Patches for supporting Sinhala script

[email protected] Sun, 14 Sep 2003 18:05:05 +0600

Newsgroups	gmane.comp.lib.icu.general
Message-ID	<OF3EFEB5EB.C2CD1DF5-ON46256DA1.0030ABEF-46256DA1.0041A5B3@keells.com>

Dear Sir,

I have made the necessary amendments to IndicClassTables.cpp and
LayoutEngine.cpp.

I have also made a small modification to saveMatra() method in
IndicReordering.cpp. This hack was done because in Sinhala there are
two-part dependent vowel signs ( DIGA KOMBUVA (0x0DDA) & SINHALA VOWEL
SIGN KOMBUVA HAA DIGA AELA-PILLA (0x0DDD) ) which are composed of a matra
and a virama/halant sign, and when they are split and reordered the virama
sign was getting dropped. I am not familiar with other indic scripts and
what affect this will have on them so I just made this temp hack for my
testing purposes.

I was not quite sure about the script_flags so I just used the tamil script
flags since Tamil script is very close to Sinhala. I have tested the shaper
using Layoutsample and microsoft 'Iskoola pota' (beta) opentype font.

If these patches are ok, I would like to update the pango code as well. My
objective is to see Sinhala on Linux desktop.

thank you.
Yours sincerely,
Harsha Senanayake.

ps will these patches go into ICU4J?

(See attached file: IndicClassTables.patch)(See attached file:
IndicReordering.patch)(See attached file: LayoutEngine.patch)(See attached
file: icu_sinhala.jpg)
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IndicClassTables.patch (application/octet-stream, 2.5 KB)

--- layout.ori\IndicClassTables.cpp	Wed Jun 04 02:58:22 2003
+++ layout\IndicClassTables.cpp	Sun Sep 14 15:09:52 2003
@@ -177,6 +178,19 @@
     _iv, _iv, _xx, _xx, _xx, _xx, _xx, _xx, _xx, _xx, _xx, _xx, _xx, _xx, _xx, _xx  // 0D60 - 0D6F
 };
 
+
+static const IndicClassTable::CharClass sinhCharClasses[] =
+{
+    _xx, _xx, _ma, _mp, _xx, _iv, _iv, _iv, _iv, _iv, _iv, _iv, _iv, _iv, _iv, _iv, // 0D80 - 0D8F
+    _iv, _iv, _iv, _iv, _iv, _iv, _iv, _xx, _xx, _xx, _ct, _ct, _ct, _ct, _ct, _ct, // 0D90 - 0D9F
+    _ct, _ct, _ct, _ct, _ct, _ct, _ct, _ct, _ct, _ct, _ct, _ct, _ct, _ct, _ct, _ct, // 0DA0 - 0DB0
+    _ct, _ct, _xx, _ct, _ct, _ct, _ct, _ct, _ct, _ct, _ct, _ct, _xx, _ct, _xx, _xx, // 0DB0 - 0DAF
+    _ct, _ct, _ct, _ct, _ct, _ct, _ct, _xx, _xx, _xx, _vr, _xx, _xx, _xx, _xx, _dr, // 0DC0 - 0DCF
+    _dr, _dr, _da, _da, _db, _xx, _db, _xx, _dr, _dl, _s1, _dl, _s2, _s3, _s4, _dr, // 0DD0 - 0DDF
+    _xx, _xx, _xx, _xx, _xx, _xx, _xx, _xx, _xx, _xx, _xx, _xx, _xx, _xx, _xx, _xx, // 0DE0 - 0DEF
+    _xx, _xx, _dr, _dr, _ct                                                         // 0DF0 - 0DF4
+};
+
 //
 // Split matra tables
 //
@@ -193,6 +207,8 @@
 
 static const SplitMatra mlymSplitTable[] = {{0x0D46, 0x0D3E}, {0x0D47, 0x0D3E}, {0x0D46, 0x0D57}};
 
+static const SplitMatra sinhSplitTable[] = {{0x0DD9, 0x0DCA}, {0x0DD9, 0x0DCF}, {0x0DD9, 0x0DCF,0x0DCA}, {0x0DD9, 0x0DF3} };
+
 //
 // Script Flags
 //
@@ -209,6 +225,7 @@
 #define TELU_SCRIPT_FLAGS (IndicClassTable::SF_MATRAS_AFTER_BASE | 3)
 #define KNDA_SCRIPT_FLAGS (IndicClassTable::SF_MATRAS_AFTER_BASE | 3)
 #define MLYM_SCRIPT_FLAGS (IndicClassTable::SF_MPRE_FIXUP | IndicClassTable::SF_NO_POST_BASE_LIMIT)
+#define SINH_SCRIPT_FLAGS (IndicClassTable::SF_MPRE_FIXUP | IndicClassTable::SF_NO_POST_BASE_LIMIT)
 
 //
 // Indic Class Tables
@@ -231,6 +248,8 @@
 
 static const IndicClassTable mlymClassTable = {0x0D00, 0x0D6F, 3, MLYM_SCRIPT_FLAGS, mlymCharClasses, mlymSplitTable};
 
+static const IndicClassTable sinhClassTable = {0x0D80, 0x0DF4, 3, SINH_SCRIPT_FLAGS, sinhCharClasses, sinhSplitTable};
+
 //
 // IndicClassTable addresses
 //
@@ -268,7 +287,7 @@
     NULL,            /* 'ital' (OLD-ITALIC) */
     &oryaClassTable, /* 'orya' (ORIYA) */
     NULL,            /* 'runr' (RUNIC) */
-    NULL,            /* 'sinh' (SINHALA) */
+    &sinhClassTable, /* 'sinh' (SINHALA) */
     NULL,            /* 'syrc' (SYRIAC) */
     &tamlClassTable, /* 'taml' (TAMIL) */
     &teluClassTable, /* 'telu' (TELUGU) */

IndicReordering.patch (application/octet-stream, 591 B)

--- layout.ori\IndicReordering.cpp	Wed Jun 04 02:58:22 2003
+++ layout\IndicReordering.cpp	Sun Sep 14 15:53:18 2003
@@ -45,7 +45,7 @@
             fMabove = matra;
         } else if (IndicClassTable::isMpost(matraClass)) {
             fMpost = matra;
-        } else if (IndicClassTable::isLengthMark(matraClass)) {
+        } else if (IndicClassTable::isLengthMark(matraClass)||IndicClassTable::isVirama(matraClass)/*temp hack for Sinhala DIGA KOMBUVA (0x0DDA) & SINHALA VOWEL SIGN KOMBUVA HAA DIGA AELA-PILLA (0x0DDD) */) {
             fLengthMark = matra;
         }
     }

LayoutEngine.patch (application/octet-stream, 380 B)

--- layout.ori\LayoutEngine.cpp	Thu Jun 05 04:39:18 2003
+++ layout\LayoutEngine.cpp	Sat Sep 13 15:55:03 2003
@@ -424,6 +424,7 @@
         case guruScriptCode:
         case tamlScriptCode:
         case teluScriptCode:
+		case sinhScriptCode:
             result = new IndicOpenTypeLayoutEngine(fontInstance, scriptCode, languageCode, gsubTable);
             break;

icu_sinhala.jpg (image/jpeg, 16.1 KB) - not displayed