| // Copyright (c) 2011 The Chromium 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 |
| |
| #define TABLE_NAME "metrics" // XXX: use individual table names |
| |
| namespace ots { |
| |
| bool ParseMetricsHeader(OpenTypeFile *file, Buffer *table, |
| OpenTypeMetricsHeader *header) { |
| if (!table->ReadS16(&header->ascent) || |
| !table->ReadS16(&header->descent) || |
| !table->ReadS16(&header->linegap) || |
| !table->ReadU16(&header->adv_width_max) || |
| !table->ReadS16(&header->min_sb1) || |
| !table->ReadS16(&header->min_sb2) || |
| !table->ReadS16(&header->max_extent) || |
| !table->ReadS16(&header->caret_slope_rise) || |
| !table->ReadS16(&header->caret_slope_run) || |
| !table->ReadS16(&header->caret_offset)) { |
| return OTS_FAILURE_MSG("Failed to read metrics header"); |
| } |
| |
| if (header->ascent < 0) { |
| OTS_WARNING("bad ascent: %d", header->ascent); |
| header->ascent = 0; |
| } |
| if (header->linegap < 0) { |
| OTS_WARNING("bad linegap: %d", header->linegap); |
| header->linegap = 0; |
| } |
| |
| if (!file->head) { |
| return OTS_FAILURE_MSG("Missing head font table"); |
| } |
| |
| // if the font is non-slanted, caret_offset should be zero. |
| if (!(file->head->mac_style & 2) && |
| (header->caret_offset != 0)) { |
| OTS_WARNING("bad caret offset: %d", header->caret_offset); |
| header->caret_offset = 0; |
| } |
| |
| // skip the reserved bytes |
| if (!table->Skip(8)) { |
| return OTS_FAILURE_MSG("Failed to skip reserverd bytes"); |
| } |
| |
| int16_t data_format; |
| if (!table->ReadS16(&data_format)) { |
| return OTS_FAILURE_MSG("Failed to read data format"); |
| } |
| if (data_format) { |
| return OTS_FAILURE_MSG("Bad data format %d", data_format); |
| } |
| |
| if (!table->ReadU16(&header->num_metrics)) { |
| return OTS_FAILURE_MSG("Failed to read number of metrics"); |
| } |
| |
| if (!file->maxp) { |
| return OTS_FAILURE_MSG("Missing maxp font table"); |
| } |
| |
| if (header->num_metrics > file->maxp->num_glyphs) { |
| return OTS_FAILURE_MSG("Bad number of metrics %d", header->num_metrics); |
| } |
| |
| return true; |
| } |
| |
| bool SerialiseMetricsHeader(const ots::OpenTypeFile *file, |
| OTSStream *out, |
| const OpenTypeMetricsHeader *header) { |
| if (!out->WriteU32(header->version) || |
| !out->WriteS16(header->ascent) || |
| !out->WriteS16(header->descent) || |
| !out->WriteS16(header->linegap) || |
| !out->WriteU16(header->adv_width_max) || |
| !out->WriteS16(header->min_sb1) || |
| !out->WriteS16(header->min_sb2) || |
| !out->WriteS16(header->max_extent) || |
| !out->WriteS16(header->caret_slope_rise) || |
| !out->WriteS16(header->caret_slope_run) || |
| !out->WriteS16(header->caret_offset) || |
| !out->WriteR64(0) || // reserved |
| !out->WriteS16(0) || // metric data format |
| !out->WriteU16(header->num_metrics)) { |
| return OTS_FAILURE_MSG("Failed to write metrics"); |
| } |
| |
| return true; |
| } |
| |
| bool ParseMetricsTable(const ots::OpenTypeFile *file, |
| Buffer *table, |
| const uint16_t num_glyphs, |
| const OpenTypeMetricsHeader *header, |
| OpenTypeMetricsTable *metrics) { |
| // |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; |
| |
| if (num_metrics > num_glyphs) { |
| return OTS_FAILURE_MSG("Bad number of metrics %d", num_metrics); |
| } |
| if (!num_metrics) { |
| return OTS_FAILURE_MSG("No metrics!"); |
| } |
| const unsigned num_sbs = num_glyphs - num_metrics; |
| |
| metrics->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 OTS_FAILURE_MSG("Failed to read metric %d", i); |
| } |
| |
| // This check is bogus, see https://github.com/khaledhosny/ots/issues/36 |
| #if 0 |
| // Since so many fonts don't have proper value on |adv| and |sb|, |
| // we should not call ots_failure() here. For example, about 20% of fonts |
| // in http://www.princexml.com/fonts/ (200+ fonts) fails these tests. |
| if (adv > header->adv_width_max) { |
| OTS_WARNING("bad adv: %u > %u", adv, header->adv_width_max); |
| adv = header->adv_width_max; |
| } |
| |
| if (sb < header->min_sb1) { |
| OTS_WARNING("bad sb: %d < %d", sb, header->min_sb1); |
| sb = header->min_sb1; |
| } |
| #endif |
| |
| metrics->entries.push_back(std::make_pair(adv, sb)); |
| } |
| |
| metrics->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 OTS_FAILURE_MSG("Failed to read side bearing %d", i + num_metrics); |
| } |
| |
| // This check is bogus, see https://github.com/khaledhosny/ots/issues/36 |
| #if 0 |
| if (sb < header->min_sb1) { |
| // The same as above. Three fonts in http://www.fontsquirrel.com/fontface |
| // (e.g., Notice2Std.otf) have weird lsb values. |
| OTS_WARNING("bad lsb: %d < %d", sb, header->min_sb1); |
| sb = header->min_sb1; |
| } |
| #endif |
| |
| metrics->sbs.push_back(sb); |
| } |
| |
| return true; |
| } |
| |
| bool SerialiseMetricsTable(const ots::OpenTypeFile *file, |
| OTSStream *out, |
| const OpenTypeMetricsTable *metrics) { |
| for (unsigned i = 0; i < metrics->entries.size(); ++i) { |
| if (!out->WriteU16(metrics->entries[i].first) || |
| !out->WriteS16(metrics->entries[i].second)) { |
| return OTS_FAILURE_MSG("Failed to write metric %d", i); |
| } |
| } |
| |
| for (unsigned i = 0; i < metrics->sbs.size(); ++i) { |
| if (!out->WriteS16(metrics->sbs[i])) { |
| return OTS_FAILURE_MSG("Failed to write side bearing %ld", i + metrics->entries.size()); |
| } |
| } |
| |
| return true; |
| } |
| |
| } // namespace ots |
| |
| #undef TABLE_NAME |