layout/generic/nsTextFrameUtils.h@b8a032363ba2 (annotated)
layout/generic/nsTextFrameUtils.h
Thu, 22 Jan 2015 13:21:57 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Thu, 22 Jan 2015 13:21:57 +0100
- branch
- TOR_BUG_9701
- changeset 15
- b8a032363ba2
- permissions
- -rw-r--r--
Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6
| michael@0 | 1 | /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- |
| michael@0 | 2 | * This Source Code Form is subject to the terms of the Mozilla Public |
| michael@0 | 3 | * License, v. 2.0. If a copy of the MPL was not distributed with this |
| michael@0 | 4 | * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ |
| michael@0 | 5 | |
| michael@0 | 6 | #ifndef NSTEXTFRAMEUTILS_H_ |
| michael@0 | 7 | #define NSTEXTFRAMEUTILS_H_ |
| michael@0 | 8 | |
| michael@0 | 9 | #include "gfxSkipChars.h" |
| michael@0 | 10 | |
| michael@0 | 11 | class nsIContent; |
| michael@0 | 12 | struct nsStyleText; |
| michael@0 | 13 | |
| michael@0 | 14 | #define BIG_TEXT_NODE_SIZE 4096 |
| michael@0 | 15 | |
| michael@0 | 16 | #define CH_NBSP 160 |
| michael@0 | 17 | #define CH_SHY 173 |
| michael@0 | 18 | #define CH_CJKSP 12288 // U+3000 IDEOGRAPHIC SPACE (CJK Full-Width Space) |
| michael@0 | 19 | |
| michael@0 | 20 | class nsTextFrameUtils { |
| michael@0 | 21 | public: |
| michael@0 | 22 | // These constants are used as textrun flags for textframe textruns. |
| michael@0 | 23 | enum { |
| michael@0 | 24 | // The following flags are set by TransformText |
| michael@0 | 25 | |
| michael@0 | 26 | // the text has at least one untransformed tab character |
| michael@0 | 27 | TEXT_HAS_TAB = 0x010000, |
| michael@0 | 28 | // the original text has at least one soft hyphen character |
| michael@0 | 29 | TEXT_HAS_SHY = 0x020000, |
| michael@0 | 30 | TEXT_WAS_TRANSFORMED = 0x040000, |
| michael@0 | 31 | TEXT_UNUSED_FLAG = 0x080000, |
| michael@0 | 32 | |
| michael@0 | 33 | // The following flags are set by nsTextFrame |
| michael@0 | 34 | |
| michael@0 | 35 | TEXT_IS_SIMPLE_FLOW = 0x100000, |
| michael@0 | 36 | TEXT_INCOMING_WHITESPACE = 0x200000, |
| michael@0 | 37 | TEXT_TRAILING_WHITESPACE = 0x400000, |
| michael@0 | 38 | TEXT_COMPRESSED_LEADING_WHITESPACE = 0x800000, |
| michael@0 | 39 | TEXT_NO_BREAKS = 0x1000000, |
| michael@0 | 40 | TEXT_IS_TRANSFORMED = 0x2000000, |
| michael@0 | 41 | // This gets set if there's a break opportunity at the end of the textrun. |
| michael@0 | 42 | // We normally don't use this break opportunity because the following text |
| michael@0 | 43 | // will have a break opportunity at the start, but it's useful for line |
| michael@0 | 44 | // layout to know about it in case the following content is not text |
| michael@0 | 45 | TEXT_HAS_TRAILING_BREAK = 0x4000000, |
| michael@0 | 46 | |
| michael@0 | 47 | // This is set if the textrun was created for a textframe whose |
| michael@0 | 48 | // NS_FRAME_IS_IN_SINGLE_CHAR_MI flag is set. This occurs if the textframe |
| michael@0 | 49 | // belongs to a MathML <mi> element whose embedded text consists of a |
| michael@0 | 50 | // single character. |
| michael@0 | 51 | TEXT_IS_SINGLE_CHAR_MI = 0x8000000 |
| michael@0 | 52 | |
| michael@0 | 53 | // The following are defined by gfxTextRunWordCache rather than here, |
| michael@0 | 54 | // so that it also has access to the _INCOMING flag |
| michael@0 | 55 | // TEXT_TRAILING_ARABICCHAR |
| michael@0 | 56 | // TEXT_INCOMING_ARABICCHAR |
| michael@0 | 57 | |
| michael@0 | 58 | // This is defined in gfxTextRunFactory to allow access in gfxFont. |
| michael@0 | 59 | // TEXT_USE_MATH_SCRIPT |
| michael@0 | 60 | }; |
| michael@0 | 61 | |
| michael@0 | 62 | // These constants are used in TransformText to represent context information |
| michael@0 | 63 | // from previous textruns. |
| michael@0 | 64 | enum { |
| michael@0 | 65 | INCOMING_NONE = 0, |
| michael@0 | 66 | INCOMING_WHITESPACE = 1, |
| michael@0 | 67 | INCOMING_ARABICCHAR = 2 |
| michael@0 | 68 | }; |
| michael@0 | 69 | |
| michael@0 | 70 | /** |
| michael@0 | 71 | * Returns true if aChars/aLength are something that make a space |
| michael@0 | 72 | * character not be whitespace when they follow the space character. |
| michael@0 | 73 | * For now, this is true if and only if aChars starts with a ZWJ. (This |
| michael@0 | 74 | * is what Uniscribe assumes.) |
| michael@0 | 75 | */ |
| michael@0 | 76 | static bool |
| michael@0 | 77 | IsSpaceCombiningSequenceTail(const char16_t* aChars, int32_t aLength) { |
| michael@0 | 78 | return aLength > 0 && aChars[0] == 0x200D; // ZWJ |
| michael@0 | 79 | } |
| michael@0 | 80 | |
| michael@0 | 81 | enum CompressionMode { |
| michael@0 | 82 | COMPRESS_NONE, |
| michael@0 | 83 | COMPRESS_WHITESPACE, |
| michael@0 | 84 | COMPRESS_WHITESPACE_NEWLINE, |
| michael@0 | 85 | DISCARD_NEWLINE |
| michael@0 | 86 | }; |
| michael@0 | 87 | |
| michael@0 | 88 | /** |
| michael@0 | 89 | * Create a text run from a run of Unicode text. The text may have whitespace |
| michael@0 | 90 | * compressed. A preformatted tab is sent to the text run as a single space. |
| michael@0 | 91 | * (Tab spacing must be performed by textframe later.) Certain other |
| michael@0 | 92 | * characters are discarded. |
| michael@0 | 93 | * |
| michael@0 | 94 | * @param aCompressWhitespace control what is compressed to a |
| michael@0 | 95 | * single space character: no compression, compress spaces (not followed |
| michael@0 | 96 | * by combining mark) and tabs, compress those plus newlines, or |
| michael@0 | 97 | * no compression except newlines are discarded. |
| michael@0 | 98 | * @param aIncomingFlags a flag indicating whether there was whitespace |
| michael@0 | 99 | * or an Arabic character preceding this text. We set it to indicate if |
| michael@0 | 100 | * there's an Arabic character or whitespace preceding the end of this text. |
| michael@0 | 101 | */ |
| michael@0 | 102 | static char16_t* TransformText(const char16_t* aText, uint32_t aLength, |
| michael@0 | 103 | char16_t* aOutput, |
| michael@0 | 104 | CompressionMode aCompression, |
| michael@0 | 105 | uint8_t * aIncomingFlags, |
| michael@0 | 106 | gfxSkipChars* aSkipChars, |
| michael@0 | 107 | uint32_t* aAnalysisFlags); |
| michael@0 | 108 | |
| michael@0 | 109 | static uint8_t* TransformText(const uint8_t* aText, uint32_t aLength, |
| michael@0 | 110 | uint8_t* aOutput, |
| michael@0 | 111 | CompressionMode aCompression, |
| michael@0 | 112 | uint8_t * aIncomingFlags, |
| michael@0 | 113 | gfxSkipChars* aSkipChars, |
| michael@0 | 114 | uint32_t* aAnalysisFlags); |
| michael@0 | 115 | |
| michael@0 | 116 | static void |
| michael@0 | 117 | AppendLineBreakOffset(nsTArray<uint32_t>* aArray, uint32_t aOffset) |
| michael@0 | 118 | { |
| michael@0 | 119 | if (aArray->Length() > 0 && (*aArray)[aArray->Length() - 1] == aOffset) |
| michael@0 | 120 | return; |
| michael@0 | 121 | aArray->AppendElement(aOffset); |
| michael@0 | 122 | } |
| michael@0 | 123 | |
| michael@0 | 124 | static uint32_t |
| michael@0 | 125 | ComputeApproximateLengthWithWhitespaceCompression(nsIContent *aContent, |
| michael@0 | 126 | const nsStyleText |
| michael@0 | 127 | *aStyleText); |
| michael@0 | 128 | }; |
| michael@0 | 129 | |
| michael@0 | 130 | class nsSkipCharsRunIterator { |
| michael@0 | 131 | public: |
| michael@0 | 132 | enum LengthMode { |
| michael@0 | 133 | LENGTH_UNSKIPPED_ONLY = false, |
| michael@0 | 134 | LENGTH_INCLUDES_SKIPPED = true |
| michael@0 | 135 | }; |
| michael@0 | 136 | nsSkipCharsRunIterator(const gfxSkipCharsIterator& aStart, |
| michael@0 | 137 | LengthMode aLengthIncludesSkipped, uint32_t aLength) |
| michael@0 | 138 | : mIterator(aStart), mRemainingLength(aLength), mRunLength(0), |
| michael@0 | 139 | mVisitSkipped(false), |
| michael@0 | 140 | mLengthIncludesSkipped(aLengthIncludesSkipped) { |
| michael@0 | 141 | } |
| michael@0 | 142 | void SetVisitSkipped() { mVisitSkipped = true; } |
| michael@0 | 143 | void SetOriginalOffset(int32_t aOffset) { |
| michael@0 | 144 | mIterator.SetOriginalOffset(aOffset); |
| michael@0 | 145 | } |
| michael@0 | 146 | void SetSkippedOffset(uint32_t aOffset) { |
| michael@0 | 147 | mIterator.SetSkippedOffset(aOffset); |
| michael@0 | 148 | } |
| michael@0 | 149 | |
| michael@0 | 150 | // guaranteed to return only positive-length runs |
| michael@0 | 151 | bool NextRun(); |
| michael@0 | 152 | bool IsSkipped() const { return mSkipped; } |
| michael@0 | 153 | // Always returns something > 0 |
| michael@0 | 154 | int32_t GetRunLength() const { return mRunLength; } |
| michael@0 | 155 | const gfxSkipCharsIterator& GetPos() const { return mIterator; } |
| michael@0 | 156 | int32_t GetOriginalOffset() const { return mIterator.GetOriginalOffset(); } |
| michael@0 | 157 | uint32_t GetSkippedOffset() const { return mIterator.GetSkippedOffset(); } |
| michael@0 | 158 | |
| michael@0 | 159 | private: |
| michael@0 | 160 | gfxSkipCharsIterator mIterator; |
| michael@0 | 161 | int32_t mRemainingLength; |
| michael@0 | 162 | int32_t mRunLength; |
| michael@0 | 163 | bool mSkipped; |
| michael@0 | 164 | bool mVisitSkipped; |
| michael@0 | 165 | bool mLengthIncludesSkipped; |
| michael@0 | 166 | }; |
| michael@0 | 167 | |
| michael@0 | 168 | #endif /*NSTEXTFRAMEUTILS_H_*/ |
