@DATABASE 0050
@(C) "Copyright © Cloanto Italia srl"
@REM Part of The Kara Collection CD-ROM, by Cloanto ®
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@WIDTH 74

@NODE Main "Personal Fonts Maker - 11. PDM: The Preferences Menu"
@TOC O0O0/Main

@{B}11.        PDM: The Preferences Menu@{UB}

   The "Preferences" menu of the Printer Driver Modifier, like the menu
having the same name in the Personal Fonts Maker, contains the functions
used to set the program parameters.


@{B}11.1       Code Table@{UB}

   When this function is first selected, a help window with a table of the
first 33 ASCII code abbreviations is displayed. The constant-codes which
are displayed are the same of those which are described in section @{"2.7.1" LINK 0055/Main 1118}
("FFDL Constants") and in appendix @{"B" LINK 0004/Main 1}.

   The window can be dragged with the mouse when the title bar is
selected, just like the main window. The window remains visible until this
function is selected again, the close box of the window is selected, or
the program terminates. The Printer Driver Modifier can be used normally
while the window is displayed.


@{B}11.2       Icons@{UB}

   This option is identical with the "Icons" parameter of the Personal
Fonts Maker, described in section @{"7.8" LINK 0054/Main 634}. When this menu item is
"checkmarked" (section @{"1.9.8" LINK 0056/Main 568}, "Menus"), the program associates a
graphical Workbench icon with the files saved through the "Save
Definitions" option (section @{"10.4" LINK 0014/Main 160}).

   Icons are never associated with printer driver files. Unlike the
Personal Fonts Maker, the Printer Driver Modifier does not have a "current
character image", therefore it is only possible to use the program's
default icon image.


@{B}11.3       Comments@{UB}

   This parameter determines the format used to store the printer control
sequences with the "Save Definitions" function (section @{"10.4" LINK 0014/Main 160}). If the
"Comments" option is set, a comment precedes each line containing a
printer control sequence in the file with the printer definitions. This
may look like the following example:

     @{B}PDM DEFS@{UB}
     @{B}; Reset
         COMM 0 = DLAY ESC \\@ DLAY
     ; Initialize
         COMM 1 = NOAV
     ; Line feed (LF)
         COMM 2 = NOAV
     ; CR+LF
         COMM 3 = CR LF

     ...

     ; ' '
         CHAR 160 = SP
     ; '¡'
         CHAR 161 = (173)
     ; '¢'
         CHAR 162 = (155)@{UB}

   The texts used to comment printer commands are the same as those which
are displayed in the "Function" field (section @{"9.4.6" LINK 0010/Main 473}). These texts may
vary depending on the current user interface language (section @{"11.6" LINK Main 261}).
Comments are particularly useful if the definitions are to be loaded with
a text editor (or word processor), without the aid of the "Function" field
of the Printer Driver Modifier.

   If the "Comments" option is not set, the printer definitions are saved
without comments. Printer definitions saved in this format occupy much
less space, but are less readable once they are loaded with a text
editor.


@{B}11.4       Decoding Mode@{UB}

   As described in section @{"2.7.1" LINK 0055/Main 1118} ("FFDL Constants"), there are several
ways to represent constant codes. Some methods can be preferred to others
for compactness or readability. The user can write an FFDL sequence in the
editing gadget freely mixing all different formats.

   This parameter determines how the Printer Driver Modifier is to
represent the constant codes extracted from the printer drivers' control
sequences. The decimal code 27, for example, may be written as:

     @{B}ESC@{UB}
or
     @{B}(27)@{UB}
or
     @{B}(0x1B)@{UB}

   The parameter can also be modified after a printer driver has already
been loaded. In this case, the program first verifies if the control
sequences associated with the commands and characters are error-free
(section @{"10.6" LINK 0014/Main 220}). If this is the case, all codes are converted to the new
format.

   Different menu subitems can be used to select the different
combinations of this parameter's settings. The following subsections
explain the options in detail.


@{B}11.4.1     Alphanumeric Symbols@{UB}

   If this option is selected, the Printer Driver Modifier uses single
ASCII characters, preceded by a backslash, to represent the codes from 33
to 126 (decimal). The code 65, for example, would be represented as "\\A"
(without quotes) in this mode. Otherwise, if the decimal constants
(section @{"11.4.4" LINK Main 135}) were selected, the same code would be written as
"(65)".


@{B}11.4.2     Codes 0-7@{UB}

   This flag determines whether the codes from 0 (zero) to 7 are to be
represented with the associated ASCII names from NUL to BEL. By default
this mode is not set, as the codes in the range from 0 to 7 are often used
as numerical parameters to printer control sequences. These values are
usually more readable if they are not converted to ASCII symbols.


@{B}11.4.3     Codes 8-32@{UB}

   If this flag is set, all codes from 8 to 32 are converted by the
Printer Driver Modifier into the equivalent ASCII control names from BS to
SP.

   Section @{"2.7.1" LINK 0055/Main 1118} ("FFDL Constants") and appendix @{"B" LINK 0004/Main 1} contain all the
codes. Section @{"11.1" LINK Main 9} ("Code Table") explains how to display a help window
containing these codes.


@{B}11.4.4     Decimal Constants@{UB}

   This option, like the following two, determines the (mathematical) base
to be used to represent numbers between parentheses. Again, it should be
noted that the user can write the constants in any format. This option
only determines the format to be used by the program when codes are
converted automatically into FFDL sequences.

   The decimal format is the default mode of the Printer Driver Modifier.


@{B}11.4.5     Hexadecimal Constants@{UB}

   When this mode is set, constants represented as a number between
parentheses are written in base 16 (sixteen). The number 27 (base 10), for
example, becomes "(0x1B)" in this format. The "0x" prefix is used by the
FFDL to identify hexadecimal numbers.


@{B}11.4.6     Octal Constants@{UB}

   This option causes numbers to be written in base 8 (eight). The number
27 (decimal), for example, becomes "(033)" in this format. The leading '0'
(zero) character is used by the FFDL to identify octal numbers.


@{B}11.5       Encoding Mode@{UB}

   This parameter determines the format in which the tables containing the
control sequences associated with the commands and characters are to be
stored inside the printer driver when the driver is saved.

   The Printer Driver Modifier, as the name implies, can be used to modify
the control sequences of an existing driver. The sequences are stored
inside the driver. Not all drivers reserve the same amount of memory for
the tables of commands and characters. The Printer Driver Modifier cannot
increase the total space dedicated to the control sequences, but different
options allow the user to decide how to make best use of the existing
space.

   The editing gadget (section @{"9.4.2" LINK 0010/Main 313}) allows the user to edit a control
sequence as long as 256 characters. This is more than enough to describe a
printer's control using the FFDL syntax. Section @{"9.4.2" LINK 0010/Main 313} explains how much
memory is occupied by the driver's internal representation of the codes.
The Printer Driver Modifier verifies whether the control sequences fit in
the driver's memory only when the "Check Definitions" function (section
@{"10.6" LINK 0014/Main 220}) is executed, either explicitly (selecting the command manually) or
implicitly (before a "Save Driver" operation or a change to the "Decoding
Mode" parameter"). If the memory of a printer driver is not sufficient to
contain the new control sequences, a driver with more memory should be
used as a point of departure.

   The encoding mode can be changed at any time. The parameter is checked
by the Printer Driver Modifier only when a driver is saved. If the program
detects that the control sequences in the printer driver which was loaded
are not stored contiguously, only the "Fixed Locations" mode (section
@{"11.5.1" LINK Main 197}) can be selected.

   The following subsections explain each of the possible options offered
by the Printer Driver Modifier to use the printer driver's memory.


@{B}11.5.1     Fixed Locations@{UB}

   In this mode, the maximum number of bytes which can be occupied by a
control sequence is determined by the original size of the sequence. This
means that a sequence associated with a command or a character can be
edited with the Printer Driver Modifier as long as the size of that
sequence is not increased. The size is not measured after the length of
the FFDL sequence, but after the driver's format in which the sequence is
converted by the Printer Driver Modifier.

   The name "Fixed Locations" means that even after the control sequences
are modified, made shorter or cleared, the starting position (location) of
each sequence within the driver is the same as it was before the driver
was modified.

   This technique does not modify the driver's internal table of pointers
to the control sequences. In some cases, for example if a control sequence
in the middle of the table is made shorter, a "hole" is created, which may
make it impossible to modify the driver again in the "Floating Locations"
mode (section @{"11.5.2" LINK Main 219}).


@{B}11.5.2     Floating Locations@{UB}

   A driver has one chunk of memory where the control sequences associated
with the commands are stored, and one chunk for the control sequences
associated with the characters. In the floating locations mode it does not
matter how much memory is occupied by the single control sequences, as
long as the sum of all the command sequences fits in the memory reserved
for the command table, and the total memory occupied by all control
sequences associated with the characters does not exceed the available
memory for the character table.

   In this mode, the program always stores the control sequences one after
the other. If one sequence is reduced by the user, more space becomes
available for the other sequences. The "Check Definitions" function
(section @{"10.6" LINK 0014/Main 220}) can be used to control whether the limits of either the
command table or the character table are being exceeded. When the driver
is saved, any free space remaining at the end of the tables is filled with
zero-bytes.


@{B}11.5.3     Strings on Word Boundary@{UB}

   This flag affects the way control sequences are stored in the "Floating
Locations" mode (section @{"11.5.2" LINK Main 219}). Normally, the distance between control
sequences in the same table (commands or characters) is an even number of
bytes. The distance is measured from the beginning (or end) of one
sequence to the beginning (or end) of the following (or preceding) control
sequence. All sequences (starting with the first in each table) are stored
on even byte positions, i.e. they are @{I}word-aligned@{UI}.

   In general, aligning data on word boundaries is a good programming
practice on the Amiga computer. In some cases, this is the only way to
store data, depending on what hardware is to process the data. In
practice, printer drivers seem to work well even if the control sequences
are not word-aligned. This saves the pad bytes which have to be inserted
if a sequence would otherwise not be word-aligned.

   If this option is disabled, the Printer Driver Modifier does not insert
pad bytes to force all control sequences to be word-aligned. This gives
the user some extra memory for control sequences.


@{B}11.6       Language@{UB}

   This is the same as the "Language" parameter of the Personal Fonts
Maker, described in section @{"7.12" LINK 0054/Main 880}.


@{B}11.7       File Requester@{UB}

   The file requester of the Printer Driver Modifier is the same file
requester which is used by the Personal Fonts Maker, which is described in
section @{"3.23" LINK 0008/Main 822}. Three menu items allow the user to control some details of
the file requester.


@{B}11.7.1     Expand Path@{UB}

   This option works like the one in the Personal Fonts Maker, described
in section @{"7.11.1" LINK 0054/Main 801}


@{B}11.7.2     List Icons@{UB}

   This option, identical to the one with the same name in the Personal
Fonts Maker program, is described in section @{"7.11.2" LINK 0054/Main 829}.


@{B}11.7.3     Double-Click@{UB}

   This is the same as the "Double-Click" option of the Personal Fonts
Maker, described in section @{"7.11.3" LINK 0054/Main 854}.

@ENDNODE