Category : Miscellaneous Language Source Code
Archive   : BGIFONT.ZIP
Filename : FE.DOC

FE

A Stroke Font Editor



Copyright (c) 1988,89 Borland International


Revision 1

09/29/88





1. Introduction
===============

Stroke fonts define characters as a sequence of lines (strokes), as opposed
to bitmap fonts that define characters as a matrix of dots.

The advantage of stroke fonts is that they can be scaled to arbitrary sizes
and still maintain full resolution. Bitmap fonts are made for a specific dot
size and do not scale gracefully. For example, if you had a bitmap font for
a 72 dot-per-inch (DPI) dot matrix printer and quadrupled the dots in height
and width to use on a 300 DPI laser printer, you would simply get an
enlargement of the jagged edges inherently present in the 72 DPI font.

Stroke fonts, on the other hand, are not converted to dots until the
desired size and resolution of the output device is known. So, if you
wanted to put stroke fonts on a 300 DPI laser printer, the dots that make up
the strokes would be printed at 300 DPI.


2. System Requirements
======================

2.1 Required Hardware
=====================

The Font Editor (FE) runs on IBM PCs, PC/XTs, PC/ATs, and most compatibles.

FE requires a mouse that supports the Microsoft External Mouse Driver
Interface. This includes the Microsoft, Mouse Systems, and
Logitec mice. (If you'll be using some other mouse, consult your
owner's manual.) The mouse driver must be installed into memory prior
to starting the FE; typically, this is accomplished by installing the
driver as a DOS device driver from your CONFIG.SYS file. Consult your mouse
documentation for details about installing the mouse driver.

FE also requires an IBM Enhanced Graphics Adapter (EGA), or compatible, and
a color display. The graphics adapter card must have at least 128K of
display RAM installed.


2.2. Optional Hardware
======================

FE supports hardcopy output to one of the following Hewlett-Packard
plotters.

HP 7470
HP 7475 (8 1/2 x 11 paper only)
HP 7440 (Color Pro)

When using a serial port mouse and using a plotter, two serial ports are
required. Be careful to select the correct port for the plotter before
allowing FE to set the parameters on the serial port.

You'll need Hewlett-Packard's standard cable for interfacing a Hewlett-
Packard plotter to an IBM PC; the part number is HP 17255D.


3. General Capabilities
=======================

FE edits Borland stroke fonts (files with the .CHR extension shipped with
Turbo C and Turbo Pascal). You can read in fonts, edit individual
characters, preview characters onscreen (and optionally on a plotter), and
save the resulting font back to disk.


4. FE Display
=============

The FE screen is divided into four major areas, each of which is explained
here. Since these areas react slightly differently with the mouse, we'll
talk about mouse use first.


4.1 Mouse Conventions
=====================

There are two major operations you'll perform with the mouse when using FE.
A "click" is a quick press-and-release of the mouse button when the cursor
is positioned on some object. This "selects" the object.

A "drag" is a press, hold, and move operation used to slide objects or
define areas. When sliding objects, the object sticks to the mouse cursor
after a button is depressed and stays with the cursor until the button is
released.

FE makes no distinction between the left and right mouse buttons; they are
completely equivalent.


4.1.2 Defining Areas
====================

When defining an area, the location where a mouse button is depressed
defines one corner of a rectangle. The diagonally opposite corner is
defined by where the button is released. So when you are defining a
rectangle, one corner is defined (and cannot be changed) when the
mouse button goes down. The other corner can be changed while you
continue to hold the button down and move the mouse.


4.1.3 In the Character Window
=============================

When the mouse pointer is in the character window, you'll find that it
moves jerkily. This is because the pointer is restricted to only those
grid intersection points where strokes can start and stop. These grid
points will be closer together or farther apart, depending on how
"Zoomed In" you are. These points will be visible if you use the Grid
command under Window.


4.1.4 Escape From Plotting
==========================

Pressing the mouse button during a plotting operation terminates the
plotter dump. Therefore, you may have to hold the mouse down for a few
seconds until the status of the button is read. Plotting may continue
for a time (as long as a minute on some plotters) because the plotter
continues to obey drawing commands in its internal buffer.


4.2. The Character Window
=========================

The character window is the large rectangular area on the left half of
the screen where character editing takes place. FE shows you the strokes
that comprise a character, and you may add or delete strokes to a character
by manipulating the mouse in this window.

Strokes are added or deleted by moving the mouse cursor to the desired
starting point, pressing the button, and dragging to the desired endpoint.
If no stroke connected these points previously, then a new stroke is added;
if one did, then it is deleted.

If you wish the stroke to bend (in effect making multiple strokes), you
must release and press the mouse button to end a stroke and start another
stroke.

Again, drawing a line where there was none before will add a stroke to the
character definition. Drawing a line on top of an existing line erases
that line from the character definition.

Combinations of adding and deleting strokes can be performed with a single
line. For example, drawing a line on the middle part of an existing line
causes the middle part to be erased and leave two lines corresponding
to the two end parts that were not drawn upon.

There is a small triangle along the baseline labeled with a 'b' on the left
end. This marker shows where the next character will start and controls
the intercharacter spacing. This width can be changed by dragging the
intercharacter spacing triangle to a new position.


4.3. The Menu
=============

The menu bar is the line of text at the top of the screen. Items in the
menu are selected by a mouse click.

Some items in the menu perform a single function and, when the function is
completed, display the same menu; examples of this are Load and Save. Other
items display a new menu that always contains an item labeled Exit. Clicking
the Exit item returns you to the your last menu location; Edit is an
example.

The Quit item in the main menu returns you to DOS. If you've made changes
to the font, you'll be asked whether you want to save them before quitting.


4.4. The Character Selector
===========================

The character selector is the large rectangular area on the right of
the screen containing a display of all the characters in IBM's extended
ASCII character set. Clicking on a character within this box changes the
current working character.

The characters shown in green have strokes defined for them. The
characters shown in red have no stroke definition yet. The character
currently being edited is shown in either bright red or bright green,
depending upon whether it has strokes defined.

Additions or deletions to the current character are never applied until
you indicate to add the new strokes. If you have made changes to the
current character, you're prompted whether the new strokes are to be added
(or subtracted) from the current character when you click on a character in
the character selector window. If you click on Yes, the character definition
will be updated. If you click on No, the new strokes will be discarded.

Alternatively, you may reclick on the current character simply to force an
update from time to time.


4.5. The Small Character
========================

For at-a-glance information, the area in the lower right-hand corner of
the screen displays a small version of the current character; nothing is
selectable here.


4.6. The Update Selector Box
============================

This box appears on the right-hand side of the screen, above the character
selector window and below the menu area. While editing a character, the
changes made to a character are saved in a edit buffer. To make the edits
permanent, the user must use the mouse to select the Update area. This
writes the edit buffer to the actual character. If you've made changes to
a character without updating the edit buffer, then you'll be prompted
to update the character when you select a new character.

!!!!! NOTE !!!!!

The edit actions on characters only affect the character data, not the
edit buffer; for example, when you add several lines to a character
but don't update the character. If you select edit and move the character,
only the information in the character buffer is affected. The new lines
added to the character will not be moved. This applies to all edit
functions, including move, flip, flop, reverse, shift, cut, and copy.


5. Editing Tools
================

This section briefly describes the editing tools available in FE. The
next section, "Command Reference," provides complete command descriptions.


5.1. Single Strokes
===================

Single strokes can be added or deleted from a character by moving the mouse
cursor into the character window and performing a drag operation between
the grid points where the stroke should be added or deleted.

As you drag the mouse, you'll notice the line being drawn. The start point
begins where you first pressed the mouse button; the endpoint follows the
mouse cursor. This process is known as "rubber banding" a line because the
line appears to be a rubber band that stretches or shrinks to follow the
cursor.

Strokes can be deleted by drawing over existing strokes.

Note that if you move the mouse cursor outside the character while rubber
banding a line, the stroke will be "canceled."


5.2. Groups of Strokes
======================

Groups of strokes can be manipulated as a single object using the Edit,
Clipboard commands. Many characters share the same stroke groups. For
example, the strokes that define the left-hand part of a 'c' will probably
be the same as those in the left-hand part of a 'd.'

The tools available in the Clipboard menu allow you to select a group of
strokes from a character and use them again in that character or another
character. Cut and Copy move a group of characters into a holding buffer
(the Clipboard). Cut removes the strokes from the current character, while
Copy leaves the originals undisturbed.

You can determine the characters to go onto the Clipboard by rubber banding
a rectangle around the strokes. Both endpoints of a given stroke must be
completely inside the rectangle in order to be selected for a Cut or Copy.

You can paste the strokes in the Clipboard into a character by selecting
Paste. The contents of the Clipboard are drawn in the character window.
You may move the strokes with a dragging operation.

Paste doesn't empty the Clipboard; the next paste operation will find the
same strokes. Cut and Copy always change the contents of the Clipboard.
Delete operates like Cut except that the Deleted strokes do not go onto
the Clipboard, they are just discarded. Move is similar to a combined Cut
and Paste operation except that the contents of the Clipboard are not
altered.

You may also Flip the contents of the Clipboard using the commands under
Edit, Flip. These may be used to flip the Clipboard contents upside down
(along a horizontal axis), or right and left (along a vertical axis).


5.3. Whole Characters
=====================

There are some special techniques for manipulating whole characters.

CopyChar, under the Edit menu, allows you to copy from one character within
a single font to another.

Flip, under the Edit menu, allows you to flip a character upside down, or
right and left, or both by using both commands.

Shift, under the Edit menu, allows you to move a whole character right,
left, up, or down.

For example, the characters, b, d, p, and q are usually just flipped
versions of one another. You can draw one and use CopyChar and Flip to
make the other three.


5.4. Whole Fonts
================

The commands under Global allow you to perform operations on the entire
font. These are primarily concerned with intercharacter spacing. Usually,
these commands are used as a part of the final editing process of a font.

LeftSpace moves every character in the font so that its leftmost part
is the specified distance from the dark solid vertical line in the
character window.

RghtSpace sets the character spacing marker of every character in the
font so that it is the specified distance from rightmost part of the
character.

BaseLine shifts every character up or down by the same amount so that
the base line corresponds to zero.

Copy allows you to select another font and copy characters from it into
the font on which you are currently working. Many characters will not
change from one font to another, such as the graphics characters. This
command allows you to copy them.


6. Command Reference
====================

This section describes each command/function in detail.


6.1. Load
=========

The Load command loads an existing font file into FE. A large rectangle
will be drawn on the screen that contains two mouse-sensitive areas: the
the file selector area and the file prompt line.

Clicking on the file prompt line allows you to enter a new file name
for loading. This prompt may include a new path. You will be warned if the
file name entered does not exist. If you confirm that the file does not
exist, the file will be created and will become the default output file
when the font is saved.

The file selector area contains a list of all of the files on the current
drive and in the current directory that have the extension .CHR. As you
move the mouse cursor over these, you'll see them appear on the file prompt
line. Clicking on one of these names will select the name as the current
file to load.


6.2. Show
=========

The tools under Show simply display how your font looks. They do not
change the font.


6.2.1. Font
===========

This tool shows all of the currently defined characters on the
monitor. This is useful to do a quick check of the intercharacter
spacing. Overlapping characters or gaps between characters indicate
improper intercharacter spacing.


6.2.2. String
=============

This tool allows you to type the characters that you want to display;
For instance, this can be useful when you want to display two special
characters together to determine appearance and spacing.

When the current line becomes full, you'll automatically go to the next
line. You can also press the Enter key to force a new line.

The display will not scroll when you reach the bottom; you must press
the Esc key to get out of String mode.


6.2.3. Plotter
==============

This tool draws the current font on an HP plotter. Refer to the
section entitled "Optional Hardware" for a discussion about con-
necting the plotter.

When you select this tool, you're asked if the plotter is COM1 or
COM2. Then the serial port on the PC must be configured to communicate
with the plotter. You can either let FE set the serial port to 9600
baud, even parity, 7 data bits, and 1 stop bit, in which case the DIP
switches on your plotter must be set this way, or you can skip this
step.

If you do not let FE initialize the serial port, then you must have
previously issued the DOS mode command prior to starting FE to match
your plotter's switch settings.

If you're using a serial mouse, be careful not to choose the serial
port to which your mouse is connected.

Finally, you'll be asked whether you want to plot to the plotter. Have
the paper loaded and the plotter ready before selecting yes.

If you start plotting and want to stop before all your plotting is
complete, press and hold down a mouse button until the screen clears.

Your plotter output will be labeled with the name of the file from
which it came, and the page number. In the case of multiple page
plots, FE will stop at the end of each page to allow you to load a new
piece of paper.


6.2.4. Exit
===========

This choice returns you to the main menu.

6.3. Global
===========

The commands under Global operate on an entire font, unlike many of the
other commands that operate on a single character or stroke.


6.3.1. LeftSpace
================

The LeftSpace choice adjusts the space between the leftmost part of a
character and the vertical guide line shown in the character window.
Typically, this should be set to zero for all fonts so that an
application that mixes fonts will maintain character spacing between a
font change.

6.3.2. RghtSpace
================

The RghtSpace choice adjusts the character width mark of all the
characters to the desired value. The character width value set for
each character is the number selected from the menu, plus the rightmost
stroke of the character. Therefore this choice gives uniform
intercharacter spacing to a proportionally spaced font.

Typically, you'll use this to prpoportionally space the entire font.
Some characters are "fixed up" individually, such as the numeric
characters and the graphics character symbols; these may all get the
same total width so that they line up in columns.


6.3.3. BaseLine
===============

The BaseLine choice adjusts each character in the font upward or
downward by the same amount. Use this choice for each font so that
all fonts refer to the same base line value. Thus, an application-
switching font will not have the baseline of the new font shifted up
or down from the previous font.


6.3.4. Copy
===========

Global Copy allows you to copy characters from a different font file.
You will be asked to select a source font file, just like when using
Load.

Once you've selected a source font file, you'll see two character
selector boxes on the screen. The left box corresponds to the source
font file that you just selected. The right box corresponds to the font
on which you are currently working.

You can copy a character by clicking on the character you want from
the source character box and then clicking on the character to which
it should be copied in the destination character box.

When you've finished, you select Done in the menu area.


6.3.5. Exit
===========


This choice returns you to the main menu.


6.4. Edit
=========

The tools under Edit are for editing whole characters or groups of
strokes. The Clipboard function under this heading are of particular
importance.


6.4.1. CopyChar
===============

This tool allows you to do intrafont copying of characters. Selecting
this tool prompts you to select the source character and then the
destination character.

If a character already exists where you selected the destination
character, then you'll be asked if that character should be replaced.


6.4.2. Flip
===========

This tool flips either the current character or the contents of the
Clipboard.

Characters are flipped within the space that they occupy. For
example, if a character only occupied the lower portion of its
character cell, then the result of flipping it vertically will only
occupy the lower portion of the character cell. You can use the Shift
tool to change this if it's not what you want.

Note that you won't see the results of flipping the Clipboard until you
paste from the Clipboard.


6.4.3. Shift
============

This tool shifts a character one dot in any direction. It does not
modify the intercharacter spacing.


6.4.4. ShowAlso
===============

This tool lets you superimpose another character over the one on which
you are currently working. This character stays drawn until you select
Update or change the current character.


6.4.5. Clipboard
================

The Clipboard contains all the tools for working on groups of strokes.
Cut, Copy, and Paste work by reading and writing a temporary storage
area called the Clipboard. Move and Delete do not use the Clipboard.

Strokes are selected from the current character by rubber banding a
rectangle around them. One corner of the rectangle is defined by
where you press a mouse button. The diagonally opposite corner is
defined by where you release the mouse button.

Both endpoints of the stroke must be completely within the rectangle
in order to be selected.

For the Move and Paste options, when a region has been defined, the
strokes contained in the region are copied within the window to the
right of the character width marker. The upper left corner of the
strokes become attached to the mouse cursor when you press a mouse
button. They stay attached until you release the mouse button.


6.4.5.1. Cut
============

Cut removes the selected strokes from the current character and places
them on the Clipboard. The previous contents of the Clipboard are
lost.


6.4.5.2. Copy
=============

Copy copies the selected strokes from the current character to the
Clipboard. The current character is not changed. The previous contents
of the Clipboard are lost.


6.4.5.3. Paste
==============

Paste copies the contents of the Clipboard to the current character.
The contents of the Clipboard are not changed.


6.4.5.4. Move
=============

Move moves the selected strokes to a new location. The contents of the
Clipboard are not changed. This is equivalent to a Cut and Paste
except that the contents of the Clipboard are not changed.


6.4.5.5. Delete
===============

Delete cuts the selected strokes from the current character. This is
equivalent to a Cut except that the contents of the Clipboard are not
changed.


6.4.5.6. Exit
=============

This choice returns you to the Edit menu.


6.4.6. Exit
===========

This choice returns you to the main menu.


6.5. Save
=========

The Save command stores the current font data to an output file. The Save
menu draws a large rectangle on the screen that contains two mouse-
sensitive areas: the file selector area and the file prompt line.

Clicking on the file prompt line allows you to enter a new file name
for saving. This prompt may include a new path. You'll be warned if the
file name entered does not exist. If you confirm that the file does not
exist, the file will be created.

The file selector area contains a list of all of the files on the current
drive and in the current directory that have the extension .CHR. As you
move the mouse cursor over these you see them appear on the file
prompt line. Clicking on one of these names selects the name as the
current destination file.


6.6. Window
===========

All of the tools under Window control how the character editing window is
displayed. These tools don't change the characters, only the way that
they are displayed. All of the values herein are set automatically when
you load a font file.

You'll need to set these values if you start with a new font file, that is,
bypass Load.


6.6.1. Zoom Out
===============

This tool reduces the magnification used to display the character
in the character editing window.

The magnification is automatically set to show all characters in the
character window as large as possible when the font file is loaded.


6.6.2. Zoom In
==============

This tool increases the magnification used to display the character
in the character editing window.

The magnification is automatically set to show all characters in the
character window as large as possible when the font file is loaded.

You can increase the magnification set by Load so that the characters
are larger than the window. Parts of characters that would be outside
the window are clipped to the window limits.

You may want to do this while working on lowercase letters or the
strokes that make up the serif of a serif font.


6.6.3. Origin
=============

This tool allows you to position the origin guide line anywhere within
the character editing window.

For most fonts, this is drawn underneath the baseline guide line and
won't be visible, however, it is still movable.

To work on descending strokes, move toward the top of the window and
zoom in. To work on uppercase letters, move this to the bottom of the
window.


6.6.4. d-ht
===========

This tool positions the descender height guide line in the character
editing window. It has no effect on the character, its edits, or
display of the character in the window; it's simply for your
convenience.


6.6.5. b-ht
===========

This tool positions the baseline height guide line in the character
editing window. It has no effect on the character, its edits, or
display of the character in the window; it's simply for your
convenience.


6.6.6. x-ht
===========

This tool positions the x-height guide line in the character editing
window. It has no effect on the character, its edits, or display of the
character in the window; it's simply for your convenience.


6.6.7. c-ht
===========

This tool positions the character height guide line in the character
editing window. It has no effect on the character, its edits, or
display of the character in the window; it's simply for your
convenience.


6.6.8. ShowMovs
===============

This tool shows each move, draw, draw, ... sequence in a different
color so that you can see how the character stroke is created.

Don't use turning this option on when drawing in the character
editing window; the results are not favorable.

This option defaults to off.


6.6.9. Grid
===========

This tool shows the grid of points in the character being editing on
which strokes begin and end.

This option defaults to on.


6.6.10. Exit
============

This choice returns you to the main menu.


6.7. Quit
=========

This choice returns you to DOS; you will be asked if you want to save any
edits.




7. Beginning a New Font from Scratch
=====================================

There are a few considerations for the user who wishes to start a new font
from scratch. To begin a new font, start FE and select a new font file name.
The screen shows a character window without any characters defined. The
four global parameters for the font are determined automatically by the font
editor when a file is loaded or saved. These parameters are the Base
Height, the Capital Height, the Descender Height, and the Lowercase Height
(or x Height). The values for these are determined by examining the
characters a typographer would use to determine the same information.

Capital Height:
This value is determined by examining the E Ligature character (144
decimal). This is the tallest of the European characters. If this
character is undefined, the capital M is used as the capital height.
If neither of these characters are defined, the value will default to
40 (of a maximum of +/-64).

Base Height:
This value is determined by examining the E Ligature or the Capital
M. This value is used as the origin for the other three dimensions.
If neither of these characters are defined, the value will default to
0 (of a maximum of +/-64).

Descender Height:
This value is determined be examining the lowercase 'q' letter. If
the lowercase 'q' is undefined, the value will default to -7 (of a
maximum of +/-64).

LowerCase Height (or x Height):
This value is determined by examining the lowercase 'x' letter. If
the lowercase 'x' is undefined, the value will default to the Capital
Height divided by two.


To define the size and placement of the characters in the font, it is best
to define the 'M', 'q', 'x', and E Ligature (if desired) as the first
characters. The next time the font is loaded, the character dimensions will
be used to define the size and placement of the character window for the
font.




Appendix 1

BGI Stroke File Format

The structure of Borland .CHR (stroke) files is as follows:

; offset 0h is a Borland header:
;
HeaderSize equ 080h
DataSize equ (size of font file)
descr equ "Triplex font"
fname equ "TRIP"
MajorVersion equ 1
MinorVersion equ 0

db 'PK',8,8
db 'BGI ',descr,' V'
db MajorVersion+'0'
db (MinorVersion / 10)+'0',(MinorVersion mod 10)+'0'
db ' - 19 October 1987',0DH,0AH
db 'Copyright (c) 1987 Borland International', 0dh,0ah
db 0,1ah ; null & ctrl-Z = end

dw HeaderSize ; size of header
db fname ; font name
dw DataSize ; font file size
db MajorVersion,MinorVersion ; version #'s
db 1,0 ; minimal version #'s

db (HeaderSize - $) DUP (0) ; pad out to header size

At offset 80h starts data for the file:

; 80h '+' flags stroke file type
; 81h-82h number chars in font file (n)
; 83h undefined
; 84h ASCII value of first char in file
; 85h-86h offset to stroke definitions (8+3n)
; 87h scan flag (normally 0)
; 88h distance from origin to top of capital
; 89h distance from origin to baseline
; 90h distance from origin to bottom descender
; 91h-95h undefined
; 96h offsets to individual character definitions
; 96h+2n width table (one word per character)
; 96h+3n start of character definitions
;
The individual character definitions consist of a variable number of words
describing the operations required to render a character. Each word
consists of an (x,y) coordinate pair and a two-bit opcode, encoded as shown
here:

Byte 1 7 6 5 4 3 2 1 0 bit #
op1

Byte 2 7 6 5 4 3 2 1 0 bit #
op2


Opcodes

op1=0 op2=0 End of character definition.
op1=1 op2=0 Move the pointer to (x,y)
op1=1 op2=1 Draw from current pointer to (x,y)