diff options
Diffstat (limited to 'gfx/ots/src/metrics.cc')
-rw-r--r-- | gfx/ots/src/metrics.cc | 165 |
1 files changed, 165 insertions, 0 deletions
diff --git a/gfx/ots/src/metrics.cc b/gfx/ots/src/metrics.cc new file mode 100644 index 000000000..cd89f4555 --- /dev/null +++ b/gfx/ots/src/metrics.cc @@ -0,0 +1,165 @@ +// 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(Font *font, 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 (!font->head) { + return OTS_FAILURE_MSG("Missing head font table"); + } + + // if the font is non-slanted, caret_offset should be zero. + if (!(font->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 (!font->maxp) { + return OTS_FAILURE_MSG("Missing maxp font table"); + } + + if (header->num_metrics > font->maxp->num_glyphs) { + return OTS_FAILURE_MSG("Bad number of metrics %d", header->num_metrics); + } + + return true; +} + +bool SerialiseMetricsHeader(const ots::Font *font, + 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::Font *font, + 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); + } + 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); + } + metrics->sbs.push_back(sb); + } + + return true; +} + +bool SerialiseMetricsTable(const ots::Font *font, + 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 |