1 /*
2  * This file is part of OpenTTD.
3  * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
4  * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
5  * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
6  */
7 
8 /** @file string_uniscribe.h Functions related to laying out text on Win32. */
9 
10 #ifndef STRING_UNISCRIBE_H
11 #define STRING_UNISCRIBE_H
12 
13 #include "../../gfx_layout.h"
14 #include "../../string_base.h"
15 #include <vector>
16 
17 
18 void UniscribeResetScriptCache(FontSize size);
19 
20 
21 /**
22  * Helper class to construct a new #UniscribeParagraphLayout.
23  */
24 class UniscribeParagraphLayoutFactory {
25 public:
26 	/** Helper for GetLayouter, to get the right type. */
27 	typedef wchar_t CharType;
28 	/** Helper for GetLayouter, to get whether the layouter supports RTL. */
29 	static const bool SUPPORTS_RTL = true;
30 
31 	/**
32 	* Get the actual ParagraphLayout for the given buffer.
33 	* @param buff The begin of the buffer.
34 	* @param buff_end The location after the last element in the buffer.
35 	* @param fontMapping THe mapping of the fonts.
36 	* @return The ParagraphLayout instance.
37 	*/
38 	static ParagraphLayouter *GetParagraphLayout(CharType *buff, CharType *buff_end, FontMap &fontMapping);
39 
40 	/**
41 	* Append a wide character to the internal buffer.
42 	* @param buff        The buffer to append to.
43 	* @param buffer_last The end of the buffer.
44 	* @param c           The character to add.
45 	* @return The number of buffer spaces that were used.
46 	*/
AppendToBuffer(CharType * buff,const CharType * buffer_last,WChar c)47 	static size_t AppendToBuffer(CharType *buff, const CharType *buffer_last, WChar c)
48 	{
49 		if (c >= 0x010000U) {
50 			/* Character is encoded using surrogates in UTF-16. */
51 			if (buff + 1 <= buffer_last) {
52 				buff[0] = (CharType)(((c - 0x010000U) >> 10) + 0xD800);
53 				buff[1] = (CharType)(((c - 0x010000U) & 0x3FF) + 0xDC00);
54 			} else {
55 				/* Not enough space in buffer. */
56 				*buff = 0;
57 			}
58 			return 2;
59 		} else {
60 			*buff = (CharType)(c & 0xFFFF);
61 			return 1;
62 		}
63 	}
64 };
65 
66 /** String iterator using Uniscribe as a backend. */
67 class UniscribeStringIterator : public StringIterator {
68 	/** */
69 	struct CharInfo {
70 		bool word_stop : 1; ///< Code point is suitable as a word break.
71 		bool char_stop : 1; ///< Code point is the start of a grapheme cluster, i.e. a "character".
72 	};
73 
74 	std::vector<CharInfo> str_info;      ///< Break information for each code point.
75 	std::vector<size_t>   utf16_to_utf8; ///< Mapping from UTF-16 code point position to index in the UTF-8 source string.
76 
77 	size_t cur_pos; ///< Current iteration position.
78 
79 public:
80 	void SetString(const char *s) override;
81 	size_t SetCurPosition(size_t pos) override;
82 	size_t Next(IterType what) override;
83 	size_t Prev(IterType what) override;
84 };
85 
86 #endif /* STRING_UNISCRIBE_H */
87