| /* |
| * Copyright (C) 2003, 2006, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved. |
| * Copyright (C) 2008 Holger Hans Peter Freyther |
| * |
| * This library is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU Library General Public |
| * License as published by the Free Software Foundation; either |
| * version 2 of the License, or (at your option) any later version. |
| * |
| * This library is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * Library General Public License for more details. |
| * |
| * You should have received a copy of the GNU Library General Public License |
| * along with this library; see the file COPYING.LIB. If not, write to |
| * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, |
| * Boston, MA 02110-1301, USA. |
| * |
| */ |
| |
| #include "config.h" |
| #include "WidthIterator.h" |
| |
| #include "CharacterProperties.h" |
| #include "Font.h" |
| #include "FontCascade.h" |
| #include "GlyphBuffer.h" |
| #include "Latin1TextIterator.h" |
| #include "SurrogatePairAwareTextIterator.h" |
| #include <wtf/MathExtras.h> |
| |
| |
| namespace WebCore { |
| |
| using namespace WTF::Unicode; |
| |
| WidthIterator::WidthIterator(const FontCascade* font, const TextRun& run, HashSet<const Font*>* fallbackFonts, bool accountForGlyphBounds, bool forTextEmphasis) |
| : m_font(font) |
| , m_run(run) |
| , m_currentCharacter(0) |
| , m_runWidthSoFar(0) |
| , m_isAfterExpansion((run.expansionBehavior() & LeadingExpansionMask) == ForbidLeadingExpansion) |
| , m_finalRoundingWidth(0) |
| , m_fallbackFonts(fallbackFonts) |
| , m_accountForGlyphBounds(accountForGlyphBounds) |
| , m_enableKerning(font->enableKerning()) |
| , m_requiresShaping(font->requiresShaping()) |
| , m_forTextEmphasis(forTextEmphasis) |
| { |
| // If the padding is non-zero, count the number of spaces in the run |
| // and divide that by the padding for per space addition. |
| m_expansion = m_run.expansion(); |
| if (!m_expansion) |
| m_expansionPerOpportunity = 0; |
| else { |
| unsigned expansionOpportunityCount = FontCascade::expansionOpportunityCount(m_run.text(), m_run.ltr() ? TextDirection::LTR : TextDirection::RTL, run.expansionBehavior()).first; |
| |
| if (!expansionOpportunityCount) |
| m_expansionPerOpportunity = 0; |
| else |
| m_expansionPerOpportunity = m_expansion / expansionOpportunityCount; |
| } |
| } |
| |
| struct OriginalAdvancesForCharacterTreatedAsSpace { |
| public: |
| explicit OriginalAdvancesForCharacterTreatedAsSpace(bool isSpace, float advanceBefore, float advanceAt) |
| : characterIsSpace(isSpace) |
| , advanceBeforeCharacter(advanceBefore) |
| , advanceAtCharacter(advanceAt) |
| { |
| } |
| |
| bool characterIsSpace; |
| float advanceBeforeCharacter; |
| float advanceAtCharacter; |
| }; |
| |
| static inline bool isSoftBankEmoji(UChar32 codepoint) |
| { |
| return codepoint >= 0xE001 && codepoint <= 0xE537; |
| } |
| |
| inline auto WidthIterator::shouldApplyFontTransforms(const GlyphBuffer* glyphBuffer, unsigned lastGlyphCount, UChar32 previousCharacter) const -> TransformsType |
| { |
| if (glyphBuffer && glyphBuffer->size() == (lastGlyphCount + 1) && isSoftBankEmoji(previousCharacter)) |
| return TransformsType::Forced; |
| if (m_run.length() <= 1 || !(m_enableKerning || m_requiresShaping)) |
| return TransformsType::None; |
| return TransformsType::NotForced; |
| } |
| |
| inline float WidthIterator::applyFontTransforms(GlyphBuffer* glyphBuffer, bool ltr, unsigned& lastGlyphCount, const Font* font, UChar32 previousCharacter, bool force, CharactersTreatedAsSpace& charactersTreatedAsSpace) |
| { |
| ASSERT_UNUSED(previousCharacter, shouldApplyFontTransforms(glyphBuffer, lastGlyphCount, previousCharacter) != WidthIterator::TransformsType::None); |
| |
| if (!glyphBuffer) |
| return 0; |
| |
| auto glyphBufferSize = glyphBuffer->size(); |
| if (!force && glyphBufferSize <= lastGlyphCount + 1) { |
| lastGlyphCount = glyphBufferSize; |
| return 0; |
| } |
| |
| GlyphBufferAdvance* advances = glyphBuffer->advances(0); |
| float widthDifference = 0; |
| for (unsigned i = lastGlyphCount; i < glyphBufferSize; ++i) |
| widthDifference -= advances[i].width(); |
| |
| ASSERT(lastGlyphCount <= glyphBufferSize); |
| if (!ltr) |
| glyphBuffer->reverse(lastGlyphCount, glyphBufferSize - lastGlyphCount); |
| |
| font->applyTransforms(*glyphBuffer, lastGlyphCount, m_enableKerning, m_requiresShaping, m_font->fontDescription().locale()); |
| glyphBufferSize = glyphBuffer->size(); |
| |
| for (unsigned i = lastGlyphCount; i < glyphBufferSize; ++i) |
| advances[i].setHeight(-advances[i].height()); |
| |
| if (!ltr) |
| glyphBuffer->reverse(lastGlyphCount, glyphBufferSize - lastGlyphCount); |
| |
| // https://bugs.webkit.org/show_bug.cgi?id=206208: This is totally, 100%, furiously, utterly, frustratingly bogus. |
| // There is absolutely no guarantee that glyph indices before shaping have any relation at all with glyph indices after shaping. |
| // One of the fundamental things that shaping does is insert glyph all over the place. |
| for (size_t i = 0; i < charactersTreatedAsSpace.size(); ++i) { |
| auto spaceOffset = charactersTreatedAsSpace[i].first; |
| // Shaping may have deleted the glyph. |
| if (spaceOffset >= glyphBufferSize) |
| continue; |
| const OriginalAdvancesForCharacterTreatedAsSpace& originalAdvances = charactersTreatedAsSpace[i].second; |
| if (spaceOffset && !originalAdvances.characterIsSpace) |
| glyphBuffer->advances(spaceOffset - 1)->setWidth(originalAdvances.advanceBeforeCharacter); |
| glyphBuffer->advances(spaceOffset)->setWidth(originalAdvances.advanceAtCharacter); |
| } |
| charactersTreatedAsSpace.clear(); |
| |
| for (unsigned i = lastGlyphCount; i < glyphBufferSize; ++i) |
| widthDifference += advances[i].width(); |
| |
| lastGlyphCount = glyphBufferSize; |
| return widthDifference; |
| } |
| |
| static inline std::pair<bool, bool> expansionLocation(bool ideograph, bool treatAsSpace, bool ltr, bool isAfterExpansion, bool forbidLeadingExpansion, bool forbidTrailingExpansion, bool forceLeadingExpansion, bool forceTrailingExpansion) |
| { |
| bool expandLeft = ideograph; |
| bool expandRight = ideograph; |
| if (treatAsSpace) { |
| if (ltr) |
| expandRight = true; |
| else |
| expandLeft = true; |
| } |
| if (isAfterExpansion) { |
| if (ltr) |
| expandLeft = false; |
| else |
| expandRight = false; |
| } |
| ASSERT(!forbidLeadingExpansion || !forceLeadingExpansion); |
| ASSERT(!forbidTrailingExpansion || !forceTrailingExpansion); |
| if (forbidLeadingExpansion) |
| expandLeft = false; |
| if (forbidTrailingExpansion) |
| expandRight = false; |
| if (forceLeadingExpansion) |
| expandLeft = true; |
| if (forceTrailingExpansion) |
| expandRight = true; |
| return std::make_pair(expandLeft, expandRight); |
| } |
| |
| template <typename TextIterator> |
| inline unsigned WidthIterator::advanceInternal(TextIterator& textIterator, GlyphBuffer* glyphBuffer) |
| { |
| // The core logic here needs to match SimpleLineLayout::widthForSimpleText() |
| bool rtl = m_run.rtl(); |
| bool hasExtraSpacing = (m_font->letterSpacing() || m_font->wordSpacing() || m_expansion) && !m_run.spacingDisabled(); |
| |
| bool runForcesLeadingExpansion = (m_run.expansionBehavior() & LeadingExpansionMask) == ForceLeadingExpansion; |
| bool runForcesTrailingExpansion = (m_run.expansionBehavior() & TrailingExpansionMask) == ForceTrailingExpansion; |
| bool runForbidsLeadingExpansion = (m_run.expansionBehavior() & LeadingExpansionMask) == ForbidLeadingExpansion; |
| bool runForbidsTrailingExpansion = (m_run.expansionBehavior() & TrailingExpansionMask) == ForbidTrailingExpansion; |
| float widthSinceLastRounding = m_runWidthSoFar; |
| float leftoverJustificationWidth = 0; |
| m_runWidthSoFar = floorf(m_runWidthSoFar); |
| widthSinceLastRounding -= m_runWidthSoFar; |
| |
| float lastRoundingWidth = m_finalRoundingWidth; |
| FloatRect bounds; |
| |
| const Font& primaryFont = m_font->primaryFont(); |
| const Font* lastFontData = &primaryFont; |
| unsigned lastGlyphCount = glyphBuffer ? glyphBuffer->size() : 0; |
| |
| UChar32 character = 0; |
| UChar32 previousCharacter = 0; |
| unsigned clusterLength = 0; |
| CharactersTreatedAsSpace charactersTreatedAsSpace; |
| String normalizedSpacesStringCache; |
| // We are iterating in string order, not glyph order. Compare this to ComplexTextController::adjustGlyphsAndAdvances() |
| while (textIterator.consume(character, clusterLength)) { |
| unsigned advanceLength = clusterLength; |
| bool characterMustDrawSomething = !isDefaultIgnorableCodePoint(character); |
| #if USE(FREETYPE) |
| // Freetype based ports only override the characters with Default_Ignorable unicode property when the font |
| // doesn't support the code point. We should ignore them at this point to ensure they are not displayed. |
| if (!characterMustDrawSomething) { |
| textIterator.advance(advanceLength); |
| continue; |
| } |
| #endif |
| int currentCharacter = textIterator.currentIndex(); |
| const GlyphData& glyphData = m_font->glyphDataForCharacter(character, rtl); |
| Glyph glyph = glyphData.glyph; |
| if (!glyph && !characterMustDrawSomething) { |
| textIterator.advance(advanceLength); |
| continue; |
| } |
| const Font* font = glyphData.font ? glyphData.font : &m_font->primaryFont(); |
| ASSERT(font); |
| |
| // Now that we have a glyph and font data, get its width. |
| float width; |
| if (character == '\t' && m_run.allowTabs()) |
| width = m_font->tabWidth(*font, m_run.tabSize(), m_run.xPos() + m_runWidthSoFar + widthSinceLastRounding); |
| else { |
| width = font->widthForGlyph(glyph); |
| |
| // SVG uses horizontalGlyphStretch(), when textLength is used to stretch/squeeze text. |
| width *= m_run.horizontalGlyphStretch(); |
| } |
| |
| if (font != lastFontData && width) { |
| auto transformsType = shouldApplyFontTransforms(glyphBuffer, lastGlyphCount, previousCharacter); |
| if (transformsType != TransformsType::None) { |
| m_runWidthSoFar += applyFontTransforms(glyphBuffer, m_run.ltr(), lastGlyphCount, lastFontData, previousCharacter, transformsType == TransformsType::Forced, charactersTreatedAsSpace); |
| if (glyphBuffer) |
| glyphBuffer->shrink(lastGlyphCount); |
| } |
| |
| lastFontData = font; |
| if (m_fallbackFonts && font != &primaryFont) { |
| // FIXME: This does a little extra work that could be avoided if |
| // glyphDataForCharacter() returned whether it chose to use a small caps font. |
| if (!m_font->isSmallCaps() || character == u_toupper(character)) |
| m_fallbackFonts->add(font); |
| else { |
| const GlyphData& uppercaseGlyphData = m_font->glyphDataForCharacter(u_toupper(character), rtl); |
| if (uppercaseGlyphData.font != &primaryFont) |
| m_fallbackFonts->add(uppercaseGlyphData.font); |
| } |
| } |
| } |
| |
| if (hasExtraSpacing) { |
| // Account for letter-spacing. |
| if (width) { |
| width += m_font->letterSpacing(); |
| width += leftoverJustificationWidth; |
| leftoverJustificationWidth = 0; |
| } |
| |
| static bool expandAroundIdeographs = FontCascade::canExpandAroundIdeographsInComplexText(); |
| bool treatAsSpace = FontCascade::treatAsSpace(character); |
| bool currentIsLastCharacter = currentCharacter + advanceLength == static_cast<size_t>(m_run.length()); |
| bool forceLeadingExpansion = false; // On the left, regardless of m_run.ltr() |
| bool forceTrailingExpansion = false; // On the right, regardless of m_run.ltr() |
| bool forbidLeadingExpansion = false; |
| bool forbidTrailingExpansion = false; |
| if (runForcesLeadingExpansion) |
| forceLeadingExpansion = m_run.ltr() ? !currentCharacter : currentIsLastCharacter; |
| if (runForcesTrailingExpansion) |
| forceTrailingExpansion = m_run.ltr() ? currentIsLastCharacter : !currentCharacter; |
| if (runForbidsLeadingExpansion) |
| forbidLeadingExpansion = m_run.ltr() ? !currentCharacter : currentIsLastCharacter; |
| if (runForbidsTrailingExpansion) |
| forbidTrailingExpansion = m_run.ltr() ? currentIsLastCharacter : !currentCharacter; |
| bool ideograph = (expandAroundIdeographs && FontCascade::isCJKIdeographOrSymbol(character)); |
| if (treatAsSpace || ideograph || forceLeadingExpansion || forceTrailingExpansion) { |
| // Distribute the run's total expansion evenly over all expansion opportunities in the run. |
| if (m_expansion) { |
| auto [expandLeft, expandRight] = expansionLocation(ideograph, treatAsSpace, m_run.ltr(), m_isAfterExpansion, forbidLeadingExpansion, forbidTrailingExpansion, forceLeadingExpansion, forceTrailingExpansion); |
| if (expandLeft) { |
| if (m_run.ltr()) { |
| // Increase previous width |
| m_expansion -= m_expansionPerOpportunity; |
| m_runWidthSoFar += m_expansionPerOpportunity; |
| if (glyphBuffer) { |
| if (glyphBuffer->isEmpty()) { |
| if (m_forTextEmphasis) |
| glyphBuffer->add(font->zeroWidthSpaceGlyph(), font, m_expansionPerOpportunity, currentCharacter); |
| else |
| glyphBuffer->add(font->spaceGlyph(), font, m_expansionPerOpportunity, currentCharacter); |
| } else |
| glyphBuffer->expandLastAdvance(m_expansionPerOpportunity); |
| } |
| } else { |
| // Increase next width |
| leftoverJustificationWidth += m_expansionPerOpportunity; |
| m_isAfterExpansion = true; |
| } |
| } |
| if (expandRight) { |
| m_expansion -= m_expansionPerOpportunity; |
| width += m_expansionPerOpportunity; |
| if (m_run.ltr()) |
| m_isAfterExpansion = true; |
| } |
| } else |
| m_isAfterExpansion = false; |
| |
| // Account for word spacing. |
| // We apply additional space between "words" by adding width to the space character. |
| if (treatAsSpace && (character != '\t' || !m_run.allowTabs()) && (currentCharacter || character == noBreakSpace) && m_font->wordSpacing()) |
| width += m_font->wordSpacing(); |
| } else |
| m_isAfterExpansion = false; |
| } |
| |
| auto transformsType = shouldApplyFontTransforms(glyphBuffer, lastGlyphCount, previousCharacter); |
| if (transformsType != TransformsType::None && glyphBuffer && FontCascade::treatAsSpace(character)) { |
| charactersTreatedAsSpace.append(std::make_pair(glyphBuffer->size(), |
| OriginalAdvancesForCharacterTreatedAsSpace(character == ' ', glyphBuffer->size() ? glyphBuffer->advanceAt(glyphBuffer->size() - 1).width() : 0, width))); |
| } |
| |
| if (m_accountForGlyphBounds) { |
| bounds = font->boundsForGlyph(glyph); |
| if (!currentCharacter) |
| m_firstGlyphOverflow = std::max<float>(0, -bounds.x()); |
| } |
| |
| if (m_forTextEmphasis && !FontCascade::canReceiveTextEmphasis(character)) |
| glyph = 0; |
| |
| // Advance past the character we just dealt with. |
| textIterator.advance(advanceLength); |
| |
| float oldWidth = width; |
| |
| widthSinceLastRounding += width; |
| |
| if (glyphBuffer) |
| glyphBuffer->add(glyph, font, (rtl ? oldWidth + lastRoundingWidth : width), currentCharacter); |
| |
| lastRoundingWidth = width - oldWidth; |
| |
| if (m_accountForGlyphBounds) { |
| m_maxGlyphBoundingBoxY = std::max(m_maxGlyphBoundingBoxY, bounds.maxY()); |
| m_minGlyphBoundingBoxY = std::min(m_minGlyphBoundingBoxY, bounds.y()); |
| m_lastGlyphOverflow = std::max<float>(0, bounds.maxX() - width); |
| } |
| previousCharacter = character; |
| } |
| |
| if (glyphBuffer && leftoverJustificationWidth) { |
| if (m_forTextEmphasis) |
| glyphBuffer->add(lastFontData->zeroWidthSpaceGlyph(), lastFontData, leftoverJustificationWidth, m_run.length() - 1); |
| else |
| glyphBuffer->add(lastFontData->spaceGlyph(), lastFontData, leftoverJustificationWidth, m_run.length() - 1); |
| } |
| |
| auto transformsType = shouldApplyFontTransforms(glyphBuffer, lastGlyphCount, previousCharacter); |
| if (transformsType != TransformsType::None) { |
| m_runWidthSoFar += applyFontTransforms(glyphBuffer, m_run.ltr(), lastGlyphCount, lastFontData, previousCharacter, transformsType == TransformsType::Forced, charactersTreatedAsSpace); |
| if (glyphBuffer) |
| glyphBuffer->shrink(lastGlyphCount); |
| } |
| |
| unsigned consumedCharacters = textIterator.currentIndex() - m_currentCharacter; |
| m_currentCharacter = textIterator.currentIndex(); |
| m_runWidthSoFar += widthSinceLastRounding; |
| m_finalRoundingWidth = lastRoundingWidth; |
| return consumedCharacters; |
| } |
| |
| unsigned WidthIterator::advance(unsigned offset, GlyphBuffer* glyphBuffer) |
| { |
| unsigned length = m_run.length(); |
| |
| if (offset > length) |
| offset = length; |
| |
| if (m_currentCharacter >= offset) |
| return 0; |
| |
| if (m_run.is8Bit()) { |
| Latin1TextIterator textIterator(m_run.data8(m_currentCharacter), m_currentCharacter, offset, length); |
| return advanceInternal(textIterator, glyphBuffer); |
| } |
| |
| SurrogatePairAwareTextIterator textIterator(m_run.data16(m_currentCharacter), m_currentCharacter, offset, length); |
| return advanceInternal(textIterator, glyphBuffer); |
| } |
| |
| bool WidthIterator::advanceOneCharacter(float& width, GlyphBuffer& glyphBuffer) |
| { |
| unsigned oldSize = glyphBuffer.size(); |
| advance(m_currentCharacter + 1, &glyphBuffer); |
| float w = 0; |
| for (unsigned i = oldSize; i < glyphBuffer.size(); ++i) |
| w += glyphBuffer.advanceAt(i).width(); |
| width = w; |
| return glyphBuffer.size() > oldSize; |
| } |
| |
| } |
