Font object

Font()#

Syntax#

new Font()

Return value#

Font object

Description#

Initialize a Font object.

The following shortcut, $Font(filelines), is equivalent to new Font().load_filelines(filelines), use it for convenience.

$Font() shortcut#

Syntax#

$Font(filelines)

Examples#

const { $Font } = require('bdfparser')
const getline = require('readlineiter') // or require('fetchline') for browsers
;(async () => {
const font = await $Font(getline('test/fonts/unifont-13.0.04.bdf'))
})()

Parameters#

NameR/OTypeDefault ValueDescription
filelinesRequiredAsyncIterableIterator<string>N/AAsynchronous iterable iterator representing each line in string text from the font file. Go to the page of my Fetch Line JavaScript packages, choose readlineiter for node file system or fetchline for browsers. See the above example

Return value#

Font object

Description#

Initialize a Font object and load the BDF font file (file line async iterator).

$Font(filelines) is a shortcut for new Font().load_filelines(filelines), so you don't need to write new and .load_filelines

.headers#

Syntax#

.headers

Examples#

console.log(font.headers)
// { bdfversion: 2.1, fontname: '-gnu-Unifont-Medium-R-Normal-Sans-16-160-75-75-c-80-iso10646-1', pointsize: 16, xres: 75, yres: 75, fbbx: 16, fbby: 16, fbbxoff: 0, fbbyoff: -2, metricsset: 0 }
font.headers.fontname
// -gnu-Unifont-Medium-R-Normal-Sans-16-160-75-75-c-80-iso10646-1

Type#

object (string as keys, number or string as values)

Description#

This attribute of a Font object represents the header information which is typically all the information before the STARTPROPERTIES line in the font file.

Font header's names (keys / property names), value types, and their descriptions in the BDF spec:

note

Headers are to be distinguished from properties (props) which are inside the block between STARTPROPERTIES and ENDPROPERTIES lines in the font file.

Header names are defined in the spec, property names are not.

.props#

Syntax#

.props

Examples#

console.log(font.props)
// {add_style_name: 'Sans Serif', average_width: '80', cap_height: '10', ..., weight_name: 'Medium', x_height: '8'}

Type#

object (string as keys, number or string as values)

Description#

This attribute of a Font object represents the property infomation which is inside the block between STARTPROPERTIES and ENDPROPERTIES lines.

note

Properties (props) are to be distinguished from headers which are typically all the information before the STARTPROPERTIES line in the font file.

.glyphs#

Syntax#

.glyphs

Type#

object (number as keys, array as values)

Description#

This attribute of a Font object represents the raw glyph data in the font.

note

As raw data with values without their keys, you usually should not use it directly. Use other API methods instead, such as .glyph() and .iterglyphs().

.load_filelines()#

Syntax#

.load_filelines(filelines)

Parameters#

NameR/OTypeDefault ValueDescription
filelinesRequiredAsyncIterableIterator<string>N/AAsynchronous iterable iterator representing each line in string text from the font file. Go to the page of my Fetch Line JavaScript packages, choose readlineiter for node file system or fetchline for browsers. See the above example

Return value#

Promise that will be resolved with the Font object itself with font loaded

Description#

Load the BDF font file (file line async iterator).

$Font(filelines) shortcut is equivalent to new Font().load_filelines(filelines).

.length#

Syntax#

.length

Examples#

console.log(font.length)
// 57086

Parameters#

No parameters

Return value#

(number) Actual glyph count in the font

Description#

The getter method always returns how many glyphs actually exist in the font. This could be different with the glyph count number next to the 'CHARS' keyword, if so, there would be a warning when the font is loaded.

.iterglyphs()#

Syntax#

.iterglyphs(order, r)

Examples#

// print all basic latin letters (A-Za-z)'s character and bitmap shape, in reverse order:
for (const glyph of font.iterglyphs(2, [[65, 90], [97, 122],])) {
console.log('Character "' + glyph.chr() + '"\'s shape:')
console.log(glyph.toString())
}
// remove `order=2 ,r=[(65, 90), (97, 122)]` to print all glyphs in the font in normal ascending order

Parameters#

NameR/OTypeDefault ValueDescription
orderOptionalnumber1-1: reverse order in the BDF font file
0: order in the BDF font file
1: ascending codepoint order
2: descending codepoint order
rOptionalSee belowNoneCodepoint range, see below

The codepoint range parameter r accepts:

  • None (default): all the glyphs in the font
  • number. Examples:
    • 128 (Basic Latin / ASCII)
    • 0x100 (Basic Latin and Latin-1 Supplement / cp1250 / cp1251 / cp1252)
  • tuple? of two numbers. Examples:
    • [0, 127] (same as 128)
    • [0, 0xff] (same as 0x100)
    • [48, 57] (all numbers 0-9)
    • [65, 90] (all uppercase basic latin letters A-Z)
    • [97, 122] (all lowercase basic latin letters a-z)
    • [1328, 0x1032F]
  • array of tuples? of two numbers. Example:
    • [[65, 90], [97, 122]] (all basic latin letters A-Za-z)
    • [[0x2E80, 0x9FFF], [0xA960, 0xA97F], [0xAC00, 0xD7FF], [0xF900, 0xFAFF], [0xFE30, 0xFE4F], [0xFF00, 0xFFEF], [0x20000, 0x3134F]] (this is roughly all CJK characters in the Unicode)

See also Wikipedia article "Unicode block"

Return value#

(iterator of Glyph objects/None) An iterator of glyphs as Glyph objects. Missing glyphs are replaced by None

Description#

This method returns an iterator of all the glyphs (as Glyph objects) in the font (default) or in the specified codepoint range in the font, sorted by the specified order (or by the ascending codepoint order by default).

.itercps()#

Syntax#

.itercps(order, r)

Examples#

// print every glyph's codepoint in the font
for (const codepoint of font.itercps()) {
console.log(codepoint)
}

Parameters#

See .iterglyphs()'s "Parameters" section

Return value#

(iterator of numbers) An iterator of the codepoints of glyphs

Description#

This method is almost identical to .iterglyphs(), except it returns an iterator of glyph codepoints instead of an iterator of Glyph objects.

.glyph()#

Syntax#

.glyph(character)

Examples#

// get glyph "a" and print its shape:
const glyph_a = font.glyph('a')
console.log(glyph_a.toString())

Parameters#

NameR/OTypeDefault ValueDescription
characterRequiredstringN/ACharacter (a one-character string) of the glyph you need

Return value#

  • Glyph object
  • None if the glyph does not exist in the font

Description#

Get a glyph (as Glyph object) by its character.

.glyphbycp()#

Syntax#

.glyphbycp(codepoint)

Examples#

// get glyph "a" whose codepoint is 97:
const glyph_a = font.glyphbycp(97)

Parameters#

NameR/OTypeDefault ValueDescription
codepointRequirednumberN/ACodepoint of the glyph you need

Return value#

  • Glyph object
  • None if the glyph does not exist in the font

Description#

Get a glyph (as Glyph object) by its codepoint.

.lacksglyphs()#

Syntax#

.lacksglyphs(str)

Examples#

// This font only has latin and arabic support
const testfont = await $Font(getline('test/fonts/unifont-13.0.04-for-test.bdf'))
console.log(testfont.lacksglyphs('Bé H好Δiب')) // ['好', 'Δ']
console.log(testfont.lacksglyphs('Bé Hiب')) // null

Parameters#

NameR/OTypeDefault ValueDescription
strRequiredstringN/Astring (one or more characters)

Return value#

  • (array of strings) array of missing glyph(s)' characters
  • None if all the glyphs in your string exist in the font

Description#

Check if there is any missing glyph and gets these glyphs' character.

.draw()#

Syntax#

.draw(str, options)
// options = {linelimit, mode, direction, usecurrentglyphspacing, missing}

Examples#

const font = await $Font(getline('test/fonts/unifont-13.0.04.bdf'))
// draw 'Bdf Hi' to a bitmap:
font.draw('Bdf Hi')
// each glyph could be wider when mode: 0:
font.draw('Bdf Hi', { mode: 0 })
// right to left:
font.draw('مرحبا', { direction: 'rl' })
// each line has 30 pixels instead of 512 by default:
font.draw('Bdf Hi', { linelimit: 30 })
// This font only has latin and arabic support
const testfont = await $Font(getline('test/fonts/unifont-13.0.04-for-test.bdf'))
// You can optionally specify the missing glyphs' replacement
// instead of a 0-width-and-height empty glyph by default
testfont.draw('Bé H好Δi的', {
missing: { glyphname: 'missing glyph', codepoint: 0, bbw: 16, bbh: 16, bbxoff: 0, bbyoff: -2, swx0: 1000, swy0: 0, dwx0: 16, dwy0: 0, swx1: null, swy1: null, dwx1: null, dwy1: null, vvectorx: null, vvectory: null, hexdata: [ '0000', '0000', '0000', '3ff8', '3018', '2828', '2448', '2288', '2108', '2288', '2448', '2828', '3018', '3ff8', '0000', '0000' ] },
}) // the missing replacement is "⌧" ("x" in a rectangle box)






Parameters#

NameR/OTypeDefault ValueDescription
strRequiredstringN/AThe words, the setences, the paragraphs you want to draw
optionsOptionalnumber512Maximum pixels per line (row)
(in options) linelimitOptionalnumber512Maximum pixels per line (row)
(in options) modeOptionalnumber10: uses ffb, glyphs will be fixed-width (monospace) and -height
1: uses dwidth horizontally, dwidth1 vertically
(in options) directionOptionalstring'lrtb'Writing direction. See below
(in options) usecurrentglyphspacingOptionalbooleanfalseUseful when direction: 'rl'. For example, font.draw('a的', {direction: 'rl'}) will misplace the wider "的" on the narrower "U" because normally we use the previous glyph's spacing (dwidth). You can use font.draw('a的', {direction: 'rl', usecurrentglyphspacing: true}) to use the current one and solve the problem
(in options) missingOptionalobject or Glyph objectAn empty glyph with glyphname 'empty', codepoint 8203, hexdata [] and metrics all 0The missing glyphs will be replaced by this one. It can be a object of glyph meta information, or a Glyph object

direction:

  • 'lrtb' or 'lr': left to right, lines from top to bottom (most common direction)
  • 'lrbt': left to right, lines from bottom to top
  • 'rltb' or 'rl': right to left, lines from top to bottom (Arabic, Hebrew, Persian, Urdu)
  • 'rlbt': right to left, lines from bottom to top
  • 'tbrl' or 'tb': top to bottom, lines from right to left (Chinese traditionally)
  • 'tblr': top to bottom, lines from left to right
  • 'btrl' or 'bt': bottom to top, lines from right to left
  • 'btlr': bottom to top, lines from left to right

Return value#

Bitmap object

Description#

Draw (render) the glyphs of the specified words / setences / paragraphs (as a string), to a Bitmap object.

note

See the missing parameter if you need to handle potentially missing glyphs.

.drawcps()#

Syntax#

.drawcps(cps, options)
// options = {linelimit, mode, direction, usecurrentglyphspacing, missing}

Examples#

// this is the same as `font.draw('Bdf Hi')`
font.drawcps([66, 100, 102, 32, 72, 105])

Parameters#

NameR/OTypeDefault ValueDescription
cpsRequirediterable of numbersN/Aiterable (array, generator or any other iterable) of codepoints

For the rest of the parameters (linelimit, mode, direction and usecurrentglyphspacing in options), see .draw()'s "Parameters" section

Return value#

Bitmap object

Description#

Draw the glyphs of the specified codepoints, to a Bitmap object.

This method is almost identical to .draw(), except in the first parameter, it uses iterable of codepoints instead of string

.drawall()#

Syntax#

.drawall(options)
// options = {order, r, linelimit, mode, direction, usecurrentglyphspacing}

Examples#

// draw all glyphs in the font, linelimit is 512 pixels by default:
font.drawall()
// change linelimit
font.drawall({linelimit: 700})
note

You can copy and paste <BDF size={1} func={(font) => font.drawall()}/> and <BDF size={1} func={(font) => font.drawall({linelimit: 700})}/> into the Live Demo & Code Editor to see the result for unifont-reduced.bdf.

Parameters#

For parameters order and r in options, see .iterglyphs()'s "Parameters" section

For the rest of the parameters (linelimit, mode, direction and usecurrentglyphspacing in options), see .draw()'s "Parameters" section

Those parameters have the same names, meanings, optional-ness (they are all optional), types and default values as the ones in .iterglyphs() and .draw(), except one thing: mode is 0 by default (mode: 0: the glyphs will have the same width and height)

Return value#

Bitmap object

Description#

Draw all the glyphs in the font (default) or in the specified codepoint range in the font, sorted by the specified order (or by the ascending codepoint order by default), to a Bitmap object.

This method is like a combined version of .iterglyphs()/.itercps() and .draw()/.drawcps().

note

Read the section for Bitmap's .tobytes() to know how to output your bitmap to BMP / PNG / JPEG files.