icuSources/layout/LookupProcessor.cpp

   1 /*
   2  *
   3  * (C) Copyright IBM Corp. 1998-2005 - All Rights Reserved
   4  *
   5  */
   6
   7 #include "LETypes.h"
   8 #include "OpenTypeUtilities.h"
   9 #include "LEFontInstance.h"
  10 #include "OpenTypeTables.h"
  11 #include "Features.h"
  12 #include "Lookups.h"
  13 #include "ScriptAndLanguage.h"
  14 #include "GlyphDefinitionTables.h"
  15 #include "GlyphIterator.h"
  16 #include "LookupProcessor.h"
  17 #include "LEGlyphStorage.h"
  18 #include "LESwaps.h"
  19
  20 U_NAMESPACE_BEGIN
  21
  22 le_uint32 LookupProcessor::applyLookupTable(const LookupTable *lookupTable, GlyphIterator *glyphIterator,
  23                                          const LEFontInstance *fontInstance) const
  24 {
  25     le_uint16 lookupType = SWAPW(lookupTable->lookupType);
  26     le_uint16 subtableCount = SWAPW(lookupTable->subTableCount);
  27     le_int32 startPosition = glyphIterator->getCurrStreamPosition();
  28     le_uint32 delta;
  29
  30     for (le_uint16 subtable = 0; subtable < subtableCount; subtable += 1) {
  31         const LookupSubtable *lookupSubtable = lookupTable->getLookupSubtable(subtable);
  32
  33         delta = applySubtable(lookupSubtable, lookupType, glyphIterator, fontInstance);
  34
  35         if (delta > 0) {
  36             return 1;
  37         }
  38
  39         glyphIterator->setCurrStreamPosition(startPosition);
  40     }
  41
  42     return 1;
  43 }
  44
  45 le_int32 LookupProcessor::process(LEGlyphStorage &glyphStorage, GlyphPositionAdjustments *glyphPositionAdjustments,
  46                               le_bool rightToLeft, const GlyphDefinitionTableHeader *glyphDefinitionTableHeader,
  47                               const LEFontInstance *fontInstance) const
  48 {
  49     le_int32 glyphCount = glyphStorage.getGlyphCount();
  50
  51     if (lookupSelectArray == NULL) {
  52         return glyphCount;
  53     }
  54
  55     GlyphIterator glyphIterator(glyphStorage, glyphPositionAdjustments,
  56                                 rightToLeft, 0, 0, glyphDefinitionTableHeader);
  57     le_int32 newGlyphCount = glyphCount;
  58
  59     for (le_uint16 order = 0; order < lookupOrderCount; order += 1) {
  60         le_uint16 lookup = lookupOrderArray[order];
  61         FeatureMask selectMask = lookupSelectArray[lookup];
  62
  63         if (selectMask != 0) {
  64             const LookupTable *lookupTable = lookupListTable->getLookupTable(lookup);
  65             le_uint16 lookupFlags = SWAPW(lookupTable->lookupFlags);
  66
  67             glyphIterator.reset(lookupFlags, selectMask);
  68
  69             while (glyphIterator.findFeatureTag()) {
  70                 le_uint32 delta = 1;
  71
  72                 while (glyphIterator.next(delta)) {
  73                     delta = applyLookupTable(lookupTable, &glyphIterator, fontInstance);
  74                 }
  75             }
  76
  77             newGlyphCount = glyphIterator.applyInsertions();
  78         }
  79     }
  80
  81     return newGlyphCount;
  82 }
  83
  84 le_uint32 LookupProcessor::applySingleLookup(le_uint16 lookupTableIndex, GlyphIterator *glyphIterator,
  85                                           const LEFontInstance *fontInstance) const
  86 {
  87     const LookupTable *lookupTable = lookupListTable->getLookupTable(lookupTableIndex);
  88     le_uint16 lookupFlags = SWAPW(lookupTable->lookupFlags);
  89     GlyphIterator tempIterator(*glyphIterator, lookupFlags);
  90     le_uint32 delta = applyLookupTable(lookupTable, &tempIterator, fontInstance);
  91
  92     return delta;
  93 }
  94
  95 le_int32 LookupProcessor::selectLookups(const FeatureTable *featureTable, FeatureMask featureMask, le_int32 order)
  96 {
  97     le_uint16 lookupCount = featureTable? SWAPW(featureTable->lookupCount) : 0;
  98     le_int32  store = order;
  99
 100     for (le_uint16 lookup = 0; lookup < lookupCount; lookup += 1) {
 101         le_uint16 lookupListIndex = SWAPW(featureTable->lookupListIndexArray[lookup]);
 102
 103         lookupSelectArray[lookupListIndex] |= featureMask;
 104         lookupOrderArray[store++] = lookupListIndex;
 105     }
 106
 107     return store - order;
 108 }
 109
 110 LookupProcessor::LookupProcessor(const char *baseAddress,
 111         Offset scriptListOffset, Offset featureListOffset, Offset lookupListOffset,
 112         LETag scriptTag, LETag languageTag, const FeatureMap *featureMap, le_int32 featureMapCount, le_bool orderFeatures)
 113     : lookupListTable(NULL), featureListTable(NULL), lookupSelectArray(NULL),
 114       lookupOrderArray(NULL), lookupOrderCount(0)
 115 {
 116     const ScriptListTable *scriptListTable = NULL;
 117     const LangSysTable *langSysTable = NULL;
 118     le_uint16 featureCount = 0;
 119     le_uint16 lookupListCount = 0;
 120     le_uint16 requiredFeatureIndex;
 121
 122     if (scriptListOffset != 0) {
 123         scriptListTable = (const ScriptListTable *) (baseAddress + scriptListOffset);
 124         langSysTable = scriptListTable->findLanguage(scriptTag, languageTag);
 125
 126         if (langSysTable != 0) {
 127             featureCount = SWAPW(langSysTable->featureCount);
 128         }
 129     }
 130
 131     if (featureListOffset != 0) {
 132         featureListTable = (const FeatureListTable *) (baseAddress + featureListOffset);
 133     }
 134
 135     if (lookupListOffset != 0) {
 136         lookupListTable = (const LookupListTable *) (baseAddress + lookupListOffset);
 137         lookupListCount = SWAPW(lookupListTable->lookupCount);
 138     }
 139
 140     if (langSysTable == NULL || featureListTable == NULL || lookupListTable == NULL ||
 141         featureCount == 0 || lookupListCount == 0) {
 142         return;
 143     }
 144
 145     requiredFeatureIndex = SWAPW(langSysTable->reqFeatureIndex);
 146
 147     lookupSelectArray = LE_NEW_ARRAY(FeatureMask, lookupListCount);
 148
 149     for (int i = 0; i < lookupListCount; i += 1) {
 150         lookupSelectArray[i] = 0;
 151     }
 152
 153     le_int32 count, order = 0;
 154     le_int32 featureReferences = 0;
 155     const FeatureTable *featureTable = NULL;
 156     LETag featureTag;
 157
 158     const FeatureTable *requiredFeatureTable = NULL;
 159     LETag requiredFeatureTag = 0x00000000U;
 160
 161     // Count the total number of lookups referenced by all features. This will
 162     // be the maximum number of entries in the lookupOrderArray. We can't use
 163     // lookupListCount because some lookups might be referenced by more than
 164     // one feature.
 165     for (le_int32 feature = 0; feature < featureCount; feature += 1) {
 166         le_uint16 featureIndex = SWAPW(langSysTable->featureIndexArray[feature]);
 167
 168         featureTable = featureListTable->getFeatureTable(featureIndex, &featureTag);
 169         featureReferences += SWAPW(featureTable->lookupCount);
 170     }
 171
 172     if (requiredFeatureIndex != 0xFFFF) {
 173         requiredFeatureTable = featureListTable->getFeatureTable(requiredFeatureIndex, &requiredFeatureTag);
 174         featureReferences += SWAPW(featureTable->lookupCount);
 175     }
 176
 177     lookupOrderArray = LE_NEW_ARRAY(le_uint16, featureReferences);
 178
 179     for (le_int32 f = 0; f < featureMapCount; f += 1) {
 180         FeatureMap fm = featureMap[f];
 181         count = 0;
 182
 183         // If this is the required feature, add its lookups
 184         if (requiredFeatureTag == fm.tag) {
 185             count += selectLookups(requiredFeatureTable, fm.mask, order);
 186         }
 187
 188         if (orderFeatures) {
 189             // If we added lookups from the required feature, sort them
 190             if (count > 1) {
 191                 OpenTypeUtilities::sort(lookupOrderArray, order);
 192             }
 193
 194             for (le_uint16 feature = 0; feature < featureCount; feature += 1) {
 195                 le_uint16 featureIndex = SWAPW(langSysTable->featureIndexArray[feature]);
 196
 197                 // don't add the required feature to the list more than once...
 198                 // TODO: Do we need this check? (Spec. says required feature won't be in feature list...)
 199                 if (featureIndex == requiredFeatureIndex) {
 200                     continue;
 201                 }
 202
 203                 featureTable = featureListTable->getFeatureTable(featureIndex, &featureTag);
 204
 205                 if (featureTag == fm.tag) {
 206                     count += selectLookups(featureTable, fm.mask, order + count);
 207                 }
 208             }
 209
 210             if (count > 1) {
 211                 OpenTypeUtilities::sort(&lookupOrderArray[order], count);
 212             }
 213
 214             order += count;
 215         } else {
 216             for (le_uint16 feature = 0; feature < featureCount; feature += 1) {
 217                 le_uint16 featureIndex = SWAPW(langSysTable->featureIndexArray[feature]);
 218
 219                 // don't add the required feature to the list more than once...
 220                 // NOTE: This check is commented out because the spec. says that
 221                 // the required feature won't be in the feature list, and because
 222                 // any duplicate entries will be removed below.
 223 #if 0
 224                 if (featureIndex == requiredFeatureIndex) {
 225                     continue;
 226                 }
 227 #endif
 228
 229                 featureTable = featureListTable->getFeatureTable(featureIndex, &featureTag);
 230
 231                 if (featureTag == fm.tag) {
 232                     order += selectLookups(featureTable, fm.mask, order);
 233                 }
 234             }
 235         }
 236     }
 237
 238     if (!orderFeatures && (order > 1)) {
 239         OpenTypeUtilities::sort(lookupOrderArray, order);
 240
 241         // If there's no specified feature order,
 242         // we will apply the lookups in the order
 243         // that they're in the font. If a particular
 244         // lookup may be referenced by more than one feature,
 245         // it will apprear in the lookupOrderArray more than
 246         // once, so remove any duplicate entries in the sorted array.
 247         le_int32 out = 1;
 248
 249         for (le_int32 in = 1; in < order; in += 1) {
 250             if (lookupOrderArray[out - 1] != lookupOrderArray[in]) {
 251                 if (out != in) {
 252                     lookupOrderArray[out] = lookupOrderArray[in];
 253                 }
 254
 255                 out += 1;
 256             }
 257         }
 258
 259         order = out;
 260     }
 261
 262     lookupOrderCount = order;
 263 }
 264
 265 LookupProcessor::LookupProcessor()
 266 {
 267 }
 268
 269 LookupProcessor::~LookupProcessor()
 270 {
 271     LE_DELETE_ARRAY(lookupOrderArray);
 272     LE_DELETE_ARRAY(lookupSelectArray);
 273 }
 274
 275 U_NAMESPACE_END