1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/gfx/ots/src/metrics.cc Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,186 @@
1.4 +// Copyright (c) 2011 The Chromium Authors. All rights reserved.
1.5 +// Use of this source code is governed by a BSD-style license that can be
1.6 +// found in the LICENSE file.
1.7 +
1.8 +#include "metrics.h"
1.9 +
1.10 +#include "head.h"
1.11 +#include "maxp.h"
1.12 +
1.13 +// OpenType horizontal and vertical common header format
1.14 +// http://www.microsoft.com/typography/otspec/hhea.htm
1.15 +// http://www.microsoft.com/typography/otspec/vhea.htm
1.16 +
1.17 +#define TABLE_NAME "metrics" // XXX: use individual table names
1.18 +
1.19 +namespace ots {
1.20 +
1.21 +bool ParseMetricsHeader(OpenTypeFile *file, Buffer *table,
1.22 + OpenTypeMetricsHeader *header) {
1.23 + if (!table->ReadS16(&header->ascent) ||
1.24 + !table->ReadS16(&header->descent) ||
1.25 + !table->ReadS16(&header->linegap) ||
1.26 + !table->ReadU16(&header->adv_width_max) ||
1.27 + !table->ReadS16(&header->min_sb1) ||
1.28 + !table->ReadS16(&header->min_sb2) ||
1.29 + !table->ReadS16(&header->max_extent) ||
1.30 + !table->ReadS16(&header->caret_slope_rise) ||
1.31 + !table->ReadS16(&header->caret_slope_run) ||
1.32 + !table->ReadS16(&header->caret_offset)) {
1.33 + return OTS_FAILURE_MSG("Failed to read metrics header");
1.34 + }
1.35 +
1.36 + if (header->ascent < 0) {
1.37 + OTS_WARNING("bad ascent: %d", header->ascent);
1.38 + header->ascent = 0;
1.39 + }
1.40 + if (header->linegap < 0) {
1.41 + OTS_WARNING("bad linegap: %d", header->linegap);
1.42 + header->linegap = 0;
1.43 + }
1.44 +
1.45 + if (!file->head) {
1.46 + return OTS_FAILURE_MSG("Missing head font table");
1.47 + }
1.48 +
1.49 + // if the font is non-slanted, caret_offset should be zero.
1.50 + if (!(file->head->mac_style & 2) &&
1.51 + (header->caret_offset != 0)) {
1.52 + OTS_WARNING("bad caret offset: %d", header->caret_offset);
1.53 + header->caret_offset = 0;
1.54 + }
1.55 +
1.56 + // skip the reserved bytes
1.57 + if (!table->Skip(8)) {
1.58 + return OTS_FAILURE_MSG("Failed to skip reserverd bytes");
1.59 + }
1.60 +
1.61 + int16_t data_format;
1.62 + if (!table->ReadS16(&data_format)) {
1.63 + return OTS_FAILURE_MSG("Failed to read data format");
1.64 + }
1.65 + if (data_format) {
1.66 + return OTS_FAILURE_MSG("Bad data format %d", data_format);
1.67 + }
1.68 +
1.69 + if (!table->ReadU16(&header->num_metrics)) {
1.70 + return OTS_FAILURE_MSG("Failed to read number of metrics");
1.71 + }
1.72 +
1.73 + if (!file->maxp) {
1.74 + return OTS_FAILURE_MSG("Missing maxp font table");
1.75 + }
1.76 +
1.77 + if (header->num_metrics > file->maxp->num_glyphs) {
1.78 + return OTS_FAILURE_MSG("Bad number of metrics %d", header->num_metrics);
1.79 + }
1.80 +
1.81 + return true;
1.82 +}
1.83 +
1.84 +bool SerialiseMetricsHeader(const ots::OpenTypeFile *file,
1.85 + OTSStream *out,
1.86 + const OpenTypeMetricsHeader *header) {
1.87 + if (!out->WriteU32(header->version) ||
1.88 + !out->WriteS16(header->ascent) ||
1.89 + !out->WriteS16(header->descent) ||
1.90 + !out->WriteS16(header->linegap) ||
1.91 + !out->WriteU16(header->adv_width_max) ||
1.92 + !out->WriteS16(header->min_sb1) ||
1.93 + !out->WriteS16(header->min_sb2) ||
1.94 + !out->WriteS16(header->max_extent) ||
1.95 + !out->WriteS16(header->caret_slope_rise) ||
1.96 + !out->WriteS16(header->caret_slope_run) ||
1.97 + !out->WriteS16(header->caret_offset) ||
1.98 + !out->WriteR64(0) || // reserved
1.99 + !out->WriteS16(0) || // metric data format
1.100 + !out->WriteU16(header->num_metrics)) {
1.101 + return OTS_FAILURE_MSG("Failed to write metrics");
1.102 + }
1.103 +
1.104 + return true;
1.105 +}
1.106 +
1.107 +bool ParseMetricsTable(const ots::OpenTypeFile *file,
1.108 + Buffer *table,
1.109 + const uint16_t num_glyphs,
1.110 + const OpenTypeMetricsHeader *header,
1.111 + OpenTypeMetricsTable *metrics) {
1.112 + // |num_metrics| is a uint16_t, so it's bounded < 65536. This limits that
1.113 + // amount of memory that we'll allocate for this to a sane amount.
1.114 + const unsigned num_metrics = header->num_metrics;
1.115 +
1.116 + if (num_metrics > num_glyphs) {
1.117 + return OTS_FAILURE_MSG("Bad number of metrics %d", num_metrics);
1.118 + }
1.119 + if (!num_metrics) {
1.120 + return OTS_FAILURE_MSG("No metrics!");
1.121 + }
1.122 + const unsigned num_sbs = num_glyphs - num_metrics;
1.123 +
1.124 + metrics->entries.reserve(num_metrics);
1.125 + for (unsigned i = 0; i < num_metrics; ++i) {
1.126 + uint16_t adv = 0;
1.127 + int16_t sb = 0;
1.128 + if (!table->ReadU16(&adv) || !table->ReadS16(&sb)) {
1.129 + return OTS_FAILURE_MSG("Failed to read metric %d", i);
1.130 + }
1.131 +
1.132 + // Since so many fonts don't have proper value on |adv| and |sb|,
1.133 + // we should not call ots_failure() here. For example, about 20% of fonts
1.134 + // in http://www.princexml.com/fonts/ (200+ fonts) fails these tests.
1.135 + if (adv > header->adv_width_max) {
1.136 + OTS_WARNING("bad adv: %u > %u", adv, header->adv_width_max);
1.137 + adv = header->adv_width_max;
1.138 + }
1.139 +
1.140 + if (sb < header->min_sb1) {
1.141 + OTS_WARNING("bad sb: %d < %d", sb, header->min_sb1);
1.142 + sb = header->min_sb1;
1.143 + }
1.144 +
1.145 + metrics->entries.push_back(std::make_pair(adv, sb));
1.146 + }
1.147 +
1.148 + metrics->sbs.reserve(num_sbs);
1.149 + for (unsigned i = 0; i < num_sbs; ++i) {
1.150 + int16_t sb;
1.151 + if (!table->ReadS16(&sb)) {
1.152 + // Some Japanese fonts (e.g., mona.ttf) fail this test.
1.153 + return OTS_FAILURE_MSG("Failed to read side bearing %d", i + num_metrics);
1.154 + }
1.155 +
1.156 + if (sb < header->min_sb1) {
1.157 + // The same as above. Three fonts in http://www.fontsquirrel.com/fontface
1.158 + // (e.g., Notice2Std.otf) have weird lsb values.
1.159 + OTS_WARNING("bad lsb: %d < %d", sb, header->min_sb1);
1.160 + sb = header->min_sb1;
1.161 + }
1.162 +
1.163 + metrics->sbs.push_back(sb);
1.164 + }
1.165 +
1.166 + return true;
1.167 +}
1.168 +
1.169 +bool SerialiseMetricsTable(const ots::OpenTypeFile *file,
1.170 + OTSStream *out,
1.171 + const OpenTypeMetricsTable *metrics) {
1.172 + for (unsigned i = 0; i < metrics->entries.size(); ++i) {
1.173 + if (!out->WriteU16(metrics->entries[i].first) ||
1.174 + !out->WriteS16(metrics->entries[i].second)) {
1.175 + return OTS_FAILURE_MSG("Failed to write metric %d", i);
1.176 + }
1.177 + }
1.178 +
1.179 + for (unsigned i = 0; i < metrics->sbs.size(); ++i) {
1.180 + if (!out->WriteS16(metrics->sbs[i])) {
1.181 + return OTS_FAILURE_MSG("Failed to write side bearing %ld", i + metrics->entries.size());
1.182 + }
1.183 + }
1.184 +
1.185 + return true;
1.186 +}
1.187 +
1.188 +} // namespace ots
1.189 +
