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/*
* Copyright (C) 2015 Google Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY GOOGLE INC. ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef THIRD_PARTY_BLINK_RENDERER_PLATFORM_FONTS_SHAPING_CACHING_WORD_SHAPE_ITERATOR_H_
#define THIRD_PARTY_BLINK_RENDERER_PLATFORM_FONTS_SHAPING_CACHING_WORD_SHAPE_ITERATOR_H_
#include "third_party/blink/renderer/platform/fonts/font.h"
#include "third_party/blink/renderer/platform/fonts/shaping/shape_cache.h"
#include "third_party/blink/renderer/platform/fonts/shaping/shape_result_spacing.h"
#include "third_party/blink/renderer/platform/fonts/simple_font_data.h"
#include "third_party/blink/renderer/platform/wtf/allocator/allocator.h"
#include "third_party/blink/renderer/platform/wtf/text/character_names.h"
namespace blink {
class PLATFORM_EXPORT CachingWordShapeIterator final {
STACK_ALLOCATED();
public:
CachingWordShapeIterator(ShapeCache* cache,
const TextRun& run,
const Font* font)
: shape_cache_(cache),
text_run_(run),
font_(font),
spacing_(run),
width_so_far_(0),
start_index_(0) {
DCHECK(font);
// Shaping word by word is faster as each word is cached. If we cannot
// use the cache or if the font doesn't support word by word shaping
// fall back on shaping the entire run.
shape_by_word_ = font_->CanShapeWordByWord();
// SVG sets SpacingDisabled because it handles spacing by themselves.
if (!run.SpacingDisabled())
spacing_.SetSpacingAndExpansion(*font);
}
bool Next(scoped_refptr<const ShapeResult>* word_result) {
if (UNLIKELY(text_run_.AllowTabs()))
return NextForAllowTabs(word_result);
if (!shape_by_word_) {
if (start_index_)
return false;
*word_result = ShapeWord(text_run_, font_);
start_index_ = 1;
return word_result->get();
}
return NextWord(word_result);
}
private:
scoped_refptr<const ShapeResult>
ShapeWordWithoutSpacing(const TextRun&, const Font*);
scoped_refptr<const ShapeResult> ShapeWord(const TextRun&,
const Font*);
bool NextWord(scoped_refptr<const ShapeResult>* word_result) {
return ShapeToEndIndex(word_result, NextWordEndIndex());
}
static bool IsWordDelimiter(UChar ch) {
return ch == kSpaceCharacter || ch == kTabulationCharacter;
}
unsigned NextWordEndIndex() const {
const unsigned length = text_run_.length();
if (start_index_ >= length)
return 0;
if (start_index_ + 1u == length || IsWordDelimiter(text_run_[start_index_]))
return start_index_ + 1;
// 8Bit words end at isWordDelimiter().
if (text_run_.Is8Bit()) {
for (unsigned i = start_index_ + 1;; i++) {
if (i == length || IsWordDelimiter(text_run_[i]))
return i;
}
}
// Non-CJK/Emoji words end at isWordDelimiter() or CJK/Emoji characters.
unsigned end = start_index_;
UChar32 ch = text_run_.CodepointAtAndNext(end);
if (!Character::IsCJKIdeographOrSymbol(ch)) {
for (unsigned next_end = end; end < length; end = next_end) {
ch = text_run_.CodepointAtAndNext(next_end);
if (IsWordDelimiter(ch) || Character::IsCJKIdeographOrSymbolBase(ch))
return end;
}
return length;
}
// For CJK/Emoji words, delimit every character because these scripts do
// not delimit words by spaces, and delimiting only at isWordDelimiter()
// worsen the cache efficiency.
bool has_any_script = !Character::IsCommonOrInheritedScript(ch);
for (unsigned next_end = end; end < length; end = next_end) {
ch = text_run_.CodepointAtAndNext(next_end);
// Modifier check in order not to split Emoji sequences.
if (U_GET_GC_MASK(ch) & (U_GC_M_MASK | U_GC_LM_MASK | U_GC_SK_MASK) ||
ch == kZeroWidthJoinerCharacter || Character::IsEmojiComponent(ch) ||
Character::IsExtendedPictographic(ch))
continue;
// Avoid delimiting COMMON/INHERITED alone, which makes harder to
// identify the script.
if (Character::IsCJKIdeographOrSymbol(ch)) {
if (Character::IsCommonOrInheritedScript(ch))
continue;
if (!has_any_script) {
has_any_script = true;
continue;
}
}
return end;
}
return length;
}
bool ShapeToEndIndex(scoped_refptr<const ShapeResult>* result,
unsigned end_index) {
if (!end_index || end_index <= start_index_)
return false;
const unsigned length = text_run_.length();
if (!start_index_ && end_index == length) {
*result = ShapeWord(text_run_, font_);
} else {
DCHECK_LE(end_index, length);
TextRun sub_run =
text_run_.SubRun(start_index_, end_index - start_index_);
*result = ShapeWord(sub_run, font_);
}
start_index_ = end_index;
return result->get();
}
unsigned EndIndexUntil(UChar ch) const {
unsigned length = text_run_.length();
DCHECK_LT(start_index_, length);
for (unsigned i = start_index_ + 1;; i++) {
if (i == length || text_run_[i] == ch)
return i;
}
}
bool NextForAllowTabs(scoped_refptr<const ShapeResult>* word_result) {
unsigned length = text_run_.length();
if (start_index_ >= length)
return false;
if (UNLIKELY(text_run_[start_index_] == kTabulationCharacter)) {
for (unsigned i = start_index_ + 1;; i++) {
if (i == length || text_run_[i] != kTabulationCharacter) {
*word_result = ShapeResult::CreateForTabulationCharacters(
font_, text_run_, width_so_far_, i - start_index_);
start_index_ = i;
break;
}
}
} else if (!shape_by_word_) {
if (!ShapeToEndIndex(word_result, EndIndexUntil(kTabulationCharacter)))
return false;
} else {
if (!NextWord(word_result))
return false;
}
DCHECK(*word_result);
width_so_far_ += (*word_result)->Width();
return true;
}
ShapeCache* shape_cache_;
const TextRun& text_run_;
const Font* font_;
ShapeResultSpacing<TextRun> spacing_;
float width_so_far_; // Used only when allowTabs()
unsigned start_index_ : 31;
unsigned shape_by_word_ : 1;
DISALLOW_COPY_AND_ASSIGN(CachingWordShapeIterator);
};
} // namespace blink
#endif // THIRD_PARTY_BLINK_RENDERER_PLATFORM_FONTS_SHAPING_CACHING_WORD_SHAPE_ITERATOR_H_
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