| /* |
| * 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 "Font.h" |
| #include "GlyphBuffer.h" |
| #include "SimpleFontData.h" |
| #include "SurrogatePairAwareTextIterator.h" |
| #include "TextRun.h" |
| #include <wtf/MathExtras.h> |
| |
| using namespace WTF; |
| using namespace Unicode; |
| using namespace std; |
| |
| namespace WebCore { |
| |
| 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_finalRoundingWidth(0) |
| , m_fallbackFonts(fallbackFonts) |
| , m_accountForGlyphBounds(accountForGlyphBounds) |
| , m_maxGlyphBoundingBoxY(numeric_limits<float>::min()) |
| , m_minGlyphBoundingBoxY(numeric_limits<float>::max()) |
| , m_firstGlyphOverflow(0) |
| , m_lastGlyphOverflow(0) |
| , 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 = Font::expansionOpportunityCount(m_run.characters(), m_run.length(), m_run.ltr() ? LTR : RTL, isAfterExpansion); |
| if (isAfterExpansion && !m_run.allowsTrailingExpansion()) |
| expansionOpportunityCount--; |
| |
| if (!expansionOpportunityCount) |
| m_expansionPerOpportunity = 0; |
| else |
| m_expansionPerOpportunity = m_expansion / expansionOpportunityCount; |
| } |
| } |
| |
| GlyphData WidthIterator::glyphDataForCharacter(UChar32 character, bool mirror, int currentCharacter, unsigned& advanceLength) |
| { |
| ASSERT(m_font); |
| |
| #if ENABLE(SVG_FONTS) |
| if (TextRun::RenderingContext* renderingContext = m_run.renderingContext()) |
| return renderingContext->glyphDataForCharacter(*m_font, m_run, *this, character, mirror, currentCharacter, advanceLength); |
| #else |
| UNUSED_PARAM(currentCharacter); |
| UNUSED_PARAM(advanceLength); |
| #endif |
| |
| return m_font->glyphDataForCharacter(character, mirror); |
| } |
| |
| unsigned WidthIterator::advance(int offset, GlyphBuffer* glyphBuffer) |
| { |
| if (offset > m_run.length()) |
| offset = m_run.length(); |
| |
| if (int(m_currentCharacter) >= offset) |
| return 0; |
| |
| bool rtl = m_run.rtl(); |
| bool hasExtraSpacing = (m_font->letterSpacing() || m_font->wordSpacing() || m_expansion) && !m_run.spacingDisabled(); |
| |
| float widthSinceLastRounding = m_runWidthSoFar; |
| m_runWidthSoFar = floorf(m_runWidthSoFar); |
| widthSinceLastRounding -= m_runWidthSoFar; |
| |
| float lastRoundingWidth = m_finalRoundingWidth; |
| FloatRect bounds; |
| |
| const SimpleFontData* primaryFont = m_font->primaryFont(); |
| const SimpleFontData* lastFontData = primaryFont; |
| |
| UChar32 character = 0; |
| unsigned clusterLength = 0; |
| SurrogatePairAwareTextIterator textIterator(m_run.data(m_currentCharacter), m_currentCharacter, offset, m_run.length()); |
| while (textIterator.consume(character, clusterLength)) { |
| unsigned advanceLength = clusterLength; |
| const GlyphData& glyphData = glyphDataForCharacter(character, rtl, textIterator.currentCharacter(), advanceLength); |
| 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; |
| if (character == '\t' && m_run.allowTabs()) { |
| float tabWidth = m_font->tabWidth(*fontData); |
| width = tabWidth - fmodf(m_run.xPos() + m_runWidthSoFar + widthSinceLastRounding, tabWidth); |
| } else { |
| width = fontData->widthForGlyph(glyph); |
| |
| #if ENABLE(SVG) |
| // SVG uses horizontalGlyphStretch(), when textLength is used to stretch/squeeze text. |
| width *= m_run.horizontalGlyphStretch(); |
| #endif |
| |
| // We special case spaces in two ways when applying word rounding. |
| // First, we round spaces to an adjusted width in all fonts. |
| // Second, in fixed-pitch fonts we ensure that all characters that |
| // match the width of the space character have the same width as the space character. |
| if (m_run.applyWordRounding() && width == fontData->spaceWidth() && (fontData->pitch() == FixedPitch || glyph == fontData->spaceGlyph())) |
| width = fontData->adjustedSpaceWidth(); |
| } |
| |
| if (fontData != lastFontData && width) { |
| lastFontData = fontData; |
| if (m_fallbackFonts && fontData != 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 == toUpper(character)) |
| m_fallbackFonts->add(fontData); |
| else { |
| const GlyphData& uppercaseGlyphData = m_font->glyphDataForCharacter(toUpper(character), rtl); |
| if (uppercaseGlyphData.fontData != primaryFont) |
| m_fallbackFonts->add(uppercaseGlyphData.fontData); |
| } |
| } |
| } |
| |
| if (hasExtraSpacing) { |
| // Account for letter-spacing. |
| if (width && m_font->letterSpacing()) |
| width += m_font->letterSpacing(); |
| |
| static bool expandAroundIdeographs = Font::canExpandAroundIdeographsInComplexText(); |
| bool treatAsSpace = Font::treatAsSpace(character); |
| if (treatAsSpace || (expandAroundIdeographs && Font::isCJKIdeographOrSymbol(character))) { |
| // Distribute the run's total expansion evenly over all expansion opportunities in the run. |
| if (m_expansion) { |
| float previousExpansion = m_expansion; |
| if (!treatAsSpace && !m_isAfterExpansion) { |
| // Take the expansion opportunity before this ideograph. |
| m_expansion -= m_expansionPerOpportunity; |
| float expansionAtThisOpportunity = !m_run.applyWordRounding() ? m_expansionPerOpportunity : roundf(previousExpansion) - roundf(m_expansion); |
| m_runWidthSoFar += expansionAtThisOpportunity; |
| if (glyphBuffer) { |
| if (glyphBuffer->isEmpty()) |
| glyphBuffer->add(fontData->spaceGlyph(), fontData, expansionAtThisOpportunity); |
| else |
| glyphBuffer->expandLastAdvance(expansionAtThisOpportunity); |
| } |
| previousExpansion = m_expansion; |
| } |
| if (m_run.allowsTrailingExpansion() || (m_run.ltr() && textIterator.currentCharacter() + advanceLength < static_cast<size_t>(m_run.length())) |
| || (m_run.rtl() && textIterator.currentCharacter())) { |
| m_expansion -= m_expansionPerOpportunity; |
| width += !m_run.applyWordRounding() ? m_expansionPerOpportunity : roundf(previousExpansion) - roundf(m_expansion); |
| 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 && textIterator.currentCharacter() && !Font::treatAsSpace(textIterator.characters()[-1]) && m_font->wordSpacing()) |
| width += m_font->wordSpacing(); |
| } else |
| m_isAfterExpansion = false; |
| } |
| |
| if (m_accountForGlyphBounds) { |
| bounds = fontData->boundsForGlyph(glyph); |
| if (!textIterator.currentCharacter()) |
| m_firstGlyphOverflow = max<float>(0, -bounds.x()); |
| } |
| |
| if (m_forTextEmphasis && !Font::canReceiveTextEmphasis(character)) |
| glyph = 0; |
| |
| // Advance past the character we just dealt with. |
| textIterator.advance(advanceLength); |
| |
| float oldWidth = width; |
| |
| // Force characters that are used to determine word boundaries for the rounding hack |
| // to be integer width, so following words will start on an integer boundary. |
| if (m_run.applyWordRounding() && Font::isRoundingHackCharacter(character)) { |
| width = ceilf(width); |
| |
| // Since widthSinceLastRounding can lose precision if we include measurements for |
| // preceding whitespace, we bypass it here. |
| m_runWidthSoFar += width; |
| |
| // Since this is a rounding hack character, we should have reset this sum on the previous |
| // iteration. |
| ASSERT(!widthSinceLastRounding); |
| } else { |
| // Check to see if the next character is a "rounding hack character", if so, adjust |
| // width so that the total run width will be on an integer boundary. |
| if ((m_run.applyWordRounding() && textIterator.currentCharacter() < m_run.length() && Font::isRoundingHackCharacter(*(textIterator.characters()))) |
| || (m_run.applyRunRounding() && textIterator.currentCharacter() >= m_run.length())) { |
| float totalWidth = widthSinceLastRounding + width; |
| widthSinceLastRounding = ceilf(totalWidth); |
| width += widthSinceLastRounding - totalWidth; |
| m_runWidthSoFar += widthSinceLastRounding; |
| widthSinceLastRounding = 0; |
| } else |
| widthSinceLastRounding += width; |
| } |
| |
| if (glyphBuffer) |
| glyphBuffer->add(glyph, fontData, (rtl ? oldWidth + lastRoundingWidth : width)); |
| |
| lastRoundingWidth = width - oldWidth; |
| |
| if (m_accountForGlyphBounds) { |
| m_maxGlyphBoundingBoxY = max(m_maxGlyphBoundingBoxY, bounds.maxY()); |
| m_minGlyphBoundingBoxY = min(m_minGlyphBoundingBoxY, bounds.y()); |
| m_lastGlyphOverflow = max<float>(0, bounds.maxX() - width); |
| } |
| } |
| |
| unsigned consumedCharacters = textIterator.currentCharacter() - m_currentCharacter; |
| m_currentCharacter = textIterator.currentCharacter(); |
| m_runWidthSoFar += widthSinceLastRounding; |
| m_finalRoundingWidth = lastRoundingWidth; |
| return consumedCharacters; |
| } |
| |
| bool WidthIterator::advanceOneCharacter(float& width, GlyphBuffer* glyphBuffer) |
| { |
| int oldSize = glyphBuffer->size(); |
| advance(m_currentCharacter + 1, glyphBuffer); |
| float w = 0; |
| for (int i = oldSize; i < glyphBuffer->size(); ++i) |
| w += glyphBuffer->advanceAt(i); |
| width = w; |
| return glyphBuffer->size() > oldSize; |
| } |
| |
| } |
