Draft for “4.2 Justification”
Of the four basic justification methods (flush left, flush right, justified, and centered), justified is the most challenging, as it requires changing the widths of the lines to a pre-defined measure.
In Arabic there are six mechanisms for changing the width of a line of text. Each one has its limitations and considerations on when and how it can be applied. Furthermore, different typographers and calligraphers have divergent preferences for these mechanisms.
This is the same mechanism widely used when justifying Latin scripts, where the width of the spaces between the words can be increased or decreased to change the width of the line.
Figure 1: Aligning lines by increasing and decreasing spaces between the words.
Minimum and maximum widths define boundaries for how much spaces can be shrunk or stretched. When it is not possible to stay within these values, the spaces stretch pass the maximum width.
Depending solely on this mechanism for aligning lines in a justified paragraph can lead to unpleasant results, such as rivers (multiple stretched spaces appearing vertically close to each other and forming a white gap inside the paragraph) and uneven distribution of spaces between different lines. Hence, typographers generally use other mechanisms as well to minimize the effect of adjusting inter-word spaces.
This solution alters the space between letters of each word to change the width of the text. Like adjusting inter-word spaces, this is used for Latin scripts as well, but using it for Arabic script involves considerations specific to Arabic.
The first consideration is to exclude the spaces between joined letters, which, obviously, can ruin the cursive joining of the letters.
Figure 2: Adjusting space between joined letters creates unwanted results.
As a result, inter-word spacing can only happen between groups of letters in a word that are not joined.
Figure 3: Altering intra-word spaces between unjoined letters.
Depending on the writing style and the typeface in use, different amounts of alteration to the intra-word space is acceptable for Arabic. Some writing styles allow more liberal adjustments to the closeness of the letter groups, while others can only accept small adjustments in this regard.
In addition to the four joining forms (isolated, initial, medial, and final), each Arabic letter can come with different shapes while preserving its joining form. For instance, a typeface or writing style can offer two or more shapes for the final form of a single letter.
These variant shapes usually have variant widths and hence can be used to adjust the width of the line.
Figure 4: Three alternative shapes for changing the width of the text.
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- Drop “elongation” from title of this section. It’s one of the mechanisms used for justification.
- Make sure “elongation,” “kashida,” and “tatweel,” have correct definitions in our glossary.
- Discussion at ALReq meeting on 28 June, 2016
- Justify Just or Just Justify
- Arabic text justification
- Thomas Milo’s “Arabic script and typography: A brief historical view”
- Tasmeem Manual
- Justifying Text using Cascading Style Sheets (CSS) in Internet Explorer 5.5
- TODO: Improve the images.