diff options
Diffstat (limited to 'gfx/ots/src/vdmx.cc')
| -rw-r--r-- | gfx/ots/src/vdmx.cc | 186 |
1 files changed, 186 insertions, 0 deletions
diff --git a/gfx/ots/src/vdmx.cc b/gfx/ots/src/vdmx.cc new file mode 100644 index 000000000..cd80946ae --- /dev/null +++ b/gfx/ots/src/vdmx.cc @@ -0,0 +1,186 @@ +// Copyright (c) 2009 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 "vdmx.h" + +// VDMX - Vertical Device Metrics +// http://www.microsoft.com/typography/otspec/vdmx.htm + +#define TABLE_NAME "VDMX" + +#define DROP_THIS_TABLE(...) \ + do { \ + OTS_FAILURE_MSG_(font->file, TABLE_NAME ": " __VA_ARGS__); \ + OTS_FAILURE_MSG("Table discarded"); \ + delete font->vdmx; \ + font->vdmx = 0; \ + } while (0) + +namespace ots { + +bool ots_vdmx_parse(Font *font, const uint8_t *data, size_t length) { + Buffer table(data, length); + font->vdmx = new OpenTypeVDMX; + OpenTypeVDMX * const vdmx = font->vdmx; + + if (!table.ReadU16(&vdmx->version) || + !table.ReadU16(&vdmx->num_recs) || + !table.ReadU16(&vdmx->num_ratios)) { + return OTS_FAILURE_MSG("Failed to read table header"); + } + + if (vdmx->version > 1) { + DROP_THIS_TABLE("bad version: %u", vdmx->version); + return true; // continue transcoding + } + + vdmx->rat_ranges.reserve(vdmx->num_ratios); + for (unsigned i = 0; i < vdmx->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 OTS_FAILURE_MSG("Failed to read ratio header %d", i); + } + + if (rec.charset > 1) { + DROP_THIS_TABLE("bad charset: %u", rec.charset); + return true; + } + + if (rec.y_start_ratio > rec.y_end_ratio) { + DROP_THIS_TABLE("bad y ratio"); + return true; + } + + // 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 < vdmx->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. + DROP_THIS_TABLE("superfluous terminator found"); + return true; + } + + vdmx->rat_ranges.push_back(rec); + } + + vdmx->offsets.reserve(vdmx->num_ratios); + const size_t current_offset = table.offset(); + // current_offset is less than (2 bytes * 3) + (4 bytes * USHRT_MAX) = 256k. + for (unsigned i = 0; i < vdmx->num_ratios; ++i) { + uint16_t offset; + if (!table.ReadU16(&offset)) { + return OTS_FAILURE_MSG("Failed to read ratio offset %d", i); + } + if (current_offset + offset >= length) { // thus doesn't overflow. + return OTS_FAILURE_MSG("Bad ratio offset %d for ration %d", offset, i); + } + + vdmx->offsets.push_back(offset); + } + + vdmx->groups.reserve(vdmx->num_recs); + for (unsigned i = 0; i < vdmx->num_recs; ++i) { + OpenTypeVDMXGroup group; + if (!table.ReadU16(&group.recs) || + !table.ReadU8(&group.startsz) || + !table.ReadU8(&group.endsz)) { + return OTS_FAILURE_MSG("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 OTS_FAILURE_MSG("Failed to read reacord %d group %d", i, j); + } + if (vt.y_max < vt.y_min) { + DROP_THIS_TABLE("bad y min/max"); + return true; + } + + // 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)) { + DROP_THIS_TABLE("the table is not sorted"); + return true; + } + + group.entries.push_back(vt); + } + vdmx->groups.push_back(group); + } + + return true; +} + +bool ots_vdmx_should_serialise(Font *font) { + if (!font->glyf) return false; // this table is not for CFF fonts. + return font->vdmx != NULL; +} + +bool ots_vdmx_serialise(OTSStream *out, Font *font) { + OpenTypeVDMX * const vdmx = font->vdmx; + + if (!out->WriteU16(vdmx->version) || + !out->WriteU16(vdmx->num_recs) || + !out->WriteU16(vdmx->num_ratios)) { + return OTS_FAILURE_MSG("Failed to write table header"); + } + + for (unsigned i = 0; i < vdmx->rat_ranges.size(); ++i) { + const OpenTypeVDMXRatioRecord& rec = vdmx->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 OTS_FAILURE_MSG("Failed to write ratio %d", i); + } + } + + for (unsigned i = 0; i < vdmx->offsets.size(); ++i) { + if (!out->WriteU16(vdmx->offsets[i])) { + return OTS_FAILURE_MSG("Failed to write ratio offset %d", i); + } + } + + for (unsigned i = 0; i < vdmx->groups.size(); ++i) { + const OpenTypeVDMXGroup& group = vdmx->groups[i]; + if (!out->WriteU16(group.recs) || + !out->Write(&group.startsz, 1) || + !out->Write(&group.endsz, 1)) { + return OTS_FAILURE_MSG("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 OTS_FAILURE_MSG("Failed to write group %d entry %d", i, j); + } + } + } + + return true; +} + +void ots_vdmx_reuse(Font *font, Font *other) { + font->vdmx = other->vdmx; + font->vdmx_reused = true; +} + +void ots_vdmx_free(Font *font) { + delete font->vdmx; +} + +} // namespace ots + +#undef TABLE_NAME +#undef DROP_THIS_TABLE |