| /* |
| * Copyright (C) 2003, 2006, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved. |
| * Copyright (C) 2008 Holger Hans Peter Freyther |
| * Copyright (C) 2014 Google Inc. All rights reserved. |
| * |
| * 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 "sky/engine/platform/fonts/WidthIterator.h" |
| |
| #include "sky/engine/platform/fonts/Character.h" |
| #include "sky/engine/platform/fonts/Font.h" |
| #include "sky/engine/platform/fonts/FontPlatformFeatures.h" |
| #include "sky/engine/platform/fonts/GlyphBuffer.h" |
| #include "sky/engine/platform/fonts/Latin1TextIterator.h" |
| #include "sky/engine/platform/fonts/SimpleFontData.h" |
| #include "sky/engine/platform/text/SurrogatePairAwareTextIterator.h" |
| #include "sky/engine/wtf/MathExtras.h" |
| |
| using namespace WTF; |
| using namespace Unicode; |
| |
| namespace blink { |
| |
| WidthIterator::WidthIterator(const Font* font, const TextRun& run, HashSet<const SimpleFontData*>* fallbackFonts, bool accountForGlyphBounds, bool forTextEmphasis) |
| : m_font(font) |
| , m_run(run) |
| , m_currentCharacter(0) |
| , m_runWidthSoFar(0) |
| , m_isAfterExpansion(!run.allowsLeadingExpansion()) |
| , m_fallbackFonts(fallbackFonts) |
| , m_maxGlyphBoundingBoxY(std::numeric_limits<float>::min()) |
| , m_minGlyphBoundingBoxY(std::numeric_limits<float>::max()) |
| , m_firstGlyphOverflow(0) |
| , m_lastGlyphOverflow(0) |
| , m_accountForGlyphBounds(accountForGlyphBounds) |
| , 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 { |
| bool isAfterExpansion = m_isAfterExpansion; |
| unsigned expansionOpportunityCount = m_run.is8Bit() ? Character::expansionOpportunityCount(m_run.characters8(), m_run.length(), m_run.direction(), isAfterExpansion) : Character::expansionOpportunityCount(m_run.characters16(), m_run.length(), m_run.direction(), isAfterExpansion); |
| if (isAfterExpansion && !m_run.allowsTrailingExpansion()) |
| expansionOpportunityCount--; |
| |
| if (!expansionOpportunityCount) |
| m_expansionPerOpportunity = 0; |
| else |
| m_expansionPerOpportunity = m_expansion / expansionOpportunityCount; |
| } |
| } |
| |
| GlyphData WidthIterator::glyphDataForCharacter(CharacterData& charData) |
| { |
| ASSERT(m_font); |
| return m_font->glyphDataForCharacter(charData.character, m_run.rtl()); |
| } |
| |
| float WidthIterator::characterWidth(UChar32 character, const GlyphData& glyphData) const |
| { |
| const SimpleFontData* fontData = glyphData.fontData; |
| ASSERT(fontData); |
| |
| if (UNLIKELY(character == '\t' && m_run.allowTabs())) |
| return m_font->tabWidth(*fontData, m_run.tabSize(), m_run.xPos() + m_runWidthSoFar); |
| |
| float width = fontData->widthForGlyph(glyphData.glyph); |
| |
| // SVG uses horizontalGlyphStretch(), when textLength is used to stretch/squeeze text. |
| if (UNLIKELY(m_run.horizontalGlyphStretch() != 1)) |
| width *= m_run.horizontalGlyphStretch(); |
| |
| return width; |
| } |
| |
| void WidthIterator::cacheFallbackFont(UChar32 character, const SimpleFontData* fontData, |
| const SimpleFontData* primaryFont) |
| { |
| if (fontData == primaryFont) |
| return; |
| |
| // 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->fontDescription().variant() == FontVariantNormal || character == toUpper(character)) { |
| m_fallbackFonts->add(fontData); |
| } else { |
| ASSERT(m_font->fontDescription().variant() == FontVariantSmallCaps); |
| const GlyphData uppercaseGlyphData = m_font->glyphDataForCharacter(toUpper(character), |
| m_run.rtl()); |
| if (uppercaseGlyphData.fontData != primaryFont) |
| m_fallbackFonts->add(uppercaseGlyphData.fontData); |
| } |
| } |
| |
| float WidthIterator::adjustSpacing(float width, const CharacterData& charData, |
| const SimpleFontData& fontData, GlyphBuffer* glyphBuffer) |
| { |
| // Account for letter-spacing. |
| if (width) |
| width += m_font->fontDescription().letterSpacing(); |
| |
| static bool expandAroundIdeographs = FontPlatformFeatures::canExpandAroundIdeographsInComplexText(); |
| bool treatAsSpace = Character::treatAsSpace(charData.character); |
| if (treatAsSpace || (expandAroundIdeographs && Character::isCJKIdeographOrSymbol(charData.character))) { |
| // Distribute the run's total expansion evenly over all expansion opportunities in the run. |
| if (m_expansion) { |
| if (!treatAsSpace && !m_isAfterExpansion) { |
| // Take the expansion opportunity before this ideograph. |
| m_expansion -= m_expansionPerOpportunity; |
| float expansionAtThisOpportunity = m_expansionPerOpportunity; |
| m_runWidthSoFar += expansionAtThisOpportunity; |
| if (glyphBuffer) { |
| if (glyphBuffer->isEmpty()) { |
| if (m_forTextEmphasis) |
| glyphBuffer->add(fontData.zeroWidthSpaceGlyph(), &fontData, m_expansionPerOpportunity); |
| else |
| glyphBuffer->add(fontData.spaceGlyph(), &fontData, expansionAtThisOpportunity); |
| } else { |
| glyphBuffer->expandLastAdvance(expansionAtThisOpportunity); |
| } |
| } |
| } |
| if (m_run.allowsTrailingExpansion() |
| || (m_run.ltr() && charData.characterOffset + charData.clusterLength < static_cast<size_t>(m_run.length())) |
| || (m_run.rtl() && charData.characterOffset)) { |
| m_expansion -= m_expansionPerOpportunity; |
| width += m_expansionPerOpportunity; |
| 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 && (charData.character != '\t' || !m_run.allowTabs()) |
| && (charData.characterOffset || charData.character == noBreakSpace) |
| && m_font->fontDescription().wordSpacing()) { |
| width += m_font->fontDescription().wordSpacing(); |
| } |
| } else { |
| m_isAfterExpansion = false; |
| } |
| |
| return width; |
| } |
| |
| void WidthIterator::updateGlyphBounds(const GlyphData& glyphData, float width, bool firstCharacter) |
| { |
| ASSERT(glyphData.fontData); |
| FloatRect bounds = glyphData.fontData->boundsForGlyph(glyphData.glyph); |
| |
| if (firstCharacter) |
| m_firstGlyphOverflow = std::max<float>(0, -bounds.x()); |
| m_lastGlyphOverflow = std::max<float>(0, bounds.maxX() - width); |
| m_maxGlyphBoundingBoxY = std::max(m_maxGlyphBoundingBoxY, bounds.maxY()); |
| m_minGlyphBoundingBoxY = std::min(m_minGlyphBoundingBoxY, bounds.y()); |
| } |
| |
| template <typename TextIterator> |
| unsigned WidthIterator::advanceInternal(TextIterator& textIterator, GlyphBuffer* glyphBuffer) |
| { |
| bool hasExtraSpacing = (m_font->fontDescription().letterSpacing() || m_font->fontDescription().wordSpacing() || m_expansion) |
| && !m_run.spacingDisabled(); |
| |
| const SimpleFontData* primaryFont = m_font->primaryFont(); |
| const SimpleFontData* lastFontData = primaryFont; |
| |
| CharacterData charData; |
| while (textIterator.consume(charData.character, charData.clusterLength)) { |
| charData.characterOffset = textIterator.currentCharacter(); |
| |
| const GlyphData glyphData = glyphDataForCharacter(charData); |
| Glyph glyph = glyphData.glyph; |
| const SimpleFontData* fontData = glyphData.fontData; |
| ASSERT(fontData); |
| |
| // Now that we have a glyph and font data, get its width. |
| float width = characterWidth(charData.character, glyphData); |
| |
| if (m_fallbackFonts && lastFontData != fontData && width) { |
| lastFontData = fontData; |
| cacheFallbackFont(charData.character, fontData, primaryFont); |
| } |
| |
| if (hasExtraSpacing) |
| width = adjustSpacing(width, charData, *fontData, glyphBuffer); |
| |
| if (m_accountForGlyphBounds) |
| updateGlyphBounds(glyphData, width, !charData.characterOffset); |
| |
| if (m_forTextEmphasis && !Character::canReceiveTextEmphasis(charData.character)) |
| glyph = 0; |
| |
| // Advance past the character we just dealt with. |
| textIterator.advance(charData.clusterLength); |
| m_runWidthSoFar += width; |
| |
| if (glyphBuffer) |
| glyphBuffer->add(glyph, fontData, width); |
| } |
| |
| unsigned consumedCharacters = textIterator.currentCharacter() - m_currentCharacter; |
| m_currentCharacter = textIterator.currentCharacter(); |
| |
| return consumedCharacters; |
| } |
| |
| unsigned WidthIterator::advance(int offset, GlyphBuffer* glyphBuffer) |
| { |
| int length = m_run.length(); |
| |
| if (offset > length) |
| offset = length; |
| |
| if (m_currentCharacter >= static_cast<unsigned>(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) |
| { |
| float initialWidth = m_runWidthSoFar; |
| |
| if (!advance(m_currentCharacter + 1)) |
| return false; |
| |
| width = m_runWidthSoFar - initialWidth; |
| return true; |
| } |
| |
| } // namespace blink |
