| /* |
| * Copyright (C) 2018 Apple 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 APPLE INC. AND ITS CONTRIBUTORS ``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 ITS 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. |
| */ |
| |
| #include "config.h" |
| #include "InlineTextItem.h" |
| |
| #if ENABLE(LAYOUT_FORMATTING_CONTEXT) |
| |
| #include "FontCascade.h" |
| #include "InlineSoftLineBreakItem.h" |
| #include "TextUtil.h" |
| #include <wtf/unicode/CharacterNames.h> |
| |
| namespace WebCore { |
| namespace Layout { |
| |
| static_assert(sizeof(InlineItem) == sizeof(InlineTextItem), ""); |
| |
| static inline bool isWhitespaceCharacter(UChar character, bool preserveNewline) |
| { |
| return character == ' ' || character == '\t' || (character == '\n' && !preserveNewline); |
| } |
| |
| static unsigned moveToNextNonWhitespacePosition(const StringView& textContent, unsigned startPosition, bool preserveNewline) |
| { |
| auto nextNonWhiteSpacePosition = startPosition; |
| while (nextNonWhiteSpacePosition < textContent.length() && isWhitespaceCharacter(textContent[nextNonWhiteSpacePosition], preserveNewline)) |
| ++nextNonWhiteSpacePosition; |
| return nextNonWhiteSpacePosition - startPosition; |
| } |
| |
| static unsigned moveToNextBreakablePosition(unsigned startPosition, LazyLineBreakIterator& lineBreakIterator, const RenderStyle& style) |
| { |
| auto textLength = lineBreakIterator.stringView().length(); |
| auto startPositionForNextBreakablePosition = startPosition; |
| while (startPositionForNextBreakablePosition < textLength) { |
| auto nextBreakablePosition = TextUtil::findNextBreakablePosition(lineBreakIterator, startPositionForNextBreakablePosition, style); |
| // Oftentimes the next breakable position comes back as the start position (most notably hyphens). |
| if (nextBreakablePosition != startPosition) |
| return nextBreakablePosition - startPosition; |
| ++startPositionForNextBreakablePosition; |
| } |
| return textLength - startPosition; |
| } |
| |
| void InlineTextItem::createAndAppendTextItems(InlineItems& inlineContent, const Box& inlineBox) |
| { |
| auto& textContext = *inlineBox.textContext(); |
| auto text = textContext.content; |
| if (!text.length()) |
| return inlineContent.append(InlineTextItem::createEmptyItem(inlineBox)); |
| |
| auto& style = inlineBox.style(); |
| auto& font = style.fontCascade(); |
| LazyLineBreakIterator lineBreakIterator(text); |
| unsigned currentPosition = 0; |
| |
| auto inlineItemWidth = [&](auto startPosition, auto length) -> Optional<InlineLayoutUnit> { |
| if (!textContext.canUseSimplifiedContentMeasuring) |
| return { }; |
| return TextUtil::width(inlineBox, startPosition, startPosition + length); |
| }; |
| |
| while (currentPosition < text.length()) { |
| auto isSegmentBreakCandidate = [](auto character) { |
| return character == '\n'; |
| }; |
| |
| // Segment breaks with preserve new line style (white-space: pre, pre-wrap, break-spaces and pre-line) compute to forced line break. |
| if (isSegmentBreakCandidate(text[currentPosition]) && style.preserveNewline()) { |
| inlineContent.append(InlineSoftLineBreakItem::createSoftLineBreakItem(inlineBox, currentPosition)); |
| ++currentPosition; |
| continue; |
| } |
| |
| if (isWhitespaceCharacter(text[currentPosition], style.preserveNewline())) { |
| auto appendWhitespaceItem = [&] (auto startPosition, auto itemLength) { |
| auto simpleSingleWhitespaceContent = textContext.canUseSimplifiedContentMeasuring && (itemLength == 1 || style.collapseWhiteSpace()); |
| auto width = simpleSingleWhitespaceContent ? makeOptional(InlineLayoutUnit { font.spaceWidth() }) : inlineItemWidth(startPosition, itemLength); |
| inlineContent.append(InlineTextItem::createWhitespaceItem(inlineBox, startPosition, itemLength, width)); |
| }; |
| |
| auto length = moveToNextNonWhitespacePosition(text, currentPosition, style.preserveNewline()); |
| if (style.whiteSpace() == WhiteSpace::BreakSpaces) { |
| // https://www.w3.org/TR/css-text-3/#white-space-phase-1 |
| // For break-spaces, a soft wrap opportunity exists after every space and every tab. |
| // FIXME: if this turns out to be a perf hit with too many individual whitespace inline items, we should transition this logic to line breaking. |
| for (unsigned i = 0; i < length; ++i) |
| appendWhitespaceItem(currentPosition + i, 1); |
| } else |
| appendWhitespaceItem(currentPosition, length); |
| currentPosition += length; |
| continue; |
| } |
| |
| auto length = moveToNextBreakablePosition(currentPosition, lineBreakIterator, style); |
| inlineContent.append(InlineTextItem::createNonWhitespaceItem(inlineBox, currentPosition, length, inlineItemWidth(currentPosition, length))); |
| currentPosition += length; |
| } |
| } |
| |
| bool InlineTextItem::isEmptyContent() const |
| { |
| // FIXME: We should check for more zero width content and not just U+200B. |
| return !m_length || (m_length == 1 && layoutBox().textContext()->content[start()] == zeroWidthSpace); |
| } |
| |
| } |
| } |
| #endif |