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-rw-r--r--gfx/ots/src/head.cc159
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