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LASI35B2.ARJ
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MAKETXT.HLP
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Text File
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1991-08-01
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Text Generation Method
Text Generation with LASI
There is no "text" component (or object) in a LASI drawing system.
Instead, recognizing that a limited amount of text often needs to be
added to a drawing or layout, a method of text generation has been
provided. The method makes text characters from path objects. The
characters are the same as any other path object, an may be changed with
normal path editing commands.
Each character is read from the pattern file TXT.DBD. This file is a
random access file which contains an single record of 128 bytes for each
of 96 characters. At entry time, the position, size of the text and the
character spacing is requested. The text string is then simply typed in
and terminated by <enter>. The layer and width of the text are taken from
the default path parameters.
Using paths for text has advantages and disadvantages. Path and vertex
space is used up. However, text may be manipulated the same as a path,
and the conversion to other drawing systems is much easier.
The Character Field
Characters start as little cells containing a drawing of a character. The
data format of the character drawing is quite different from a cell and
will be describe later. A character is drawn as a rank 1 cell using paths
(of 0 width) on a 16x16 field of basic drawing units. The lower left
corner of the field is position 0,0. The vertices of the paths fall on
the basic unit grid points. The vertices may be on any grid point except
15,15.
15
. . . . . . . . . . . . . . . x 15 (15,15 not used)
. . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . ^
. . . . . . . . . . . . . . . . |
. . . . . . . . . . . . . . . . Y
. . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . .
(origin)0 . . . . . . . . . . . . . . . .
0
X -->
Character Drawing Field in basic units
Once a character cell is drawn, the program MAKETXT.EXE is used to
install the character in the TXT.DBD file.
There can be any character drawing in the pattern file corresponding to a
given typed character. In fact, different TXT.DBD files (with different
names) with different drawings or fonts can be kept for different uses.
The TXT.DBD File
The pattern file TXT.DBD is ninety-six 128 byte records long. Each record
corresponds to an ASCII character starting at decimal 32 (space) and
ending at decimal 127 (delete, non-printing). When a character is typed
under LASI, the correct record is found and the information is used to
make path objects in the drawing. The records are randomly written by the
MAKETXT.EXE program by typing the desired character and then giving the
name of the cell which contains the character drawing.
The vertices of the path pattern are written in a single byte of a record
in the form of the X-coordinate as the upper 4 bits and the Y-coordinate
as the lower 4 bits (nibbles). The coordinates may then be only the
numbers 0-15. The coordinate combination (15,15) is however prohibited
because it is used to indicate the end of a path.
A record therefore contains vertex coordinate bytes from 0-254, with 255
decimal (or FF in Hex) bytes marking the end of a path. The remaining
bytes in a record are always filled with FF bytes to prevent further
paths being made as the record is read.
The maximum number of vertices that a record can hold is dependent on the
number of independent paths, but can be determined from:
total no. vertices = 128 - total no. paths
Text and the CALMA
The text made by LASI is treated like any path or poly object by the
CALMA when converted using LASI2CSF.EXE. Paths of 0 width or poly are
converted to boundaries. Boundaries however are automatically closed by
the CALMA itself, which will cause characters made from poly to be
distorted by the CALMA. The solution is of course to give a character
some width. This then will make the CALMA think that the character is a
path and it will not be closed. If characters are to be converted to
CALMA, then one should create a TXT.DBD file that contains characters
that look good with the desired width.
Character Cell Collection
The cell collection that contains all the cells that are used to make the
text characters is not usually included with the LASI System
distribution. If you don't have a copy of this collection, and it is not
available from your distribution source, it will be sent on request.