--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/fontservices/textshaperplugin/IcuSource/layout/ArabicLayoutEngine.h Tue Feb 02 02:02:46 2010 +0200
@@ -0,0 +1,238 @@
+
+/*
+ *
+ * (C) Copyright IBM Corp. 1998-2005 - All Rights Reserved
+ *
+ */
+
+#ifndef __ARABICLAYOUTENGINE_H
+#define __ARABICLAYOUTENGINE_H
+
+#include "LETypes.h"
+#include "LEFontInstance.h"
+#include "LEGlyphFilter.h"
+#include "LayoutEngine.h"
+#include "OpenTypeLayoutEngine.h"
+
+#include "GlyphSubstitutionTables.h"
+#include "GlyphDefinitionTables.h"
+#include "GlyphPositioningTables.h"
+
+U_NAMESPACE_BEGIN
+
+/**
+ * This class implements OpenType layout for Arabic fonts. It overrides
+ * the characerProcessing method to assign the correct OpenType feature
+ * tags for the Arabic contextual forms. It also overrides the adjustGlyphPositions
+ * method to guarantee that all vowel and accent glyphs have zero advance width.
+ *
+ * @internal
+ */
+class ArabicOpenTypeLayoutEngine : public OpenTypeLayoutEngine
+{
+public:
+ /**
+ * This is the main constructor. It constructs an instance of ArabicOpenTypeLayoutEngine for
+ * a particular font, script and language. It takes the GSUB table as a parameter since
+ * LayoutEngine::layoutEngineFactory has to read the GSUB table to know that it has an
+ * Indic OpenType font.
+ *
+ * @param fontInstance - the font
+ * @param scriptCode - the script
+ * @param langaugeCode - the language
+ * @param gsubTable - the GSUB table
+ *
+ * @see LayoutEngine::layoutEngineFactory
+ * @see OpenTypeLayoutEngine
+ * @see ScriptAndLanguageTags.h for script and language codes
+ *
+ * @internal
+ */
+ ArabicOpenTypeLayoutEngine(const LEFontInstance *fontInstance, le_int32 scriptCode, le_int32 languageCode,
+ le_int32 typoFlags, const GlyphSubstitutionTableHeader *gsubTable);
+
+ /**
+ * This constructor is used when the font requires a "canned" GSUB table which can't be known
+ * until after this constructor has been invoked.
+ *
+ * @param fontInstance - the font
+ * @param scriptCode - the script
+ * @param langaugeCode - the language
+ *
+ * @see OpenTypeLayoutEngine
+ * @see ScriptAndLanguageTags.h for script and language codes
+ *
+ * @internal
+ */
+ ArabicOpenTypeLayoutEngine(const LEFontInstance *fontInstance, le_int32 scriptCode, le_int32 languageCode,
+ le_int32 typoFlags);
+
+ /**
+ * The destructor, virtual for correct polymorphic invocation.
+ *
+ * @internal
+ */
+ virtual ~ArabicOpenTypeLayoutEngine();
+
+ /**
+ * ICU "poor man's RTTI", returns a UClassID for the actual class.
+ *
+ * @stable ICU 2.8
+ */
+ virtual UClassID getDynamicClassID() const;
+
+ /**
+ * ICU "poor man's RTTI", returns a UClassID for this class.
+ *
+ * @stable ICU 2.8
+ */
+ static UClassID getStaticClassID();
+
+protected:
+
+ /**
+ * This method does Arabic OpenType character processing. It assigns the OpenType feature
+ * tags to the characters to generate the correct contextual forms and ligatures.
+ *
+ * Input parameters:
+ * @param chars - the input character context
+ * @param offset - the index of the first character to process
+ * @param count - the number of characters to process
+ * @param max - the number of characters in the input context
+ * @param rightToLeft - <code>TRUE</code> if the characters are in a right to left directional run
+ *
+ * Output parameters:
+ * @param outChars - the output character arrayt
+ * @param charIndices - the output character index array
+ * @param featureTags - the output feature tag array
+ * @param success - set to an error code if the operation fails
+ *
+ * @return the output character count
+ *
+ * @internal
+ */
+ virtual le_int32 characterProcessing(const LEUnicode chars[], le_int32 offset, le_int32 count, le_int32 max, le_bool rightToLeft,
+ LEUnicode *&outChars, LEGlyphStorage &glyphStorage, LEErrorCode &success);
+
+ /**
+ * This method applies the GPOS table if it is present, otherwise it ensures that all vowel
+ * and accent glyphs have a zero advance width by calling the adjustMarkGlyphs method.
+ * If the font contains a GDEF table, that is used to identify voewls and accents. Otherwise
+ * the character codes are used.
+ *
+ * @param chars - the input character context
+ * @param offset - the offset of the first character to process
+ * @param count - the number of characters to process
+ * @param reverse - <code>TRUE</code> if the glyphs in the glyph array have been reordered
+ * @param glyphs - the input glyph array
+ * @param glyphCount - the number of glyphs
+ * @param positions - the position array, will be updated as needed
+ * @param success - output parameter set to an error code if the operation fails
+ *
+ * @internal
+ */
+ virtual void adjustGlyphPositions(const LEUnicode chars[], le_int32 offset, le_int32 count, le_bool reverse, LEGlyphStorage &glyphStorage, LEErrorCode &success);
+
+ // static void adjustMarkGlyphs(const LEUnicode chars[], le_int32 offset, le_int32 count, le_bool rightToLeft, LEGlyphStorage &glyphStorage, LEErrorCode &success);
+
+};
+
+/**
+ * The class implements OpenType layout for Arabic fonts which don't
+ * contain a GSUB table, using a canned GSUB table based on Unicode
+ * Arabic Presentation Forms. It overrides the mapCharsToGlyphs method
+ * to use the Presentation Forms as logical glyph indices. It overrides the
+ * glyphPostProcessing method to convert the Presentation Forms to actual
+ * glyph indices.
+ *
+ * @see ArabicOpenTypeLayoutEngine
+ *
+ * @internal
+ */
+class UnicodeArabicOpenTypeLayoutEngine : public ArabicOpenTypeLayoutEngine
+{
+public:
+ /**
+ * This constructs an instance of UnicodeArabicOpenTypeLayoutEngine for a specific font,
+ * script and language.
+ *
+ * @param fontInstance - the font
+ * @param scriptCode - the script
+ * @param languageCode - the language
+ *
+ * @see LEFontInstance
+ * @see ScriptAndLanguageTags.h for script and language codes
+ *
+ * @internal
+ */
+ UnicodeArabicOpenTypeLayoutEngine(const LEFontInstance *fontInstance, le_int32 scriptCode, le_int32 languageCode,
+ le_int32 typoFlags);
+
+ /**
+ * The destructor, virtual for correct polymorphic invocation.
+ *
+ * @internal
+ */
+ virtual ~UnicodeArabicOpenTypeLayoutEngine();
+
+protected:
+
+ /**
+ * This method converts the Arabic Presentation Forms in the temp glyph array
+ * into actual glyph indices using ArabicOpenTypeLayoutEngine::mapCharsToGlyps.
+ *
+ * Input paramters:
+ * @param tempGlyphs - the input presentation forms
+ * @param tempCharIndices - the input character index array
+ * @param tempGlyphCount - the number of Presentation Froms
+ *
+ * Output parameters:
+ * @param glyphs - the output glyph index array
+ * @param charIndices - the output character index array
+ * @param success - set to an error code if the operation fails
+ *
+ * @return the number of glyph indices in the output glyph index array
+ *
+ * @internal
+ */
+ virtual le_int32 glyphPostProcessing(LEGlyphStorage &tempGlyphStorage, LEGlyphStorage &glyphStorage, LEErrorCode &success);
+
+ /**
+ * This method copies the input characters into the output glyph index array,
+ * for use by the canned GSUB table. It also generates the character index array.
+ *
+ * Input parameters:
+ * @param chars - the input character context
+ * @param offset - the offset of the first character to be mapped
+ * @param count - the number of characters to be mapped
+ * @param reverse - if <code>TRUE</code>, the output will be in reverse order
+ * @param mirror - if <code>TRUE</code>, do character mirroring
+ * @param glyphStorage - the glyph storage object. Glyph and char index arrays will be updated.
+ *
+ * @param success - set to an error code if the operation fails
+ *
+ * @internal
+ */
+ virtual void mapCharsToGlyphs(const LEUnicode chars[], le_int32 offset, le_int32 count, le_bool reverse, le_bool mirror,
+ LEGlyphStorage &glyphStorage, LEErrorCode &success);
+
+ /**
+ * This method ensures that all vowel and accent glyphs have a zero advance width by calling
+ * the adjustMarkGlyphs method. The character codes are used to identify the vowel and mark
+ * glyphs.
+ *
+ * @param chars - the input character context
+ * @param offset - the offset of the first character to process
+ * @param count - the number of characters to process
+ * @param reverse - <code>TRUE</code> if the glyphs in the glyph array have been reordered
+ * @param glyphStorage - the glyph storage object. The glyph positions will be updated as needed.
+ * @param success - output parameter set to an error code if the operation fails
+ *
+ * @internal
+ */
+ virtual void adjustGlyphPositions(const LEUnicode chars[], le_int32 offset, le_int32 count, le_bool reverse, LEGlyphStorage &glyphStorage, LEErrorCode &success);
+};
+
+U_NAMESPACE_END
+#endif
+