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/*
* Copyright (C) 2003, 2006, 2008 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 <wtf/MathExtras.h>
#if USE(ICU_UNICODE)
#include <unicode/unorm.h>
#endif
using namespace WTF;
using namespace Unicode;
namespace WebCore {
// According to http://www.unicode.org/Public/UNIDATA/UCD.html#Canonical_Combining_Class_Values
static const uint8_t hiraganaKatakanaVoicingMarksCombiningClass = 8;
WidthIterator::WidthIterator(const Font* font, const TextRun& run, HashSet<const SimpleFontData*>* fallbackFonts)
: m_font(font)
, m_run(run)
, m_end(run.length())
, m_currentCharacter(0)
, m_runWidthSoFar(0)
, m_finalRoundingWidth(0)
, m_fallbackFonts(fallbackFonts)
{
// 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_padding = m_run.padding();
if (!m_padding)
m_padPerSpace = 0;
else {
float numSpaces = 0;
for (int i = 0; i < run.length(); i++)
if (Font::treatAsSpace(m_run[i]))
numSpaces++;
if (numSpaces == 0)
m_padPerSpace = 0;
else
m_padPerSpace = ceilf(m_run.padding() / numSpaces);
}
}
void WidthIterator::advance(int offset, GlyphBuffer* glyphBuffer)
{
if (offset > m_end)
offset = m_end;
int currentCharacter = m_currentCharacter;
const UChar* cp = m_run.data(currentCharacter);
bool rtl = m_run.rtl();
bool hasExtraSpacing = (m_font->letterSpacing() || m_font->wordSpacing() || m_padding) && !m_run.spacingDisabled();
float runWidthSoFar = m_runWidthSoFar;
float lastRoundingWidth = m_finalRoundingWidth;
const SimpleFontData* primaryFont = m_font->primaryFont();
const SimpleFontData* lastFontData = primaryFont;
while (currentCharacter < offset) {
UChar32 c = *cp;
unsigned clusterLength = 1;
if (c >= 0x3041) {
if (c <= 0x30FE) {
// Deal with Hiragana and Katakana voiced and semi-voiced syllables.
// Normalize into composed form, and then look for glyph with base + combined mark.
// Check above for character range to minimize performance impact.
UChar32 normalized = normalizeVoicingMarks(currentCharacter);
if (normalized) {
c = normalized;
clusterLength = 2;
}
} else if (U16_IS_SURROGATE(c)) {
if (!U16_IS_SURROGATE_LEAD(c))
break;
// Do we have a surrogate pair? If so, determine the full Unicode (32 bit)
// code point before glyph lookup.
// Make sure we have another character and it's a low surrogate.
if (currentCharacter + 1 >= m_run.length())
break;
UChar low = cp[1];
if (!U16_IS_TRAIL(low))
break;
c = U16_GET_SUPPLEMENTARY(c, low);
clusterLength = 2;
}
}
const GlyphData& glyphData = m_font->glyphDataForCharacter(c, rtl);
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 (c == '\t' && m_run.allowTabs()) {
float tabWidth = m_font->tabWidth();
width = tabWidth - fmodf(m_run.xPos() + runWidthSoFar, tabWidth);
} else {
width = fontData->widthForGlyph(glyph);
// 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 (width == fontData->spaceWidth() && (fontData->pitch() == FixedPitch || glyph == fontData->spaceGlyph()) && m_run.applyWordRounding())
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() || c == toUpper(c))
m_fallbackFonts->add(fontData);
else {
const GlyphData& uppercaseGlyphData = m_font->glyphDataForCharacter(toUpper(c), 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();
if (Font::treatAsSpace(c)) {
// Account for padding. WebCore uses space padding to justify text.
// We distribute the specified padding over the available spaces in the run.
if (m_padding) {
// Use left over padding if not evenly divisible by number of spaces.
if (m_padding < m_padPerSpace) {
width += m_padding;
m_padding = 0;
} else {
width += m_padPerSpace;
m_padding -= m_padPerSpace;
}
}
// Account for word spacing.
// We apply additional space between "words" by adding width to the space character.
if (currentCharacter != 0 && !Font::treatAsSpace(cp[-1]) && m_font->wordSpacing())
width += m_font->wordSpacing();
}
}
// Advance past the character we just dealt with.
cp += clusterLength;
currentCharacter += clusterLength;
// Account for float/integer impedance mismatch between CG and KHTML. "Words" (characters
// followed by a character defined by isRoundingHackCharacter()) are always an integer width.
// We adjust the width of the last character of a "word" to ensure an integer width.
// If we move KHTML to floats we can remove this (and related) hacks.
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(c))
width = ceilf(width);
// 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() && currentCharacter < m_run.length() && Font::isRoundingHackCharacter(*cp))
|| (m_run.applyRunRounding() && currentCharacter >= m_end)) {
float totalWidth = runWidthSoFar + width;
width += ceilf(totalWidth) - totalWidth;
}
runWidthSoFar += width;
if (glyphBuffer)
glyphBuffer->add(glyph, fontData, (rtl ? oldWidth + lastRoundingWidth : width));
lastRoundingWidth = width - oldWidth;
}
m_currentCharacter = currentCharacter;
m_runWidthSoFar = runWidthSoFar;
m_finalRoundingWidth = lastRoundingWidth;
}
bool WidthIterator::advanceOneCharacter(float& width, GlyphBuffer* glyphBuffer)
{
glyphBuffer->clear();
advance(m_currentCharacter + 1, glyphBuffer);
float w = 0;
for (int i = 0; i < glyphBuffer->size(); ++i)
w += glyphBuffer->advanceAt(i);
width = w;
return !glyphBuffer->isEmpty();
}
UChar32 WidthIterator::normalizeVoicingMarks(int currentCharacter)
{
if (currentCharacter + 1 < m_end) {
if (combiningClass(m_run[currentCharacter + 1]) == hiraganaKatakanaVoicingMarksCombiningClass) {
#if USE(ICU_UNICODE)
// Normalize into composed form using 3.2 rules.
UChar normalizedCharacters[2] = { 0, 0 };
UErrorCode uStatus = U_ZERO_ERROR;
int32_t resultLength = unorm_normalize(m_run.data(currentCharacter), 2,
UNORM_NFC, UNORM_UNICODE_3_2, &normalizedCharacters[0], 2, &uStatus);
if (resultLength == 1 && uStatus == 0)
return normalizedCharacters[0];
#elif USE(QT4_UNICODE)
QString tmp(reinterpret_cast<const QChar*>(m_run.data(currentCharacter)), 2);
QString res = tmp.normalized(QString::NormalizationForm_C, QChar::Unicode_3_2);
if (res.length() == 1)
return res.at(0).unicode();
#endif
}
}
return 0;
}
}
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