source/layout/ArabicShaping.cpp

   1 /*
   2  *
   3  * (C) Copyright IBM Corp. 1998-2013 - All Rights Reserved
   4  *
   5  */
   6
   7 #include "LETypes.h"
   8 #include "OpenTypeTables.h"
   9 #include "ArabicShaping.h"
  10 #include "LEGlyphStorage.h"
  11 #include "ClassDefinitionTables.h"
  12
  13 U_NAMESPACE_BEGIN
  14
  15 // This table maps Unicode joining types to
  16 // ShapeTypes.
  17 const ArabicShaping::ShapeType ArabicShaping::shapeTypes[] =
  18 {
  19     ArabicShaping::ST_NOSHAPE_NONE, // [U]
  20     ArabicShaping::ST_NOSHAPE_DUAL, // [C]
  21     ArabicShaping::ST_DUAL,         // [D]
  22     ArabicShaping::ST_LEFT,         // [L]
  23     ArabicShaping::ST_RIGHT,        // [R]
  24     ArabicShaping::ST_TRANSPARENT   // [T]
  25 };
  26
  27 /*
  28     shaping array holds types for Arabic chars between 0610 and 0700
  29     other values are either unshaped, or transparent if a mark or format
  30     code, except for format codes 200c (zero-width non-joiner) and 200d
  31     (dual-width joiner) which are both unshaped and non_joining or
  32     dual-joining, respectively.
  33 */
  34 ArabicShaping::ShapeType ArabicShaping::getShapeType(LEUnicode c)
  35 {
  36   LEErrorCode success = LE_NO_ERROR;
  37   const LEReferenceTo<ClassDefinitionTable> joiningTypes((const ClassDefinitionTable *) ArabicShaping::shapingTypeTable,
  38                                                          ArabicShaping::shapingTypeTableLen);
  39   le_int32 joiningType = joiningTypes->getGlyphClass(joiningTypes, c, success);
  40
  41   if (joiningType >= 0 && joiningType < ArabicShaping::JT_COUNT && LE_SUCCESS(success)) {
  42     return ArabicShaping::shapeTypes[joiningType];
  43   }
  44
  45   return ArabicShaping::ST_NOSHAPE_NONE;
  46 }
  47
  48 #define isolFeatureTag LE_ISOL_FEATURE_TAG
  49 #define initFeatureTag LE_INIT_FEATURE_TAG
  50 #define mediFeatureTag LE_MEDI_FEATURE_TAG
  51 #define finaFeatureTag LE_FINA_FEATURE_TAG
  52 #define ligaFeatureTag LE_LIGA_FEATURE_TAG
  53 #define msetFeatureTag LE_MSET_FEATURE_TAG
  54 #define markFeatureTag LE_MARK_FEATURE_TAG
  55 #define ccmpFeatureTag LE_CCMP_FEATURE_TAG
  56 #define rligFeatureTag LE_RLIG_FEATURE_TAG
  57 #define caltFeatureTag LE_CALT_FEATURE_TAG
  58 #define dligFeatureTag LE_DLIG_FEATURE_TAG
  59 #define cswhFeatureTag LE_CSWH_FEATURE_TAG
  60 #define cursFeatureTag LE_CURS_FEATURE_TAG
  61 #define kernFeatureTag LE_KERN_FEATURE_TAG
  62 #define mkmkFeatureTag LE_MKMK_FEATURE_TAG
  63
  64 // NOTE:
  65 // The isol, fina, init and medi features must be
  66 // defined in the above order, and have masks that
  67 // are all in the same nibble.
  68 #define isolFeatureMask 0x80000000UL
  69 #define finaFeatureMask 0x40000000UL
  70 #define initFeatureMask 0x20000000UL
  71 #define mediFeatureMask 0x10000000UL
  72 #define ccmpFeatureMask 0x08000000UL
  73 #define rligFeatureMask 0x04000000UL
  74 #define caltFeatureMask 0x02000000UL
  75 #define ligaFeatureMask 0x01000000UL
  76 #define dligFeatureMask 0x00800000UL
  77 #define cswhFeatureMask 0x00400000UL
  78 #define msetFeatureMask 0x00200000UL
  79 #define cursFeatureMask 0x00100000UL
  80 #define kernFeatureMask 0x00080000UL
  81 #define markFeatureMask 0x00040000UL
  82 #define mkmkFeatureMask 0x00020000UL
  83
  84 #define NO_FEATURES   0
  85 #define ISOL_FEATURES (isolFeatureMask | ligaFeatureMask | msetFeatureMask | markFeatureMask | ccmpFeatureMask | rligFeatureMask | caltFeatureMask | dligFeatureMask | cswhFeatureMask | cursFeatureMask | kernFeatureMask | mkmkFeatureMask)
  86
  87 #define SHAPE_MASK 0xF0000000UL
  88
  89 static const FeatureMap featureMap[] = {
  90     {ccmpFeatureTag, ccmpFeatureMask},
  91     {isolFeatureTag, isolFeatureMask},
  92     {finaFeatureTag, finaFeatureMask},
  93     {mediFeatureTag, mediFeatureMask},
  94     {initFeatureTag, initFeatureMask},
  95     {rligFeatureTag, rligFeatureMask},
  96     {caltFeatureTag, caltFeatureMask},
  97     {ligaFeatureTag, ligaFeatureMask},
  98     {dligFeatureTag, dligFeatureMask},
  99     {cswhFeatureTag, cswhFeatureMask},
 100     {msetFeatureTag, msetFeatureMask},
 101     {cursFeatureTag, cursFeatureMask},
 102     {kernFeatureTag, kernFeatureMask},
 103     {markFeatureTag, markFeatureMask},
 104     {mkmkFeatureTag, mkmkFeatureMask}
 105 };
 106
 107 const FeatureMap *ArabicShaping::getFeatureMap(le_int32 &count)
 108 {
 109     count = LE_ARRAY_SIZE(featureMap);
 110
 111     return featureMap;
 112 }
 113
 114 void ArabicShaping::adjustTags(le_int32 outIndex, le_int32 shapeOffset, LEGlyphStorage &glyphStorage)
 115 {
 116     LEErrorCode success = LE_NO_ERROR;
 117     FeatureMask featureMask = (FeatureMask) glyphStorage.getAuxData(outIndex, success);
 118     FeatureMask shape = featureMask & SHAPE_MASK;
 119
 120     shape >>= shapeOffset;
 121
 122     glyphStorage.setAuxData(outIndex, ((featureMask & ~SHAPE_MASK) | shape), success);
 123 }
 124
 125 void ArabicShaping::shape(const LEUnicode *chars, le_int32 offset, le_int32 charCount, le_int32 charMax,
 126                           le_bool rightToLeft, LEGlyphStorage &glyphStorage)
 127 {
 128     // iterate in logical order, store tags in visible order
 129     //
 130     // the effective right char is the most recently encountered
 131     // non-transparent char
 132     //
 133     // four boolean states:
 134     //   the effective right char shapes
 135     //   the effective right char causes left shaping
 136     //   the current char shapes
 137     //   the current char causes right shaping
 138     //
 139     // if both cause shaping, then
 140     //   shaper.shape(errout, 2) (isolate to initial, or final to medial)
 141     //   shaper.shape(out, 1) (isolate to final)
 142
 143     ShapeType rightType = ST_NOSHAPE_NONE, leftType = ST_NOSHAPE_NONE;
 144     LEErrorCode success = LE_NO_ERROR;
 145     le_int32 i;
 146
 147     for (i = offset - 1; i >= 0; i -= 1) {
 148         rightType = getShapeType(chars[i]);
 149
 150         if (rightType != ST_TRANSPARENT) {
 151             break;
 152         }
 153     }
 154
 155     for (i = offset + charCount; i < charMax; i += 1) {
 156         leftType = getShapeType(chars[i]);
 157
 158         if (leftType != ST_TRANSPARENT) {
 159             break;
 160         }
 161     }
 162
 163     // erout is effective right logical index
 164     le_int32 erout = -1;
 165     le_bool rightShapes = FALSE;
 166     le_bool rightCauses = (rightType & MASK_SHAPE_LEFT) != 0;
 167     le_int32 in, e, out = 0, dir = 1;
 168
 169     if (rightToLeft) {
 170         out = charCount - 1;
 171         erout = charCount;
 172         dir = -1;
 173     }
 174
 175     for (in = offset, e = offset + charCount; in < e; in += 1, out += dir) {
 176         LEUnicode c = chars[in];
 177         ShapeType t = getShapeType(c);
 178
 179         if (t == ST_NOSHAPE_NONE) {
 180             glyphStorage.setAuxData(out, NO_FEATURES, success);
 181         } else {
 182             glyphStorage.setAuxData(out, ISOL_FEATURES, success);
 183         }
 184
 185         if ((t & MASK_TRANSPARENT) != 0) {
 186             continue;
 187         }
 188
 189         le_bool curShapes = (t & MASK_NOSHAPE) == 0;
 190         le_bool curCauses = (t & MASK_SHAPE_RIGHT) != 0;
 191
 192         if (rightCauses && curCauses) {
 193             if (rightShapes) {
 194                 adjustTags(erout, 2, glyphStorage);
 195             }
 196
 197             if (curShapes) {
 198                 adjustTags(out, 1, glyphStorage);
 199             }
 200         }
 201
 202         rightShapes = curShapes;
 203         rightCauses = (t & MASK_SHAPE_LEFT) != 0;
 204         erout = out;
 205     }
 206
 207     if (rightShapes && rightCauses && (leftType & MASK_SHAPE_RIGHT) != 0) {
 208         adjustTags(erout, 2, glyphStorage);
 209     }
 210 }
 211
 212 U_NAMESPACE_END