2.3.9 font%

► |  | GUI: Racket Graphics Toolkit

1 | Overview
2 | Reference
3 | Configuration
4 | Dynamic Loading
| Bibliography
| Index

► | 2 | Reference

2.1 | Windowing Classes
2.2 | Windowing Functions
2.3 | Drawing Classes
2.4 | Drawing Functions
2.5 | Editor Classes
2.6 | Editor Functions
2.7 | WXME Decoding

▼ | 2.3 | Drawing Classes

2.3.1 | bitmap%
2.3.2 | bitmap-dc%
2.3.3 | brush%
2.3.4 | brush-list%
2.3.5 | color%
2.3.6 | color-database<%>
2.3.7 | dc<%>
2.3.8 | dc-path%
2.3.9 | font%
2.3.10 | font-list%
2.3.11 | font-name-directory<%>
2.3.12 | gl-config%
2.3.13 | gl-context<%>
2.3.14 | pen%
2.3.15 | pen-list%
2.3.16 | point%
2.3.17 | post-script-dc%
2.3.18 | printer-dc%
2.3.19 | ps-setup%
2.3.20 | region%

On this page:

get-face
get-family
get-font-id
get-point-size
get-size-in-pixels
get-smoothing
get-style
get-underlined
get-weight
screen-glyph-exists?

top← prev up next →

font% : class?
superclass: object%

A font is an object which determines the appearance of text, primarily when drawing text to a device context. A font is determined by seven properties:

- size – The size of the text, either in points (the default) or logical drawing units, depending on the “size-in-pixels?” property (see below).

- family – A platform- and device-independent font designation. The families are:

  - 'default

  - 'decorative

  - 'roman

  - 'script

  - 'swiss

  - 'modern (fixed width)

  - 'symbol (Greek letters and more)

  - 'system (used to draw control labels)

  The 'symbol designation is special under Mac OS X and X with fontconfig/Xft; characters in the ASCII range 0-255 are converted to Unicode characters that match Adobe symbols. For example, a is converted to α.

- face – A string face name, such as "Courier" (under Windows and Mac OS X), "-*-courier" (under X), or " Luxi Sans" (under X with fontconfig/Xft; note the leading space). The format and meaning of a face name is platform- and device-specific. If a font’s face name is #f, then the font’s appearance depends only on the family. If a face is provided but no mapping is available for the face name (for a specific platform or device), then the face name is ignored and the family is used. See font-name-directory<%> for information about how face names are mapped for drawing text.

- style – The slant style of the font, one of:

  - 'normal

  - 'slant (Windows, Mac OS X: same as 'italic; X: tries 'italic if 'slant font does not exist)

  - 'italic (X: tries 'slant if 'italic font does not exist)

- weight – The weight of the font, one of:

  - 'normal

  - 'light

  - 'bold

- underline? – #t for underlined, #f for plain.

- smoothing – Amount of anti-alias smoothing, one of:

  - 'default (platform-specific, sometimes user-configurable)

  - 'partly-smoothed (Windows: TrueType when available; Mac OS X: 4-bit, pixel-aligned smoothing; X: fontconfig/Xft when available)

  - 'smoothed (Windows: ClearType when available, XP and up; Mac OS X: Quartz smoothing; X: fontconfig/Xft when available)

  - 'unsmoothed

  Special case: 'default corresponds to 'partly-smoothed when used with the 'modern family and a font size between 9 and 13 (inclusive).

- size-in-pixels? – #t if the size of the font is in logical drawing units (i.e., pixels for an unscaled screen or bitmap drawing context), #f if the size of the font is in points (which can depend on screen resolution).

To avoid creating multiple fonts with the same characteristics, use the global font-list% object the-font-list.

See also font-name-directory<%>.

( make-object font%) → ( is-a?/c font%)

( make-object font% |  | size |  |  |  |
|  | family |  |  |  |
| [ | style |  |  |  |
|  | weight |  |  |  |
|  | underline? |  |  |  |
|  | smoothing |  |  |  |
|  | size-in-pixels?]) |  | → |  | ( is-a?/c font%)

size : ( integer-in 1 255)

family

:

( one-of/c 'default 'decorative 'roman 'script
'swiss 'modern 'symbol 'system)

style : ( one-of/c 'normal 'italic 'slant) = 'normal
weight : ( one-of/c 'normal 'bold 'light) = 'normal
underline? : any/c = #f

| smoothing |  | : |  | ( one-of/c 'default 'partly-smoothed 'smoothed 'unsmoothed)
|  |  | = |  | 'default

size-in-pixels? : any/c = #f

( make-object font% |  | size |  |  |  |
|  | face |  |  |  |
|  | family |  |  |  |
| [ | style |  |  |  |
|  | weight |  |  |  |
|  | underline? |  |  |  |
|  | smoothing |  |  |  |
|  | size-in-pixels?]) |  | → |  | ( is-a?/c font%)

size : ( integer-in 1 255)
face : string?

family

:

( one-of/c 'default 'decorative 'roman 'script
'swiss 'modern 'symbol 'system)

style : ( one-of/c 'normal 'italic 'slant) = 'normal
weight : ( one-of/c 'normal 'bold 'light) = 'normal
underline? : any/c = #f

| smoothing |  | : |  | ( one-of/c 'default 'partly-smoothed 'smoothed 'unsmoothed)
|  |  | = |  | 'default

size-in-pixels? : any/c = #f

When no arguments are provided, creates an instance of the default font. If no face name is provided, the font is created without a face name. Otherwise, see font-name-directory<%> for information about the way face is interpreted for drawing text on various platforms and devices; when a platform- or device-specific interpretation of face is not available, the family is used to draw text.

See font% for information about family, style, and weight. font-name-directory<%>.

( send a-font get-face) → ( or/c string? false/c)

Gets the font’s face name, or #f if none is specified.

( send a-font get-family)

→

( one-of/c 'default 'decorative 'roman 'script
'swiss 'modern 'symbol 'system)

Gets the font’s family. See font% for information about families.

( send a-font get-font-id) → exact-integer?

Gets the font’s ID, for use with a font-name-directory<%>. The ID is determined by the font’s face and family specifications, only.

( send a-font get-point-size) → ( integer-in 1 255)

Gets the font’s size (roughly the height). Despite the method name, the size may be in logical units instead of points, depending on the result of get-size-in-pixels.

Due to space included in a font by a font designer, a font tends to generate text that is slightly taller than the nominal size.

( send a-font get-size-in-pixels) → boolean?

Returns #t if the size reported by get-point-size is in logical drawing units, #f if it is in points.

For a size in points and a screen or bitmap drawing context, the logical height depends on the resolution of the screen.

( send a-font get-smoothing)
→ ( one-of/c 'default 'partly-smoothed 'smoothed 'unsmoothed)

Gets the font’s anti-alias smoothing mode. See font% for information about smoothing.

( send a-font get-style) → ( one-of/c 'normal 'italic 'slant)

Gets the font’s slant style. See font% for information about styles.

( send a-font get-underlined) → boolean?

Returns #t if the font is underlined or #f otherwise.

( send a-font get-weight) → ( one-of/c 'normal 'bold 'light)

Gets the font’s weight. See font% for information about weights.

( send a-font screen-glyph-exists? |  | c |  |  |  |
| [ | for-label?]) |  | → |  | boolean?

c : char
for-label? : any/c = #f

Returns #t if the given character has a corresponding glyph when drawing to the screen or a bitmap, #f otherwise.

If the second argument is true, the result indicates whether the glyph is available for control labels. Otherwise, it indicates whether the glyph is available for dc<%> drawing.

For dc<%> drawing, due to automatic font substitution when drawing or measuring text, the result of this method does not depend on this font’s attributes (size, face, etc.). The font’s attributes merely provide a hint for the glyph search.

See also glyph-exists? .
top← prev up next →