--- /dev/null
+/*
+ * @(#)KernTable.cpp 1.1 04/10/13
+ *
+ * (C) Copyright IBM Corp. 2004-2005 - All Rights Reserved
+ *
+ */
+
+#include "KernTable.h"
+#include "LEFontInstance.h"
+#include "LEGlyphStorage.h"
+
+#include "LESwaps.h"
+
+#include <stdio.h>
+
+#define DEBUG 0
+
+U_NAMESPACE_BEGIN
+
+struct PairInfo {
+ le_uint32 key; // sigh, MSVC compiler gags on union here
+ le_int16 value; // fword, kern value in funits
+};
+#define KERN_PAIRINFO_SIZE 6
+
+struct Subtable_0 {
+ le_uint16 nPairs;
+ le_uint16 searchRange;
+ le_uint16 entrySelector;
+ le_uint16 rangeShift;
+};
+#define KERN_SUBTABLE_0_HEADER_SIZE 8
+
+// Kern table version 0 only
+struct SubtableHeader {
+ le_uint16 version;
+ le_uint16 length;
+ le_uint16 coverage;
+};
+#define KERN_SUBTABLE_HEADER_SIZE 6
+
+// Version 0 only, version 1 has different layout
+struct KernTableHeader {
+ le_uint16 version;
+ le_uint16 nTables;
+};
+#define KERN_TABLE_HEADER_SIZE 4
+
+#define COVERAGE_HORIZONTAL 0x1
+#define COVERAGE_MINIMUM 0x2
+#define COVERAGE_CROSS 0x4
+#define COVERAGE_OVERRIDE 0x8
+
+/*
+ * This implementation has support for only one subtable, so if the font has
+ * multiple subtables, only the first will be used. If this turns out to
+ * be a problem in practice we should add it.
+ *
+ * This also supports only version 0 of the kern table header, only
+ * Apple supports the latter.
+ *
+ * This implementation isn't careful about the kern table flags, and
+ * might invoke kerning when it is not supposed to. That too I'm
+ * leaving for a bug fix.
+ *
+ * TODO: support multiple subtables
+ * TODO: respect header flags
+ */
+KernTable::KernTable(const LEFontInstance* font, const void* tableData)
+ : pairs(0), font(font)
+{
+ const KernTableHeader* header = (const KernTableHeader*)tableData;
+ if (header == 0) {
+#if DEBUG
+ fprintf(stderr, "no kern data\n");
+#endif
+ return;
+ }
+
+#if DEBUG
+ // dump first 32 bytes of header
+ for (int i = 0; i < 64; ++i) {
+ fprintf(stderr, "%0.2x ", ((const char*)tableData)[i]&0xff);
+ if (((i+1)&0xf) == 0) {
+ fprintf(stderr, "\n");
+ } else if (((i+1)&0x7) == 0) {
+ fprintf(stderr, " ");
+ }
+ }
+#endif
+
+ if (header->version == 0 && SWAPW(header->nTables) > 0) {
+ const SubtableHeader* subhead = (const SubtableHeader*)((char*)tableData + KERN_TABLE_HEADER_SIZE);
+ if (subhead->version == 0) {
+ coverage = SWAPW(subhead->coverage);
+ if (coverage & COVERAGE_HORIZONTAL) { // only handle horizontal kerning
+ const Subtable_0* table = (const Subtable_0*)((char*)subhead + KERN_SUBTABLE_HEADER_SIZE);
+ nPairs = SWAPW(table->nPairs);
+ searchRange = SWAPW(table->searchRange);
+ entrySelector = SWAPW(table->entrySelector);
+ rangeShift = SWAPW(table->rangeShift);
+ pairs = (const PairInfo*)((char*)table + KERN_SUBTABLE_0_HEADER_SIZE);
+
+#if DEBUG
+ fprintf(stderr, "coverage: %0.4x nPairs: %d pairs 0x%x\n", coverage, nPairs, pairs);
+ fprintf(stderr, " searchRange: %d entrySelector: %d rangeShift: %d\n", searchRange, entrySelector, rangeShift);
+
+ {
+ // dump part of the pair list
+ char ids[256];
+ for (int i = 256; --i >= 0;) {
+ LEGlyphID id = font->mapCharToGlyph(i);
+ if (id < 256) {
+ ids[id] = (char)i;
+ }
+ }
+
+ const PairInfo* p = pairs;
+ for (i = 0; i < nPairs; ++i, p = (const PairInfo*)((char*)p+KERN_PAIRINFO_SIZE)) {
+ le_uint32 k = SWAPL(p->key);
+ le_uint16 left = (k >> 16) & 0xffff;
+ le_uint16 right = k & 0xffff;
+ if (left < 256 && right < 256) {
+ char c = ids[left];
+ if (c > 0x20 && c < 0x7f) {
+ fprintf(stderr, "%c/", c & 0xff);
+ } else {
+ fprintf(stderr, "%0.2x/", c & 0xff);
+ }
+ c = ids[right];
+ if (c > 0x20 && c < 0x7f) {
+ fprintf(stderr, "%c ", c & 0xff);
+ } else {
+ fprintf(stderr, "%0.2x ", c & 0xff);
+ }
+ }
+ }
+ }
+#endif
+ }
+ }
+ }
+}
+
+
+/*
+ * Process the glyph positions. The positions array has two floats for each
+ * glyph, plus a trailing pair to mark the end of the last glyph.
+ */
+void KernTable::process(LEGlyphStorage& storage)
+{
+ if (pairs) {
+ LEErrorCode success = LE_NO_ERROR;
+
+ le_uint32 key = storage[0]; // no need to mask off high bits
+ float adjust = 0;
+ for (int i = 1, e = storage.getGlyphCount(); i < e; ++i) {
+ key = key << 16 | (storage[i] & 0xffff);
+
+ // argh, to do a binary search, we need to have the pair list in sorted order
+ // but it is not in sorted order on win32 platforms because of the endianness difference
+ // so either I have to swap the element each time I examine it, or I have to swap
+ // all the elements ahead of time and store them in the font
+
+ const PairInfo* p = pairs;
+ const PairInfo* tp = (const PairInfo*)((char*)p + rangeShift);
+ if (key > SWAPL(tp->key)) {
+ p = tp;
+ }
+
+#if DEBUG
+ fprintf(stderr, "binary search for %0.8x\n", key);
+#endif
+
+ le_uint32 probe = searchRange;
+ while (probe > KERN_PAIRINFO_SIZE) {
+ probe >>= 1;
+ tp = (const PairInfo*)((char*)p + probe);
+ le_uint32 tkey = SWAPL(tp->key);
+#if DEBUG
+ fprintf(stdout, " %.3d (%0.8x)\n", ((char*)tp - (char*)pairs)/KERN_PAIRINFO_SIZE, tkey);
+#endif
+ if (tkey <= key) {
+ if (tkey == key) {
+ le_int16 value = SWAPW(tp->value);
+#if DEBUG
+ fprintf(stdout, "binary found kerning pair %x:%x at %d, value: 0x%x (%g)\n",
+ storage[i-1], storage[i], i, value & 0xffff, font->xUnitsToPoints(value));
+ fflush(stdout);
+#endif
+ adjust += font->xUnitsToPoints(value);
+ break;
+ }
+ p = tp;
+ }
+ }
+
+ storage.adjustPosition(i, adjust, 0, success);
+ }
+ storage.adjustPosition(storage.getGlyphCount(), adjust, 0, success);
+ }
+}
+
+U_NAMESPACE_END
+
projects / apple / icu.git / blobdiff