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Fix an issue with the vhea/vmtx tables

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This commit is contained in:
Vivien Nicolas 2011-09-09 16:37:56 +02:00
parent 841fabd4e9
commit 5cb2a07b3d
1 changed files with 45 additions and 21 deletions
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66
fonts.js
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@ -1032,9 +1032,9 @@ var Font = (function Font() {
var end = denseRange[1];
var index = firstCode;
for (var j = start; j <= end; j++) {
var code = j - firstCode - 1;
var code = glyphs[j - start];
var mapping = encoding[index] || {};
mapping.unicode = glyphs[code].unicode;
mapping.unicode = code.unicode;
encoding[index++] = mapping;
}
return cmap.data = createCMapTable(glyphs);
@ -1043,6 +1043,39 @@ var Font = (function Font() {
return cmap.data;
};
function sanitizeMetrics(font, header, metrics, numGlyphs) {
if (!header && !metrics)
return;
// The vhea/vmtx tables are not required, so it happens that
// some fonts embed a vmtx table without a vhea table. In this
// situation the sanitizer assume numOfLongVerMetrics = 1. As
// a result it tries to read numGlyphs - 1 SHORT from the vmtx
// table, and if it is not possible, the font is rejected.
// So remove the vmtx table if there is no vhea table.
if (!header && metrics) {
metrics.data = null;
return;
}
font.pos = (font.start ? font.start : 0) + header.offset;
font.pos += header.length - 2;
var numOfMetrics = int16(font.getBytes(2));
var numOfSidebearings = numGlyphs - numOfMetrics;
var numMissing = numOfSidebearings -
((hmtx.length - numOfMetrics * 4) >> 1);
if (numMissing > 0) {
font.pos = (font.start ? font.start : 0) + metrics.offset;
var entries = '';
for (var i = 0; i < hmtx.length; i++)
entries += String.fromCharCode(font.getByte());
for (var i = 0; i < numMissing; i++)
entries += '\x00\x00';
metrics.data = stringToArray(entries);
}
};
// Check that required tables are present
var requiredTables = ['OS/2', 'cmap', 'head', 'hhea',
'hmtx', 'maxp', 'name', 'post'];
@ -1050,7 +1083,7 @@ var Font = (function Font() {
var header = readOpenTypeHeader(font);
var numTables = header.numTables;
var cmap, maxp, hhea, hmtx;
var cmap, maxp, hhea, hmtx, vhea, vmtx;
var tables = [];
for (var i = 0; i < numTables; i++) {
var table = readTableEntry(font);
@ -1066,6 +1099,11 @@ var Font = (function Font() {
hmtx = table;
requiredTables.splice(index, 1);
} else {
if (table.tag == 'vmtx')
vmtx = table;
else if (table.tag == 'vhea')
vhea = table;
}
tables.push(table);
}
@ -1091,28 +1129,14 @@ var Font = (function Font() {
});
}
// Ensure the hmtx tables contains an advance width and a sidebearing
// for the number of glyphs declared in the maxp table
// Ensure the [h/v]mtx tables contains the advance width and
// sidebearings information for numGlyphs in the maxp table
font.pos = (font.start ? font.start : 0) + maxp.offset;
var version = int16(font.getBytes(4));
var numGlyphs = int16(font.getBytes(2));
font.pos = (font.start ? font.start : 0) + hhea.offset;
font.pos += hhea.length - 2;
var numOfHMetrics = int16(font.getBytes(2));
var numOfSidebearings = numGlyphs - numOfHMetrics;
var numMissing = numOfSidebearings -
((hmtx.length - numOfHMetrics * 4) >> 1);
if (numMissing > 0) {
font.pos = (font.start ? font.start : 0) + hmtx.offset;
var metrics = '';
for (var i = 0; i < hmtx.length; i++)
metrics += String.fromCharCode(font.getByte());
for (var i = 0; i < numMissing; i++)
metrics += '\x00\x00';
hmtx.data = stringToArray(metrics);
}
sanitizeMetrics(font, hhea, hmtx, numGlyphs);
sanitizeMetrics(font, vhea, vmtx, numGlyphs);
// Sanitizer reduces the glyph advanceWidth to the maxAdvanceWidth
// Sometimes it's 0. That needs to be fixed