fontservices/textshaperplugin/IcuSource/layout/ThaiLayoutEngine.h
changeset 0 1fb32624e06b
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/fontservices/textshaperplugin/IcuSource/layout/ThaiLayoutEngine.h	Tue Feb 02 02:02:46 2010 +0200
@@ -0,0 +1,121 @@
+
+/*
+ *
+ * (C) Copyright IBM Corp. 1998-2005 - All Rights Reserved
+ *
+ */
+
+#ifndef __THAILAYOUTENGINE_H
+#define __THAILAYOUTENGINE_H
+
+#include "LETypes.h"
+#include "LEFontInstance.h"
+#include "LayoutEngine.h"
+
+#include "ThaiShaping.h"
+
+U_NAMESPACE_BEGIN
+
+class LEGlyphStorage;
+
+/**
+ * This class implements layout for the Thai script, using the ThaiShapingClass.
+ * All existing Thai fonts use an encoding which assigns character codes to all
+ * the variant forms needed to display accents and tone marks correctly in context.
+ * This class can deal with fonts using the Microsoft, Macintosh, and WorldType encodings.
+ *
+ * @internal
+ */
+class ThaiLayoutEngine : public LayoutEngine
+{
+public:
+    /**
+     * This constructs an instance of ThaiLayoutEngine for the given font, script and
+     * language. It examines the font, using LEFontInstance::canDisplay, to set fGlyphSet
+     * and fErrorChar. (see below)
+     *
+     * @param fontInstance - the font
+     * @param scriptCode - the script
+     * @param languageCode - the language
+     *
+     * @see LEFontInstance
+     * @see ScriptAndLanguageTags.h for script and language codes
+     *
+     * @internal
+     */
+    ThaiLayoutEngine(const LEFontInstance *fontInstance, le_int32 scriptCode, le_int32 languageCode, le_int32 typoFlags);
+
+    /**
+     * The destructor, virtual for correct polymorphic invocation.
+     *
+     * @internal
+     */
+    virtual ~ThaiLayoutEngine();
+
+    /**
+     * 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:
+    /**
+     * A small integer indicating which Thai encoding
+     * the font uses.
+     *
+     * @see ThaiShaping
+     *
+     * @internal
+     */
+    le_uint8 fGlyphSet;
+
+    /**
+     * The character used as a base for vowels and
+     * tone marks that are out of sequence. Usually
+     * this will be Unicode 0x25CC, if the font can
+     * display it.
+     *
+     * @see ThaiShaping
+     *
+     * @internal
+     */
+    LEUnicode fErrorChar;
+
+    /**
+     * This method performs Thai layout. It calls ThaiShaping::compose to
+     * generate the correct contextual character codes, and then calls
+     * mapCharsToGlyphs to generate the glyph indices.
+     *
+     * 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 text is in a right to left directional run
+     * @param glyphStorage - the glyph storage object. The glyph and char index arrays will be set.
+     *
+     * Output parameters:
+     * @param success - set to an error code if the operation fails
+     *
+     * @return the number of glyphs in the glyph index array
+     *
+     * @see ThaiShaping
+     *
+     * @internal
+     */
+    virtual le_int32 computeGlyphs(const LEUnicode chars[], le_int32 offset, le_int32 count, le_int32 max, le_bool rightToLeft,
+        LEGlyphStorage &glyphStorage, LEErrorCode &success);
+
+};
+
+U_NAMESPACE_END
+#endif
+