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Diffstat (limited to 'gfx/ots/src/head.cc')
-rw-r--r-- | gfx/ots/src/head.cc | 159 |
1 files changed, 159 insertions, 0 deletions
diff --git a/gfx/ots/src/head.cc b/gfx/ots/src/head.cc new file mode 100644 index 000000000..229ea71f9 --- /dev/null +++ b/gfx/ots/src/head.cc @@ -0,0 +1,159 @@ +// 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 "head.h" + +#include <cstring> + +// head - Font Header +// http://www.microsoft.com/typography/otspec/head.htm + +#define TABLE_NAME "head" + +namespace ots { + +bool ots_head_parse(Font* font, const uint8_t *data, size_t length) { + Buffer table(data, length); + OpenTypeHEAD *head = new OpenTypeHEAD; + font->head = head; + + uint32_t version = 0; + if (!table.ReadU32(&version) || + !table.ReadU32(&head->revision)) { + return OTS_FAILURE_MSG("Failed to read head header"); + } + + if (version >> 16 != 1) { + return OTS_FAILURE_MSG("Bad head table version of %d", version); + } + + // Skip the checksum adjustment + if (!table.Skip(4)) { + return OTS_FAILURE_MSG("Failed to read checksum"); + } + + uint32_t magic; + if (!table.ReadU32(&magic) || magic != 0x5F0F3CF5) { + return OTS_FAILURE_MSG("Failed to read font magic number"); + } + + if (!table.ReadU16(&head->flags)) { + return OTS_FAILURE_MSG("Failed to read head flags"); + } + + // We allow bits 0..4, 11..13 + head->flags &= 0x381f; + + if (!table.ReadU16(&head->ppem)) { + return OTS_FAILURE_MSG("Failed to read pixels per em"); + } + + // ppem must be in range + if (head->ppem < 16 || + head->ppem > 16384) { + return OTS_FAILURE_MSG("Bad ppm of %d", head->ppem); + } + + // ppem must be a power of two +#if 0 + // We don't call ots_failure() for now since lots of TrueType fonts are + // not following this rule. Putting OTS_WARNING here is too noisy. + if ((head->ppem - 1) & head->ppem) { + return OTS_FAILURE_MSG("ppm not a power of two: %d", head->ppem); + } +#endif + + if (!table.ReadR64(&head->created) || + !table.ReadR64(&head->modified)) { + return OTS_FAILURE_MSG("Can't read font dates"); + } + + if (!table.ReadS16(&head->xmin) || + !table.ReadS16(&head->ymin) || + !table.ReadS16(&head->xmax) || + !table.ReadS16(&head->ymax)) { + return OTS_FAILURE_MSG("Failed to read font bounding box"); + } + + if (head->xmin > head->xmax) { + return OTS_FAILURE_MSG("Bad x dimension in the font bounding box (%d, %d)", head->xmin, head->xmax); + } + if (head->ymin > head->ymax) { + return OTS_FAILURE_MSG("Bad y dimension in the font bounding box (%d, %d)", head->ymin, head->ymax); + } + + if (!table.ReadU16(&head->mac_style)) { + return OTS_FAILURE_MSG("Failed to read font style"); + } + + // We allow bits 0..6 + head->mac_style &= 0x7f; + + if (!table.ReadU16(&head->min_ppem)) { + return OTS_FAILURE_MSG("Failed to read font minimum ppm"); + } + + // We don't care about the font direction hint + if (!table.Skip(2)) { + return OTS_FAILURE_MSG("Failed to skip font direction hint"); + } + + if (!table.ReadS16(&head->index_to_loc_format)) { + return OTS_FAILURE_MSG("Failed to read index to loc format"); + } + if (head->index_to_loc_format < 0 || + head->index_to_loc_format > 1) { + return OTS_FAILURE_MSG("Bad index to loc format %d", head->index_to_loc_format); + } + + int16_t glyph_data_format; + if (!table.ReadS16(&glyph_data_format) || + glyph_data_format) { + return OTS_FAILURE_MSG("Failed to read glyph data format"); + } + + return true; +} + +bool ots_head_should_serialise(Font *font) { + return font->head != NULL; +} + +bool ots_head_serialise(OTSStream *out, Font *font) { + const OpenTypeHEAD *head = font->head; + if (!out->WriteU32(0x00010000) || + !out->WriteU32(head->revision) || + !out->WriteU32(0) || // check sum not filled in yet + !out->WriteU32(0x5F0F3CF5) || + !out->WriteU16(head->flags) || + !out->WriteU16(head->ppem) || + !out->WriteR64(head->created) || + !out->WriteR64(head->modified) || + !out->WriteS16(head->xmin) || + !out->WriteS16(head->ymin) || + !out->WriteS16(head->xmax) || + !out->WriteS16(head->ymax) || + !out->WriteU16(head->mac_style) || + !out->WriteU16(head->min_ppem) || + !out->WriteS16(2) || + !out->WriteS16(head->index_to_loc_format) || + !out->WriteS16(0)) { + return OTS_FAILURE_MSG("Failed to write head table"); + } + + return true; +} + +void ots_head_reuse(Font *font, Font *other) { + font->head = other->head; + font->head_reused = true; +} + +void ots_head_free(Font *font) { + delete font->head; +} + +} // namespace + +#undef TABLE_NAME |