michael@0: // Copyright (c) 2011 The Chromium Authors. All rights reserved.
michael@0: // Use of this source code is governed by a BSD-style license that can be
michael@0: // found in the LICENSE file.
michael@0: 
michael@0: #include "metrics.h"
michael@0: 
michael@0: #include "head.h"
michael@0: #include "maxp.h"
michael@0: 
michael@0: // OpenType horizontal and vertical common header format
michael@0: // http://www.microsoft.com/typography/otspec/hhea.htm
michael@0: // http://www.microsoft.com/typography/otspec/vhea.htm
michael@0: 
michael@0: #define TABLE_NAME "metrics" // XXX: use individual table names
michael@0: 
michael@0: namespace ots {
michael@0: 
michael@0: bool ParseMetricsHeader(OpenTypeFile *file, Buffer *table,
michael@0:                         OpenTypeMetricsHeader *header) {
michael@0:   if (!table->ReadS16(&header->ascent) ||
michael@0:       !table->ReadS16(&header->descent) ||
michael@0:       !table->ReadS16(&header->linegap) ||
michael@0:       !table->ReadU16(&header->adv_width_max) ||
michael@0:       !table->ReadS16(&header->min_sb1) ||
michael@0:       !table->ReadS16(&header->min_sb2) ||
michael@0:       !table->ReadS16(&header->max_extent) ||
michael@0:       !table->ReadS16(&header->caret_slope_rise) ||
michael@0:       !table->ReadS16(&header->caret_slope_run) ||
michael@0:       !table->ReadS16(&header->caret_offset)) {
michael@0:     return OTS_FAILURE_MSG("Failed to read metrics header");
michael@0:   }
michael@0: 
michael@0:   if (header->ascent < 0) {
michael@0:     OTS_WARNING("bad ascent: %d", header->ascent);
michael@0:     header->ascent = 0;
michael@0:   }
michael@0:   if (header->linegap < 0) {
michael@0:     OTS_WARNING("bad linegap: %d", header->linegap);
michael@0:     header->linegap = 0;
michael@0:   }
michael@0: 
michael@0:   if (!file->head) {
michael@0:     return OTS_FAILURE_MSG("Missing head font table");
michael@0:   }
michael@0: 
michael@0:   // if the font is non-slanted, caret_offset should be zero.
michael@0:   if (!(file->head->mac_style & 2) &&
michael@0:       (header->caret_offset != 0)) {
michael@0:     OTS_WARNING("bad caret offset: %d", header->caret_offset);
michael@0:     header->caret_offset = 0;
michael@0:   }
michael@0: 
michael@0:   // skip the reserved bytes
michael@0:   if (!table->Skip(8)) {
michael@0:     return OTS_FAILURE_MSG("Failed to skip reserverd bytes");
michael@0:   }
michael@0: 
michael@0:   int16_t data_format;
michael@0:   if (!table->ReadS16(&data_format)) {
michael@0:     return OTS_FAILURE_MSG("Failed to read data format");
michael@0:   }
michael@0:   if (data_format) {
michael@0:     return OTS_FAILURE_MSG("Bad data format %d", data_format);
michael@0:   }
michael@0: 
michael@0:   if (!table->ReadU16(&header->num_metrics)) {
michael@0:     return OTS_FAILURE_MSG("Failed to read number of metrics");
michael@0:   }
michael@0: 
michael@0:   if (!file->maxp) {
michael@0:     return OTS_FAILURE_MSG("Missing maxp font table");
michael@0:   }
michael@0: 
michael@0:   if (header->num_metrics > file->maxp->num_glyphs) {
michael@0:     return OTS_FAILURE_MSG("Bad number of metrics %d", header->num_metrics);
michael@0:   }
michael@0: 
michael@0:   return true;
michael@0: }
michael@0: 
michael@0: bool SerialiseMetricsHeader(const ots::OpenTypeFile *file,
michael@0:                             OTSStream *out,
michael@0:                             const OpenTypeMetricsHeader *header) {
michael@0:   if (!out->WriteU32(header->version) ||
michael@0:       !out->WriteS16(header->ascent) ||
michael@0:       !out->WriteS16(header->descent) ||
michael@0:       !out->WriteS16(header->linegap) ||
michael@0:       !out->WriteU16(header->adv_width_max) ||
michael@0:       !out->WriteS16(header->min_sb1) ||
michael@0:       !out->WriteS16(header->min_sb2) ||
michael@0:       !out->WriteS16(header->max_extent) ||
michael@0:       !out->WriteS16(header->caret_slope_rise) ||
michael@0:       !out->WriteS16(header->caret_slope_run) ||
michael@0:       !out->WriteS16(header->caret_offset) ||
michael@0:       !out->WriteR64(0) ||  // reserved
michael@0:       !out->WriteS16(0) ||  // metric data format
michael@0:       !out->WriteU16(header->num_metrics)) {
michael@0:     return OTS_FAILURE_MSG("Failed to write metrics");
michael@0:   }
michael@0: 
michael@0:   return true;
michael@0: }
michael@0: 
michael@0: bool ParseMetricsTable(const ots::OpenTypeFile *file,
michael@0:                        Buffer *table,
michael@0:                        const uint16_t num_glyphs,
michael@0:                        const OpenTypeMetricsHeader *header,
michael@0:                        OpenTypeMetricsTable *metrics) {
michael@0:   // |num_metrics| is a uint16_t, so it's bounded < 65536. This limits that
michael@0:   // amount of memory that we'll allocate for this to a sane amount.
michael@0:   const unsigned num_metrics = header->num_metrics;
michael@0: 
michael@0:   if (num_metrics > num_glyphs) {
michael@0:     return OTS_FAILURE_MSG("Bad number of metrics %d", num_metrics);
michael@0:   }
michael@0:   if (!num_metrics) {
michael@0:     return OTS_FAILURE_MSG("No metrics!");
michael@0:   }
michael@0:   const unsigned num_sbs = num_glyphs - num_metrics;
michael@0: 
michael@0:   metrics->entries.reserve(num_metrics);
michael@0:   for (unsigned i = 0; i < num_metrics; ++i) {
michael@0:     uint16_t adv = 0;
michael@0:     int16_t sb = 0;
michael@0:     if (!table->ReadU16(&adv) || !table->ReadS16(&sb)) {
michael@0:       return OTS_FAILURE_MSG("Failed to read metric %d", i);
michael@0:     }
michael@0: 
michael@0:     // Since so many fonts don't have proper value on |adv| and |sb|,
michael@0:     // we should not call ots_failure() here. For example, about 20% of fonts
michael@0:     // in http://www.princexml.com/fonts/ (200+ fonts) fails these tests.
michael@0:     if (adv > header->adv_width_max) {
michael@0:       OTS_WARNING("bad adv: %u > %u", adv, header->adv_width_max);
michael@0:       adv = header->adv_width_max;
michael@0:     }
michael@0: 
michael@0:     if (sb < header->min_sb1) {
michael@0:       OTS_WARNING("bad sb: %d < %d", sb, header->min_sb1);
michael@0:       sb = header->min_sb1;
michael@0:     }
michael@0: 
michael@0:     metrics->entries.push_back(std::make_pair(adv, sb));
michael@0:   }
michael@0: 
michael@0:   metrics->sbs.reserve(num_sbs);
michael@0:   for (unsigned i = 0; i < num_sbs; ++i) {
michael@0:     int16_t sb;
michael@0:     if (!table->ReadS16(&sb)) {
michael@0:       // Some Japanese fonts (e.g., mona.ttf) fail this test.
michael@0:       return OTS_FAILURE_MSG("Failed to read side bearing %d", i + num_metrics);
michael@0:     }
michael@0: 
michael@0:     if (sb < header->min_sb1) {
michael@0:       // The same as above. Three fonts in http://www.fontsquirrel.com/fontface
michael@0:       // (e.g., Notice2Std.otf) have weird lsb values.
michael@0:       OTS_WARNING("bad lsb: %d < %d", sb, header->min_sb1);
michael@0:       sb = header->min_sb1;
michael@0:     }
michael@0: 
michael@0:     metrics->sbs.push_back(sb);
michael@0:   }
michael@0: 
michael@0:   return true;
michael@0: }
michael@0: 
michael@0: bool SerialiseMetricsTable(const ots::OpenTypeFile *file,
michael@0:                            OTSStream *out,
michael@0:                            const OpenTypeMetricsTable *metrics) {
michael@0:   for (unsigned i = 0; i < metrics->entries.size(); ++i) {
michael@0:     if (!out->WriteU16(metrics->entries[i].first) ||
michael@0:         !out->WriteS16(metrics->entries[i].second)) {
michael@0:       return OTS_FAILURE_MSG("Failed to write metric %d", i);
michael@0:     }
michael@0:   }
michael@0: 
michael@0:   for (unsigned i = 0; i < metrics->sbs.size(); ++i) {
michael@0:     if (!out->WriteS16(metrics->sbs[i])) {
michael@0:       return OTS_FAILURE_MSG("Failed to write side bearing %ld", i + metrics->entries.size());
michael@0:     }
michael@0:   }
michael@0: 
michael@0:   return true;
michael@0: }
michael@0: 
michael@0: }  // namespace ots
michael@0: