icuSources/test/letest/FontObject.cpp

   1 /***************************************************************************
   2 *
   3 *   Copyright (C) 1998-2002, International Business Machines
   4 *   Corporation and others.  All Rights Reserved.
   5 *
   6 ************************************************************************/
   7
   8 #include <stdio.h>
   9
  10 #include "LETypes.h"
  11 #include "FontObject.h"
  12 #include "LESwaps.h"
  13
  14 FontObject::FontObject(char *fileName)
  15   : directory(NULL), numTables(0), searchRange(0),entrySelector(0),
  16     cmapTable(NULL), cmSegCount(0), cmSearchRange(0), cmEntrySelector(0),
  17     cmEndCodes(NULL), cmStartCodes(NULL), cmIdDelta(0), cmIdRangeOffset(0),
  18     headTable(NULL), hmtxTable(NULL), numGlyphs(0), numOfLongHorMetrics(0), file(NULL)
  19 {
  20     file = fopen(fileName, "rb");
  21
  22     if (file == NULL) {
  23         printf("?? Couldn't open %s", fileName);
  24         return;
  25     }
  26
  27     SFNTDirectory tempDir;
  28
  29     fread(&tempDir, sizeof tempDir, 1, file);
  30
  31     numTables       = SWAPW(tempDir.numTables);
  32     searchRange     = SWAPW(tempDir.searchRange) >> 4;
  33     entrySelector   = SWAPW(tempDir.entrySelector);
  34     rangeShift      = SWAPW(tempDir.rangeShift) >> 4;
  35
  36     int dirSize = sizeof tempDir + ((numTables - ANY_NUMBER) * sizeof(DirectoryEntry));
  37
  38     directory = (SFNTDirectory *) new char[dirSize];
  39
  40     fseek(file, 0L, SEEK_SET);
  41     fread(directory, sizeof(char), dirSize, file);
  42
  43     initUnicodeCMAP();
  44 }
  45
  46 FontObject::~FontObject()
  47 {
  48     fclose(file);
  49     delete[] directory;
  50     delete[] cmapTable;
  51     delete[] headTable;
  52     delete[] hmtxTable;
  53 }
  54
  55 void FontObject::deleteTable(void *table)
  56 {
  57     delete[] (char *) table;
  58 }
  59
  60 DirectoryEntry *FontObject::findTable(LETag tag)
  61 {
  62     le_uint16 table = 0;
  63     le_uint16 probe = 1 << entrySelector;
  64
  65     if (SWAPL(directory->tableDirectory[rangeShift].tag) <= tag) {
  66         table = rangeShift;
  67     }
  68
  69     while (probe > (1 << 0)) {
  70         probe >>= 1;
  71
  72         if (SWAPL(directory->tableDirectory[table + probe].tag) <= tag) {
  73             table += probe;
  74         }
  75     }
  76
  77     if (SWAPL(directory->tableDirectory[table].tag) == tag) {
  78         return &directory->tableDirectory[table];
  79     }
  80
  81     return NULL;
  82 }
  83
  84 void *FontObject::readTable(LETag tag, le_uint32 *length)
  85 {
  86     DirectoryEntry *entry = findTable(tag);
  87
  88     if (entry == NULL) {
  89         *length = 0;
  90         return NULL;
  91     }
  92
  93     *length = SWAPL(entry->length);
  94
  95     void *table = new char[*length];
  96
  97     fseek(file, SWAPL(entry->offset), SEEK_SET);
  98     fread(table, sizeof(char), *length, file);
  99
 100     return table;
 101 }
 102
 103 CMAPEncodingSubtable *FontObject::findCMAP(le_uint16 platformID, le_uint16 platformSpecificID)
 104 {
 105     LETag cmapTag = 0x636D6170; // 'cmap'
 106
 107     if (cmapTable == NULL) {
 108         le_uint32 length;
 109
 110         cmapTable = (CMAPTable *) readTable(cmapTag, &length);
 111     }
 112
 113     if (cmapTable != NULL) {
 114         le_uint16 i;
 115         le_uint16 nSubtables = SWAPW(cmapTable->numberSubtables);
 116
 117
 118         for (i = 0; i < nSubtables; i += 1) {
 119             CMAPEncodingSubtableHeader *esh = &cmapTable->encodingSubtableHeaders[i];
 120
 121             if (SWAPW(esh->platformID) == platformID &&
 122                 SWAPW(esh->platformSpecificID) == platformSpecificID) {
 123                 return (CMAPEncodingSubtable *) ((char *) cmapTable + SWAPL(esh->encodingOffset));
 124             }
 125         }
 126     }
 127
 128     return NULL;
 129 }
 130
 131 void FontObject::initUnicodeCMAP()
 132 {
 133     CMAPEncodingSubtable *encodingSubtable = findCMAP(3, 1);
 134
 135     if (encodingSubtable == 0 ||
 136         SWAPW(encodingSubtable->format) != 4) {
 137         printf("Can't find unicode 'cmap'");
 138         return;
 139     }
 140
 141     CMAPFormat4Encoding *header = (CMAPFormat4Encoding *) encodingSubtable;
 142
 143     cmSegCount = SWAPW(header->segCountX2) / 2;
 144     cmSearchRange = SWAPW(header->searchRange);
 145     cmEntrySelector = SWAPW(header->entrySelector);
 146     cmRangeShift = SWAPW(header->rangeShift) / 2;
 147     cmEndCodes = &header->endCodes[0];
 148     cmStartCodes = &header->endCodes[cmSegCount + 1]; // + 1 for reservedPad...
 149     cmIdDelta = &cmStartCodes[cmSegCount];
 150     cmIdRangeOffset = &cmIdDelta[cmSegCount];
 151 }
 152
 153 LEGlyphID FontObject::unicodeToGlyph(LEUnicode32 unicode32)
 154 {
 155     if (unicode32 >= 0x10000) {
 156         return 0;
 157     }
 158
 159     LEUnicode16 unicode = (LEUnicode16) unicode32;
 160     le_uint16 index = 0;
 161     le_uint16 probe = 1 << cmEntrySelector;
 162     LEGlyphID result = 0;
 163
 164     if (SWAPW(cmStartCodes[cmRangeShift]) <= unicode) {
 165         index = cmRangeShift;
 166     }
 167
 168     while (probe > (1 << 0)) {
 169         probe >>= 1;
 170
 171         if (SWAPW(cmStartCodes[index + probe]) <= unicode) {
 172             index += probe;
 173         }
 174     }
 175
 176     if (unicode >= SWAPW(cmStartCodes[index]) && unicode <= SWAPW(cmEndCodes[index])) {
 177         if (cmIdRangeOffset[index] == 0) {
 178             result = (LEGlyphID) unicode;
 179         } else {
 180             le_uint16 offset = unicode - SWAPW(cmStartCodes[index]);
 181             le_uint16 rangeOffset = SWAPW(cmIdRangeOffset[index]);
 182             le_uint16 *glyphIndexTable = (le_uint16 *) ((char *) &cmIdRangeOffset[index] + rangeOffset);
 183
 184             result = SWAPW(glyphIndexTable[offset]);
 185         }
 186
 187         result += SWAPW(cmIdDelta[index]);
 188     } else {
 189         result = 0;
 190     }
 191
 192     return result;
 193 }
 194
 195 le_uint16 FontObject::getUnitsPerEM()
 196 {
 197     if (headTable == NULL) {
 198         LETag headTag = 0x68656164; // 'head'
 199         le_uint32 length;
 200
 201         headTable = (HEADTable *) readTable(headTag, &length);
 202     }
 203
 204     return SWAPW(headTable->unitsPerEm);
 205 }
 206
 207 le_uint16 FontObject::getGlyphAdvance(LEGlyphID glyph)
 208 {
 209     if (hmtxTable == NULL) {
 210         LETag maxpTag = 0x6D617870; // 'maxp'
 211         LETag hheaTag = 0x68686561; // 'hhea'
 212         LETag hmtxTag = 0x686D7478; // 'hmtx'
 213         le_uint32 length;
 214         HHEATable *hheaTable;
 215         MAXPTable *maxpTable = (MAXPTable *) readTable(maxpTag, &length);
 216
 217         numGlyphs = SWAPW(maxpTable->numGlyphs);
 218         deleteTable(maxpTable);
 219
 220         hheaTable = (HHEATable *) readTable(hheaTag, &length);
 221         numOfLongHorMetrics = SWAPW(hheaTable->numOfLongHorMetrics);
 222         deleteTable(hheaTable);
 223
 224         hmtxTable = (HMTXTable *) readTable(hmtxTag, &length);
 225     }
 226
 227     le_uint16 index = glyph;
 228
 229     if (glyph >= numGlyphs) {
 230         return 0;
 231     }
 232
 233     if (glyph >= numOfLongHorMetrics) {
 234         index = numOfLongHorMetrics - 1;
 235     }
 236
 237     return SWAPW(hmtxTable->hMetrics[index].advanceWidth);
 238 }
 239
 240