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      1 
      2 /*
      3  *
      4  * (C) Copyright IBM Corp. 1998-2008 - All Rights Reserved
      5  *
      6  */
      7 
      8 #include "LETypes.h"
      9 #include "LayoutEngine.h"
     10 #include "ThaiLayoutEngine.h"
     11 #include "ScriptAndLanguageTags.h"
     12 #include "LEGlyphStorage.h"
     13 
     14 #include "KernTable.h"
     15 
     16 #include "ThaiShaping.h"
     17 
     18 U_NAMESPACE_BEGIN
     19 
     20 UOBJECT_DEFINE_RTTI_IMPLEMENTATION(ThaiLayoutEngine)
     21 
     22 ThaiLayoutEngine::ThaiLayoutEngine(const LEFontInstance *fontInstance, le_int32 scriptCode, le_int32 languageCode, le_int32 typoFlags, LEErrorCode &success)
     23     : LayoutEngine(fontInstance, scriptCode, languageCode, typoFlags, success)
     24 {
     25     fErrorChar = 0x25CC;
     26 
     27     // Figure out which presentation forms the font uses
     28     if (! fontInstance->canDisplay(0x0E01)) {
     29         // No Thai in font; don't use presentation forms.
     30         fGlyphSet = 3;
     31     } else if (fontInstance->canDisplay(0x0E64)) {
     32         // WorldType uses reserved space in Thai block
     33         fGlyphSet = 0;
     34     } else if (fontInstance->canDisplay(0xF701)) {
     35         // Microsoft corporate zone
     36         fGlyphSet = 1;
     37 
     38         if (!fontInstance->canDisplay(fErrorChar)) {
     39             fErrorChar = 0xF71B;
     40         }
     41     } else if (fontInstance->canDisplay(0xF885)) {
     42         // Apple corporate zone
     43         fGlyphSet = 2;
     44     } else {
     45         // no presentation forms in the font
     46         fGlyphSet = 3;
     47     }
     48 }
     49 
     50 ThaiLayoutEngine::~ThaiLayoutEngine()
     51 {
     52     // nothing to do
     53 }
     54 
     55 // Input: characters (0..max provided for context)
     56 // Output: glyphs, char indices
     57 // Returns: the glyph count
     58 // NOTE: this assumes that ThaiShaping::compose will allocate the outChars array...
     59 le_int32 ThaiLayoutEngine::computeGlyphs(const LEUnicode chars[], le_int32 offset, le_int32 count, le_int32 max, le_bool /*rightToLeft*/, LEGlyphStorage &glyphStorage, LEErrorCode &success)
     60 {
     61     if (LE_FAILURE(success)) {
     62         return 0;
     63     }
     64 
     65     if (chars == NULL || offset < 0 || count < 0 || max < 0 || offset >= max || offset + count > max) {
     66         success = LE_ILLEGAL_ARGUMENT_ERROR;
     67         return 0;
     68     }
     69 
     70     LEUnicode *outChars;
     71     le_int32 glyphCount;
     72 
     73     // This is enough room for the worst-case expansion
     74     // (it says here...)
     75     outChars = LE_NEW_ARRAY(LEUnicode, count * 2);
     76 
     77     if (outChars == NULL) {
     78         success = LE_MEMORY_ALLOCATION_ERROR;
     79         return 0;
     80     }
     81 
     82     glyphStorage.allocateGlyphArray(count * 2, FALSE, success);
     83 
     84     if (LE_FAILURE(success)) {
     85         LE_DELETE_ARRAY(outChars);
     86         success = LE_MEMORY_ALLOCATION_ERROR;
     87         return 0;
     88     }
     89 
     90     glyphCount = ThaiShaping::compose(chars, offset, count, fGlyphSet, fErrorChar, outChars, glyphStorage);
     91     mapCharsToGlyphs(outChars, 0, glyphCount, FALSE, FALSE, glyphStorage, success);
     92 
     93     LE_DELETE_ARRAY(outChars);
     94 
     95     glyphStorage.adoptGlyphCount(glyphCount);
     96     return glyphCount;
     97 }
     98 
     99 // This is the same as LayoutEngline::adjustGlyphPositions() except that it doesn't call adjustMarkGlyphs
    100 void ThaiLayoutEngine::adjustGlyphPositions(const LEUnicode chars[], le_int32 offset, le_int32 count, le_bool  /*reverse*/,
    101                                         LEGlyphStorage &glyphStorage, LEErrorCode &success)
    102 {
    103     if (LE_FAILURE(success)) {
    104         return;
    105     }
    106 
    107     if (chars == NULL || offset < 0 || count < 0) {
    108         success = LE_ILLEGAL_ARGUMENT_ERROR;
    109         return;
    110     }
    111 
    112     if (fTypoFlags & 0x1) { /* kerning enabled */
    113       static const le_uint32 kernTableTag = LE_KERN_TABLE_TAG;
    114 
    115       KernTable kt(fFontInstance, getFontTable(kernTableTag));
    116       kt.process(glyphStorage);
    117     }
    118 
    119     // default is no adjustments
    120     return;
    121 }
    122 
    123 U_NAMESPACE_END
    124