graphics fonts description of fonts used in graphic figures

## Description

Some Graphic entities such as Text, Axes, Label or Legend entities display one or more character strings in graphic figures. The appearance of the displayed strings can be modified by specifying different fonts and character sizes.

Changing font

  Fonts used in graphic figures are selected from a set of fonts called loaded fonts. In other words, the loaded fonts are the ones currently available in graphic figures. The list of these fonts can be obtained using the `xlfont` function without argument. By default, Scilab contains a set of 11 loaded fonts. This set can be modified and extended using the `xlfont` function with a font name as argument. The added font can either be loaded from a file or be one of the system. To know the list of fonts available on the system use the `xlfont('AVAILABLE_FONTS')` command. For more information on how to manipulate fonts see xlfont.

  Here is the list of the 11 default fonts.

  Font number | Font Family | Bold | Italic
  0 | Monospaced | No | No
  1 | ScilabSymbols | No | No
  2 | Serif | No | No
  3 | Serif | No | Yes
  4 | Serif | Yes | No
  5 | Serif | Yes | Yes
  6 | SansSerif | No | No
  7 | SansSerif | No | Yes
  8 | SansSerif | Yes | No
  9 | SansSerif | Yes | Yes
  10 | SansSerif | Yes | Yes

  The font used by a graphic entities can be modified with its `font_style` property. This is a positive integer referencing one of the loaded fonts. Its value must be between 0, referencing the first font, and the number of loaded fonts minus one, referencing the last font.

  The `fractional_font` controls the font anti-aliasing. Its value can be either `'on'` or `'off'`. If its value is `'on'` the font is smoothed, otherwise it's not.

Changing character size

  The text size of a graphic entity is modified using the `font_size` property. It is a scalar specifying the displayed character size.

  The Scilab character size is different from the point size. Here is the equivalence between the two scales.

  Scilab Size | Point Size
  0 | 8
  1 | 10
  2 | 12
  3 | 14
  4 | 18
  5 | 24
  6 | 30
  7 | 36
  8 | 42
  9 | 48
  10 | 54

  The character size might not be an integer. In this case, the result depends on the entities `fractional_font` property. If `fractional_font` property is `'on'` then the displayed font size is interpolated between the two closest integer. For example, a font size of 2.5 displays characters of 13pt. If `fractional_font` property is `'off'` then the displayed font size is truncated to its integer part. For example, a font size of 2.5 displays characters of 12pt.

## See also

- xlfont
- graphics_entities