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comparison: layout/generic/nsTextFrameUtils.h
layout/generic/nsTextFrameUtils.h
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| 1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- | |
| 2 * This Source Code Form is subject to the terms of the Mozilla Public | |
| 3 * License, v. 2.0. If a copy of the MPL was not distributed with this | |
| 4 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ | |
| 5 | |
| 6 #ifndef NSTEXTFRAMEUTILS_H_ | |
| 7 #define NSTEXTFRAMEUTILS_H_ | |
| 8 | |
| 9 #include "gfxSkipChars.h" | |
| 10 | |
| 11 class nsIContent; | |
| 12 struct nsStyleText; | |
| 13 | |
| 14 #define BIG_TEXT_NODE_SIZE 4096 | |
| 15 | |
| 16 #define CH_NBSP 160 | |
| 17 #define CH_SHY 173 | |
| 18 #define CH_CJKSP 12288 // U+3000 IDEOGRAPHIC SPACE (CJK Full-Width Space) | |
| 19 | |
| 20 class nsTextFrameUtils { | |
| 21 public: | |
| 22 // These constants are used as textrun flags for textframe textruns. | |
| 23 enum { | |
| 24 // The following flags are set by TransformText | |
| 25 | |
| 26 // the text has at least one untransformed tab character | |
| 27 TEXT_HAS_TAB = 0x010000, | |
| 28 // the original text has at least one soft hyphen character | |
| 29 TEXT_HAS_SHY = 0x020000, | |
| 30 TEXT_WAS_TRANSFORMED = 0x040000, | |
| 31 TEXT_UNUSED_FLAG = 0x080000, | |
| 32 | |
| 33 // The following flags are set by nsTextFrame | |
| 34 | |
| 35 TEXT_IS_SIMPLE_FLOW = 0x100000, | |
| 36 TEXT_INCOMING_WHITESPACE = 0x200000, | |
| 37 TEXT_TRAILING_WHITESPACE = 0x400000, | |
| 38 TEXT_COMPRESSED_LEADING_WHITESPACE = 0x800000, | |
| 39 TEXT_NO_BREAKS = 0x1000000, | |
| 40 TEXT_IS_TRANSFORMED = 0x2000000, | |
| 41 // This gets set if there's a break opportunity at the end of the textrun. | |
| 42 // We normally don't use this break opportunity because the following text | |
| 43 // will have a break opportunity at the start, but it's useful for line | |
| 44 // layout to know about it in case the following content is not text | |
| 45 TEXT_HAS_TRAILING_BREAK = 0x4000000, | |
| 46 | |
| 47 // This is set if the textrun was created for a textframe whose | |
| 48 // NS_FRAME_IS_IN_SINGLE_CHAR_MI flag is set. This occurs if the textframe | |
| 49 // belongs to a MathML <mi> element whose embedded text consists of a | |
| 50 // single character. | |
| 51 TEXT_IS_SINGLE_CHAR_MI = 0x8000000 | |
| 52 | |
| 53 // The following are defined by gfxTextRunWordCache rather than here, | |
| 54 // so that it also has access to the _INCOMING flag | |
| 55 // TEXT_TRAILING_ARABICCHAR | |
| 56 // TEXT_INCOMING_ARABICCHAR | |
| 57 | |
| 58 // This is defined in gfxTextRunFactory to allow access in gfxFont. | |
| 59 // TEXT_USE_MATH_SCRIPT | |
| 60 }; | |
| 61 | |
| 62 // These constants are used in TransformText to represent context information | |
| 63 // from previous textruns. | |
| 64 enum { | |
| 65 INCOMING_NONE = 0, | |
| 66 INCOMING_WHITESPACE = 1, | |
| 67 INCOMING_ARABICCHAR = 2 | |
| 68 }; | |
| 69 | |
| 70 /** | |
| 71 * Returns true if aChars/aLength are something that make a space | |
| 72 * character not be whitespace when they follow the space character. | |
| 73 * For now, this is true if and only if aChars starts with a ZWJ. (This | |
| 74 * is what Uniscribe assumes.) | |
| 75 */ | |
| 76 static bool | |
| 77 IsSpaceCombiningSequenceTail(const char16_t* aChars, int32_t aLength) { | |
| 78 return aLength > 0 && aChars[0] == 0x200D; // ZWJ | |
| 79 } | |
| 80 | |
| 81 enum CompressionMode { | |
| 82 COMPRESS_NONE, | |
| 83 COMPRESS_WHITESPACE, | |
| 84 COMPRESS_WHITESPACE_NEWLINE, | |
| 85 DISCARD_NEWLINE | |
| 86 }; | |
| 87 | |
| 88 /** | |
| 89 * Create a text run from a run of Unicode text. The text may have whitespace | |
| 90 * compressed. A preformatted tab is sent to the text run as a single space. | |
| 91 * (Tab spacing must be performed by textframe later.) Certain other | |
| 92 * characters are discarded. | |
| 93 * | |
| 94 * @param aCompressWhitespace control what is compressed to a | |
| 95 * single space character: no compression, compress spaces (not followed | |
| 96 * by combining mark) and tabs, compress those plus newlines, or | |
| 97 * no compression except newlines are discarded. | |
| 98 * @param aIncomingFlags a flag indicating whether there was whitespace | |
| 99 * or an Arabic character preceding this text. We set it to indicate if | |
| 100 * there's an Arabic character or whitespace preceding the end of this text. | |
| 101 */ | |
| 102 static char16_t* TransformText(const char16_t* aText, uint32_t aLength, | |
| 103 char16_t* aOutput, | |
| 104 CompressionMode aCompression, | |
| 105 uint8_t * aIncomingFlags, | |
| 106 gfxSkipChars* aSkipChars, | |
| 107 uint32_t* aAnalysisFlags); | |
| 108 | |
| 109 static uint8_t* TransformText(const uint8_t* aText, uint32_t aLength, | |
| 110 uint8_t* aOutput, | |
| 111 CompressionMode aCompression, | |
| 112 uint8_t * aIncomingFlags, | |
| 113 gfxSkipChars* aSkipChars, | |
| 114 uint32_t* aAnalysisFlags); | |
| 115 | |
| 116 static void | |
| 117 AppendLineBreakOffset(nsTArray<uint32_t>* aArray, uint32_t aOffset) | |
| 118 { | |
| 119 if (aArray->Length() > 0 && (*aArray)[aArray->Length() - 1] == aOffset) | |
| 120 return; | |
| 121 aArray->AppendElement(aOffset); | |
| 122 } | |
| 123 | |
| 124 static uint32_t | |
| 125 ComputeApproximateLengthWithWhitespaceCompression(nsIContent *aContent, | |
| 126 const nsStyleText | |
| 127 *aStyleText); | |
| 128 }; | |
| 129 | |
| 130 class nsSkipCharsRunIterator { | |
| 131 public: | |
| 132 enum LengthMode { | |
| 133 LENGTH_UNSKIPPED_ONLY = false, | |
| 134 LENGTH_INCLUDES_SKIPPED = true | |
| 135 }; | |
| 136 nsSkipCharsRunIterator(const gfxSkipCharsIterator& aStart, | |
| 137 LengthMode aLengthIncludesSkipped, uint32_t aLength) | |
| 138 : mIterator(aStart), mRemainingLength(aLength), mRunLength(0), | |
| 139 mVisitSkipped(false), | |
| 140 mLengthIncludesSkipped(aLengthIncludesSkipped) { | |
| 141 } | |
| 142 void SetVisitSkipped() { mVisitSkipped = true; } | |
| 143 void SetOriginalOffset(int32_t aOffset) { | |
| 144 mIterator.SetOriginalOffset(aOffset); | |
| 145 } | |
| 146 void SetSkippedOffset(uint32_t aOffset) { | |
| 147 mIterator.SetSkippedOffset(aOffset); | |
| 148 } | |
| 149 | |
| 150 // guaranteed to return only positive-length runs | |
| 151 bool NextRun(); | |
| 152 bool IsSkipped() const { return mSkipped; } | |
| 153 // Always returns something > 0 | |
| 154 int32_t GetRunLength() const { return mRunLength; } | |
| 155 const gfxSkipCharsIterator& GetPos() const { return mIterator; } | |
| 156 int32_t GetOriginalOffset() const { return mIterator.GetOriginalOffset(); } | |
| 157 uint32_t GetSkippedOffset() const { return mIterator.GetSkippedOffset(); } | |
| 158 | |
| 159 private: | |
| 160 gfxSkipCharsIterator mIterator; | |
| 161 int32_t mRemainingLength; | |
| 162 int32_t mRunLength; | |
| 163 bool mSkipped; | |
| 164 bool mVisitSkipped; | |
| 165 bool mLengthIncludesSkipped; | |
| 166 }; | |
| 167 | |
| 168 #endif /*NSTEXTFRAMEUTILS_H_*/ |
