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Sanitize 'loca' font table: some fonts have first glyph with length 10

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notmasteryet 2011-09-18 21:25:05 -05:00
parent 537eb8f47b
commit f401a64eb2
1 changed files with 53 additions and 1 deletions
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54
fonts.js
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@ -1053,6 +1053,49 @@ var Font = (function Font() {
} }
}; };
function sanitizeGlyphLocations(loca, glyf, numGlyphs,
isGlyphLocationsLong) {
var itemSize, itemDecode, itemEncode;
if (isGlyphLocationsLong) {
itemSize = 4;
itemDecode = function(data, offset) {
return (data[offset] << 24) | (data[offset + 1] << 16) |
(data[offset + 2] << 8) | data[offset + 3];
};
itemEncode = function(data, offset, value) {
data[offset] = (value >>> 24) & 0xFF;
data[offset + 1] = (value >> 16) & 0xFF;
data[offset + 2] = (value >> 8) & 0xFF;
data[offset + 3] = value & 0xFF;
};
} else {
itemSize = 2;
itemDecode = function(data, offset) {
return (data[offset] << 8) | data[offset + 1];
};
itemEncode = function(data, offset, value) {
data[offset] = (value >> 8) & 0xFF;
data[offset + 1] = value & 0xFF;
};
}
var locaData = loca.data;
var startOffset = itemDecode(locaData, 0);
var firstOffset = itemDecode(locaData, itemSize);
if (firstOffset - startOffset < 12 || startOffset > 0) {
// removing first glyph
glyf.data = glyf.data.subarray(firstOffset);
glyf.length -= firstOffset;
itemEncode(locaData, 0, 0);
var i, pos = itemSize;
for (i = 1; i <= numGlyphs; ++i) {
itemEncode(locaData, pos,
itemDecode(locaData, pos) - firstOffset);
pos += itemSize;
}
}
}
// Check that required tables are present // Check that required tables are present
var requiredTables = ['OS/2', 'cmap', 'head', 'hhea', var requiredTables = ['OS/2', 'cmap', 'head', 'hhea',
'hmtx', 'maxp', 'name', 'post']; 'hmtx', 'maxp', 'name', 'post'];
@ -1060,7 +1103,7 @@ var Font = (function Font() {
var header = readOpenTypeHeader(font); var header = readOpenTypeHeader(font);
var numTables = header.numTables; var numTables = header.numTables;
var cmap, maxp, hhea, hmtx, vhea, vmtx, head; var cmap, maxp, hhea, hmtx, vhea, vmtx, head, loca, glyf;
var tables = []; var tables = [];
for (var i = 0; i < numTables; i++) { for (var i = 0; i < numTables; i++) {
var table = readTableEntry(font); var table = readTableEntry(font);
@ -1083,6 +1126,10 @@ var Font = (function Font() {
vmtx = table; vmtx = table;
else if (table.tag == 'vhea') else if (table.tag == 'vhea')
vhea = table; vhea = table;
else if (table.tag == 'loca')
loca = table;
else if (table.tag == 'glyf')
glyf = table;
} }
tables.push(table); tables.push(table);
} }
@ -1127,6 +1174,11 @@ var Font = (function Font() {
sanitizeMetrics(font, hhea, hmtx, numGlyphs); sanitizeMetrics(font, hhea, hmtx, numGlyphs);
sanitizeMetrics(font, vhea, vmtx, numGlyphs); sanitizeMetrics(font, vhea, vmtx, numGlyphs);
if (head && loca && glyf) {
var isGlyphLocationsLong = int16([head.data[50], head.data[51]]);
sanitizeGlyphLocations(loca, glyf, numGlyphs, isGlyphLocationsLong);
}
// Sanitizer reduces the glyph advanceWidth to the maxAdvanceWidth // Sanitizer reduces the glyph advanceWidth to the maxAdvanceWidth
// Sometimes it's 0. That needs to be fixed // Sometimes it's 0. That needs to be fixed
if (hhea.data[10] == 0 && hhea.data[11] == 0) { if (hhea.data[10] == 0 && hhea.data[11] == 0) {