Correcting Poor Formatting
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## Correcting Poor Formatting

LaTeX does not invariably produce good looking output. To remedy this it can sometimes be useful to guide LaTeX in the formatting of individual characters, words, sentences, and pages. It is best to adjust with caution, making adjustments only to fix specific problems and limiting adjustments to the affected area.

### Tip

Adjustments to formatting are best done late in the production process so that subsequent changes to content do not produce new problems.

This section provides an overview of common problems and summarizes methods which may be used to resolve issues related to formatting. Much more detail can be found in the Chapter 4, Customization chapter and the Appendix A, Dblatex XSL Parameter Reference and Appendix B, Dblatex Processing Instruction Reference appendixes. Be sure to look through these, especially the appendixes, to see whether there is an adjustment which will solve your particular problem. Of course the DocBook documentation should also be consulted to see if a DocBook attribute can be used to adjust document presentation.

### Floats

Floats are figures, tables, examples, images, and so forth which do not necessarily appear in the output document in the location in which they appear in the DocBook source. The placement of floats can result in visually poor or otherwise undesirable output.

One direct approach is to use the “informal” versions of the affected DocBook elements. E.g. use `informaltable` instead of `table`. The “informal” elements do not float. Bear in mind though that “informal” elements do not appear in the table of contents.

The alternative to eliminating the float entirely is to make an adjustment by parameter, attributes, or processing instruction. For figure, example, and equation, you can play with these methods:

- In a specific element, use the `floatstyle` attribute to specify the latex float placement policy. For example `'[H]'` tries to place the element where it is declared.

- Use the parameter ``element`.defaut.position` to specify globaly the placement policy for this element.

Look at page for more details about the meaning of the placement choice letters.

### Tables

Placement problems with tables relate to their classification as a float. For resolution regarding these issues see the section on floats above.

Tables exceeding the length of a page, or tables that otherwise need to cross page boundaries, have special requirements. They must not be floats and must be rendered using the LaTeX longtable environment. Among the available controls are: use of a `informaltable` element in place of a `table` element, the `table` element's `tabstyle` attribute, the `table.default.tabstyle` parameter, the `table.in.float` parameter.

It is worth mentioning that good typesetting design practice for tables generally calls for eliminating all vertical rules (the lines between columns) and most horizontal rules.

Better vertical placement of table horizontal rules can be obtained by providing values for the `newtbl.format.thead` and `newtbl.format.tbody` parameters. Depending on the font in use, a value like `\rule{0pt}{2.6ex}\rule[-0.9ex]{0pt}{0pt}` can be used for both parameters. This inserts a strut, a 0 width character, in each row of the table which “pushes” the horizontal rules upwards and downwards to provide adequate vertical spacing.

### Examples

Placement of examples has the same issue than tables, that is, it is an element that can contain many materials and need to split over several pages. In this case it cannot be considered as a float.

To avoid an example floating and to allow it cover several pages, set the parameter `example.float.type` to `none`.

### Hyphenation and over-long lines

LaTeX is generally very good at hyphenation, but this applies only to actual words. Technical writing may include long character sequences that are not actual words. Hyphenation failure will typically result in lines of text that flow past the expected right-hand edge of a line. In LaTeX terminology this is known as a “overfull hbox”.

The `hyphenation.format` parameter can be helpful to flag some formats for more agressive hyphenation.

Various adjustments can be made with the `<?latex?>` processing instruction to add raw latex directives and eliminate overfull hboxes but it often makes sense to address hyphenation problems directly. This can be done either on an ad-hoc basis, telling LaTeX how to hyphenate specific occurrences of words where a problem exists, or by telling LaTeX how to hyphenate words it does not know. The first method is accomplished by inserting “soft hyphens” into words in your DocBook source using the latex processing instruction. This is described in the the section called “Safe LaTeX Insertions” section.

To educate LaTeX as to how to hyphenate your special vocabulary a custom LaTeX style is required. Setting this up is described in the the section called “Customized LaTeX style” section. The LaTeX command to use is `\hyphenation`. For example `\hyphenation{PostgreSQL trans-mog-re-fi-ca-tion}` tells LaTeX that PostgreSQL should not be hyphenated and where to hyphenate transmogrification.

Finally, long URLs can cause over-long lines. Especially in footnotes. Using the LaTeX breakurl package is one way to solve this. This can be done with a custom latex stylesheet. See the section called “Customized LaTeX style”.

### Characters and Manual Spacing

The `<?latex?>` processing instruction may be used to limit character kerning, the joining of pairs of characters.

The following DocBook entity declarations can be useful to control spacing. These may be declared in your DocBook `DTD` within the trailing pair of square braces (`[]`) or elsewhere. Once declared the entities may be used in your document text. E.g. `Von&nbsp;Trapp` puts a non-breaking space between `Von` and `Trapp`, ensuring that these two words will not appear on separate lines.

      <!ENTITY nbsp  "&#x000A0;" >
      <!ENTITY ensp  "&#x02002;" >
      <!ENTITY emsp  "&#x02003;" >

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