Change papersize to S4

By default, ConTeXt uses A4 paper size, which does not look good in
presentations. So, we change the paper size to S5: a predefined ConTeXt
papersize that is 500pt x 375pt.

Run:

    context example

and not that the paper size has changed.

See:

- http://wiki.contextgarden.net/PaperSetup
- http://wiki.contextgarden.net/Command/setuppapersize

for details on `\setuppapersize`.
Visualize layout

By default, ConTeXt uses large margins, which make sense for paper documents
but not for presentations. I will change the margin in multiple steps. The
first step is just to visualize the margins.

Run:

    context example

and notice the green rectangles that show the text area and the margins. Read

- http://wiki.contextgarden.net/Layout
- http://context.aanhet.net/svn/contextman/context-reference/en/co-pagedesign.pdf

for more details on the layout, and

- http://wiki.contextgarden.net/Command/showframe

for details on the `\showframe` command.
Set horizontal margins

Set the horizontal margins to be 3mm.

Read:

- http://wiki.contextgarden.net/Layout
- http://context.aanhet.net/svn/contextman/context-reference/en/co-pagedesign.pdf

for more details on the layout.
Set vertical margin

Set the top margin to be 2mm and the bottom margin to be 1mm.

Disable headers, but keep some small space for footers (to show page number
etc. in a smaller font size).
Remove layout visualization

Now that the margins are set, remove layout visualization.
Change fonts

Latin Modern, the default ConTeXt font, does not look good in presentations.
Use the `simplefonts` module to change fonts easily. First we load the module,
and set the font size to 12pt (personal preference).
Use prefered font setup

The `simplefonts` module makes it easy to choose a font setup. I use:

- Fontin as main font
- Delicious as Sans font (for headings etc)
- Dejavu Mono Sans as Monoface font
- Neo Euler as math font
Enable composed characters

Fontin does not have all accented characters (e.g, ü or ç). When `compose=yes`
is added to default font features, ConTeXt uses fallback _composed_ characters
for these missing characters.

A discussion on composed characters is out of the scope of this example. Just
think of this as a workaround for an incomplete font.
Disable font features in monotype fonts

This is also a workaround for a wrong default in ConTeXt. By default, TeX
ligatures are enabled for monotype fonts. I think that this does more harm than
good (e.g., \type{--enable} will typeset as "–enable"). So, I disable **all**
font features for monotype fonts.
Enable hanging punctuation

I think that hanging punctuation is useful for presentation. See

- http://wiki.contextgarden.net/Protrusion

for details.
Increase interparagraph spacing

This is again a personal preference. I think that a large interparagraph
spacing looks good in presentations.

By default, ConTeXt the inter-paragraph space and blanks in ConTeXt are
stretchable. This causes the text to juggle around when stepping through slides.
The `fixed` paramter gets rid of this glue.
Set alignment

I do not like hyphenated text in presentations, so I set alignment to
`nothyphenated`. This is a tricky setting, as TeX has to work harder to justify
paragraphs. So, I also set a low value of tolerance to avoid overfull boxes.
This is not perfect, and in some cases, it is upto the author to insert `\crlf`
to manually break the lines.
Add `slide` structure

The basic structural element of a presentation is a slide. Amongst the various
ways to create a slide environment, I define slides as a _section heading_ and
make it borrow all the default elements from `subject` heading.
Tweak slide style

Set the slide style according to your preference. I use the following setup:

- font: Sans Serif Bold font at 1.72 times the default bodysize (the `c` at the
  end of `\ssbfc`)
- interlinespace: 10pt, useful for multiline titles
- color: darkred
- alignment: middle aligned slide title
- page: yes, force a pagebreak before slides
- before, after: set these to empty.

Read:

- http://wiki.contextgarden.net/Titles
- http://wiki.contextgarden.net/Command/setupheads

for details on how to configure section heads.
Add page numbers to footer

I use a simple pagenumber in footers. See

- http://wiki.contextgarden.net/Headers_and_Footers

for details.
Change background color

I remember reading somewhere that white is not a good color for slides. So, I
change the background color to lightgray. See

- http://wiki.contextgarden.net/Command/setupbackgrounds

for more details.
An example for itemized list

By default, ConTeXt uses $\bullet$ as the marker for top level itemization. The
font that I am using, Neo Euler, does not have a `\bullet` glyph, so the item
marker is not shown.

In the next few steps, I will show how to change them item marker.
Setup itemize head style

The itemize environment in ConTeXt provides two types of items: normal items
that are created using `\item` or `\startitem ... \stopitem` and items with
heads, created using `\head` or `\starthead ... \stophead`.

I like to use the second alternative in presentations. The advantage is that the
item head can be typeset in a different style than the regular items; so it adds
some emphasis to the main points.

See:

- http://wiki.contextgarden.net/Command/head

for more details.
Use metapost to create a item marker

I like to use filled square as the top-level item marker. Rather than using math
symbols for the item marker, I use Metapost to draw the square.

After using this style for a while, I prefered not to use bullets for first
level of itemize, so I set the bullet symbol to empty.

For more details on using MetaPost, read:

- http://wiki.contextgarden.net/MetaPost_in_ConTeXt
- http://www.pragma-ade.com/general/manuals/metafun-s.pdf

For details on symbols, read:

- http://wiki.contextgarden.net/Symbols
Set spacing for itemize

Tweak the spacing around bullet according to your preference.