icuSources/layout/ThaiLayoutEngine.cpp

   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