121 lines
3.7 KiB
C++
121 lines
3.7 KiB
C++
// Copyright (c) 2009-2017 The OTS Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#include "hdmx.h"
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#include "head.h"
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#include "maxp.h"
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// hdmx - Horizontal Device Metrics
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// http://www.microsoft.com/typography/otspec/hdmx.htm
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namespace ots {
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bool OpenTypeHDMX::Parse(const uint8_t *data, size_t length) {
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Buffer table(data, length);
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OpenTypeMAXP *maxp = static_cast<OpenTypeMAXP*>(
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GetFont()->GetTypedTable(OTS_TAG_MAXP));
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OpenTypeHEAD *head = static_cast<OpenTypeHEAD*>(
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GetFont()->GetTypedTable(OTS_TAG_HEAD));
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if (!head || !maxp) {
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return Error("Missing maxp or head tables in font, needed by hdmx");
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}
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if ((head->flags & 0x14) == 0) {
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// http://www.microsoft.com/typography/otspec/recom.htm#hdmx
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return Drop("the table should not be present when bit 2 and 4 of the "
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"head->flags are not set");
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}
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int16_t num_recs;
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if (!table.ReadU16(&this->version) ||
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!table.ReadS16(&num_recs) ||
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!table.ReadS32(&this->size_device_record)) {
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return Error("Failed to read table header");
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}
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if (this->version != 0) {
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return Drop("Unsupported version: %u", this->version);
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}
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if (num_recs <= 0) {
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return Drop("Bad numRecords: %d", num_recs);
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}
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const int32_t actual_size_device_record = maxp->num_glyphs + 2;
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if (this->size_device_record < actual_size_device_record) {
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return Drop("Bad sizeDeviceRecord: %d", this->size_device_record);
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}
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this->pad_len = this->size_device_record - actual_size_device_record;
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if (this->pad_len > 3) {
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return Error("Bad DeviceRecord padding %d", this->pad_len);
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}
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uint8_t last_pixel_size = 0;
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this->records.reserve(num_recs);
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for (int i = 0; i < num_recs; ++i) {
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OpenTypeHDMXDeviceRecord rec;
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if (!table.ReadU8(&rec.pixel_size) ||
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!table.ReadU8(&rec.max_width)) {
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return Error("Failed to read DeviceRecord %d", i);
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}
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if ((i != 0) &&
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(rec.pixel_size <= last_pixel_size)) {
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return Drop("DeviceRecord's are not sorted");
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}
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last_pixel_size = rec.pixel_size;
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rec.widths.reserve(maxp->num_glyphs);
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for (unsigned j = 0; j < maxp->num_glyphs; ++j) {
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uint8_t width;
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if (!table.ReadU8(&width)) {
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return Error("Failed to read glyph width %d in DeviceRecord %d", j, i);
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}
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rec.widths.push_back(width);
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}
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if ((this->pad_len > 0) &&
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!table.Skip(this->pad_len)) {
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return Error("DeviceRecord %d should be padded by %d", i, this->pad_len);
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}
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this->records.push_back(rec);
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}
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return true;
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}
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bool OpenTypeHDMX::ShouldSerialize() {
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return Table::ShouldSerialize() &&
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// this table is not for CFF fonts.
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GetFont()->GetTable(OTS_TAG_GLYF) != NULL;
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}
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bool OpenTypeHDMX::Serialize(OTSStream *out) {
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const int16_t num_recs = static_cast<int16_t>(this->records.size());
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if (this->records.size() >
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static_cast<size_t>(std::numeric_limits<int16_t>::max()) ||
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!out->WriteU16(this->version) ||
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!out->WriteS16(num_recs) ||
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!out->WriteS32(this->size_device_record)) {
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return Error("Failed to write table header");
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}
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for (int16_t i = 0; i < num_recs; ++i) {
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const OpenTypeHDMXDeviceRecord& rec = this->records[i];
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if (!out->Write(&rec.pixel_size, 1) ||
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!out->Write(&rec.max_width, 1) ||
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!out->Write(&rec.widths[0], rec.widths.size())) {
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return Error("Failed to write DeviceRecord %d", i);
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}
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if ((this->pad_len > 0) &&
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!out->Write((const uint8_t *)"\x00\x00\x00", this->pad_len)) {
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return Error("Failed to write padding of length %d", this->pad_len);
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}
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}
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return true;
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}
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} // namespace ots
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