/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
* This file is part of the LibreOffice project.
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
*
* This file incorporates work covered by the following license notice:
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed
* with this work for additional information regarding copyright
* ownership. The ASF licenses this file to you under the Apache
* License, Version 2.0 (the "License"); you may not use this file
* except in compliance with the License. You may obtain a copy of
* the License at http://www.apache.org/licenses/LICENSE-2.0 .
*/
#include <memory>
#include <hb-icu.h>
#include <hb-ot.h>
#include <hb-graphite2.h>
#include <sallayout.hxx>
#include <o3tl/temporary.hxx>
#include <sal/log.hxx>
#include <unotools/configmgr.hxx>
#include <vcl/unohelp.hxx>
#include <vcl/font/Feature.hxx>
#include <vcl/font/FeatureParser.hxx>
#include <scrptrun.h>
#include <com/sun/star/i18n/CharacterIteratorMode.hpp>
#include <salgdi.hxx>
#include <unicode/uchar.h>
#include <fontselect.hxx>
#if !HB_VERSION_ATLEAST(1, 1, 0)
// Disabled Unicode compatibility decomposition, see fdo#66715
static unsigned int unicodeDecomposeCompatibility(hb_unicode_funcs_t* /*ufuncs*/,
hb_codepoint_t /*u*/,
hb_codepoint_t* /*decomposed*/,
void* /*user_data*/)
{
return 0;
}
static hb_unicode_funcs_t* getUnicodeFuncs()
{
static hb_unicode_funcs_t* ufuncs = hb_unicode_funcs_create(hb_icu_get_unicode_funcs());
hb_unicode_funcs_set_decompose_compatibility_func(ufuncs, unicodeDecomposeCompatibility, nullptr, nullptr);
return ufuncs;
}
#endif
GenericSalLayout::GenericSalLayout(LogicalFontInstance &rFont)
: m_GlyphItems(rFont)
, mpVertGlyphs(nullptr)
, mbFuzzing(utl::ConfigManager::IsFuzzing())
{
}
GenericSalLayout::~GenericSalLayout()
{
}
void GenericSalLayout::ParseFeatures(const OUString& aName)
{
vcl::font::FeatureParser aParser(aName);
const OUString& sLanguage = aParser.getLanguage();
if (!sLanguage.isEmpty())
msLanguage = OUStringToOString(sLanguage, RTL_TEXTENCODING_ASCII_US);
for (auto const &rFeat : aParser.getFeatures())
{
hb_feature_t aFeature { rFeat.m_nTag, rFeat.m_nValue, rFeat.m_nStart, rFeat.m_nEnd };
maFeatures.push_back(aFeature);
}
}
namespace {
struct SubRun
{
int32_t mnMin;
int32_t mnEnd;
hb_script_t maScript;
hb_direction_t maDirection;
};
}
namespace vcl {
namespace {
struct Run
{
int32_t nStart;
int32_t nEnd;
UScriptCode nCode;
Run(int32_t nStart_, int32_t nEnd_, UScriptCode nCode_)
: nStart(nStart_)
, nEnd(nEnd_)
, nCode(nCode_)
{}
};
}
class TextLayoutCache
{
public:
std::vector<vcl::Run> runs;
TextLayoutCache(sal_Unicode const* pStr, sal_Int32 const nEnd)
{
vcl::ScriptRun aScriptRun(
reinterpret_cast<const UChar *>(pStr),
nEnd);
while (aScriptRun.next())
{
runs.emplace_back(aScriptRun.getScriptStart(),
aScriptRun.getScriptEnd(), aScriptRun.getScriptCode());
}
}
};
} // namespace vcl
namespace {
#if U_ICU_VERSION_MAJOR_NUM >= 63
enum class VerticalOrientation {
Upright = U_VO_UPRIGHT,
Rotated = U_VO_ROTATED,
TransformedUpright = U_VO_TRANSFORMED_UPRIGHT,
TransformedRotated = U_VO_TRANSFORMED_ROTATED
};
#else
#include "VerticalOrientationData.cxx"
// These must match the values in the file included above.
enum class VerticalOrientation {
Upright = 0,
Rotated = 1,
TransformedUpright = 2,
TransformedRotated = 3
};
#endif
VerticalOrientation GetVerticalOrientation(sal_UCS4 cCh, const LanguageTag& rTag)
{
// Override orientation of fullwidth colon , semi-colon,
// and Bopomofo tonal marks.
if ((cCh == 0xff1a || cCh == 0xff1b
|| cCh == 0x2ca || cCh == 0x2cb || cCh == 0x2c7 || cCh == 0x2d9)
&& rTag.getLanguage() == "zh")
return VerticalOrientation::TransformedUpright;
#if U_ICU_VERSION_MAJOR_NUM >= 63
int32_t nRet = u_getIntPropertyValue(cCh, UCHAR_VERTICAL_ORIENTATION);
#else
uint8_t nRet = 1;
if (cCh < 0x10000)
{
nRet = sVerticalOrientationValues[sVerticalOrientationPages[0][cCh >> kVerticalOrientationCharBits]]
[cCh & ((1 << kVerticalOrientationCharBits) - 1)];
}
else if (cCh < (kVerticalOrientationMaxPlane + 1) * 0x10000)
{
nRet = sVerticalOrientationValues[sVerticalOrientationPages[sVerticalOrientationPlanes[(cCh >> 16) - 1]]
[(cCh & 0xffff) >> kVerticalOrientationCharBits]]
[cCh & ((1 << kVerticalOrientationCharBits) - 1)];
}
else
{
// Default value for unassigned
SAL_WARN("vcl.gdi", "Getting VerticalOrientation for codepoint outside Unicode range");
}
#endif
return VerticalOrientation(nRet);
}
} // namespace
std::shared_ptr<vcl::TextLayoutCache> GenericSalLayout::CreateTextLayoutCache(OUString const& rString)
{
return std::make_shared<vcl::TextLayoutCache>(rString.getStr(), rString.getLength());
}
SalLayoutGlyphs GenericSalLayout::GetGlyphs() const
{
SalLayoutGlyphs glyphs;
glyphs.AppendImpl(m_GlyphItems.clone());
return glyphs;
}
void GenericSalLayout::SetNeedFallback(ImplLayoutArgs& rArgs, sal_Int32 nCharPos, bool bRightToLeft)
{
if (nCharPos < 0 || mbFuzzing)
return;
using namespace ::com::sun::star;
if (!mxBreak.is())
mxBreak = vcl::unohelper::CreateBreakIterator();
lang::Locale aLocale(rArgs.maLanguageTag.getLocale());
//if position nCharPos is missing in the font, grab the entire grapheme and
//mark all glyphs as missing so the whole thing is rendered with the same
//font
sal_Int32 nDone;
sal_Int32 nGraphemeEndPos =
mxBreak->nextCharacters(rArgs.mrStr, nCharPos, aLocale,
i18n::CharacterIteratorMode::SKIPCELL, 1, nDone);
// Safely advance nCharPos in case it is a non-BMP character.
rArgs.mrStr.iterateCodePoints(&nCharPos);
sal_Int32 nGraphemeStartPos =
mxBreak->previousCharacters(rArgs.mrStr, nCharPos, aLocale,
i18n::CharacterIteratorMode::SKIPCELL, 1, nDone);
rArgs.NeedFallback(nGraphemeStartPos, nGraphemeEndPos, bRightToLeft);
}
void GenericSalLayout::AdjustLayout(ImplLayoutArgs& rArgs)
{
SalLayout::AdjustLayout(rArgs);
if (rArgs.mpDXArray)
ApplyDXArray(rArgs);
else if (rArgs.mnLayoutWidth)
Justify(rArgs.mnLayoutWidth);
// apply asian kerning if the glyphs are not already formatted
else if ((rArgs.mnFlags & SalLayoutFlags::KerningAsian)
&& !(rArgs.mnFlags & SalLayoutFlags::Vertical))
ApplyAsianKerning(rArgs.mrStr);
}
void GenericSalLayout::DrawText(SalGraphics& rSalGraphics) const
{
//call platform dependent DrawText functions
rSalGraphics.DrawTextLayout( *this );
}
// Find if the nominal glyph of the character is an input to “vert” feature.
// We don’t check for a specific script or language as it shouldn’t matter
// here; if the glyph would be the result from applying “vert” for any
// script/language then we want to always treat it as upright glyph.
bool GenericSalLayout::HasVerticalAlternate(sal_UCS4 aChar, sal_UCS4 aVariationSelector)
{
hb_codepoint_t nGlyphIndex = 0;
hb_font_t *pHbFont = GetFont().GetHbFont();
if (!hb_font_get_glyph(pHbFont, aChar, aVariationSelector, &nGlyphIndex))
return false;
if (!mpVertGlyphs)
{
hb_face_t* pHbFace = hb_font_get_face(pHbFont);
mpVertGlyphs = hb_set_create();
// Find all GSUB lookups for “vert” feature.
hb_set_t* pLookups = hb_set_create();
hb_tag_t const pFeatures[] = { HB_TAG('v','e','r','t'), HB_TAG_NONE };
hb_ot_layout_collect_lookups(pHbFace, HB_OT_TAG_GSUB, nullptr, nullptr, pFeatures, pLookups);
if (!hb_set_is_empty(pLookups))
{
// Find the output glyphs in each lookup (i.e. the glyphs that
// would result from applying this lookup).
hb_codepoint_t nIdx = HB_SET_VALUE_INVALID;
while (hb_set_next(pLookups, &nIdx))
{
hb_set_t* pGlyphs = hb_set_create();
hb_ot_layout_lookup_collect_glyphs(pHbFace, HB_OT_TAG_GSUB, nIdx,
nullptr, // glyphs before
pGlyphs, // glyphs input
nullptr, // glyphs after
nullptr); // glyphs out
hb_set_union(mpVertGlyphs, pGlyphs);
}
}
}
return hb_set_has(mpVertGlyphs, nGlyphIndex) != 0;
}
bool GenericSalLayout::LayoutText(ImplLayoutArgs& rArgs, const SalLayoutGlyphsImpl* pGlyphs)
{
// No need to touch m_GlyphItems at all for an empty string.
if (rArgs.mnEndCharPos - rArgs.mnMinCharPos <= 0)
return true;
if (pGlyphs)
{
// Work with pre-computed glyph items.
m_GlyphItems = *pGlyphs;
for(const GlyphItem& item : m_GlyphItems)
if(!item.glyphId())
SetNeedFallback(rArgs, item.charPos(), item.IsRTLGlyph());
// Some flags are set as a side effect of text layout, restore them here.
rArgs.mnFlags |= pGlyphs->mnFlags;
return true;
}
hb_font_t *pHbFont = GetFont().GetHbFont();
bool isGraphite = GetFont().IsGraphiteFont();
int nGlyphCapacity = 2 * (rArgs.mnEndCharPos - rArgs.mnMinCharPos);
m_GlyphItems.reserve(nGlyphCapacity);
const int nLength = rArgs.mrStr.getLength();
const sal_Unicode *pStr = rArgs.mrStr.getStr();
std::unique_ptr<vcl::TextLayoutCache> pNewScriptRun;
vcl::TextLayoutCache const* pTextLayout;
if (rArgs.m_pTextLayoutCache)
{
pTextLayout = rArgs.m_pTextLayoutCache; // use cache!
}
else
{
pNewScriptRun.reset(new vcl::TextLayoutCache(pStr, rArgs.mnEndCharPos));
pTextLayout = pNewScriptRun.get();
}
// nBaseOffset is used to align vertical text to the center of rotated
// horizontal text. That is the offset from original baseline to
// the center of EM box. Maybe we can use OpenType base table to improve this
// in the future.
DeviceCoordinate nBaseOffset = 0;
if (rArgs.mnFlags & SalLayoutFlags::Vertical)
{
hb_font_extents_t extents;
if (hb_font_get_h_extents(pHbFont, &extents))
nBaseOffset = ( extents.ascender + extents.descender ) / 2;
}
hb_buffer_t* pHbBuffer = hb_buffer_create();
hb_buffer_pre_allocate(pHbBuffer, nGlyphCapacity);
#if !HB_VERSION_ATLEAST(1, 1, 0)
static hb_unicode_funcs_t* pHbUnicodeFuncs = getUnicodeFuncs();
hb_buffer_set_unicode_funcs(pHbBuffer, pHbUnicodeFuncs);
#endif
const FontSelectPattern& rFontSelData = GetFont().GetFontSelectPattern();
if (rArgs.mnFlags & SalLayoutFlags::DisableKerning)
{
SAL_INFO("vcl.harfbuzz", "Disabling kerning for font: " << rFontSelData.maTargetName);
maFeatures.push_back({ HB_TAG('k','e','r','n'), 0, 0, static_cast<unsigned int>(-1) });
}
ParseFeatures(rFontSelData.maTargetName);
double nXScale = 0;
double nYScale = 0;
GetFont().GetScale(&nXScale, &nYScale);
Point aCurrPos(0, 0);
while (true)
{
int nBidiMinRunPos, nBidiEndRunPos;
bool bRightToLeft;
if (!rArgs.GetNextRun(&nBidiMinRunPos, &nBidiEndRunPos, &bRightToLeft))
break;
// Find script subruns.
std::vector<SubRun> aSubRuns;
int nCurrentPos = nBidiMinRunPos;
size_t k = 0;
for (; k < pTextLayout->runs.size(); ++k)
{
vcl::Run const& rRun(pTextLayout->runs[k]);
if (rRun.nStart <= nCurrentPos && nCurrentPos < rRun.nEnd)
{
break;
}
}
if (isGraphite)
{
hb_script_t aScript = hb_icu_script_to_script(pTextLayout->runs[k].nCode);
aSubRuns.push_back({ nBidiMinRunPos, nBidiEndRunPos, aScript, bRightToLeft ? HB_DIRECTION_RTL : HB_DIRECTION_LTR });
}
else
{
while (nCurrentPos < nBidiEndRunPos && k < pTextLayout->runs.size())
{
int32_t nMinRunPos = nCurrentPos;
int32_t nEndRunPos = std::min(pTextLayout->runs[k].nEnd, nBidiEndRunPos);
hb_direction_t aDirection = bRightToLeft ? HB_DIRECTION_RTL : HB_DIRECTION_LTR;
hb_script_t aScript = hb_icu_script_to_script(pTextLayout->runs[k].nCode);
// For vertical text, further divide the runs based on character
// orientation.
if (rArgs.mnFlags & SalLayoutFlags::Vertical)
{
sal_Int32 nIdx = nMinRunPos;
while (nIdx < nEndRunPos)
{
sal_Int32 nPrevIdx = nIdx;
sal_UCS4 aChar = rArgs.mrStr.iterateCodePoints(&nIdx);
VerticalOrientation aVo = GetVerticalOrientation(aChar, rArgs.maLanguageTag);
sal_UCS4 aVariationSelector = 0;
if (nIdx < nEndRunPos)
{
sal_Int32 nNextIdx = nIdx;
sal_UCS4 aNextChar = rArgs.mrStr.iterateCodePoints(&nNextIdx);
if (u_hasBinaryProperty(aNextChar, UCHAR_VARIATION_SELECTOR))
{
nIdx = nNextIdx;
aVariationSelector = aNextChar;
}
}
// Charters with U and Tu vertical orientation should
// be shaped in vertical direction. But characters
// with Tr should be shaped in vertical direction
// only if they have vertical alternates, otherwise
// they should be shaped in horizontal direction
// and then rotated.
// See http://unicode.org/reports/tr50/#vo
if (aVo == VerticalOrientation::Upright ||
aVo == VerticalOrientation::TransformedUpright ||
(aVo == VerticalOrientation::TransformedRotated &&
HasVerticalAlternate(aChar, aVariationSelector)))
{
aDirection = HB_DIRECTION_TTB;
}
else
{
aDirection = bRightToLeft ? HB_DIRECTION_RTL : HB_DIRECTION_LTR;
}
if (aSubRuns.empty() || aSubRuns.back().maDirection != aDirection)
aSubRuns.push_back({ nPrevIdx, nIdx, aScript, aDirection });
else
aSubRuns.back().mnEnd = nIdx;
}
}
else
{
aSubRuns.push_back({ nMinRunPos, nEndRunPos, aScript, aDirection });
}
nCurrentPos = nEndRunPos;
++k;
}
}
// RTL subruns should be reversed to ensure that final glyph order is
// correct.
if (bRightToLeft)
std::reverse(aSubRuns.begin(), aSubRuns.end());
for (const auto& aSubRun : aSubRuns)
{
hb_buffer_clear_contents(pHbBuffer);
const int nMinRunPos = aSubRun.mnMin;
const int nEndRunPos = aSubRun.mnEnd;
const int nRunLen = nEndRunPos - nMinRunPos;
OString sLanguage = msLanguage;
if (sLanguage.isEmpty())
sLanguage = OUStringToOString(rArgs.maLanguageTag.getBcp47(), RTL_TEXTENCODING_ASCII_US);
int nHbFlags = HB_BUFFER_FLAGS_DEFAULT;
if (nMinRunPos == 0)
nHbFlags |= HB_BUFFER_FLAG_BOT; /* Beginning-of-text */
if (nEndRunPos == nLength)
nHbFlags |= HB_BUFFER_FLAG_EOT; /* End-of-text */
hb_buffer_set_direction(pHbBuffer, aSubRun.maDirection);
hb_buffer_set_script(pHbBuffer, aSubRun.maScript);
hb_buffer_set_language(pHbBuffer, hb_language_from_string(sLanguage.getStr(), -1));
hb_buffer_set_flags(pHbBuffer, static_cast<hb_buffer_flags_t>(nHbFlags));
hb_buffer_add_utf16(
pHbBuffer, reinterpret_cast<uint16_t const *>(pStr), nLength,
nMinRunPos, nRunLen);
hb_buffer_set_cluster_level(pHbBuffer, HB_BUFFER_CLUSTER_LEVEL_MONOTONE_CHARACTERS);
// The shapers that we want HarfBuzz to use, in the order of
// preference. The coretext_aat shaper is available only on macOS,
// but there is no harm in always including it, HarfBuzz will
// ignore unavailable shapers.
const char*const pHbShapers[] = { "graphite2", "coretext_aat", "ot", "fallback", nullptr };
bool ok = hb_shape_full(pHbFont, pHbBuffer, maFeatures.data(), maFeatures.size(), pHbShapers);
assert(ok);
(void) ok;
int nRunGlyphCount = hb_buffer_get_length(pHbBuffer);
hb_glyph_info_t *pHbGlyphInfos = hb_buffer_get_glyph_infos(pHbBuffer, nullptr);
hb_glyph_position_t *pHbPositions = hb_buffer_get_glyph_positions(pHbBuffer, nullptr);
for (int i = 0; i < nRunGlyphCount; ++i) {
int32_t nGlyphIndex = pHbGlyphInfos[i].codepoint;
int32_t nCharPos = pHbGlyphInfos[i].cluster;
int32_t nCharCount = 0;
bool bInCluster = false;
bool bClusterStart = false;
// Find the number of characters that make up this glyph.
if (!bRightToLeft)
{
// If the cluster is the same as previous glyph, then this
// already consumed, skip.
if (i > 0 && pHbGlyphInfos[i].cluster == pHbGlyphInfos[i - 1].cluster)
{
nCharCount = 0;
bInCluster = true;
}
else
{
// Find the next glyph with a different cluster, or the
// end of text.
int j = i;
int32_t nNextCharPos = nCharPos;
while (nNextCharPos == nCharPos && j < nRunGlyphCount)
nNextCharPos = pHbGlyphInfos[j++].cluster;
if (nNextCharPos == nCharPos)
nNextCharPos = nEndRunPos;
nCharCount = nNextCharPos - nCharPos;
if ((i == 0 || pHbGlyphInfos[i].cluster != pHbGlyphInfos[i - 1].cluster) &&
(i < nRunGlyphCount - 1 && pHbGlyphInfos[i].cluster == pHbGlyphInfos[i + 1].cluster))
bClusterStart = true;
}
}
else
{
// If the cluster is the same as previous glyph, then this
// will be consumed later, skip.
if (i < nRunGlyphCount - 1 && pHbGlyphInfos[i].cluster == pHbGlyphInfos[i + 1].cluster)
{
nCharCount = 0;
bInCluster = true;
}
else
{
// Find the previous glyph with a different cluster, or
// the end of text.
int j = i;
int32_t nNextCharPos = nCharPos;
while (nNextCharPos == nCharPos && j >= 0)
nNextCharPos = pHbGlyphInfos[j--].cluster;
if (nNextCharPos == nCharPos)
nNextCharPos = nEndRunPos;
nCharCount = nNextCharPos - nCharPos;
if ((i == nRunGlyphCount - 1 || pHbGlyphInfos[i].cluster != pHbGlyphInfos[i + 1].cluster) &&
(i > 0 && pHbGlyphInfos[i].cluster == pHbGlyphInfos[i - 1].cluster))
bClusterStart = true;
}
}
// if needed request glyph fallback by updating LayoutArgs
if (!nGlyphIndex)
{
SetNeedFallback(rArgs, nCharPos, bRightToLeft);
if (SalLayoutFlags::ForFallback & rArgs.mnFlags)
continue;
}
GlyphItemFlags nGlyphFlags = GlyphItemFlags::NONE;
if (bRightToLeft)
nGlyphFlags |= GlyphItemFlags::IS_RTL_GLYPH;
if (bClusterStart)
nGlyphFlags |= GlyphItemFlags::IS_CLUSTER_START;
if (bInCluster)
nGlyphFlags |= GlyphItemFlags::IS_IN_CLUSTER;
sal_UCS4 aChar
= rArgs.mrStr.iterateCodePoints(&o3tl::temporary(sal_Int32(nCharPos)), 0);
if (u_getIntPropertyValue(aChar, UCHAR_GENERAL_CATEGORY) == U_NON_SPACING_MARK)
nGlyphFlags |= GlyphItemFlags::IS_DIACRITIC;
if (u_isUWhiteSpace(aChar))
nGlyphFlags |= GlyphItemFlags::IS_SPACING;
if (aSubRun.maScript == HB_SCRIPT_ARABIC &&
HB_DIRECTION_IS_BACKWARD(aSubRun.maDirection) &&
!(nGlyphFlags & GlyphItemFlags::IS_SPACING))
{
nGlyphFlags |= GlyphItemFlags::ALLOW_KASHIDA;
rArgs.mnFlags |= SalLayoutFlags::KashidaJustification;
}
DeviceCoordinate nAdvance, nXOffset, nYOffset;
if (aSubRun.maDirection == HB_DIRECTION_TTB)
{
nGlyphFlags |= GlyphItemFlags::IS_VERTICAL;
nAdvance = -pHbPositions[i].y_advance;
nXOffset = -pHbPositions[i].y_offset;
nYOffset = -pHbPositions[i].x_offset - nBaseOffset;
}
else
{
nAdvance = pHbPositions[i].x_advance;
nXOffset = pHbPositions[i].x_offset;
nYOffset = -pHbPositions[i].y_offset;
}
nAdvance = std::lround(nAdvance * nXScale);
nXOffset = std::lround(nXOffset * nXScale);
nYOffset = std::lround(nYOffset * nYScale);
Point aNewPos(aCurrPos.X() + nXOffset, aCurrPos.Y() + nYOffset);
const GlyphItem aGI(nCharPos, nCharCount, nGlyphIndex, aNewPos, nGlyphFlags,
nAdvance, nXOffset, &GetFont());
m_GlyphItems.push_back(aGI);
aCurrPos.AdjustX(nAdvance );
}
}
}
hb_buffer_destroy(pHbBuffer);
// Some flags are set as a side effect of text layout, save them here.
if (rArgs.mnFlags & SalLayoutFlags::GlyphItemsOnly)
m_GlyphItems.mnFlags = rArgs.mnFlags;
return true;
}
void GenericSalLayout::GetCharWidths(DeviceCoordinate* pCharWidths) const
{
const int nCharCount = mnEndCharPos - mnMinCharPos;
for (int i = 0; i < nCharCount; ++i)
pCharWidths[i] = 0;
for (auto const& aGlyphItem : m_GlyphItems)
{
const int nIndex = aGlyphItem.charPos() - mnMinCharPos;
if (nIndex >= nCharCount)
continue;
pCharWidths[nIndex] += aGlyphItem.m_nNewWidth;
}
}
// A note on how Kashida justification is implemented (because it took me 5
// years to figure it out):
// The decision to insert Kashidas, where and how much is taken by Writer.
// This decision is communicated to us in a very indirect way; by increasing
// the width of the character after which Kashidas should be inserted by the
// desired amount.
//
// Writer eventually calls IsKashidaPosValid() to check whether it can insert a
// Kashida between two characters or not.
//
// Here we do:
// - In LayoutText() set KashidaJustification flag based on text script.
// - In ApplyDXArray():
// * Check the above flag to decide whether to insert Kashidas or not.
// * For any RTL glyph that has DX adjustment, insert enough Kashidas to
// fill in the added space.
void GenericSalLayout::ApplyDXArray(const ImplLayoutArgs& rArgs)
{
if (rArgs.mpDXArray == nullptr)
return;
int nCharCount = mnEndCharPos - mnMinCharPos;
std::unique_ptr<DeviceCoordinate[]> const pOldCharWidths(new DeviceCoordinate[nCharCount]);
std::unique_ptr<DeviceCoordinate[]> const pNewCharWidths(new DeviceCoordinate[nCharCount]);
// Get the natural character widths (i.e. before applying DX adjustments).
GetCharWidths(pOldCharWidths.get());
// Calculate the character widths after DX adjustments.
for (int i = 0; i < nCharCount; ++i)
{
if (i == 0)
pNewCharWidths[i] = rArgs.mpDXArray[i];
else
pNewCharWidths[i] = rArgs.mpDXArray[i] - rArgs.mpDXArray[i - 1];
}
bool bKashidaJustify = false;
DeviceCoordinate nKashidaWidth = 0;
hb_codepoint_t nKashidaIndex = 0;
if (rArgs.mnFlags & SalLayoutFlags::KashidaJustification)
{
hb_font_t *pHbFont = GetFont().GetHbFont();
// Find Kashida glyph width and index.
if (hb_font_get_glyph(pHbFont, 0x0640, 0, &nKashidaIndex))
nKashidaWidth = GetFont().GetKashidaWidth();
bKashidaJustify = nKashidaWidth != 0;
}
// Map of Kashida insertion points (in the glyph items vector) and the
// requested width.
std::map<size_t, DeviceCoordinate> pKashidas;
// The accumulated difference in X position.
DeviceCoordinate nDelta = 0;
// Apply the DX adjustments to glyph positions and widths.
size_t i = 0;
while (i < m_GlyphItems.size())
{
// Accumulate the width difference for all characters corresponding to
// this glyph.
int nCharPos = m_GlyphItems[i].charPos() - mnMinCharPos;
DeviceCoordinate nDiff = 0;
for (int j = 0; j < m_GlyphItems[i].charCount(); j++)
nDiff += pNewCharWidths[nCharPos + j] - pOldCharWidths[nCharPos + j];
if (!m_GlyphItems[i].IsRTLGlyph())
{
// Adjust the width and position of the first (leftmost) glyph in
// the cluster.
m_GlyphItems[i].m_nNewWidth += nDiff;
m_GlyphItems[i].m_aLinearPos.AdjustX(nDelta);
// Adjust the position of the rest of the glyphs in the cluster.
while (++i < m_GlyphItems.size())
{
if (!m_GlyphItems[i].IsInCluster())
break;
m_GlyphItems[i].m_aLinearPos.AdjustX(nDelta);
}
}
else if (m_GlyphItems[i].IsInCluster())
{
// RTL glyph in the middle of the cluster, will be handled in the
// loop below.
i++;
}
else
{
// Adjust the width and position of the first (rightmost) glyph in
// the cluster.
// For RTL, we put all the adjustment to the left of the glyph.
m_GlyphItems[i].m_nNewWidth += nDiff;
m_GlyphItems[i].m_aLinearPos.AdjustX(nDelta + nDiff);
// Adjust the X position of all glyphs in the cluster.
size_t j = i;
while (j > 0)
{
--j;
if (!m_GlyphItems[j].IsInCluster())
break;
m_GlyphItems[j].m_aLinearPos.AdjustX(nDelta + nDiff);
}
// If this glyph is Kashida-justifiable, then mark this as a
// Kashida position. Since this must be a RTL glyph, we mark the
// last glyph in the cluster not the first as this would be the
// base glyph.
if (bKashidaJustify && m_GlyphItems[i].AllowKashida() &&
nDiff > m_GlyphItems[i].charCount()) // Rounding errors, 1 pixel per character!
{
pKashidas[i] = nDiff;
// Move any non-spacing marks attached to this cluster as well.
// Looping backward because this is RTL glyph.
while (j > 0)
{
if (!m_GlyphItems[j].IsDiacritic())
break;
m_GlyphItems[j--].m_aLinearPos.AdjustX(nDiff);
}
}
i++;
}
// Increment the delta, the loop above makes sure we do so only once
// for every character (cluster) not for every glyph (otherwise we
// would apply it multiple times for each glyphs belonging to the same
// character which is wrong since DX adjustments are character based).
nDelta += nDiff;
}
// Insert Kashida glyphs.
if (!bKashidaJustify || pKashidas.empty())
return;
size_t nInserted = 0;
for (auto const& pKashida : pKashidas)
{
auto pGlyphIter = m_GlyphItems.begin() + nInserted + pKashida.first;
// The total Kashida width.
DeviceCoordinate nTotalWidth = pKashida.second;
// Number of times to repeat each Kashida.
int nCopies = 1;
if (nTotalWidth > nKashidaWidth)
nCopies = nTotalWidth / nKashidaWidth;
// See if we can improve the fit by adding an extra Kashidas and
// squeezing them together a bit.
DeviceCoordinate nOverlap = 0;
DeviceCoordinate nShortfall = nTotalWidth - nKashidaWidth * nCopies;
if (nShortfall > 0)
{
++nCopies;
DeviceCoordinate nExcess = nCopies * nKashidaWidth - nTotalWidth;
if (nExcess > 0)
nOverlap = nExcess / (nCopies - 1);
}
Point aPos(pGlyphIter->m_aLinearPos.getX() - nTotalWidth, 0);
int nCharPos = pGlyphIter->charPos();
GlyphItemFlags const nFlags = GlyphItemFlags::IS_IN_CLUSTER | GlyphItemFlags::IS_RTL_GLYPH;
while (nCopies--)
{
GlyphItem aKashida(nCharPos, 0, nKashidaIndex, aPos, nFlags, nKashidaWidth, 0, &GetFont());
pGlyphIter = m_GlyphItems.insert(pGlyphIter, aKashida);
aPos.AdjustX(nKashidaWidth );
aPos.AdjustX( -nOverlap );
++pGlyphIter;
++nInserted;
}
}
}
bool GenericSalLayout::IsKashidaPosValid(int nCharPos) const
{
for (auto pIter = m_GlyphItems.begin(); pIter != m_GlyphItems.end(); ++pIter)
{
if (pIter->charPos() == nCharPos)
{
// The position is the first glyph, this would happen if we
// changed the text styling in the middle of a word. Since we don’t
// do ligatures across layout engine instances, this can’t be a
// ligature so it should be fine.
if (pIter == m_GlyphItems.begin())
return true;
// If the character is not supported by this layout, return false
// so that fallback layouts would be checked for it.
if (pIter->glyphId() == 0)
break;
// Search backwards for previous glyph belonging to a different
// character. We are looking backwards because we are dealing with
// RTL glyphs, which will be in visual order.
for (auto pPrev = pIter - 1; pPrev != m_GlyphItems.begin(); --pPrev)
{
if (pPrev->charPos() != nCharPos)
{
// Check if the found glyph belongs to the next character,
// otherwise the current glyph will be a ligature which is
// invalid kashida position.
if (pPrev->charPos() == (nCharPos + 1))
return true;
break;
}
}
}
}
return false;
}
/* vim:set shiftwidth=4 softtabstop=4 expandtab: */