diff options
Diffstat (limited to '')
| -rw-r--r-- | gfx/ots/src/vdmx.cc | 173 |
1 files changed, 173 insertions, 0 deletions
diff --git a/gfx/ots/src/vdmx.cc b/gfx/ots/src/vdmx.cc new file mode 100644 index 0000000000..17433f8894 --- /dev/null +++ b/gfx/ots/src/vdmx.cc @@ -0,0 +1,173 @@ +// Copyright (c) 2009-2017 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 "vdmx.h" + +#include <set> + +// VDMX - Vertical Device Metrics +// http://www.microsoft.com/typography/otspec/vdmx.htm + +namespace ots { + +#define TABLE_NAME "VDMX" + +bool OpenTypeVDMX::Parse(const uint8_t *data, size_t length) { + Buffer table(data, length); + ots::Font* font = this->GetFont(); + + if (!table.ReadU16(&this->version) || + !table.ReadU16(&this->num_recs) || + !table.ReadU16(&this->num_ratios)) { + return Drop("Failed to read table header"); + } + + if (this->version > 1) { + return Drop("Unsupported table version: %u", this->version); + } + + this->rat_ranges.reserve(this->num_ratios); + for (unsigned i = 0; i < this->num_ratios; ++i) { + OpenTypeVDMXRatioRecord rec; + + if (!table.ReadU8(&rec.charset) || + !table.ReadU8(&rec.x_ratio) || + !table.ReadU8(&rec.y_start_ratio) || + !table.ReadU8(&rec.y_end_ratio)) { + return Drop("Failed to read RatioRange record %d", i); + } + + if (rec.charset > 1) { + return Drop("Unsupported character set: %u", rec.charset); + } + + if (rec.y_start_ratio > rec.y_end_ratio) { + return Drop("Bad y ratio"); + } + + // All values set to zero signal the default grouping to use; + // if present, this must be the last Ratio group in the table. + if ((i < this->num_ratios - 1u) && + (rec.x_ratio == 0) && + (rec.y_start_ratio == 0) && + (rec.y_end_ratio == 0)) { + // workaround for fonts which have 2 or more {0, 0, 0} terminators. + return Drop("Superfluous terminator found"); + } + + this->rat_ranges.push_back(rec); + } + + this->offsets.reserve(this->num_ratios); + const size_t current_offset = table.offset(); + std::set<uint16_t> unique_offsets; + // current_offset is less than (2 bytes * 3) + (4 bytes * USHRT_MAX) = 256k. + for (unsigned i = 0; i < this->num_ratios; ++i) { + uint16_t offset; + if (!table.ReadU16(&offset)) { + return Drop("Failed to read ratio offset %d", i); + } + if (current_offset + offset >= length) { // thus doesn't overflow. + return Drop("Bad ratio offset %d for ration %d", offset, i); + } + + this->offsets.push_back(offset); + unique_offsets.insert(offset); + } + + // Check that num_recs is sufficient to provide as many VDMXGroup records + // as there are unique offsets; if not, update it (we'll return an error + // below if they're not actually present). + if (unique_offsets.size() > this->num_recs) { + OTS_WARNING("increasing num_recs (%u is too small for %u unique offsets)", + this->num_recs, unique_offsets.size()); + this->num_recs = unique_offsets.size(); + } + + this->groups.reserve(this->num_recs); + for (unsigned i = 0; i < this->num_recs; ++i) { + OpenTypeVDMXGroup group; + if (!table.ReadU16(&group.recs) || + !table.ReadU8(&group.startsz) || + !table.ReadU8(&group.endsz)) { + return Drop("Failed to read record header %d", i); + } + group.entries.reserve(group.recs); + for (unsigned j = 0; j < group.recs; ++j) { + OpenTypeVDMXVTable vt; + if (!table.ReadU16(&vt.y_pel_height) || + !table.ReadS16(&vt.y_max) || + !table.ReadS16(&vt.y_min)) { + return Drop("Failed to read record %d group %d", i, j); + } + if (vt.y_max < vt.y_min) { + return Drop("bad y min/max"); + } + + // This table must appear in sorted order (sorted by yPelHeight), + // but need not be continuous. + if ((j != 0) && (group.entries[j - 1].y_pel_height >= vt.y_pel_height)) { + return Drop("The table is not sorted"); + } + + group.entries.push_back(vt); + } + this->groups.push_back(group); + } + + return true; +} + +bool OpenTypeVDMX::ShouldSerialize() { + return Table::ShouldSerialize() && + // this table is not for CFF fonts. + GetFont()->GetTable(OTS_TAG_GLYF) != NULL; +} + +bool OpenTypeVDMX::Serialize(OTSStream *out) { + if (!out->WriteU16(this->version) || + !out->WriteU16(this->num_recs) || + !out->WriteU16(this->num_ratios)) { + return Error("Failed to write table header"); + } + + for (unsigned i = 0; i < this->rat_ranges.size(); ++i) { + const OpenTypeVDMXRatioRecord& rec = this->rat_ranges[i]; + if (!out->Write(&rec.charset, 1) || + !out->Write(&rec.x_ratio, 1) || + !out->Write(&rec.y_start_ratio, 1) || + !out->Write(&rec.y_end_ratio, 1)) { + return Error("Failed to write RatioRange record %d", i); + } + } + + for (unsigned i = 0; i < this->offsets.size(); ++i) { + if (!out->WriteU16(this->offsets[i])) { + return Error("Failed to write ratio offset %d", i); + } + } + + for (unsigned i = 0; i < this->groups.size(); ++i) { + const OpenTypeVDMXGroup& group = this->groups[i]; + if (!out->WriteU16(group.recs) || + !out->Write(&group.startsz, 1) || + !out->Write(&group.endsz, 1)) { + return Error("Failed to write group %d", i); + } + for (unsigned j = 0; j < group.entries.size(); ++j) { + const OpenTypeVDMXVTable& vt = group.entries[j]; + if (!out->WriteU16(vt.y_pel_height) || + !out->WriteS16(vt.y_max) || + !out->WriteS16(vt.y_min)) { + return Error("Failed to write group %d entry %d", i, j); + } + } + } + + return true; +} + +#undef TABLE_NAME + +} // namespace ots |