parseBuffer top-level property
Parse the OpenType file data (as an ArrayBuffer) and return a Font object. Throws an error if the font could not be parsed. @param {ArrayBuffer} @param {Object} opt - options for parsing @return {opentype.Font}
Implementation
Function parseBuffer = (Uint8List buffer, opt) {
opt = (opt == null || opt == null) ? {} : opt;
var indexToLocFormat;
var ltagTable;
// Since the constructor can also be called to create new fonts from scratch, we indicate this
// should be an empty font that we'll fill with our own data.
var font = new Font({"empty": true});
// OpenType fonts use big endian byte ordering.
// We can't rely on typed array view types, because they operate with the endianness of the host computer.
// Instead we use DataViews where we can specify endianness.
// var data = DataView(buffer, 0);
var data = ByteData.view(buffer.buffer);
var numTables;
var tableEntries = [];
var signature = getTag(data, 0);
if (signature == String.fromCharCodes([0, 1, 0, 0]) || signature == 'true' || signature == 'typ1') {
font.outlinesFormat = 'truetype';
numTables = getUShort(data, 4);
tableEntries = parseOpenTypeTableEntries(data, numTables);
} else if (signature == 'OTTO') {
font.outlinesFormat = 'cff';
numTables = getUShort(data, 4);
tableEntries = parseOpenTypeTableEntries(data, numTables);
} else if (signature == 'wOFF') {
var flavor = getTag(data, 4);
if (flavor == String.fromCharCodes([0, 1, 0, 0])) {
font.outlinesFormat = 'truetype';
} else if (flavor == 'OTTO') {
font.outlinesFormat = 'cff';
} else {
throw('Unsupported OpenType flavor ' + signature);
}
numTables = getUShort(data, 12);
tableEntries = parseWOFFTableEntries(data, numTables);
} else {
throw('Unsupported OpenType signature ' + signature);
}
var cffTableEntry;
var fvarTableEntry;
var glyfTableEntry;
var gdefTableEntry;
var gposTableEntry;
var gsubTableEntry;
var hmtxTableEntry;
var kernTableEntry;
var locaTableEntry;
var nameTableEntry;
var metaTableEntry;
var p;
for (var i = 0; i < numTables; i += 1) {
Map<String, dynamic> tableEntry = tableEntries[i];
Map<String, dynamic> table;
switch (tableEntry["tag"]) {
case 'cmap':
table = uncompressTable(data, tableEntry);
font.tables["cmap"] = parseCmapTable(table["data"], table["offset"]);
font.encoding = new CmapEncoding(font.tables["cmap"]);
break;
case 'cvt ' :
table = uncompressTable(data, tableEntry);
p = new Parser(table["data"], table["offset"]);
font.tables["cvt"] = p.parseShortList(tableEntry.length / 2);
break;
case 'fvar':
fvarTableEntry = tableEntry;
break;
case 'fpgm' :
table = uncompressTable(data, tableEntry);
p = new Parser(table["data"], table["offset"]);
font.tables["fpgm"] = p.parseByteList(tableEntry.length);
break;
case 'head':
table = uncompressTable(data, tableEntry);
font.tables["head"] = parseHeadTable(table["data"], table["offset"]);
font.unitsPerEm = font.tables["head"]["unitsPerEm"];
indexToLocFormat = font.tables["head"]["indexToLocFormat"];
break;
case 'hhea':
table = uncompressTable(data, tableEntry);
font.tables["hhea"] = parseHheaTable(table["data"], table["offset"]);
font.ascender = font.tables["hhea"]["ascender"];
font.descender = font.tables["hhea"]["descender"];
font.numberOfHMetrics = font.tables["hhea"]["numberOfHMetrics"];
break;
case 'hmtx':
hmtxTableEntry = tableEntry;
break;
case 'ltag':
table = uncompressTable(data, tableEntry);
ltagTable = parseLtagTable(table["data"], table["offset"]);
break;
case 'maxp':
table = uncompressTable(data, tableEntry);
font.tables["maxp"] = parseMaxpTable(table["data"], table["offset"]);
font.numGlyphs = font.tables["maxp"]["numGlyphs"];
break;
case 'name':
nameTableEntry = tableEntry;
break;
case 'OS/2':
table = uncompressTable(data, tableEntry);
font.tables["os2"] = parseOS2Table(table["data"], table["offset"]);
break;
case 'post':
table = uncompressTable(data, tableEntry);
font.tables["post"] = parsePostTable(table["data"], table["offset"]);
font.glyphNames = new GlyphNames(font.tables["post"]);
break;
case 'prep' :
table = uncompressTable(data, tableEntry);
p = new Parser(table["data"], table["offset"]);
font.tables["prep"] = p.parseByteList(tableEntry.length);
break;
case 'glyf':
glyfTableEntry = tableEntry;
break;
case 'loca':
locaTableEntry = tableEntry;
break;
case 'CFF ':
cffTableEntry = tableEntry;
break;
case 'kern':
kernTableEntry = tableEntry;
break;
case 'GDEF':
gdefTableEntry = tableEntry;
break;
case 'GPOS':
gposTableEntry = tableEntry;
break;
case 'GSUB':
gsubTableEntry = tableEntry;
break;
case 'meta':
metaTableEntry = tableEntry;
break;
}
}
var nameTable = uncompressTable(data, nameTableEntry);
font.tables["name"] = parseNameTable(nameTable["data"], nameTable["offset"], ltagTable);
font.names = font.tables["name"];
if ( glyfTableEntry != null && locaTableEntry != null ) {
var shortVersion = indexToLocFormat == 0;
Map<String, dynamic> locaTable = uncompressTable(data, locaTableEntry);
var locaOffsets = parseLocaTable(locaTable["data"], locaTable["offset"], font.numGlyphs, shortVersion);
Map<String, dynamic> glyfTable = uncompressTable(data, glyfTableEntry);
font.glyphs = parseGlyfTable(glyfTable["data"], glyfTable["offset"], locaOffsets, font, opt);
} else if (cffTableEntry != null) {
Map<String, dynamic> cffTable = uncompressTable(data, cffTableEntry);
parseCFFTable(cffTable["data"], cffTable["offset"], font, opt);
} else {
throw('Font doesn\'t contain TrueType or CFF outlines.');
}
Map<String, dynamic> hmtxTable = uncompressTable(data, hmtxTableEntry);
parseHmtxTable(font, hmtxTable["data"], hmtxTable["offset"], font.numberOfHMetrics, font.numGlyphs, font.glyphs, opt);
addGlyphNames(font, opt);
if (kernTableEntry != null) {
Map<String, dynamic> kernTable = uncompressTable(data, kernTableEntry);
font.kerningPairs = parseKernTable(kernTable["data"], kernTable["offset"]);
} else {
font.kerningPairs = {};
}
if ( gdefTableEntry != null ) {
Map<String, dynamic> gdefTable = uncompressTable(data, gdefTableEntry);
font.tables["gdef"] = parseGDEFTable(gdefTable["data"], gdefTable["offset"]);
}
if (gposTableEntry != null) {
Map<String, dynamic> gposTable = uncompressTable(data, gposTableEntry);
font.tables["gpos"] = parseGposTable(gposTable["data"], gposTable["offset"]);
font.position.init();
}
if (gsubTableEntry != null ) {
Map<String, dynamic> gsubTable = uncompressTable(data, gsubTableEntry);
font.tables["gsub"] = parseGsubTable(gsubTable["data"], gsubTable["offset"]);
}
if (fvarTableEntry != null) {
Map<String, dynamic> fvarTable = uncompressTable(data, fvarTableEntry);
font.tables["fvar"] = parseFvarTable(fvarTable["data"], fvarTable["offset"], font.names);
}
if (metaTableEntry != null) {
Map<String, dynamic> metaTable = uncompressTable(data, metaTableEntry);
font.tables["meta"] = parseMetaTable(metaTable["data"], metaTable["offset"]);
font.metas = Map<String, dynamic>.from(font.tables["meta"]);
}
return font;
};