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Rebuilding invalid OS/2 table

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This commit is contained in:
Yury Delendik 2012-04-06 15:52:57 -07:00
parent d8235925ac
commit be6ccdca34
3 changed files with 44 additions and 17 deletions
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52
src/fonts.js
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@ -1727,6 +1727,16 @@ var Font = (function FontClosure() {
properties.glyphNames = glyphNames;
}
function isOS2Valid(os2Table) {
var data = os2Table.data;
// usWinAscent == 0 makes font unreadable by windows
var usWinAscent = (data[74] << 8) | data[75];
if (usWinAscent == 0)
return false;
return true;
}
// Check that required tables are present
var requiredTables = ['OS/2', 'cmap', 'head', 'hhea',
'hmtx', 'maxp', 'name', 'post'];
@ -1734,7 +1744,7 @@ var Font = (function FontClosure() {
var header = readOpenTypeHeader(font);
var numTables = header.numTables;
var cmap, post, maxp, hhea, hmtx, vhea, vmtx, head, loca, glyf;
var cmap, post, maxp, hhea, hmtx, vhea, vmtx, head, loca, glyf, os2;
var tables = [];
for (var i = 0; i < numTables; i++) {
var table = readTableEntry(font);
@ -1752,6 +1762,8 @@ var Font = (function FontClosure() {
hmtx = table;
else if (table.tag == 'head')
head = table;
else if (table.tag == 'OS/2')
os2 = table;
requiredTables.splice(index, 1);
} else {
@ -1767,7 +1779,7 @@ var Font = (function FontClosure() {
tables.push(table);
}
var numTables = header.numTables + requiredTables.length;
var numTables = tables.length + requiredTables.length;
// header and new offsets. Table entry information is appended to the
// end of file. The virtualOffset represents where to put the actual
@ -1781,21 +1793,10 @@ var Font = (function FontClosure() {
// of missing tables
createOpenTypeHeader(header.version, ttf, numTables);
if (requiredTables.indexOf('OS/2') != -1) {
// extract some more font properties from the OpenType head and
// hhea tables; yMin and descent value are always negative
var override = {
unitsPerEm: int16([head.data[18], head.data[19]]),
yMax: int16([head.data[42], head.data[43]]),
yMin: int16([head.data[38], head.data[39]]) - 0x10000,
ascent: int16([hhea.data[4], hhea.data[5]]),
descent: int16([hhea.data[6], hhea.data[7]]) - 0x10000
};
tables.push({
tag: 'OS/2',
data: stringToArray(createOS2Table(properties, null, override))
});
// Invalid OS/2 can break the font for the Windows
if (os2 && !isOS2Valid(os2)) {
tables.splice(tables.indexOf(os2), 1);
os2 = null;
}
// Ensure the [h/v]mtx tables contains the advance width and
@ -2076,6 +2077,23 @@ var Font = (function FontClosure() {
}
this.unicodeIsEnabled = unicodeIsEnabled;
if (!os2) {
// extract some more font properties from the OpenType head and
// hhea tables; yMin and descent value are always negative
var override = {
unitsPerEm: int16([head.data[18], head.data[19]]),
yMax: int16([head.data[42], head.data[43]]),
yMin: int16([head.data[38], head.data[39]]) - 0x10000,
ascent: int16([hhea.data[4], hhea.data[5]]),
descent: int16([hhea.data[6], hhea.data[7]]) - 0x10000
};
tables.push({
tag: 'OS/2',
data: stringToArray(createOS2Table(properties, glyphs, override))
});
}
// Rewrite the 'post' table if needed
if (requiredTables.indexOf('post') != -1) {
tables.push({