaintType = 1
.
-
The name of an encoding file may be specified. Included in the
distribution is only one file, IsoLatin1.enc
. It contains the
standard X11 encoding in a format acceptable by t1lib. If no name
is given here, or the file with the name given here cannot not be
parsed as an encoding file, the encoding is switched back to the fonts
internal encoding. Again, this is done at the time of the next
action.
-
The angle at which the next character or string is rastered is
specified here. There are no restrictions concerning the angle. Rotation is
applied after setting the transformation matrix (see above).
-
The value specified here represents an offset added to the
spacewidth when rastering the next string. For this, it is
interpreted in PostScript charspace units and thus subject to
scaling.
-
A number between 0 and 255 inclusive should be specified here. It is
used as the index into the current encoding vector when rasterizing
a character. This gives the user access to all currently encoded
characters, regardless of the current X11 keyboard mapping. If an
index is given whose encoding entry would produce no black pixels,
an error message is generated at the next character-rastering
time. The default value is 65, which corresponds
to the character ``A'' in most encoding vectors.
-
In this dialog, a complete string may be specified. It will be
rastered when the next string-rastering button is pressed. It can be
of arbitrary length (well, almost). If this field is left empty, the
standard string ``Test'' will be used for rastering.
-
This is a toggle button. Its state determines whether pairwise
kerning information from the AFM file will be used to correct the
horizontal spacing during string rastering or not. A typical example
is the word ``Test''; enabling kerning should--at least in
fonts of good quality--move the ``T'' and the ``e'' significantly
closer together.
-
This is a toggle button. Its state specifies whether the
string is checked for ligatures prior to rastering it.
Suitable character sequences are replaced with the corresponding
ligature. For a good example, you should switch to
font ID 4 and type in the string --difficult---
. If ligature
detection is switched on, the two hyphens should be converted to an
en-dash ``-'', the three hyphens should be converted to an em-dash
``--'' and the character series ``ffi
'' should be replaced
with the ligature ``ffi'', rather than to be displayed as ``ffi''.
-
/
This button allows
to change the writing direction that t1lib will use in subsequent calls
to the string rastering functions, the default being Left To Right as
used in most European languages. This item is simply meant to demonstrate the
capabilities of t1lib. The package does not come with fonts that are
intended to be used for Right To Left typesetting.
-
This toggle button determines whether strings are underlined or not.
-
Same as above for overlining.
-
Same as above for overstriking.
-
/
This button allows to select the subsampling factor for antialiasing in
subsequent rastering operations. AA-Low means subsampling by factor 2
which gives 5 gray values including black and white, whereas AA-High
means subsampling by 4 which yields 17 gray values including black and
white.
Notice that, aside from the latter, the toggle buttons only affect the string
rastering functions.
Next: Buttons that Influence the
Up: The Program xglyph
Previous: The Program xglyph
Contents
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2004-10-04