1
2/*
3 *
4 * (C) Copyright IBM Corp. 1998-2008 - All Rights Reserved
5 *
6 */
7
8#ifndef __HANGULAYOUTENGINE_H
9#define __HANGULAYOUTENGINE_H
10
11#include "LETypes.h"
12#include "LEFontInstance.h"
13#include "LEGlyphFilter.h"
14#include "LayoutEngine.h"
15#include "OpenTypeLayoutEngine.h"
16
17#include "GlyphSubstitutionTables.h"
18#include "GlyphDefinitionTables.h"
19#include "GlyphPositioningTables.h"
20
21U_NAMESPACE_BEGIN
22
23class MPreFixups;
24class LEGlyphStorage;
25
26/**
27 * This class implements OpenType layout for Old Hangul OpenType fonts, as
28 * specified by Microsoft in "Creating and Supporting OpenType Fonts for
29 * The Korean Hangul Script" (http://www.microsoft.com/typography/otfntdev/hangulot/default.htm)
30 *
31 * This class overrides the characterProcessing method to do Hangul character processing.
32 * (See the MS spec. for more details)
33 *
34 * @internal
35 */
36class HangulOpenTypeLayoutEngine : public OpenTypeLayoutEngine
37{
38public:
39    /**
40     * This is the main constructor. It constructs an instance of HangulOpenTypeLayoutEngine for
41     * a particular font, script and language. It takes the GSUB table as a parameter since
42     * LayoutEngine::layoutEngineFactory has to read the GSUB table to know that it has an
43     * Hangul OpenType font.
44     *
45     * @param fontInstance - the font
46     * @param scriptCode - the script
47     * @param langaugeCode - the language
48     * @param gsubTable - the GSUB table
49     * @param success - set to an error code if the operation fails
50     *
51     * @see LayoutEngine::layoutEngineFactory
52     * @see OpenTypeLayoutEngine
53     * @see ScriptAndLangaugeTags.h for script and language codes
54     *
55     * @internal
56     */
57    HangulOpenTypeLayoutEngine(const LEFontInstance *fontInstance, le_int32 scriptCode, le_int32 languageCode,
58                            le_int32 typoFlags, const GlyphSubstitutionTableHeader *gsubTable, LEErrorCode &success);
59
60    /**
61     * This constructor is used when the font requires a "canned" GSUB table which can't be known
62     * until after this constructor has been invoked.
63     *
64     * @param fontInstance - the font
65     * @param scriptCode - the script
66     * @param langaugeCode - the language
67     * @param success - set to an error code if the operation fails
68     *
69     * @see OpenTypeLayoutEngine
70     * @see ScriptAndLangaugeTags.h for script and language codes
71     *
72     * @internal
73     */
74    HangulOpenTypeLayoutEngine(const LEFontInstance *fontInstance, le_int32 scriptCode, le_int32 languageCode,
75			      le_int32 typoFlags, LEErrorCode &success);
76
77    /**
78     * The destructor, virtual for correct polymorphic invocation.
79     *
80     * @internal
81     */
82   virtual ~HangulOpenTypeLayoutEngine();
83
84    /**
85     * ICU "poor man's RTTI", returns a UClassID for the actual class.
86     *
87     * @stable ICU 2.8
88     */
89    virtual UClassID getDynamicClassID() const;
90
91    /**
92     * ICU "poor man's RTTI", returns a UClassID for this class.
93     *
94     * @stable ICU 2.8
95     */
96    static UClassID getStaticClassID();
97
98protected:
99
100    /**
101     * This method does Hangul OpenType character processing. It assigns the OpenType feature
102     * tags to the characters, and may compose a character sequence into a modern Hangul syllable,
103     * or decompose a modern Hangul syllable if it forms part of an old Hangul syllable.
104     *
105     * Input parameters:
106     * @param chars - the input character context
107     * @param offset - the index of the first character to process
108     * @param count - the number of characters to process
109     * @param max - the number of characters in the input context
110     * @param rightToLeft - <code>TRUE</code> if the characters are in a right to left directional run
111     * @param glyphStorage - the glyph storage object. The glyph and character index arrays will be set.
112     *                       the auxillary data array will be set to the feature tags.
113     *
114     * Output parameters:
115     * @param success - set to an error code if the operation fails
116     *
117     * @return the output character count
118     *
119     * @internal
120     */
121    virtual le_int32 characterProcessing(const LEUnicode chars[], le_int32 offset, le_int32 count, le_int32 max, le_bool rightToLeft,
122            LEUnicode *&outChars, LEGlyphStorage &glyphStorage, LEErrorCode &success);
123};
124
125U_NAMESPACE_END
126#endif
127
128