Bitmap font format for the GRUB 2 bootloader.
This page hosts a formal specification of GRUB 2 font using Kaitai Struct. This specification can be automatically translated into a variety of programming languages to get a parsing library.
All parsing code for JavaScript generated by Kaitai Struct depends on the JavaScript runtime library. You have to install it before you can parse data.
The JavaScript runtime library is available at npm:
npm install kaitai-structSee the usage examples in the JavaScript notes.
Parse structure from an ArrayBuffer:
var arrayBuffer = ...;
var data = new Grub2Font(new KaitaiStream(arrayBuffer));
After that, one can get various attributes from the structure by accessing fields or properties like:
data.sections // => The "DATA" section acts as a terminator. The documentation says:
"A marker that indicates the remainder of the file is data accessed
via the character index (CHIX) section. When reading this font file,
the rest of the file can be ignored when scanning the sections."
// This is a generated file! Please edit source .ksy file and use kaitai-struct-compiler to rebuild
(function (root, factory) {
if (typeof define === 'function' && define.amd) {
define(['kaitai-struct/KaitaiStream'], factory);
} else if (typeof module === 'object' && module.exports) {
module.exports = factory(require('kaitai-struct/KaitaiStream'));
} else {
root.Grub2Font = factory(root.KaitaiStream);
}
}(typeof self !== 'undefined' ? self : this, function (KaitaiStream) {
/**
* Bitmap font format for the GRUB 2 bootloader.
* @see {@link https://grub.gibibit.com/New_font_format|Source}
*/
var Grub2Font = (function() {
function Grub2Font(_io, _parent, _root) {
this._io = _io;
this._parent = _parent;
this._root = _root || this;
this._read();
}
Grub2Font.prototype._read = function() {
this.magic = this._io.readBytes(12);
if (!((KaitaiStream.byteArrayCompare(this.magic, [70, 73, 76, 69, 0, 0, 0, 4, 80, 70, 70, 50]) == 0))) {
throw new KaitaiStream.ValidationNotEqualError([70, 73, 76, 69, 0, 0, 0, 4, 80, 70, 70, 50], this.magic, this._io, "/seq/0");
}
this.sections = [];
var i = 0;
do {
var _ = new Section(this._io, this, this._root);
this.sections.push(_);
i++;
} while (!(_.sectionType == "DATA"));
}
var PtszSection = Grub2Font.PtszSection = (function() {
function PtszSection(_io, _parent, _root) {
this._io = _io;
this._parent = _parent;
this._root = _root || this;
this._read();
}
PtszSection.prototype._read = function() {
this.fontPointSize = this._io.readU2be();
}
return PtszSection;
})();
var FamiSection = Grub2Font.FamiSection = (function() {
function FamiSection(_io, _parent, _root) {
this._io = _io;
this._parent = _parent;
this._root = _root || this;
this._read();
}
FamiSection.prototype._read = function() {
this.fontFamilyName = KaitaiStream.bytesToStr(this._io.readBytesTerm(0, false, true, true), "ASCII");
}
return FamiSection;
})();
var WeigSection = Grub2Font.WeigSection = (function() {
function WeigSection(_io, _parent, _root) {
this._io = _io;
this._parent = _parent;
this._root = _root || this;
this._read();
}
WeigSection.prototype._read = function() {
this.fontWeight = KaitaiStream.bytesToStr(this._io.readBytesTerm(0, false, true, true), "ASCII");
}
return WeigSection;
})();
var MaxwSection = Grub2Font.MaxwSection = (function() {
function MaxwSection(_io, _parent, _root) {
this._io = _io;
this._parent = _parent;
this._root = _root || this;
this._read();
}
MaxwSection.prototype._read = function() {
this.maximumCharacterWidth = this._io.readU2be();
}
return MaxwSection;
})();
var DescSection = Grub2Font.DescSection = (function() {
function DescSection(_io, _parent, _root) {
this._io = _io;
this._parent = _parent;
this._root = _root || this;
this._read();
}
DescSection.prototype._read = function() {
this.descentInPixels = this._io.readU2be();
}
return DescSection;
})();
var Section = Grub2Font.Section = (function() {
function Section(_io, _parent, _root) {
this._io = _io;
this._parent = _parent;
this._root = _root || this;
this._read();
}
Section.prototype._read = function() {
this.sectionType = KaitaiStream.bytesToStr(this._io.readBytes(4), "ASCII");
this.lenBody = this._io.readU4be();
if (this.sectionType != "DATA") {
switch (this.sectionType) {
case "MAXH":
this._raw_body = this._io.readBytes(this.lenBody);
var _io__raw_body = new KaitaiStream(this._raw_body);
this.body = new MaxhSection(_io__raw_body, this, this._root);
break;
case "FAMI":
this._raw_body = this._io.readBytes(this.lenBody);
var _io__raw_body = new KaitaiStream(this._raw_body);
this.body = new FamiSection(_io__raw_body, this, this._root);
break;
case "PTSZ":
this._raw_body = this._io.readBytes(this.lenBody);
var _io__raw_body = new KaitaiStream(this._raw_body);
this.body = new PtszSection(_io__raw_body, this, this._root);
break;
case "MAXW":
this._raw_body = this._io.readBytes(this.lenBody);
var _io__raw_body = new KaitaiStream(this._raw_body);
this.body = new MaxwSection(_io__raw_body, this, this._root);
break;
case "SLAN":
this._raw_body = this._io.readBytes(this.lenBody);
var _io__raw_body = new KaitaiStream(this._raw_body);
this.body = new SlanSection(_io__raw_body, this, this._root);
break;
case "WEIG":
this._raw_body = this._io.readBytes(this.lenBody);
var _io__raw_body = new KaitaiStream(this._raw_body);
this.body = new WeigSection(_io__raw_body, this, this._root);
break;
case "CHIX":
this._raw_body = this._io.readBytes(this.lenBody);
var _io__raw_body = new KaitaiStream(this._raw_body);
this.body = new ChixSection(_io__raw_body, this, this._root);
break;
case "DESC":
this._raw_body = this._io.readBytes(this.lenBody);
var _io__raw_body = new KaitaiStream(this._raw_body);
this.body = new DescSection(_io__raw_body, this, this._root);
break;
case "NAME":
this._raw_body = this._io.readBytes(this.lenBody);
var _io__raw_body = new KaitaiStream(this._raw_body);
this.body = new NameSection(_io__raw_body, this, this._root);
break;
case "ASCE":
this._raw_body = this._io.readBytes(this.lenBody);
var _io__raw_body = new KaitaiStream(this._raw_body);
this.body = new AsceSection(_io__raw_body, this, this._root);
break;
default:
this.body = this._io.readBytes(this.lenBody);
break;
}
}
}
/**
* Should be set to `0xFFFF_FFFF` for `section_type != "DATA"`
*/
return Section;
})();
var AsceSection = Grub2Font.AsceSection = (function() {
function AsceSection(_io, _parent, _root) {
this._io = _io;
this._parent = _parent;
this._root = _root || this;
this._read();
}
AsceSection.prototype._read = function() {
this.ascentInPixels = this._io.readU2be();
}
return AsceSection;
})();
var ChixSection = Grub2Font.ChixSection = (function() {
function ChixSection(_io, _parent, _root) {
this._io = _io;
this._parent = _parent;
this._root = _root || this;
this._read();
}
ChixSection.prototype._read = function() {
this.characters = [];
var i = 0;
while (!this._io.isEof()) {
this.characters.push(new Character(this._io, this, this._root));
i++;
}
}
var Character = ChixSection.Character = (function() {
function Character(_io, _parent, _root) {
this._io = _io;
this._parent = _parent;
this._root = _root || this;
this._read();
}
Character.prototype._read = function() {
this.codePoint = this._io.readU4be();
this.flags = this._io.readU1();
this.ofsDefinition = this._io.readU4be();
}
Object.defineProperty(Character.prototype, 'definition', {
get: function() {
if (this._m_definition !== undefined)
return this._m_definition;
var io = this._root._io;
var _pos = io.pos;
io.seek(this.ofsDefinition);
this._m_definition = new CharacterDefinition(io, this, this._root);
io.seek(_pos);
return this._m_definition;
}
});
/**
* Unicode code point
*/
return Character;
})();
var CharacterDefinition = ChixSection.CharacterDefinition = (function() {
function CharacterDefinition(_io, _parent, _root) {
this._io = _io;
this._parent = _parent;
this._root = _root || this;
this._read();
}
CharacterDefinition.prototype._read = function() {
this.width = this._io.readU2be();
this.height = this._io.readU2be();
this.xOffset = this._io.readS2be();
this.yOffset = this._io.readS2be();
this.deviceWidth = this._io.readS2be();
this.bitmapData = this._io.readBytes(Math.floor(((this.width * this.height) + 7) / 8));
}
/**
* A two-dimensional bitmap, one bit per pixel. It is organized as
* row-major, top-down, left-to-right. The most significant bit of
* each byte corresponds to the leftmost or uppermost pixel from all
* bits of the byte. If a bit is set (1, `true`), the pixel is set to
* the font color, if a bit is clear (0, `false`), the pixel is
* transparent.
*
* Rows are **not** padded to byte boundaries (i.e., a
* single byte may contain bits belonging to multiple rows). The last
* byte of the bitmap _is_ padded with zero bits at all unused least
* significant bit positions so that the bitmap ends on a byte
* boundary.
*/
return CharacterDefinition;
})();
return ChixSection;
})();
var MaxhSection = Grub2Font.MaxhSection = (function() {
function MaxhSection(_io, _parent, _root) {
this._io = _io;
this._parent = _parent;
this._root = _root || this;
this._read();
}
MaxhSection.prototype._read = function() {
this.maximumCharacterHeight = this._io.readU2be();
}
return MaxhSection;
})();
var NameSection = Grub2Font.NameSection = (function() {
function NameSection(_io, _parent, _root) {
this._io = _io;
this._parent = _parent;
this._root = _root || this;
this._read();
}
NameSection.prototype._read = function() {
this.fontName = KaitaiStream.bytesToStr(this._io.readBytesTerm(0, false, true, true), "ASCII");
}
return NameSection;
})();
var SlanSection = Grub2Font.SlanSection = (function() {
function SlanSection(_io, _parent, _root) {
this._io = _io;
this._parent = _parent;
this._root = _root || this;
this._read();
}
SlanSection.prototype._read = function() {
this.fontSlant = KaitaiStream.bytesToStr(this._io.readBytesTerm(0, false, true, true), "ASCII");
}
return SlanSection;
})();
/**
* The "DATA" section acts as a terminator. The documentation says:
* "A marker that indicates the remainder of the file is data accessed
* via the character index (CHIX) section. When reading this font file,
* the rest of the file can be ignored when scanning the sections."
*/
return Grub2Font;
})();
return Grub2Font;
}));