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// Copyright (c) 2011-2017 The OTS Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "metrics.h"
#include "head.h"
#include "maxp.h"
// OpenType horizontal and vertical common header format
// http://www.microsoft.com/typography/otspec/hhea.htm
// http://www.microsoft.com/typography/otspec/vhea.htm
namespace ots {
bool OpenTypeMetricsHeader::Parse(const uint8_t *data, size_t length) {
Buffer table(data, length);
// Skip already read version.
if (!table.Skip(4)) {
return false;
}
if (!table.ReadS16(&this->ascent) ||
!table.ReadS16(&this->descent) ||
!table.ReadS16(&this->linegap) ||
!table.ReadU16(&this->adv_width_max) ||
!table.ReadS16(&this->min_sb1) ||
!table.ReadS16(&this->min_sb2) ||
!table.ReadS16(&this->max_extent) ||
!table.ReadS16(&this->caret_slope_rise) ||
!table.ReadS16(&this->caret_slope_run) ||
!table.ReadS16(&this->caret_offset)) {
return Error("Failed to read table");
}
if (this->ascent < 0) {
Warning("Negative ascent, setting to 0: %d", this->ascent);
this->ascent = 0;
}
if (this->linegap < 0) {
Warning("Negative linegap, setting to: %d", this->linegap);
this->linegap = 0;
}
OpenTypeHEAD *head = static_cast<OpenTypeHEAD*>(
GetFont()->GetTypedTable(OTS_TAG_HEAD));
if (!head) {
return Error("Missing head font table");
}
// if the font is non-slanted, caret_offset should be zero.
if (!(head->mac_style & 2) &&
(this->caret_offset != 0)) {
Warning("Non-zero caretOffset but head.macStyle italic bit is not set, setting to caretOffset to 0: %d", this->caret_offset);
this->caret_offset = 0;
}
// skip the reserved bytes
if (!table.Skip(8)) {
return Error("Failed to read reserved bytes");
}
int16_t data_format;
if (!table.ReadS16(&data_format)) {
return Error("Failed to read metricDataFormat");
}
if (data_format) {
return Error("Unsupported metricDataFormat: %d", data_format);
}
if (!table.ReadU16(&this->num_metrics)) {
return Error("Failed to read number of metrics");
}
OpenTypeMAXP *maxp = static_cast<OpenTypeMAXP*>(
GetFont()->GetTypedTable(OTS_TAG_MAXP));
if (!maxp) {
return Error("Missing maxp font table");
}
if (this->num_metrics > maxp->num_glyphs) {
return Error("Bad number of metrics %d", this->num_metrics);
}
return true;
}
bool OpenTypeMetricsHeader::Serialize(OTSStream *out) {
if (!out->WriteU32(this->version) ||
!out->WriteS16(this->ascent) ||
!out->WriteS16(this->descent) ||
!out->WriteS16(this->linegap) ||
!out->WriteU16(this->adv_width_max) ||
!out->WriteS16(this->min_sb1) ||
!out->WriteS16(this->min_sb2) ||
!out->WriteS16(this->max_extent) ||
!out->WriteS16(this->caret_slope_rise) ||
!out->WriteS16(this->caret_slope_run) ||
!out->WriteS16(this->caret_offset) ||
!out->WriteR64(0) || // reserved
!out->WriteS16(0) || // metric data format
!out->WriteU16(this->num_metrics)) {
return Error("Failed to write metrics");
}
return true;
}
bool OpenTypeMetricsTable::Parse(const uint8_t *data, size_t length) {
Buffer table(data, length);
// OpenTypeMetricsHeader is a superclass of both 'hhea' and 'vhea',
// so the cast here is OK, whichever m_header_tag we have.
OpenTypeMetricsHeader *header = static_cast<OpenTypeMetricsHeader*>(
GetFont()->GetTypedTable(m_header_tag));
if (!header) {
return Error("Required %c%c%c%c table missing", OTS_UNTAG(m_header_tag));
}
// |num_metrics| is a uint16_t, so it's bounded < 65536. This limits that
// amount of memory that we'll allocate for this to a sane amount.
const unsigned num_metrics = header->num_metrics;
OpenTypeMAXP *maxp = static_cast<OpenTypeMAXP*>(
GetFont()->GetTypedTable(OTS_TAG_MAXP));
if (!maxp) {
return Error("Required maxp table missing");
}
if (num_metrics > maxp->num_glyphs) {
return Error("Bad number of metrics %d", num_metrics);
}
if (!num_metrics) {
return Error("No metrics!");
}
const unsigned num_sbs = maxp->num_glyphs - num_metrics;
this->entries.reserve(num_metrics);
for (unsigned i = 0; i < num_metrics; ++i) {
uint16_t adv = 0;
int16_t sb = 0;
if (!table.ReadU16(&adv) || !table.ReadS16(&sb)) {
return Error("Failed to read metric %d", i);
}
this->entries.push_back(std::make_pair(adv, sb));
}
this->sbs.reserve(num_sbs);
for (unsigned i = 0; i < num_sbs; ++i) {
int16_t sb;
if (!table.ReadS16(&sb)) {
// Some Japanese fonts (e.g., mona.ttf) fail this test.
return Error("Failed to read side bearing %d", i + num_metrics);
}
this->sbs.push_back(sb);
}
return true;
}
bool OpenTypeMetricsTable::Serialize(OTSStream *out) {
for (unsigned i = 0; i < this->entries.size(); ++i) {
if (!out->WriteU16(this->entries[i].first) ||
!out->WriteS16(this->entries[i].second)) {
return Error("Failed to write metric %d", i);
}
}
for (unsigned i = 0; i < this->sbs.size(); ++i) {
if (!out->WriteS16(this->sbs[i])) {
return Error("Failed to write side bearing %ld", i + this->entries.size());
}
}
return true;
}
} // namespace ots
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