icuSources/layout/ArabicShaping.cpp

   1 /*
   2  *
   3  * (C) Copyright IBM Corp. 1998-2004 - All Rights Reserved
   4  *
   5  */
   6
   7 #include "LETypes.h"
   8 #include "OpenTypeTables.h"
   9 #include "ArabicShaping.h"
  10 #include "LEGlyphStorage.h"
  11
  12 U_NAMESPACE_BEGIN
  13
  14 enum {
  15     _c_ = ArabicShaping::ST_NOSHAPE_DUAL,
  16     _d_ = ArabicShaping::ST_DUAL,
  17     _n_ = ArabicShaping::ST_NONE,
  18     _r_ = ArabicShaping::ST_RIGHT,
  19     _t_ = ArabicShaping::ST_TRANSPARENT,
  20     _x_ = ArabicShaping::ST_NOSHAPE_NONE
  21 };
  22
  23 const ArabicShaping::ShapeType ArabicShaping::shapeTypes[] =
  24 {
  25     _t_, _t_, _t_, _t_, _t_, _t_, _x_, _x_, _x_, _x_, _x_, _n_, _x_, _x_, _x_, _n_,   // 0x610 - 0x61f
  26     _x_, _n_, _r_, _r_, _r_, _r_, _d_, _r_, _d_, _r_, _d_, _d_, _d_, _d_, _d_, _r_,   // 0x620 - 0x62f
  27     _r_, _r_, _r_, _d_, _d_, _d_, _d_, _d_, _d_, _d_, _d_, _x_, _x_, _x_, _x_, _x_,   // 0x630 - 0x63f
  28     _c_, _d_, _d_, _d_, _d_, _d_, _d_, _d_, _r_, _d_, _d_, _t_, _t_, _t_, _t_, _t_,   // 0x640 - 0x64f
  29     _t_, _t_, _t_, _t_, _t_, _t_, _t_, _t_, _t_, _x_, _x_, _x_, _x_, _x_, _x_, _x_,   // 0x650 - 0x65f
  30     _n_, _n_, _n_, _n_, _n_, _n_, _n_, _n_, _n_, _n_, _n_, _n_, _n_, _n_, _d_, _d_,   // 0x660 - 0x66f
  31     _t_, _r_, _r_, _r_, _n_, _r_, _r_, _r_, _d_, _d_, _d_, _d_, _d_, _d_, _d_, _d_,   // 0x670 - 0x67f
  32     _d_, _d_, _d_, _d_, _d_, _d_, _d_, _d_, _r_, _r_, _r_, _r_, _r_, _r_, _r_, _r_,   // 0x680 - 0x68f
  33     _r_, _r_, _r_, _r_, _r_, _r_, _r_, _r_, _r_, _r_, _d_, _d_, _d_, _d_, _d_, _d_,   // 0x690 - 0x69f
  34     _d_, _d_, _d_, _d_, _d_, _d_, _d_, _d_, _d_, _d_, _d_, _d_, _d_, _d_, _d_, _d_,   // 0x6a0 - 0x6af
  35     _d_, _d_, _d_, _d_, _d_, _d_, _d_, _d_, _d_, _d_, _d_, _d_, _d_, _d_, _d_, _d_,   // 0x6b0 - 0x6bf
  36     _r_, _d_, _r_, _r_, _r_, _r_, _r_, _r_, _r_, _r_, _r_, _r_, _d_, _r_, _d_, _r_,   // 0x6c0 - 0x6cf
  37     _d_, _d_, _r_, _r_, _n_, _r_, _t_, _t_, _t_, _t_, _t_, _t_, _t_, _x_, _t_, _t_,   // 0x6d0 - 0x6df
  38     _t_, _t_, _t_, _t_, _t_, _n_, _n_, _t_, _t_, _n_, _t_, _t_, _t_, _t_, _r_, _r_,   // 0x6e0 - 0x6ef
  39     _n_, _n_, _n_, _n_, _n_, _n_, _n_, _n_, _n_, _n_, _d_, _d_, _d_, _n_, _n_, _d_    // 0x6f0 - 0x6ff
  40 };
  41
  42 /*
  43     shaping array holds types for Arabic chars between 0610 and 0700
  44     other values are either unshaped, or transparent if a mark or format
  45     code, except for format codes 200c (zero-width non-joiner) and 200d
  46     (dual-width joiner) which are both unshaped and non_joining or
  47     dual-joining, respectively.
  48 */
  49 ArabicShaping::ShapeType ArabicShaping::getShapeType(LEUnicode c)
  50 {
  51     if (c >= 0x0610 && c <= 0x206f) {
  52         if (c < 0x0700) {
  53             return shapeTypes[c - 0x0610];
  54         } else if (c == 0x200c) {   // ZWNJ
  55             return ST_NOSHAPE_NONE;
  56         } else if (c == 0x200d) {   // ZWJ
  57             return ST_NOSHAPE_DUAL;
  58         } else if (c >= 0x202a && c <= 0x202e) { // LRE - RLO
  59             return ST_TRANSPARENT;
  60         } else if (c >= 0x206a && c <= 0x206f) { // Inhibit Symmetric Swapping - Nominal Digit Shapes
  61             return ST_TRANSPARENT;
  62         }
  63     }
  64
  65     return ST_NOSHAPE_NONE;
  66 }
  67
  68 static const LETag isolFeatureTag = LE_ISOL_FEATURE_TAG;
  69 static const LETag initFeatureTag = LE_INIT_FEATURE_TAG;
  70 static const LETag mediFeatureTag = LE_MEDI_FEATURE_TAG;
  71 static const LETag finaFeatureTag = LE_FINA_FEATURE_TAG;
  72 static const LETag ligaFeatureTag = LE_LIGA_FEATURE_TAG;
  73 static const LETag msetFeatureTag = LE_MSET_FEATURE_TAG;
  74 static const LETag markFeatureTag = LE_MARK_FEATURE_TAG;
  75 static const LETag ccmpFeatureTag = LE_CCMP_FEATURE_TAG;
  76 static const LETag rligFeatureTag = LE_RLIG_FEATURE_TAG;
  77 static const LETag caltFeatureTag = LE_CALT_FEATURE_TAG;
  78 static const LETag dligFeatureTag = LE_DLIG_FEATURE_TAG;
  79 static const LETag cswhFeatureTag = LE_CSWH_FEATURE_TAG;
  80 static const LETag cursFeatureTag = LE_CURS_FEATURE_TAG;
  81 static const LETag kernFeatureTag = LE_KERN_FEATURE_TAG;
  82 static const LETag mkmkFeatureTag = LE_MKMK_FEATURE_TAG;
  83
  84 static const LETag emptyTag       = 0x00000000; // ''
  85
  86 static const LETag featureOrder[] =
  87 {
  88     ccmpFeatureTag, isolFeatureTag, finaFeatureTag, mediFeatureTag, initFeatureTag, rligFeatureTag,
  89     caltFeatureTag, ligaFeatureTag, dligFeatureTag, cswhFeatureTag, msetFeatureTag, cursFeatureTag,
  90     kernFeatureTag, markFeatureTag, mkmkFeatureTag, emptyTag
  91 };
  92
  93 const LETag ArabicShaping::tagArray[] =
  94 {
  95     isolFeatureTag, ligaFeatureTag, msetFeatureTag, markFeatureTag, ccmpFeatureTag, rligFeatureTag,
  96         caltFeatureTag, dligFeatureTag, cswhFeatureTag, cursFeatureTag, kernFeatureTag, mkmkFeatureTag, emptyTag,
  97
  98     finaFeatureTag, ligaFeatureTag, msetFeatureTag, markFeatureTag, ccmpFeatureTag, rligFeatureTag,
  99         caltFeatureTag, dligFeatureTag, cswhFeatureTag, cursFeatureTag, kernFeatureTag, mkmkFeatureTag, emptyTag,
 100
 101     initFeatureTag, ligaFeatureTag, msetFeatureTag, markFeatureTag, ccmpFeatureTag, rligFeatureTag,
 102         caltFeatureTag, dligFeatureTag, cswhFeatureTag, cursFeatureTag, kernFeatureTag, mkmkFeatureTag, emptyTag,
 103
 104     mediFeatureTag, ligaFeatureTag, msetFeatureTag, markFeatureTag, ccmpFeatureTag, rligFeatureTag,
 105         caltFeatureTag, dligFeatureTag, cswhFeatureTag, cursFeatureTag, kernFeatureTag, mkmkFeatureTag, emptyTag
 106 };
 107
 108 #define TAGS_PER_GLYPH ((sizeof ArabicShaping::tagArray / sizeof ArabicShaping::tagArray[0]) / 4)
 109
 110 const LETag *ArabicShaping::getFeatureOrder()
 111 {
 112     return featureOrder;
 113 }
 114
 115 void ArabicShaping::adjustTags(le_int32 outIndex, le_int32 shapeOffset, LEGlyphStorage &glyphStorage)
 116 {
 117     LEErrorCode success = LE_NO_ERROR;
 118     const LETag *glyphTags = (const LETag *) glyphStorage.getAuxData(outIndex, success);
 119
 120     glyphStorage.setAuxData(outIndex, (void *) &glyphTags[TAGS_PER_GLYPH * shapeOffset], success);
 121 }
 122
 123 void ArabicShaping::shape(const LEUnicode *chars, le_int32 offset, le_int32 charCount, le_int32 charMax,
 124                           le_bool rightToLeft, LEGlyphStorage &glyphStorage)
 125 {
 126     // iterate in logical order, store tags in visible order
 127     //
 128     // the effective right char is the most recently encountered
 129     // non-transparent char
 130     //
 131     // four boolean states:
 132     //   the effective right char shapes
 133     //   the effective right char causes left shaping
 134     //   the current char shapes
 135     //   the current char causes right shaping
 136     //
 137     // if both cause shaping, then
 138     //   shaper.shape(errout, 2) (isolate to initial, or final to medial)
 139     //   shaper.shape(out, 1) (isolate to final)
 140
 141     ShapeType rightType = ST_NOSHAPE_NONE, leftType = ST_NOSHAPE_NONE;
 142     LEErrorCode success = LE_NO_ERROR;
 143     le_int32 i;
 144
 145     for (i = offset - 1; i >= 0; i -= 1) {
 146         rightType = getShapeType(chars[i]);
 147
 148         if (rightType != ST_TRANSPARENT) {
 149             break;
 150         }
 151     }
 152
 153     for (i = offset + charCount; i < charMax; i += 1) {
 154         leftType = getShapeType(chars[i]);
 155
 156         if (leftType != ST_TRANSPARENT) {
 157             break;
 158         }
 159     }
 160
 161     // erout is effective right logical index
 162     le_int32 erout = -1;
 163     le_bool rightShapes = FALSE;
 164     le_bool rightCauses = (rightType & MASK_SHAPE_LEFT) != 0;
 165     le_int32 in, e, out = 0, dir = 1;
 166
 167     if (rightToLeft) {
 168         out = charCount - 1;
 169         erout = charCount;
 170         dir = -1;
 171     }
 172
 173     for (in = offset, e = offset + charCount; in < e; in += 1, out += dir) {
 174         LEUnicode c = chars[in];
 175         ShapeType t = getShapeType(c);
 176
 177         glyphStorage.setAuxData(out, (void *) tagArray, success);
 178
 179         if ((t & MASK_TRANSPARENT) != 0) {
 180             continue;
 181         }
 182
 183         le_bool curShapes = (t & MASK_NOSHAPE) == 0;
 184         le_bool curCauses = (t & MASK_SHAPE_RIGHT) != 0;
 185
 186         if (rightCauses && curCauses) {
 187             if (rightShapes) {
 188                 adjustTags(erout, 2, glyphStorage);
 189             }
 190
 191             if (curShapes) {
 192                 adjustTags(out, 1, glyphStorage);
 193             }
 194         }
 195
 196         rightShapes = curShapes;
 197         rightCauses = (t & MASK_SHAPE_LEFT) != 0;
 198         erout = out;
 199     }
 200
 201     if (rightShapes && rightCauses && (leftType & MASK_SHAPE_RIGHT) != 0) {
 202         adjustTags(erout, 2, glyphStorage);
 203     }
 204 }
 205
 206 U_NAMESPACE_END