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Verifies some of the OS2 font table fields

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This commit is contained in:
Yury Delendik 2012-11-07 11:11:36 -06:00
parent 1d87a8c7b6
commit 4da7be8d28
3 changed files with 61 additions and 0 deletions
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23
src/fonts.js
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@ -2565,6 +2565,24 @@ var Font = (function FontClosure() {
format314);
};
function validateOS2Table(os2) {
var stream = new Stream(os2.data);
var version = int16(stream.getBytes(2));
// TODO verify all OS/2 tables fields, but currently we validate only those
// that give us issues
stream.getBytes(60); // skipping type, misc sizes, panose, unicode ranges
var selection = int16(stream.getBytes(2));
if (version < 4 && (selection & 0x0300)) {
return false;
}
var firstChar = int16(stream.getBytes(2));
var lastChar = int16(stream.getBytes(2));
if (firstChar > lastChar) {
return false;
}
return true;
}
function createOS2Table(properties, charstrings, override) {
override = override || {
unitsPerEm: 0,
@ -3596,6 +3614,11 @@ var Font = (function FontClosure() {
}
this.unicodeIsEnabled = unicodeIsEnabled;
if (os2 && !validateOS2Table(os2)) {
tables.splice(tables.indexOf(os2), 1);
os2 = null;
}
if (!os2) {
// extract some more font properties from the OpenType head and
// hhea tables; yMin and descent value are always negative