icuSources/layout/LookupProcessor.cpp

   1 /*
   2  *
   3  * (C) Copyright IBM Corp. 1998-2007 - 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                 applyLookupTable(lookupTable, &glyphIterator, fontInstance);
  71             }
  72
  73             newGlyphCount = glyphIterator.applyInsertions();
  74         }
  75     }
  76
  77     return newGlyphCount;
  78 }
  79
  80 le_uint32 LookupProcessor::applySingleLookup(le_uint16 lookupTableIndex, GlyphIterator *glyphIterator,
  81                                           const LEFontInstance *fontInstance) const
  82 {
  83     const LookupTable *lookupTable = lookupListTable->getLookupTable(lookupTableIndex);
  84     le_uint16 lookupFlags = SWAPW(lookupTable->lookupFlags);
  85     GlyphIterator tempIterator(*glyphIterator, lookupFlags);
  86     le_uint32 delta = applyLookupTable(lookupTable, &tempIterator, fontInstance);
  87
  88     return delta;
  89 }
  90
  91 le_int32 LookupProcessor::selectLookups(const FeatureTable *featureTable, FeatureMask featureMask, le_int32 order)
  92 {
  93     le_uint16 lookupCount = featureTable? SWAPW(featureTable->lookupCount) : 0;
  94     le_int32  store = order;
  95
  96     for (le_uint16 lookup = 0; lookup < lookupCount; lookup += 1) {
  97         le_uint16 lookupListIndex = SWAPW(featureTable->lookupListIndexArray[lookup]);
  98
  99         lookupSelectArray[lookupListIndex] |= featureMask;
 100         lookupOrderArray[store++] = lookupListIndex;
 101     }
 102
 103     return store - order;
 104 }
 105
 106 LookupProcessor::LookupProcessor(const char *baseAddress,
 107         Offset scriptListOffset, Offset featureListOffset, Offset lookupListOffset,
 108         LETag scriptTag, LETag languageTag, const FeatureMap *featureMap, le_int32 featureMapCount, le_bool orderFeatures)
 109     : lookupListTable(NULL), featureListTable(NULL), lookupSelectArray(NULL),
 110       lookupOrderArray(NULL), lookupOrderCount(0)
 111 {
 112     const ScriptListTable *scriptListTable = NULL;
 113     const LangSysTable *langSysTable = NULL;
 114     le_uint16 featureCount = 0;
 115     le_uint16 lookupListCount = 0;
 116     le_uint16 requiredFeatureIndex;
 117
 118     if (scriptListOffset != 0) {
 119         scriptListTable = (const ScriptListTable *) (baseAddress + scriptListOffset);
 120         langSysTable = scriptListTable->findLanguage(scriptTag, languageTag);
 121
 122         if (langSysTable != 0) {
 123             featureCount = SWAPW(langSysTable->featureCount);
 124         }
 125     }
 126
 127     if (featureListOffset != 0) {
 128         featureListTable = (const FeatureListTable *) (baseAddress + featureListOffset);
 129     }
 130
 131     if (lookupListOffset != 0) {
 132         lookupListTable = (const LookupListTable *) (baseAddress + lookupListOffset);
 133         lookupListCount = SWAPW(lookupListTable->lookupCount);
 134     }
 135
 136     if (langSysTable == NULL || featureListTable == NULL || lookupListTable == NULL ||
 137         featureCount == 0 || lookupListCount == 0) {
 138         return;
 139     }
 140
 141     requiredFeatureIndex = SWAPW(langSysTable->reqFeatureIndex);
 142
 143     lookupSelectArray = LE_NEW_ARRAY(FeatureMask, lookupListCount);
 144
 145     for (int i = 0; i < lookupListCount; i += 1) {
 146         lookupSelectArray[i] = 0;
 147     }
 148
 149     le_int32 count, order = 0;
 150     le_int32 featureReferences = 0;
 151     const FeatureTable *featureTable = NULL;
 152     LETag featureTag;
 153
 154     const FeatureTable *requiredFeatureTable = NULL;
 155     LETag requiredFeatureTag = 0x00000000U;
 156
 157     // Count the total number of lookups referenced by all features. This will
 158     // be the maximum number of entries in the lookupOrderArray. We can't use
 159     // lookupListCount because some lookups might be referenced by more than
 160     // one feature.
 161     for (le_int32 feature = 0; feature < featureCount; feature += 1) {
 162         le_uint16 featureIndex = SWAPW(langSysTable->featureIndexArray[feature]);
 163
 164         featureTable = featureListTable->getFeatureTable(featureIndex, &featureTag);
 165         featureReferences += SWAPW(featureTable->lookupCount);
 166     }
 167
 168     if (requiredFeatureIndex != 0xFFFF) {
 169         requiredFeatureTable = featureListTable->getFeatureTable(requiredFeatureIndex, &requiredFeatureTag);
 170         featureReferences += SWAPW(featureTable->lookupCount);
 171     }
 172
 173     lookupOrderArray = LE_NEW_ARRAY(le_uint16, featureReferences);
 174
 175     for (le_int32 f = 0; f < featureMapCount; f += 1) {
 176         FeatureMap fm = featureMap[f];
 177         count = 0;
 178
 179         // If this is the required feature, add its lookups
 180         if (requiredFeatureTag == fm.tag) {
 181             count += selectLookups(requiredFeatureTable, fm.mask, order);
 182         }
 183
 184         if (orderFeatures) {
 185             // If we added lookups from the required feature, sort them
 186             if (count > 1) {
 187                 OpenTypeUtilities::sort(lookupOrderArray, order);
 188             }
 189
 190             for (le_uint16 feature = 0; feature < featureCount; feature += 1) {
 191                 le_uint16 featureIndex = SWAPW(langSysTable->featureIndexArray[feature]);
 192
 193                 // don't add the required feature to the list more than once...
 194                 // TODO: Do we need this check? (Spec. says required feature won't be in feature list...)
 195                 if (featureIndex == requiredFeatureIndex) {
 196                     continue;
 197                 }
 198
 199                 featureTable = featureListTable->getFeatureTable(featureIndex, &featureTag);
 200
 201                 if (featureTag == fm.tag) {
 202                     count += selectLookups(featureTable, fm.mask, order + count);
 203                 }
 204             }
 205
 206             if (count > 1) {
 207                 OpenTypeUtilities::sort(&lookupOrderArray[order], count);
 208             }
 209
 210             order += count;
 211         } else {
 212             for (le_uint16 feature = 0; feature < featureCount; feature += 1) {
 213                 le_uint16 featureIndex = SWAPW(langSysTable->featureIndexArray[feature]);
 214
 215                 // don't add the required feature to the list more than once...
 216                 // NOTE: This check is commented out because the spec. says that
 217                 // the required feature won't be in the feature list, and because
 218                 // any duplicate entries will be removed below.
 219 #if 0
 220                 if (featureIndex == requiredFeatureIndex) {
 221                     continue;
 222                 }
 223 #endif
 224
 225                 featureTable = featureListTable->getFeatureTable(featureIndex, &featureTag);
 226
 227                 if (featureTag == fm.tag) {
 228                     order += selectLookups(featureTable, fm.mask, order);
 229                 }
 230             }
 231         }
 232     }
 233
 234     if (!orderFeatures && (order > 1)) {
 235         OpenTypeUtilities::sort(lookupOrderArray, order);
 236
 237         // If there's no specified feature order,
 238         // we will apply the lookups in the order
 239         // that they're in the font. If a particular
 240         // lookup may be referenced by more than one feature,
 241         // it will apprear in the lookupOrderArray more than
 242         // once, so remove any duplicate entries in the sorted array.
 243         le_int32 out = 1;
 244
 245         for (le_int32 in = 1; in < order; in += 1) {
 246             if (lookupOrderArray[out - 1] != lookupOrderArray[in]) {
 247                 if (out != in) {
 248                     lookupOrderArray[out] = lookupOrderArray[in];
 249                 }
 250
 251                 out += 1;
 252             }
 253         }
 254
 255         order = out;
 256     }
 257
 258     lookupOrderCount = order;
 259 }
 260
 261 LookupProcessor::LookupProcessor()
 262 {
 263 }
 264
 265 LookupProcessor::~LookupProcessor()
 266 {
 267     LE_DELETE_ARRAY(lookupOrderArray);
 268     LE_DELETE_ARRAY(lookupSelectArray);
 269 }
 270
 271 U_NAMESPACE_END