blob: 229ea71f9035c5832ee86c343c0b0c79e2d6349c [file] [log] [blame]
// 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