1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/gfx/ots/src/head.cc Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,151 @@
1.4 +// Copyright (c) 2009 The Chromium Authors. All rights reserved.
1.5 +// Use of this source code is governed by a BSD-style license that can be
1.6 +// found in the LICENSE file.
1.7 +
1.8 +#include "head.h"
1.9 +
1.10 +#include <cstring>
1.11 +
1.12 +// head - Font Header
1.13 +// http://www.microsoft.com/typography/otspec/head.htm
1.14 +
1.15 +#define TABLE_NAME "head"
1.16 +
1.17 +namespace ots {
1.18 +
1.19 +bool ots_head_parse(OpenTypeFile *file, const uint8_t *data, size_t length) {
1.20 + Buffer table(data, length);
1.21 + file->head = new OpenTypeHEAD;
1.22 +
1.23 + uint32_t version = 0;
1.24 + if (!table.ReadU32(&version) ||
1.25 + !table.ReadU32(&file->head->revision)) {
1.26 + return OTS_FAILURE_MSG("Failed to read head header");
1.27 + }
1.28 +
1.29 + if (version >> 16 != 1) {
1.30 + return OTS_FAILURE_MSG("Bad head table version of %d", version);
1.31 + }
1.32 +
1.33 + // Skip the checksum adjustment
1.34 + if (!table.Skip(4)) {
1.35 + return OTS_FAILURE_MSG("Failed to read checksum");
1.36 + }
1.37 +
1.38 + uint32_t magic;
1.39 + if (!table.ReadTag(&magic) ||
1.40 + std::memcmp(&magic, "\x5F\x0F\x3C\xF5", 4)) {
1.41 + return OTS_FAILURE_MSG("Failed to read font magic number");
1.42 + }
1.43 +
1.44 + if (!table.ReadU16(&file->head->flags)) {
1.45 + return OTS_FAILURE_MSG("Failed to read head flags");
1.46 + }
1.47 +
1.48 + // We allow bits 0..4, 11..13
1.49 + file->head->flags &= 0x381f;
1.50 +
1.51 + if (!table.ReadU16(&file->head->ppem)) {
1.52 + return OTS_FAILURE_MSG("Failed to read pixels per em");
1.53 + }
1.54 +
1.55 + // ppem must be in range
1.56 + if (file->head->ppem < 16 ||
1.57 + file->head->ppem > 16384) {
1.58 + return OTS_FAILURE_MSG("Bad ppm of %d", file->head->ppem);
1.59 + }
1.60 +
1.61 + // ppem must be a power of two
1.62 +#if 0
1.63 + // We don't call ots_failure() for now since lots of TrueType fonts are
1.64 + // not following this rule. Putting OTS_WARNING here is too noisy.
1.65 + if ((file->head->ppem - 1) & file->head->ppem) {
1.66 + return OTS_FAILURE_MSG("ppm not a power of two: %d", file->head->ppem);
1.67 + }
1.68 +#endif
1.69 +
1.70 + if (!table.ReadR64(&file->head->created) ||
1.71 + !table.ReadR64(&file->head->modified)) {
1.72 + return OTS_FAILURE_MSG("Can't read font dates");
1.73 + }
1.74 +
1.75 + if (!table.ReadS16(&file->head->xmin) ||
1.76 + !table.ReadS16(&file->head->ymin) ||
1.77 + !table.ReadS16(&file->head->xmax) ||
1.78 + !table.ReadS16(&file->head->ymax)) {
1.79 + return OTS_FAILURE_MSG("Failed to read font bounding box");
1.80 + }
1.81 +
1.82 + if (file->head->xmin > file->head->xmax) {
1.83 + return OTS_FAILURE_MSG("Bad x dimension in the font bounding box (%d, %d)", file->head->xmin, file->head->xmax);
1.84 + }
1.85 + if (file->head->ymin > file->head->ymax) {
1.86 + return OTS_FAILURE_MSG("Bad y dimension in the font bounding box (%d, %d)", file->head->ymin, file->head->ymax);
1.87 + }
1.88 +
1.89 + if (!table.ReadU16(&file->head->mac_style)) {
1.90 + return OTS_FAILURE_MSG("Failed to read font style");
1.91 + }
1.92 +
1.93 + // We allow bits 0..6
1.94 + file->head->mac_style &= 0x7f;
1.95 +
1.96 + if (!table.ReadU16(&file->head->min_ppem)) {
1.97 + return OTS_FAILURE_MSG("Failed to read font minimum ppm");
1.98 + }
1.99 +
1.100 + // We don't care about the font direction hint
1.101 + if (!table.Skip(2)) {
1.102 + return OTS_FAILURE_MSG("Failed to skip font direction hint");
1.103 + }
1.104 +
1.105 + if (!table.ReadS16(&file->head->index_to_loc_format)) {
1.106 + return OTS_FAILURE_MSG("Failed to read index to loc format");
1.107 + }
1.108 + if (file->head->index_to_loc_format < 0 ||
1.109 + file->head->index_to_loc_format > 1) {
1.110 + return OTS_FAILURE_MSG("Bad index to loc format %d", file->head->index_to_loc_format);
1.111 + }
1.112 +
1.113 + int16_t glyph_data_format;
1.114 + if (!table.ReadS16(&glyph_data_format) ||
1.115 + glyph_data_format) {
1.116 + return OTS_FAILURE_MSG("Failed to read glyph data format");
1.117 + }
1.118 +
1.119 + return true;
1.120 +}
1.121 +
1.122 +bool ots_head_should_serialise(OpenTypeFile *file) {
1.123 + return file->head != NULL;
1.124 +}
1.125 +
1.126 +bool ots_head_serialise(OTSStream *out, OpenTypeFile *file) {
1.127 + if (!out->WriteU32(0x00010000) ||
1.128 + !out->WriteU32(file->head->revision) ||
1.129 + !out->WriteU32(0) || // check sum not filled in yet
1.130 + !out->WriteU32(0x5F0F3CF5) ||
1.131 + !out->WriteU16(file->head->flags) ||
1.132 + !out->WriteU16(file->head->ppem) ||
1.133 + !out->WriteR64(file->head->created) ||
1.134 + !out->WriteR64(file->head->modified) ||
1.135 + !out->WriteS16(file->head->xmin) ||
1.136 + !out->WriteS16(file->head->ymin) ||
1.137 + !out->WriteS16(file->head->xmax) ||
1.138 + !out->WriteS16(file->head->ymax) ||
1.139 + !out->WriteU16(file->head->mac_style) ||
1.140 + !out->WriteU16(file->head->min_ppem) ||
1.141 + !out->WriteS16(2) ||
1.142 + !out->WriteS16(file->head->index_to_loc_format) ||
1.143 + !out->WriteS16(0)) {
1.144 + return OTS_FAILURE_MSG("Failed to write head table");
1.145 + }
1.146 +
1.147 + return true;
1.148 +}
1.149 +
1.150 +void ots_head_free(OpenTypeFile *file) {
1.151 + delete file->head;
1.152 +}
1.153 +
1.154 +} // namespace
