Alpha Fonts

Alpha
Version:	9.2.3 - "Suhail"
Last update:	2021-05-21 14:43:30

Font specification
- Syntax of -font option
- Examples
Font preferences
The [getFontList] command
The [getFontInfo] command
The [showFontPanel] command
The [getFont] command

This help file explains how fonts are specified in AlphaTcl and describes some core commands which provide information about fonts or let you define a font specification.

Font specification

Syntax of -font option

Many Alpha commands accept a -font option. The value of this option is a Tcl dictionary containing some of the following keys:

name: the value is the name of a font. Use the [getFontList] command to get a list of the available fonts.
size: the value is a floating number or an integer specifying the size of the font.
meta: the value is a metafont name. This designates a font which is system dependent.

The name and meta keys in the font dictionary are mutually exclusive.
If the size key is not specified, the default value is 10 points for named fonts or a default size provided by the system for metafonts.
The possible metafont names used for the meta entry in the dictionary are:

control: the font used for the content of controls.
label: the Aqua font used for standard interface labels.
menuBar: the font used for menu bar items.
menu: the font used for menu items.
message: the font used for standard interface items, such as button labels, menu items, and so on.
palette: the font used for palette window title bars.
system: the Aqua system font used for standard interface items, such as button labels, menu items, and so on.
systemBold: the Aqua system font used for standard interface items that are rendered in boldface type.
titleBar: the font used for window title bars.
toolTips: the font used for tool tips labels.
userFixed: the font used by default for documents and other text under the user's control (that is, text whose font the user can normally change), when that font should be fixed-pitch.
user: the font used by default for documents and other text under the user's control (that is, text whose font the user can normally change).

These metafont names are case insensitive.

Examples

Here are some examples of specification of a -font option which could be used in commands such as [getTextDimensions], [abbreviateText] or [view configure]:

    -font [list name "Monaco" size 10]
    -font [list name "Menlo-Italic" size 11.0]
    -font [list name "Arial-BoldItalicMT" size 11.0]
    -font [list meta system size 14]
    -font [list meta label]

In the last example, the size of the metafont is not specified: in that case, the system decides on a default value which may vary depending on the version of the system and the machine.

Font preferences

Older versions of AlphaTcl had separate preferences for font names and for font sizes. This is no longer the case. There is a new preference type called font whose value is specified by a font dictionary.
In particular, the Default Font preference (in the Appearance Preferences panel), used when a new document window is opened, adopts the new syntax. Its value is currently defined as:

    name Menlo-Regular size 11

From the user's point of view, the selection of a font is completely transparent: a dialog window asks to select a font (and possibly a size and a style) from the Fonts Panel and, once the user presses OK, takes care of retrieving the selected value in the expected format.

The [getFontList] command

• getFontList ?-mask num?
If no argument is specified, return the list of available fixed-size fonts. If the -mask option is specified, the command returns all the fonts corresponding to the specified value (not only fixed-size fonts). The value of this option is an additive value containing some of the following flags:

Italic	1
Bold	2
Unbold	4
Narrow	16
Expanded	32
Condensed	64
Small Caps	128
Poster	256
Compressed	512
Fixed Size	1024

If the -mask option is explicitely set to 0 (rather than being unspecified), the command returns the list of all available font families. The following pairs of flags are mutually exclusive: Condensed and Expanded, Bold and Unbold.

The [getFontInfo] command

• getFontInfo font ?option?
If an option is specified, return the value for this option. Otherwise return a dictionary of key/value pairs for all possible options. The currently available options are:

angle	amount that the font is slanted in degrees counterclockwise from the vertical
ascender	top y-coordinate, offset from the baseline, of the longest ascender
boundRect	union of the bounding rectangles of every glyph in the font
capHeight	height of a capital letter above the baseline
count	number of glyphs in the font
descender	bottom y-coordinate, offset from the baseline, of the longest descender
displayName	name, including family and face, localized for the user's language
family	family name
fixed	indicates if the font has fixed size
leading	leading of the font
maxAdvance	maximum advancement
name	name of the font
rendering	rendering mode
size	point size of the font
xHeight	distance between the baseline and the mean line of lower-case letters

The rendering mode returned by the rendering option can have one of the following values:

0	Default
1	Antialiased
2	Integer Advancements
3	Antialiased Integer Advancements

The [showFontPanel] command

• showFontPanel
Display the font selection panel. Selecting a font or size from this panel automatically effects the current document window.

The [getFont] command

• getFont ?-prompt str? ?-sample str? ?-title str? ?-defaut font?
Prompt the user to select a font and a size. The command also displays the system font panel: fonts are selected in the font panel and echoed in the dialog. Press the OK button to end up the selection and validate the choice. The returned value is a font specification (i-e a Tcl dictionary with name and size keys), or an error if the Cancel button was pressed.
The -prompt option specifies a text to display at the top of the dialog. If it is not specified, a default string is used.
The -title option specifies a title for the dialog. By default, there is no title.
The -sample option specifies a string to use as sample text. This sample text is displayed using the currently selected font: each time the user changes the font in the font panel, the sample field is updated.
The -default option specifies a default font to display as a suggestion in the dialog. If it is not specified, the default font preference is used.