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Diffstat (limited to 'layout/generic/nsTextFrameUtils.h')
| -rw-r--r-- | layout/generic/nsTextFrameUtils.h | 178 |
1 files changed, 178 insertions, 0 deletions
diff --git a/layout/generic/nsTextFrameUtils.h b/layout/generic/nsTextFrameUtils.h new file mode 100644 index 000000000..6274705bc --- /dev/null +++ b/layout/generic/nsTextFrameUtils.h @@ -0,0 +1,178 @@ +/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- + * This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +#ifndef NSTEXTFRAMEUTILS_H_ +#define NSTEXTFRAMEUTILS_H_ + +#include "gfxSkipChars.h" +#include "nsBidiUtils.h" +#include "nsUnicodeProperties.h" + +class nsIContent; +struct nsStyleText; + +#define BIG_TEXT_NODE_SIZE 4096 + +#define CH_NBSP 160 +#define CH_SHY 173 +#define CH_CJKSP 12288 // U+3000 IDEOGRAPHIC SPACE (CJK Full-Width Space) + +class nsTextFrameUtils { +public: + // These constants are used as textrun flags for textframe textruns. + enum { + // The following flags are set by TransformText + + // the text has at least one untransformed tab character + TEXT_HAS_TAB = 0x010000, + // the original text has at least one soft hyphen character + TEXT_HAS_SHY = 0x020000, + TEXT_WAS_TRANSFORMED = 0x040000, + TEXT_UNUSED_FLAG = 0x080000, + + // The following flags are set by nsTextFrame + + TEXT_IS_SIMPLE_FLOW = 0x100000, + TEXT_INCOMING_WHITESPACE = 0x200000, + TEXT_TRAILING_WHITESPACE = 0x400000, + TEXT_COMPRESSED_LEADING_WHITESPACE = 0x800000, + TEXT_NO_BREAKS = 0x1000000, + TEXT_IS_TRANSFORMED = 0x2000000, + // This gets set if there's a break opportunity at the end of the textrun. + // We normally don't use this break opportunity because the following text + // will have a break opportunity at the start, but it's useful for line + // layout to know about it in case the following content is not text + TEXT_HAS_TRAILING_BREAK = 0x4000000, + + // This is set if the textrun was created for a textframe whose + // NS_FRAME_IS_IN_SINGLE_CHAR_MI flag is set. This occurs if the textframe + // belongs to a MathML <mi> element whose embedded text consists of a + // single character. + TEXT_IS_SINGLE_CHAR_MI = 0x8000000, + + // This is set if the text run might be observing for glyph changes. + TEXT_MIGHT_HAVE_GLYPH_CHANGES = 0x10000000, + + // The following are defined by gfxTextRunWordCache rather than here, + // so that it also has access to the _INCOMING flag + // TEXT_TRAILING_ARABICCHAR + // TEXT_INCOMING_ARABICCHAR + + // This is defined in gfxTextRunFactory to allow access in gfxFont. + // TEXT_USE_MATH_SCRIPT + }; + + // These constants are used in TransformText to represent context information + // from previous textruns. + enum { + INCOMING_NONE = 0, + INCOMING_WHITESPACE = 1, + INCOMING_ARABICCHAR = 2 + }; + + /** + * Returns true if aChars/aLength are something that make a space + * character not be whitespace when they follow the space character + * (combining mark or join control, ignoring intervening direction + * controls). + */ + static bool + IsSpaceCombiningSequenceTail(const char16_t* aChars, int32_t aLength) { + return aLength > 0 && + (mozilla::unicode::IsClusterExtender(aChars[0]) || + (IsBidiControl(aChars[0]) && + IsSpaceCombiningSequenceTail(aChars + 1, aLength - 1) + ) + ); + } + + enum CompressionMode { + COMPRESS_NONE, + COMPRESS_WHITESPACE, + COMPRESS_WHITESPACE_NEWLINE, + COMPRESS_NONE_TRANSFORM_TO_SPACE + }; + + /** + * Create a text run from a run of Unicode text. The text may have whitespace + * compressed. A preformatted tab is sent to the text run as a single space. + * (Tab spacing must be performed by textframe later.) Certain other + * characters are discarded. + * + * @param aCompressWhitespace control what is compressed to a + * single space character: no compression, compress spaces (not followed + * by combining mark) and tabs, compress those plus newlines, or + * no compression except newlines are discarded. + * @param aIncomingFlags a flag indicating whether there was whitespace + * or an Arabic character preceding this text. We set it to indicate if + * there's an Arabic character or whitespace preceding the end of this text. + */ + static char16_t* TransformText(const char16_t* aText, uint32_t aLength, + char16_t* aOutput, + CompressionMode aCompression, + uint8_t * aIncomingFlags, + gfxSkipChars* aSkipChars, + uint32_t* aAnalysisFlags); + + static uint8_t* TransformText(const uint8_t* aText, uint32_t aLength, + uint8_t* aOutput, + CompressionMode aCompression, + uint8_t * aIncomingFlags, + gfxSkipChars* aSkipChars, + uint32_t* aAnalysisFlags); + + static void + AppendLineBreakOffset(nsTArray<uint32_t>* aArray, uint32_t aOffset) + { + if (aArray->Length() > 0 && (*aArray)[aArray->Length() - 1] == aOffset) + return; + aArray->AppendElement(aOffset); + } + + static uint32_t + ComputeApproximateLengthWithWhitespaceCompression(nsIContent *aContent, + const nsStyleText + *aStyleText); +}; + +class nsSkipCharsRunIterator { +public: + enum LengthMode { + LENGTH_UNSKIPPED_ONLY = false, + LENGTH_INCLUDES_SKIPPED = true + }; + nsSkipCharsRunIterator(const gfxSkipCharsIterator& aStart, + LengthMode aLengthIncludesSkipped, uint32_t aLength) + : mIterator(aStart), mRemainingLength(aLength), mRunLength(0), + mVisitSkipped(false), + mLengthIncludesSkipped(aLengthIncludesSkipped) { + } + void SetVisitSkipped() { mVisitSkipped = true; } + void SetOriginalOffset(int32_t aOffset) { + mIterator.SetOriginalOffset(aOffset); + } + void SetSkippedOffset(uint32_t aOffset) { + mIterator.SetSkippedOffset(aOffset); + } + + // guaranteed to return only positive-length runs + bool NextRun(); + bool IsSkipped() const { return mSkipped; } + // Always returns something > 0 + int32_t GetRunLength() const { return mRunLength; } + const gfxSkipCharsIterator& GetPos() const { return mIterator; } + int32_t GetOriginalOffset() const { return mIterator.GetOriginalOffset(); } + uint32_t GetSkippedOffset() const { return mIterator.GetSkippedOffset(); } + +private: + gfxSkipCharsIterator mIterator; + int32_t mRemainingLength; + int32_t mRunLength; + bool mSkipped; + bool mVisitSkipped; + bool mLengthIncludesSkipped; +}; + +#endif /*NSTEXTFRAMEUTILS_H_*/ |