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/*
* Copyright (c) 2012 Google 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:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * 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.
* * Neither the name of Google Inc. nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND 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 THE COPYRIGHT
* OWNER OR 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 "HarfBuzzShaperBase.h"
#include "Font.h"
#include <unicode/normlzr.h>
#include <unicode/uchar.h>
#include <wtf/MathExtras.h>
#include <wtf/unicode/Unicode.h>
namespace WebCore {
HarfBuzzShaperBase::HarfBuzzShaperBase(const Font* font, const TextRun& run)
: m_font(font)
, m_normalizedBufferLength(0)
, m_run(run)
, m_wordSpacingAdjustment(font->wordSpacing())
, m_padding(0)
, m_padPerWordBreak(0)
, m_padError(0)
, m_letterSpacing(font->letterSpacing())
{
}
static void normalizeSpacesAndMirrorChars(const UChar* source, UChar* destination, int length, HarfBuzzShaperBase::NormalizeMode normalizeMode)
{
int position = 0;
bool error = false;
// Iterate characters in source and mirror character if needed.
while (position < length) {
UChar32 character;
int nextPosition = position;
U16_NEXT(source, nextPosition, length, character);
// Don't normalize tabs as they are not treated as spaces for word-end
if (Font::treatAsSpace(character) && character != '\t')
character = ' ';
else if (Font::treatAsZeroWidthSpace(character))
character = zeroWidthSpace;
else if (normalizeMode == HarfBuzzShaperBase::NormalizeMirrorChars)
character = u_charMirror(character);
U16_APPEND(destination, position, length, character, error);
ASSERT_UNUSED(error, !error);
position = nextPosition;
}
}
void HarfBuzzShaperBase::setNormalizedBuffer(NormalizeMode normalizeMode)
{
// Normalize the text run in three ways:
// 1) Convert the |originalRun| to NFC normalized form if combining diacritical marks
// (U+0300..) are used in the run. This conversion is necessary since most OpenType
// fonts (e.g., Arial) don't have substitution rules for the diacritical marks in
// their GSUB tables.
//
// Note that we don't use the icu::Normalizer::isNormalized(UNORM_NFC) API here since
// the API returns FALSE (= not normalized) for complex runs that don't require NFC
// normalization (e.g., Arabic text). Unless the run contains the diacritical marks,
// HarfBuzz will do the same thing for us using the GSUB table.
// 2) Convert spacing characters into plain spaces, as some fonts will provide glyphs
// for characters like '\n' otherwise.
// 3) Convert mirrored characters such as parenthesis for rtl text.
// Convert to NFC form if the text has diacritical marks.
icu::UnicodeString normalizedString;
UErrorCode error = U_ZERO_ERROR;
for (int i = 0; i < m_run.length(); ++i) {
UChar ch = m_run[i];
if (::ublock_getCode(ch) == UBLOCK_COMBINING_DIACRITICAL_MARKS) {
icu::Normalizer::normalize(icu::UnicodeString(m_run.characters16(),
m_run.length()), UNORM_NFC, 0 /* no options */,
normalizedString, error);
if (U_FAILURE(error))
normalizedString.remove();
break;
}
}
const UChar* sourceText;
if (normalizedString.isEmpty()) {
m_normalizedBufferLength = m_run.length();
sourceText = m_run.characters16();
} else {
m_normalizedBufferLength = normalizedString.length();
sourceText = normalizedString.getBuffer();
}
m_normalizedBuffer = adoptArrayPtr(new UChar[m_normalizedBufferLength + 1]);
normalizeSpacesAndMirrorChars(sourceText, m_normalizedBuffer.get(), m_normalizedBufferLength, normalizeMode);
}
bool HarfBuzzShaperBase::isWordEnd(unsigned index)
{
// This could refer a high-surrogate, but should work.
return index && isCodepointSpace(m_normalizedBuffer[index]);
}
int HarfBuzzShaperBase::determineWordBreakSpacing()
{
int wordBreakSpacing = m_wordSpacingAdjustment;
if (m_padding > 0) {
int toPad = roundf(m_padPerWordBreak + m_padError);
m_padError += m_padPerWordBreak - toPad;
if (m_padding < toPad)
toPad = m_padding;
m_padding -= toPad;
wordBreakSpacing += toPad;
}
return wordBreakSpacing;
}
// setPadding sets a number of pixels to be distributed across the TextRun.
// WebKit uses this to justify text.
void HarfBuzzShaperBase::setPadding(int padding)
{
m_padding = padding;
m_padError = 0;
if (!m_padding)
return;
// If we have padding to distribute, then we try to give an equal
// amount to each space. The last space gets the smaller amount, if
// any.
unsigned numWordEnds = 0;
for (unsigned i = 0; i < m_normalizedBufferLength; i++) {
if (isWordEnd(i))
numWordEnds++;
}
if (numWordEnds)
m_padPerWordBreak = m_padding / numWordEnds;
else
m_padPerWordBreak = 0;
}
} // namespace WebCore
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