Nisus Writer Pro - Manual (Page 485)

Appendix III
Displaying Fonts and Text
About Displaying Fonts
To display your text, Unicode or not, Nisus Writer Pro must know how to draw the letters on the
screen. A “font” tells Nisus Writer Pro how to do this. A font contains drawing instructions for
various letters and combinations of letters. These are called “glyphs”. It also contains information
on how to map letters of text to glyphs.
If you have a Unicode font, that means that the fonts “knows” how to convert text stored in the
Unicode format (remember, text in a computer is just a bunch of numbers) to glyphs. That’s it.
Nothing special. Because the font understands Unicode, it generally includes the ability to draw
letters from lots of different alphabets instead of just Roman or Japanese or whatever. But that is
not always the case.
Incidentally, mapping your text to glyphs is not always a simple process. For example, usually
it’s a one to one mapping. The letter ‘A’ maps to glyph 1, etc. Sometimes, however, it can be
quite complex, as in ligatures or the cursive Arabic characters that have initial, medial and final
forms.
To see an example of this, open Nisus Writer Pro and choose the OS X font Zapfino Now, type
the word “Zapfino”. As soon as you type the whole word, you will see the whole thing change to
a specialized cursive form. In the following two occurrences of the word Zapfino, the first has
ligatures turned on, the second turned off
! !
The reason for this is that the Zapfino font contains a special glyph that is displayed whenever it
encounters the text “Zapfino” (with ligatures on), but no other time.
How Nisus Writer Pro Displays Your Text
Whenever you open an existing (or a Nisus Writer Classic) file in Nisus Writer Pro…
• First Nisus Writer Pro converts the text to Unicode (if it was not already such). No matter what
type of file you open, when your file is open and displayed on the screen, we keep a copy of your
file as Unicode stored in memory. When you save the file you can choose the encoding to use.
• Second Nisus Writer Pro determines how to draw each letter of your text. To do this, it uses the
font you have applied from a style, the Character palette, etc. Nisus Writer Pro checks each
letter of your text to make sure the font you have chosen can draw that letter. If not, then a
substitute font is found and used.
• Third Nisus Writer Pro places each letter on lines of text. The application may place this text
going left to right or right to left, depending on the direction of your paragraph and the text
involved.
• Finally, Nisus Writer Pro must place the lines of text on the page. This depends on your
paragraph alignment.
So you can see, that to take your text—even if it is “pure” Unicode—Nisus Writer Pro must pick
a
• font
• alignment
• other paragraph settings
to display it with. Even if you think there are “no” attributes applied, there has to be something.
It’s a bit like asking for a car with only “fuel” and no vehicle.
Typing on a Computer
Here are some rules to remember
• Type only one space between sentences.
The fractional fonts (in which an “m” uses more space than an “l”) that the computer uses make
the extra spacing between sentences superfluous.
Compare a fractional font (11 point Bookman Old Style)