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skia/skia.git/ed0a9a175b53ee9792f2acdcafe4000f7d919aff/./modules/skparagraph/src/TextLine.cpp
blob: a429260b335dfb2b1ea1a1868b36867e7d772d5c [file]
// Copyright 2019 Google LLC
#include "modules/skparagraph/src/TextLine.h"
#include "include/core/SkBlurTypes.h"
#include "include/core/SkFont.h"
#include "include/core/SkFontMetrics.h"
#include "include/core/SkMaskFilter.h"
#include "include/core/SkPaint.h"
#include "include/core/SkSpan.h"
#include "include/core/SkString.h"
#include "include/core/SkTextBlob.h"
#include "include/core/SkTypes.h"
#include "include/private/SkTemplates.h"
#include "include/private/SkTo.h"
#include "modules/skparagraph/include/DartTypes.h"
#include "modules/skparagraph/include/Metrics.h"
#include "modules/skparagraph/include/ParagraphPainter.h"
#include "modules/skparagraph/include/ParagraphStyle.h"
#include "modules/skparagraph/include/TextShadow.h"
#include "modules/skparagraph/include/TextStyle.h"
#include "modules/skparagraph/src/Decorations.h"
#include "modules/skparagraph/src/ParagraphImpl.h"
#include "modules/skparagraph/src/ParagraphPainterImpl.h"
#include "modules/skshaper/include/SkShaper.h"
#include "modules/skshaper/include/SkShaper_harfbuzz.h"
#include "modules/skshaper/include/SkShaper_skunicode.h"
#include "modules/skunicode/include/SkUnicode.h"
#include <algorithm>
#include <iterator>
#include <limits>
#include <map>
#include <memory>
#include <tuple>
#include <type_traits>
#include <utility>
#include <vector>
using namespace skia_private;
namespace skia {
namespace textlayout {
namespace {
// Whether `text` resolves to a single bidi run when its base direction is `dir`.
bool isSingleBidiRun(SkUnicode* unicode, const SkString& text, SkUnicode::TextDirection dir) {
std::vector<SkUnicode::BidiRegion> regions;
return unicode->getBidiRegions(text.c_str(), SkToInt(text.size()), dir, &regions) &&
regions.size() <= 1;
}
// TODO: deal with all the intersection functionality
TextRange intersected(const TextRange& a, const TextRange& b) {
if (a.start == b.start && a.end == b.end) return a;
auto begin = std::max(a.start, b.start);
auto end = std::min(a.end, b.end);
return end >= begin ? TextRange(begin, end) : EMPTY_TEXT;
}
SkScalar littleRound(SkScalar a) {
// This rounding is done to match Flutter tests. Must be removed..
return SkScalarRoundToScalar(a * 100.0)/100.0;
}
TextRange operator*(const TextRange& a, const TextRange& b) {
if (a.start == b.start && a.end == b.end) return a;
auto begin = std::max(a.start, b.start);
auto end = std::min(a.end, b.end);
return end > begin ? TextRange(begin, end) : EMPTY_TEXT;
}
int compareRound(SkScalar a, SkScalar b, bool applyRoundingHack) {
// There is a rounding error that gets bigger when maxWidth gets bigger
// VERY long zalgo text (> 100000) on a VERY long line (> 10000)
// Canvas scaling affects it
// Letter spacing affects it
// It has to be relative to be useful
auto base = std::max(SkScalarAbs(a), SkScalarAbs(b));
auto diff = SkScalarAbs(a - b);
if (nearlyZero(base) || diff / base < 0.001f) {
return 0;
}
auto ra = a;
auto rb = b;
if (applyRoundingHack) {
ra = littleRound(a);
rb = littleRound(b);
}
if (ra < rb) {
return -1;
} else {
return 1;
}
}
bool shouldIsolateCluster(const ParagraphImpl* owner, const Cluster* cluster) {
int graphemes = 0;
for (size_t i = cluster->textRange().start; i < cluster->textRange().end; ++i) {
if (owner->codeUnitHasProperty(i, SkUnicode::CodeUnitFlags::kGraphemeStart)) {
++graphemes;
}
}
return graphemes <= 1;
}
std::pair<size_t, size_t> isolateClusterGlyphs(const ParagraphImpl* owner,
const Run* run,
const Cluster* cluster,
TextRange originalTextRange,
bool isStart) {
const char* textStr = owner->text().data();
const char* ptr = textStr + cluster->textRange().start;
const char* endPtr = textStr + cluster->textRange().end;
if (cluster->size() > 1 &&
cluster->size() == SkToSizeT(SkUTF::CountUTF8(ptr, cluster->textRange().width()))) {
size_t g0 = cluster->endPos();
size_t g1 = cluster->startPos();
for (size_t k = 0; ptr < endPtr; ++k) {
size_t idx = ptr - textStr;
SkUTF::NextUTF8(&ptr, endPtr);
if (idx < originalTextRange.start || idx >= originalTextRange.end) {
continue;
}
size_t g = run->leftToRight() ? (cluster->startPos() + k)
: (cluster->endPos() - 1 - k);
g0 = std::min(g0, g);
g1 = std::max(g1, g + 1);
}
if (g0 < g1) {
return {g0, g1};
}
} else if (cluster->textRange().start >= originalTextRange.start) {
return {cluster->startPos(), cluster->endPos()};
}
size_t fallback =
(isStart == run->leftToRight()) ? cluster->endPos() : cluster->startPos();
return {fallback, fallback};
}
} // namespace
TextLine::TextLine(ParagraphImpl* owner,
SkVector offset,
SkVector advance,
BlockRange blocks,
TextRange textExcludingSpaces,
TextRange text,
TextRange textIncludingNewlines,
ClusterRange clusters,
ClusterRange clustersWithGhosts,
SkScalar widthWithSpaces,
InternalLineMetrics sizes)
: fOwner(owner)
, fBlockRange(blocks)
, fTextExcludingSpaces(textExcludingSpaces)
, fText(text)
, fTextIncludingNewlines(textIncludingNewlines)
, fClusterRange(clusters)
, fGhostClusterRange(clustersWithGhosts)
, fRunsInVisualOrder()
, fAdvance(advance)
, fOffset(offset)
, fShift(0.0)
, fWidthWithSpaces(widthWithSpaces)
, fEllipsis(nullptr)
, fSizes(sizes)
, fHasBackground(false)
, fHasShadows(false)
, fHasDecorations(false)
, fAscentStyle(LineMetricStyle::CSS)
, fDescentStyle(LineMetricStyle::CSS)
, fTextBlobCachePopulated(false) {
// Reorder visual runs
auto& start = owner->cluster(fGhostClusterRange.start);
auto& end = owner->cluster(fGhostClusterRange.end - 1);
size_t numRuns = end.runIndex() - start.runIndex() + 1;
for (BlockIndex index = fBlockRange.start; index < fBlockRange.end; ++index) {
auto b = fOwner->styles().begin() + index;
if (b->fStyle.hasBackground()) {
fHasBackground = true;
}
if (b->fStyle.getDecorationType() != TextDecoration::kNoDecoration) {
fHasDecorations = true;
}
if (b->fStyle.getShadowNumber() > 0) {
fHasShadows = true;
}
}
// Get the logical order
// This is just chosen to catch the common/fast cases. Feel free to tweak.
constexpr int kPreallocCount = 4;
AutoSTArray<kPreallocCount, SkUnicode::BidiLevel> runLevels(numRuns);
size_t runLevelsIndex = 0;
for (auto runIndex = start.runIndex(); runIndex <= end.runIndex(); ++runIndex) {
auto& run = fOwner->run(runIndex);
runLevels[runLevelsIndex++] = run.fBidiLevel;
fMaxRunMetrics.add(
InternalLineMetrics(run.correctAscent(), run.correctDescent(), run.fFontMetrics.fLeading));
}
SkASSERT(runLevelsIndex == numRuns);
AutoSTArray<kPreallocCount, int32_t> logicalOrder(numRuns);
// TODO: hide all these logic in SkUnicode?
fOwner->getUnicode()->reorderVisual(runLevels.data(), numRuns, logicalOrder.data());
auto firstRunIndex = start.runIndex();
for (auto index : logicalOrder) {
fRunsInVisualOrder.push_back(firstRunIndex + index);
}
// TODO: This is the fix for flutter. Must be removed...
for (auto cluster = &start; cluster <= &end; ++cluster) {
if (!cluster->run().isPlaceholder() && !cluster->run().isCursiveScript()) {
fShift += cluster->getHalfLetterSpacing();
break;
}
}
}
void TextLine::paint(ParagraphPainter* painter, SkScalar x, SkScalar y) {
if (fHasBackground) {
this->iterateThroughVisualRuns(false,
[painter, x, y, this]
(const Run* run, SkScalar runOffsetInLine, TextRange textRange, SkScalar* runWidthInLine) {
*runWidthInLine = this->iterateThroughSingleRunByStyles(
TextAdjustment::GlyphCluster, run, runOffsetInLine, textRange, StyleType::kBackground,
[painter, x, y, this](TextRange textRange, const TextStyle& style, const ClipContext& context) {
this->paintBackground(painter, x, y, textRange, style, context);
});
return true;
});
}
if (fHasShadows) {
this->iterateThroughVisualRuns(false,
[painter, x, y, this]
(const Run* run, SkScalar runOffsetInLine, TextRange textRange, SkScalar* runWidthInLine) {
*runWidthInLine = this->iterateThroughSingleRunByStyles(
TextAdjustment::GlyphCluster, run, runOffsetInLine, textRange, StyleType::kShadow,
[painter, x, y, this]
(TextRange textRange, const TextStyle& style, const ClipContext& context) {
this->paintShadow(painter, x, y, textRange, style, context);
});
return true;
});
}
this->ensureTextBlobCachePopulated();
for (auto& record : fTextBlobCache) {
record.paint(painter, x, y);
}
if (fHasDecorations) {
this->iterateThroughVisualRuns(false,
[painter, x, y, this]
(const Run* run, SkScalar runOffsetInLine, TextRange textRange, SkScalar* runWidthInLine) {
*runWidthInLine = this->iterateThroughSingleRunByStyles(
TextAdjustment::GlyphCluster, run, runOffsetInLine, textRange, StyleType::kDecorations,
[painter, x, y, this]
(TextRange textRange, const TextStyle& style, const ClipContext& context) {
this->paintDecorations(painter, x, y, textRange, style, context);
});
return true;
});
}
}
void TextLine::ensureTextBlobCachePopulated() {
if (fTextBlobCachePopulated) {
return;
}
if (fBlockRange.width() == 1 && fRunsInVisualOrder.size() == 1 && fEllipsis == nullptr &&
fHyphen == nullptr && fOwner->run(fRunsInVisualOrder[0]).placeholderStyle() == nullptr) {
if (fClusterRange.width() == 0) {
return;
}
// Most common and most simple case
const auto& style = fOwner->block(fBlockRange.start).fStyle;
const auto& run = fOwner->run(fRunsInVisualOrder[0]);
auto clip = SkRect::MakeXYWH(0.0f, this->sizes().runTop(&run, this->fAscentStyle),
fAdvance.fX,
run.calculateHeight(this->fAscentStyle, this->fDescentStyle));
auto& start = fOwner->cluster(fClusterRange.start);
auto& end = fOwner->cluster(fClusterRange.end - 1);
SkASSERT(start.runIndex() == end.runIndex());
GlyphRange glyphs;
if (run.leftToRight()) {
glyphs = GlyphRange(start.startPos(),
end.isHardBreak() ? end.startPos() : end.endPos());
} else {
glyphs = GlyphRange(end.startPos(),
start.isHardBreak() ? start.startPos() : start.endPos());
}
ClipContext context = {/*run=*/&run,
/*pos=*/glyphs.start,
/*size=*/glyphs.width(),
/*fTextShift=*/-run.positionX(glyphs.start), // starting position
/*clip=*/clip, // entire line
/*fExcludedTrailingSpaces=*/0.0f, // no need for that
/*clippingNeeded=*/false}; // no need for that
this->buildTextBlob(fTextExcludingSpaces, style, context);
} else {
this->iterateThroughVisualRuns(false,
[this](const Run* run,
SkScalar runOffsetInLine,
TextRange textRange,
SkScalar* runWidthInLine) {
if (run->placeholderStyle() != nullptr) {
*runWidthInLine = run->advance().fX;
return true;
}
*runWidthInLine = this->iterateThroughSingleRunByStyles(
TextAdjustment::GlyphCluster,
run,
runOffsetInLine,
textRange,
StyleType::kForeground,
[this](TextRange textRange, const TextStyle& style, const ClipContext& context) {
this->buildTextBlob(textRange, style, context);
});
return true;
});
}
fTextBlobCachePopulated = true;
}
void TextLine::format(TextAlign align, SkScalar maxWidth) {
SkScalar delta = maxWidth - this->width();
if (delta <= 0) {
return;
}
// We do nothing for left align
if (align == TextAlign::kJustify) {
if (!this->endsWithHardLineBreak()) {
this->justify(maxWidth);
} else if (fOwner->paragraphStyle().getTextDirection() == TextDirection::kRtl) {
// Justify -> Right align
fShift = delta;
}
} else if (align == TextAlign::kRight) {
fShift = delta;
} else if (align == TextAlign::kCenter) {
fShift = delta / 2;
}
}
void TextLine::scanStyles(StyleType styleType, const RunStyleVisitor& visitor) {
if (this->empty()) {
return;
}
this->iterateThroughVisualRuns(
false,
[this, visitor, styleType](
const Run* run, SkScalar runOffset, TextRange textRange, SkScalar* width) {
*width = this->iterateThroughSingleRunByStyles(
TextAdjustment::GlyphCluster,
run,
runOffset,
textRange,
styleType,
[visitor](TextRange textRange,
const TextStyle& style,
const ClipContext& context) {
visitor(textRange, style, context);
});
return true;
});
}
SkRect TextLine::extendHeight(const ClipContext& context) const {
SkRect result = context.clip;
result.fBottom += std::max(this->fMaxRunMetrics.height() - this->height(), 0.0f);
return result;
}
void TextLine::buildTextBlob(TextRange textRange, const TextStyle& style, const ClipContext& context) {
if (context.run->placeholderStyle() != nullptr) {
return;
}
fTextBlobCache.emplace_back();
TextBlobRecord& record = fTextBlobCache.back();
if (style.hasForeground()) {
record.fPaint = style.getForegroundPaintOrID();
} else {
std::get<SkPaint>(record.fPaint).setColor(style.getColor());
}
record.fVisitor_Run = context.run;
record.fVisitor_Pos = context.pos;
// TODO: This is the change for flutter, must be removed later
SkTextBlobBuilder builder;
context.run->copyTo(builder, SkToU32(context.pos), context.size);
record.fClippingNeeded = context.clippingNeeded;
if (context.clippingNeeded) {
record.fClipRect = extendHeight(context).makeOffset(this->offset());
} else {
record.fClipRect = context.clip.makeOffset(this->offset());
}
SkASSERT(nearlyEqual(context.run->baselineShift(), style.getBaselineShift()));
SkScalar correctedBaseline = SkScalarFloorToScalar(this->baseline() + style.getBaselineShift() + 0.5);
record.fBlob = builder.make();
if (record.fBlob != nullptr) {
record.fBounds.joinPossiblyEmptyRect(record.fBlob->bounds());
}
record.fOffset = SkPoint::Make(this->offset().fX + context.fTextShift,
this->offset().fY + correctedBaseline);
}
void TextLine::TextBlobRecord::paint(ParagraphPainter* painter, SkScalar x, SkScalar y) {
if (fClippingNeeded) {
painter->save();
painter->clipRect(fClipRect.makeOffset(x, y));
}
painter->drawTextBlob(fBlob, x + fOffset.x(), y + fOffset.y(), fPaint);
if (fClippingNeeded) {
painter->restore();
}
}
void TextLine::paintBackground(ParagraphPainter* painter,
SkScalar x,
SkScalar y,
TextRange textRange,
const TextStyle& style,
const ClipContext& context) const {
if (style.hasBackground()) {
painter->drawRect(context.clip.makeOffset(this->offset() + SkPoint::Make(x, y)),
style.getBackgroundPaintOrID());
}
}
void TextLine::paintShadow(ParagraphPainter* painter,
SkScalar x,
SkScalar y,
TextRange textRange,
const TextStyle& style,
const ClipContext& context) const {
SkScalar correctedBaseline = SkScalarFloorToScalar(this->baseline() + style.getBaselineShift() + 0.5);
for (TextShadow shadow : style.getShadows()) {
if (!shadow.hasShadow()) continue;
SkTextBlobBuilder builder;
context.run->copyTo(builder, context.pos, context.size);
if (context.clippingNeeded) {
painter->save();
SkRect clip = extendHeight(context);
clip.offset(x, y);
clip.offset(this->offset());
painter->clipRect(clip);
}
auto blob = builder.make();
painter->drawTextShadow(blob,
x + this->offset().fX + shadow.fOffset.x() + context.fTextShift,
y + this->offset().fY + shadow.fOffset.y() + correctedBaseline,
shadow.fColor,
SkDoubleToScalar(shadow.fBlurSigma));
if (context.clippingNeeded) {
painter->restore();
}
}
}
void TextLine::paintDecorations(ParagraphPainter* painter, SkScalar x, SkScalar y, TextRange textRange, const TextStyle& style, const ClipContext& context) const {
ParagraphPainterAutoRestore ppar(painter);
painter->translate(x + this->offset().fX, y + this->offset().fY + style.getBaselineShift());
Decorations decorations;
SkScalar correctedBaseline = SkScalarFloorToScalar(-this->sizes().rawAscent() + style.getBaselineShift() + 0.5);
decorations.paint(painter, style, context, correctedBaseline);
}
void TextLine::justify(SkScalar maxWidth) {
int whitespacePatches = 0;
SkScalar textLen = 0;
SkScalar whitespaceLen = 0;
bool whitespacePatch = false;
// Take leading whitespaces width but do not increment a whitespace patch number
bool leadingWhitespaces = false;
this->iterateThroughClustersInGlyphsOrder(false, false,
[&](const Cluster* cluster, ClusterIndex index, bool ghost) {
if (cluster->isWhitespaceBreak()) {
if (index == 0) {
leadingWhitespaces = true;
} else if (!whitespacePatch && !leadingWhitespaces) {
// We only count patches BETWEEN words, not before
++whitespacePatches;
}
whitespacePatch = !leadingWhitespaces;
whitespaceLen += cluster->width();
} else if (cluster->isIdeographic()) {
// Whitespace break before and after
if (!whitespacePatch && index != 0) {
// We only count patches BETWEEN words, not before
++whitespacePatches; // before
}
whitespacePatch = true;
leadingWhitespaces = false;
++whitespacePatches; // after
} else {
whitespacePatch = false;
leadingWhitespaces = false;
}
textLen += cluster->width();
return true;
});
if (whitespacePatch) {
// We only count patches BETWEEN words, not after
--whitespacePatches;
}
if (whitespacePatches == 0) {
if (fOwner->paragraphStyle().getTextDirection() == TextDirection::kRtl) {
// Justify -> Right align
fShift = maxWidth - textLen;
}
return;
}
SkScalar step = (maxWidth - textLen + whitespaceLen) / whitespacePatches;
SkScalar shift = 0.0f;
SkScalar prevShift = 0.0f;
// Deal with the ghost spaces
auto ghostShift = maxWidth - this->fAdvance.fX;
// Spread the extra whitespaces
whitespacePatch = false;
// Do not break on leading whitespaces
leadingWhitespaces = false;
this->iterateThroughClustersInGlyphsOrder(false, true, [&](const Cluster* cluster, ClusterIndex index, bool ghost) {
if (ghost) {
if (cluster->run().leftToRight()) {
this->shiftCluster(cluster, ghostShift, ghostShift);
}
return true;
}
if (cluster->isWhitespaceBreak()) {
if (index == 0) {
leadingWhitespaces = true;
} else if (!whitespacePatch && !leadingWhitespaces) {
shift += step;
whitespacePatch = true;
--whitespacePatches;
}
shift -= cluster->width();
} else if (cluster->isIdeographic()) {
if (!whitespacePatch && index != 0) {
shift += step;
--whitespacePatches;
}
whitespacePatch = false;
leadingWhitespaces = false;
} else {
whitespacePatch = false;
leadingWhitespaces = false;
}
this->shiftCluster(cluster, shift, prevShift);
prevShift = shift;
// We skip ideographic whitespaces
if (!cluster->isWhitespaceBreak() && cluster->isIdeographic()) {
shift += step;
whitespacePatch = true;
--whitespacePatches;
}
return true;
});
if (whitespacePatch && whitespacePatches < 0) {
whitespacePatches++;
shift -= step;
}
SkAssertResult(nearlyEqual(shift, maxWidth - textLen));
SkASSERT(whitespacePatches == 0);
this->fWidthWithSpaces += ghostShift;
this->fAdvance.fX = maxWidth;
}
void TextLine::shiftCluster(const Cluster* cluster, SkScalar shift, SkScalar prevShift) {
auto& run = cluster->run();
auto start = cluster->startPos();
auto end = cluster->endPos();
if (end == run.size()) {
// Set the same shift for the fake last glyph (to avoid all extra checks)
++end;
}
if (run.fJustificationShifts.empty()) {
// Do not fill this array until needed
run.fJustificationShifts.push_back_n(run.size() + 1, { 0, 0 });
}
for (size_t pos = start; pos < end; ++pos) {
run.fJustificationShifts[pos] = { shift, prevShift };
}
}
void TextLine::createEllipsis(SkScalar maxWidth, const SkString& ellipsis, bool) {
// Replace some clusters with the ellipsis
// Go through the clusters in the reverse logical order
// taking off cluster by cluster until the ellipsis fits
SkScalar width = fAdvance.fX;
RunIndex lastRun = EMPTY_RUN;
std::unique_ptr<Run> ellipsisRun;
for (auto clusterIndex = fGhostClusterRange.end; clusterIndex > fGhostClusterRange.start; --clusterIndex) {
auto& cluster = fOwner->cluster(clusterIndex - 1);
// Shape the ellipsis if the run has changed
if (lastRun != cluster.runIndex()) {
ellipsisRun = this->shapeEllipsis(ellipsis, &cluster);
if (ellipsisRun->advance().fX > maxWidth) {
// Ellipsis is bigger than the entire line; no way we can add it at all
// BUT! We can keep scanning in case the next run will give us better results
lastRun = EMPTY_RUN;
continue;
} else {
// We may need to continue
lastRun = cluster.runIndex();
}
}
// See if it fits
if (width + ellipsisRun->advance().fX > maxWidth) {
width -= cluster.width();
// Continue if the ellipsis does not fit
continue;
}
// We found enough room for the ellipsis
fAdvance.fX = width;
fEllipsis = std::move(ellipsisRun);
fEllipsis->setOwner(fOwner);
// Let's update the line
fClusterRange.end = clusterIndex;
fGhostClusterRange.end = fClusterRange.end;
fEllipsis->fClusterStart = cluster.textRange().start;
fText.end = cluster.textRange().end;
fTextIncludingNewlines.end = cluster.textRange().end;
fTextExcludingSpaces.end = cluster.textRange().end;
break;
}
if (!fEllipsis) {
// Weird situation: ellipsis does not fit; no ellipsis then
fClusterRange.end = fClusterRange.start;
fGhostClusterRange.end = fClusterRange.start;
fText.end = fText.start;
fTextIncludingNewlines.end = fTextIncludingNewlines.start;
fTextExcludingSpaces.end = fTextExcludingSpaces.start;
fAdvance.fX = 0;
}
}
void TextLine::createSoftHyphen() {
if (fEllipsis) {
return;
}
if (fClusterRange.width() == 0) {
return;
}
auto& lastCluster = fOwner->cluster(fClusterRange.end - 1);
if (!lastCluster.isSoftHyphen()) {
return;
}
// Only draw the hyphen if the line actually broke at the soft hyphen. It
// didn't if spaces or a hard line break follow it, which are trimmed into
// the ghost clusters, or if the soft hyphen ends the paragraph.
if (fClusterRange.end != fGhostClusterRange.end ||
fTextIncludingNewlines.end >= fOwner->text().size()) {
return;
}
const SkString& hyphenStr = fOwner->paragraphStyle().getSoftHyphenString();
if (hyphenStr.isEmpty()) {
return;
}
fHyphen = this->shapeEllipsis(hyphenStr, &lastCluster, /*isHyphen=*/true);
if (fHyphen) {
fHyphen->fClusterStart = lastCluster.textRange().start;
}
}
std::unique_ptr<Run> TextLine::shapeEllipsis(const SkString& ellipsis,
const Cluster* cluster,
bool isHyphen) {
class ShapeHandler final : public SkShaper::RunHandler {
public:
ShapeHandler(SkScalar lineHeight,
bool useHalfLeading,
SkScalar baselineShift,
const SkString& ellipsis,
bool isHyphen)
: fRun(nullptr)
, fLineHeight(lineHeight)
, fUseHalfLeading(useHalfLeading)
, fBaselineShift(baselineShift)
, fEllipsis(ellipsis)
, fIsHyphen(isHyphen) {}
std::unique_ptr<Run> run() & { return std::move(fRun); }
private:
void beginLine() override {}
void runInfo(const RunInfo&) override {}
void commitRunInfo() override {}
Buffer runBuffer(const RunInfo& info) override {
SkASSERT(!fRun);
fRun = std::make_unique<Run>(nullptr, info, 0, fLineHeight, fUseHalfLeading, fBaselineShift, 0, 0);
return fRun->newRunBuffer();
}
void commitRunBuffer(const RunInfo& info) override {
fRun->fAdvance.fX = info.fAdvance.fX;
fRun->fAdvance.fY = fRun->advance().fY;
fRun->fPlaceholderIndex = std::numeric_limits<size_t>::max();
fRun->fEllipsis = true;
fRun->fHyphen = fIsHyphen;
}
void commitLine() override {}
std::unique_ptr<Run> fRun;
SkScalar fLineHeight;
bool fUseHalfLeading;
SkScalar fBaselineShift;
SkString fEllipsis;
bool fIsHyphen;
};
const Run& run = cluster->run();
TextStyle textStyle = fOwner->paragraphStyle().getTextStyle();
for (auto i = fBlockRange.start; i < fBlockRange.end; ++i) {
auto& block = fOwner->block(i);
if (run.leftToRight() && cluster->textRange().end <= block.fRange.end) {
textStyle = block.fStyle;
break;
} else if (!run.leftToRight() && cluster->textRange().start <= block.fRange.end) {
textStyle = block.fStyle;
break;
}
}
// Shape the affix in the surrounding run's direction, so neutral and weak
// characters in it (like a "!" after Arabic letters, or the default "-" and
// "…") take that direction instead of LTR. ShapeHandler only supports a
// single run, so if the affix would split in that direction (like
// "Read more…" in RTL text), shape it in the opposite direction instead.
SkBidiIterator::Level bidiLevel = run.bidiLevel();
if (sk_sp<SkUnicode> unicode = fOwner->getUnicode()) {
const bool ltr = run.leftToRight();
const auto runDir = ltr ? SkUnicode::TextDirection::kLTR : SkUnicode::TextDirection::kRTL;
const auto otherDir = ltr ? SkUnicode::TextDirection::kRTL : SkUnicode::TextDirection::kLTR;
if (!isSingleBidiRun(unicode.get(), ellipsis, runDir) &&
isSingleBidiRun(unicode.get(), ellipsis, otherDir)) {
bidiLevel = ltr ? SkBidiIterator::kRTL : SkBidiIterator::kLTR;
}
}
auto shaped = [&](sk_sp<SkTypeface> typeface, sk_sp<SkFontMgr> fallback) -> std::unique_ptr<Run> {
ShapeHandler handler(run.heightMultiplier(),
run.useHalfLeading(),
run.baselineShift(),
ellipsis,
isHyphen);
SkFont font(std::move(typeface), textStyle.getFontSize());
font.setEdging(textStyle.getFontEdging());
font.setHinting(textStyle.getFontHinting());
font.setSubpixel(textStyle.getSubpixel());
std::unique_ptr<SkShaper> shaper = SkShapers::HB::ShapeDontWrapOrReorder(
fOwner->getUnicode(), fallback ? fallback : SkFontMgr::RefEmpty());
const char* utf8 = ellipsis.c_str();
size_t utf8Bytes = ellipsis.size();
std::unique_ptr<SkShaper::BiDiRunIterator> bidi = SkShapers::unicode::BidiRunIterator(
fOwner->getUnicode(), utf8, utf8Bytes, bidiLevel);
SkASSERT(bidi);
std::unique_ptr<SkShaper::LanguageRunIterator> language =
SkShaper::MakeStdLanguageRunIterator(utf8, utf8Bytes);
SkASSERT(language);
std::unique_ptr<SkShaper::ScriptRunIterator> script =
SkShapers::HB::ScriptRunIterator(utf8, utf8Bytes);
SkASSERT(script);
std::unique_ptr<SkShaper::FontRunIterator> fontRuns = SkShaper::MakeFontMgrRunIterator(
utf8, utf8Bytes, font, fallback ? fallback : SkFontMgr::RefEmpty());
SkASSERT(fontRuns);
shaper->shape({ utf8, utf8Bytes },
*fontRuns,
*bidi,
*script,
*language,
{},
{},
&handler);
auto ellipsisRun = handler.run();
ellipsisRun->fTextRange = TextRange(0, ellipsis.size());
ellipsisRun->fOwner = fOwner;
return ellipsisRun;
};
// Check the current font
auto ellipsisRun = shaped(run.fFont.refTypeface(), nullptr);
if (ellipsisRun->isResolved()) {
return ellipsisRun;
}
// Check all allowed fonts
std::vector<sk_sp<SkTypeface>> typefaces = fOwner->fontCollection()->findTypefaces(
textStyle.getFontFamilies(), textStyle.getFontStyle(), textStyle.getFontArguments());
for (const auto& typeface : typefaces) {
ellipsisRun = shaped(typeface, nullptr);
if (ellipsisRun->isResolved()) {
return ellipsisRun;
}
}
// Try the fallback
if (fOwner->fontCollection()->fontFallbackEnabled()) {
const char* ch = ellipsis.c_str();
SkUnichar unicode = SkUTF::NextUTF8WithReplacement(&ch,
ellipsis.c_str()
+ ellipsis.size());
// We do not expect emojis in ellipsis so if they appeat there
// they will not be resolved with the pretiest color emoji font
auto typeface = fOwner->fontCollection()->defaultFallback(
unicode,
textStyle.getFontFamilies(),
textStyle.getFontStyle(),
textStyle.getLocale(),
textStyle.getFontArguments());
if (typeface) {
ellipsisRun = shaped(typeface, fOwner->fontCollection()->getFallbackManager());
if (ellipsisRun->isResolved()) {
return ellipsisRun;
}
}
}
return ellipsisRun;
}
TextLine::ClipContext TextLine::measureTextInsideOneRun(TextRange textRange,
const Run* run,
SkScalar runOffsetInLine,
SkScalar textOffsetInRunInLine,
bool includeGhostSpaces,
TextAdjustment textAdjustment) const {
ClipContext result = { run, 0, run->size(), 0, SkRect::MakeEmpty(), 0, false };
if (run->fEllipsis) {
// Both ellipsis and placeholders can only be measured as one glyph
result.fTextShift = runOffsetInLine;
result.clip = SkRect::MakeXYWH(runOffsetInLine,
sizes().runTop(run, this->fAscentStyle),
run->advance().fX,
run->calculateHeight(this->fAscentStyle,this->fDescentStyle));
return result;
} else if (run->isPlaceholder()) {
// Placeholder glyph positions retain their origin from shaping. Translate
// that origin to the visual run position, just as for regular text runs.
result.fTextShift = runOffsetInLine - run->positionX(0);
if (SkIsFinite(run->fFontMetrics.fAscent)) {
result.clip = SkRect::MakeXYWH(runOffsetInLine,
sizes().runTop(run, this->fAscentStyle),
run->advance().fX,
run->calculateHeight(this->fAscentStyle,this->fDescentStyle));
} else {
result.clip = SkRect::MakeXYWH(runOffsetInLine, run->fFontMetrics.fAscent, run->advance().fX, 0);
}
return result;
} else if (textRange.empty()) {
return result;
}
TextRange originalTextRange(textRange); // We need it for proportional measurement
// Find [start:end] clusters for the text
while (true) {
// Update textRange by cluster edges (shift start up to the edge of the cluster)
// TODO: remove this limitation?
TextRange updatedTextRange;
bool found;
std::tie(found, updatedTextRange.start, updatedTextRange.end) =
run->findLimitingGlyphClusters(textRange);
if (!found) {
return result;
}
if ((textAdjustment & TextAdjustment::Grapheme) == 0) {
textRange = updatedTextRange;
break;
}
// Update text range by grapheme edges (shift start up to the edge of the grapheme)
std::tie(found, updatedTextRange.start, updatedTextRange.end) =
run->findLimitingGraphemes(updatedTextRange);
if (updatedTextRange == textRange) {
break;
}
// Some clusters are inside graphemes and we need to adjust them
//SkDebugf("Correct range: [%d:%d) -> [%d:%d)\n", textRange.start, textRange.end, startIndex, endIndex);
textRange = updatedTextRange;
// Move the start until it's on the grapheme edge (and glypheme, too)
}
Cluster* start = &fOwner->cluster(fOwner->clusterIndex(textRange.start));
Cluster* end = &fOwner->cluster(fOwner->clusterIndex(textRange.end - (textRange.width() == 0 ? 0 : 1)));
if (!run->leftToRight()) {
std::swap(start, end);
}
result.pos = start->startPos();
result.size = (end->isHardBreak() ? end->startPos() : end->endPos()) - start->startPos();
auto textStartInRun = run->positionX(start->startPos());
auto textStartInLine = runOffsetInLine + textOffsetInRunInLine;
if (!run->leftToRight()) {
std::swap(start, end);
}
/*
if (!run->fJustificationShifts.empty()) {
SkDebugf("Justification for [%d:%d)\n", textRange.start, textRange.end);
for (auto i = result.pos; i < result.pos + result.size; ++i) {
auto j = run->fJustificationShifts[i];
SkDebugf("[%d] = %f %f\n", i, j.fX, j.fY);
}
}
*/
// Calculate the clipping rectangle for the text with cluster edges
// There are 2 cases:
// EOL (when we expect the last cluster clipped without any spaces)
// Anything else (when we want the cluster width contain all the spaces -
// coming from letter spacing or word spacing or justification)
result.clip =
SkRect::MakeXYWH(0,
sizes().runTop(run, this->fAscentStyle),
run->calculateWidth(result.pos, result.pos + result.size, false),
run->calculateHeight(this->fAscentStyle,this->fDescentStyle));
// When a style boundary splits a grapheme cluster (base + combining marks), isolate
// the glyphs belonging to originalTextRange instead of geometrically slicing the
// cluster's bounding box; proportional clipping is reserved for multi-grapheme ligatures
SkScalar leftCorrection = 0;
SkScalar rightCorrection = 0;
bool startSplit = originalTextRange.start > start->textRange().start;
bool endSplit = originalTextRange.end < end->textRange().end;
if (startSplit || endSplit) {
size_t startG0 = start->startPos();
size_t startG1 = start->endPos();
size_t endG0 = end->startPos();
size_t endG1 = end->isHardBreak() ? end->startPos() : end->endPos();
bool isolated = false;
if (startSplit) {
if (shouldIsolateCluster(fOwner, start)) {
std::tie(startG0, startG1) =
isolateClusterGlyphs(fOwner, run, start, originalTextRange, true);
isolated = true;
} else {
leftCorrection = start->sizeToChar(originalTextRange.start);
}
}
if (endSplit) {
if (start == end && isolated) {
endG0 = startG0;
endG1 = startG1;
} else if (shouldIsolateCluster(fOwner, end)) {
std::tie(endG0, endG1) =
isolateClusterGlyphs(fOwner, run, end, originalTextRange, false);
isolated = true;
} else {
rightCorrection = end->sizeFromChar(originalTextRange.end - 1);
}
}
if (isolated) {
result.pos = run->leftToRight() ? startG0 : endG0;
size_t endPos = run->leftToRight() ? endG1 : startG1;
result.size = endPos > result.pos ? (endPos - result.pos) : 0;
result.clip = SkRect::MakeXYWH(
0,
sizes().runTop(run, this->fAscentStyle),
run->calculateWidth(result.pos, result.pos + result.size, false),
run->calculateHeight(this->fAscentStyle, this->fDescentStyle));
textStartInRun = run->positionX(result.pos);
}
}
/*
SkDebugf("[%d: %d) => [%d: %d), @%d, %d: [%f:%f) + [%f:%f) = ", // جَآَهُ
originalTextRange.start, originalTextRange.end, textRange.start, textRange.end,
result.pos, result.size,
result.clip.fLeft, result.clip.fRight, leftCorrection, rightCorrection);
*/
result.clippingNeeded = leftCorrection != 0 || rightCorrection != 0;
if (run->leftToRight()) {
result.clip.fLeft += leftCorrection;
result.clip.fRight -= rightCorrection;
textStartInLine -= leftCorrection;
} else {
result.clip.fRight -= leftCorrection;
result.clip.fLeft += rightCorrection;
textStartInLine -= rightCorrection;
}
result.clip.offset(textStartInLine, 0);
//SkDebugf("@%f[%f:%f)\n", textStartInLine, result.clip.fLeft, result.clip.fRight);
if (compareRound(result.clip.fRight, fAdvance.fX, fOwner->getApplyRoundingHack()) > 0 && !includeGhostSpaces) {
// There are few cases when we need it.
// The most important one: we measure the text with spaces at the end (or at the beginning in RTL)
// and we should ignore these spaces
if (fOwner->paragraphStyle().getTextDirection() == TextDirection::kLtr) {
// We only use this member for LTR
result.fExcludedTrailingSpaces = std::max(result.clip.fRight - fAdvance.fX, 0.0f);
result.clippingNeeded = true;
result.clip.fRight = fAdvance.fX;
}
}
if (result.clip.width() < 0) {
// Weird situation when glyph offsets move the glyph to the left
// (happens with zalgo texts, for instance)
result.clip.fRight = result.clip.fLeft;
}
// The text must be aligned with the lineOffset
result.fTextShift = textStartInLine - textStartInRun;
return result;
}
void TextLine::iterateThroughClustersInGlyphsOrder(bool reversed,
bool includeGhosts,
const ClustersVisitor& visitor) const {
// Walk through the clusters in the logical order (or reverse)
SkSpan<const size_t> runs(fRunsInVisualOrder.data(), fRunsInVisualOrder.size());
bool ignore = false;
ClusterIndex index = 0;
directional_for_each(runs, !reversed, [&](decltype(runs[0]) r) {
if (ignore) return;
auto run = this->fOwner->run(r);
auto trimmedRange = fClusterRange.intersection(run.clusterRange());
auto trailedRange = fGhostClusterRange.intersection(run.clusterRange());
SkASSERT(trimmedRange.start == trailedRange.start);
auto trailed = fOwner->clusters(trailedRange);
auto trimmed = fOwner->clusters(trimmedRange);
directional_for_each(trailed, reversed != run.leftToRight(), [&](Cluster& cluster) {
if (ignore) return;
bool ghost = &cluster >= trimmed.data() + trimmed.size();
if (!includeGhosts && ghost) {
return;
}
if (!visitor(&cluster, index++, ghost)) {
ignore = true;
return;
}
});
});
}
SkScalar TextLine::iterateThroughSingleRunByStyles(TextAdjustment textAdjustment,
const Run* run,
SkScalar runOffset,
TextRange textRange,
StyleType styleType,
const RunStyleVisitor& visitor) const {
auto correctContext = [&](TextRange textRange, SkScalar textOffsetInRun) -> ClipContext {
auto result = this->measureTextInsideOneRun(
textRange, run, runOffset, textOffsetInRun, false, textAdjustment);
if (styleType == StyleType::kDecorations) {
// Decorations are drawn based on the real font metrics (regardless of styles and strut)
result.clip.fTop = this->sizes().runTop(run, LineMetricStyle::CSS);
result.clip.fBottom = result.clip.fTop +
run->calculateHeight(LineMetricStyle::CSS, LineMetricStyle::CSS);
}
return result;
};
if (run->fEllipsis) {
// Extra efforts to get the ellipsis text style
ClipContext clipContext = correctContext(run->textRange(), 0.0f);
TextRange testRange(run->fClusterStart, run->fClusterStart + run->textRange().width());
for (BlockIndex index = fBlockRange.start; index < fBlockRange.end; ++index) {
auto block = fOwner->styles().begin() + index;
auto intersect = intersected(block->fRange, testRange);
if (intersect.width() > 0) {
visitor(testRange, block->fStyle, clipContext);
return run->advance().fX;
}
}
SkASSERT(false);
}
if (styleType == StyleType::kNone) {
ClipContext clipContext = correctContext(textRange, 0.0f);
// The placehoder can have height=0 or (exclusively) width=0 and still be a thing
if (clipContext.clip.height() > 0.0f || clipContext.clip.width() > 0.0f) {
visitor(textRange, TextStyle(), clipContext);
return clipContext.clip.width();
} else {
return 0;
}
}
TextIndex start = EMPTY_INDEX;
size_t size = 0;
const TextStyle* prevStyle = nullptr;
SkScalar textOffsetInRun = 0;
const BlockIndex blockRangeSize = fBlockRange.end - fBlockRange.start;
for (BlockIndex index = 0; index <= blockRangeSize; ++index) {
TextRange intersect;
TextStyle* style = nullptr;
if (index < blockRangeSize) {
auto block = fOwner->styles().begin() +
(run->leftToRight() ? fBlockRange.start + index : fBlockRange.end - index - 1);
// Get the text
intersect = intersected(block->fRange, textRange);
if (intersect.width() == 0) {
if (start == EMPTY_INDEX) {
// This style is not applicable to the text yet
continue;
} else {
// We have found all the good styles already
// but we need to process the last one of them
intersect = TextRange(start, start + size);
index = fBlockRange.end;
}
} else {
// Get the style
style = &block->fStyle;
if (start != EMPTY_INDEX && style->matchOneAttribute(styleType, *prevStyle)) {
size += intersect.width();
// RTL text intervals move backward
start = std::min(intersect.start, start);
continue;
} else if (start == EMPTY_INDEX ) {
// First time only
prevStyle = style;
size = intersect.width();
start = intersect.start;
continue;
}
}
} else if (prevStyle != nullptr) {
// This is the last style
} else {
break;
}
// We have the style and the text
auto runStyleTextRange = TextRange(start, start + size);
ClipContext clipContext = correctContext(runStyleTextRange, textOffsetInRun);
textOffsetInRun += clipContext.clip.width();
if (clipContext.clip.height() == 0) {
continue;
}
visitor(runStyleTextRange, *prevStyle, clipContext);
// Start all over again
prevStyle = style;
start = intersect.start;
size = intersect.width();
}
return textOffsetInRun;
}
void TextLine::iterateThroughVisualRuns(bool includingGhostSpaces, const RunVisitor& visitor) const {
// Walk through all the runs that intersect with the line in visual order
SkScalar width = 0;
SkScalar runOffset = 0;
SkScalar totalWidth = 0;
auto textRange = includingGhostSpaces ? this->textWithNewlines() : this->trimmedText();
if (this->ellipsis() != nullptr && fOwner->paragraphStyle().getTextDirection() == TextDirection::kRtl) {
runOffset = this->ellipsis()->offset().fX;
if (visitor(ellipsis(), runOffset, ellipsis()->textRange(), &width)) {
}
}
if (this->hyphen() != nullptr &&
fOwner->paragraphStyle().getTextDirection() == TextDirection::kRtl) {
runOffset = this->hyphen()->offset().fX;
if (visitor(hyphen(), runOffset, hyphen()->textRange(), &width)) {
}
}
for (auto& runIndex : fRunsInVisualOrder) {
const auto run = &this->fOwner->run(runIndex);
auto lineIntersection = intersected(run->textRange(), textRange);
if (lineIntersection.width() == 0 && this->width() != 0) {
// TODO: deal with empty runs in a better way
continue;
}
if (!run->leftToRight() && runOffset == 0 && includingGhostSpaces) {
// runOffset does not take in account a possibility
// that RTL run could start before the line (trailing spaces)
// so we need to do runOffset -= "trailing whitespaces length"
TextRange whitespaces = intersected(
TextRange(fTextExcludingSpaces.end, fTextIncludingNewlines.end), run->fTextRange);
if (whitespaces.width() > 0) {
auto whitespacesLen = measureTextInsideOneRun(whitespaces, run, runOffset, 0, true, TextAdjustment::GlyphCluster).clip.width();
runOffset -= whitespacesLen;
}
}
runOffset += width;
totalWidth += width;
if (!visitor(run, runOffset, lineIntersection, &width)) {
return;
}
}
runOffset += width;
totalWidth += width;
if (this->ellipsis() != nullptr && fOwner->paragraphStyle().getTextDirection() == TextDirection::kLtr) {
if (visitor(ellipsis(), runOffset, ellipsis()->textRange(), &width)) {
totalWidth += width;
}
}
if (this->hyphen() != nullptr &&
fOwner->paragraphStyle().getTextDirection() == TextDirection::kLtr) {
if (visitor(hyphen(), runOffset, hyphen()->textRange(), &width)) {
totalWidth += width;
}
}
if (!includingGhostSpaces && compareRound(totalWidth, this->width(), fOwner->getApplyRoundingHack()) != 0) {
// This is a very important assert!
// It asserts that 2 different ways of calculation come with the same results
SkDEBUGFAILF("ASSERT: %f != %f\n", totalWidth, this->width());
}
}
SkVector TextLine::offset() const {
return fOffset + SkVector::Make(fShift, 0);
}
LineMetrics TextLine::getMetrics() const {
LineMetrics result;
SkASSERT(fOwner);
// Fill out the metrics
fOwner->ensureUTF16Mapping();
result.fStartIndex = fOwner->getUTF16Index(fTextExcludingSpaces.start);
result.fEndExcludingWhitespaces = fOwner->getUTF16Index(fTextExcludingSpaces.end);
result.fEndIndex = fOwner->getUTF16Index(fText.end);
result.fEndIncludingNewline = fOwner->getUTF16Index(fTextIncludingNewlines.end);
result.fHardBreak = endsWithHardLineBreak();
result.fAscent = - fMaxRunMetrics.ascent();
result.fDescent = fMaxRunMetrics.descent();
result.fUnscaledAscent = - fMaxRunMetrics.ascent(); // TODO: implement
result.fHeight = fAdvance.fY;
result.fWidth = fAdvance.fX;
if (fOwner->getApplyRoundingHack()) {
result.fHeight = littleRound(result.fHeight);
result.fWidth = littleRound(result.fWidth);
}
result.fLeft = this->offset().fX;
// This is Flutter definition of a baseline
result.fBaseline = this->offset().fY + this->height() - this->sizes().descent();
result.fLineNumber = this - fOwner->lines().data();
// Fill out the style parts
this->iterateThroughVisualRuns(false,
[this, &result]
(const Run* run, SkScalar runOffsetInLine, TextRange textRange, SkScalar* runWidthInLine) {
if (run->placeholderStyle() != nullptr) {
*runWidthInLine = run->advance().fX;
return true;
}
*runWidthInLine = this->iterateThroughSingleRunByStyles(
TextAdjustment::GlyphCluster, run, runOffsetInLine, textRange, StyleType::kForeground,
[&result, &run](TextRange textRange, const TextStyle& style, const ClipContext& context) {
SkFontMetrics fontMetrics;
run->fFont.getMetrics(&fontMetrics);
StyleMetrics styleMetrics(&style, fontMetrics);
result.fLineMetrics.emplace(textRange.start, styleMetrics);
});
return true;
});
return result;
}
bool TextLine::isFirstLine() const {
return this == &fOwner->lines().front();
}
bool TextLine::isLastLine() const {
return this == &fOwner->lines().back();
}
bool TextLine::endsWithHardLineBreak() const {
// TODO: For some reason Flutter imagines a hard line break at the end of the last line.
// To be removed...
return (fGhostClusterRange.width() > 0 && fOwner->cluster(fGhostClusterRange.end - 1).isHardBreak()) ||
fEllipsis != nullptr ||
fGhostClusterRange.end == fOwner->clusters().size() - 1;
}
void TextLine::getRectsForRange(TextRange textRange0,
RectHeightStyle rectHeightStyle,
RectWidthStyle rectWidthStyle,
std::vector<TextBox>& boxes) const
{
const Run* lastRun = nullptr;
auto startBox = boxes.size();
this->iterateThroughVisualRuns(true,
[textRange0, rectHeightStyle, rectWidthStyle, &boxes, &lastRun, startBox, this]
(const Run* run, SkScalar runOffsetInLine, TextRange textRange, SkScalar* runWidthInLine) {
// The rendered soft hyphen is a synthetic glyph run that does not correspond
// to any source text. Its synthetic textRange (offsets into the "-" string)
// would falsely intersect caller-supplied source ranges and produce a
// spurious selection rect at the line-end hyphen position. Skip it.
if (run->isHyphen()) {
return true;
}
*runWidthInLine = this->iterateThroughSingleRunByStyles(
TextAdjustment::GraphemeGluster, run, runOffsetInLine, textRange, StyleType::kNone,
[run, runOffsetInLine, textRange0, rectHeightStyle, rectWidthStyle, &boxes, &lastRun, startBox, this]
(TextRange textRange, const TextStyle& style, const TextLine::ClipContext& lineContext) {
auto intersect = textRange * textRange0;
if (intersect.empty()) {
return true;
}
auto paragraphStyle = fOwner->paragraphStyle();
// Found a run that intersects with the text
auto context = this->measureTextInsideOneRun(
intersect, run, runOffsetInLine, 0, true, TextAdjustment::GraphemeGluster);
SkRect clip = context.clip;
clip.offset(lineContext.fTextShift - context.fTextShift, 0);
switch (rectHeightStyle) {
case RectHeightStyle::kMax:
// TODO: Change it once flutter rolls into google3
// (probably will break things if changed before)
clip.fBottom = this->height();
clip.fTop = this->sizes().delta();
break;
case RectHeightStyle::kIncludeLineSpacingTop: {
clip.fBottom = this->height();
clip.fTop = this->sizes().delta();
auto verticalShift = this->sizes().rawAscent() - this->sizes().ascent();
if (isFirstLine()) {
clip.fTop += verticalShift;
}
break;
}
case RectHeightStyle::kIncludeLineSpacingMiddle: {
clip.fBottom = this->height();
clip.fTop = this->sizes().delta();
auto verticalShift = this->sizes().rawAscent() - this->sizes().ascent();
clip.offset(0, verticalShift / 2.0);
if (isFirstLine()) {
clip.fTop += verticalShift / 2.0;
}
if (isLastLine()) {
clip.fBottom -= verticalShift / 2.0;
}
break;
}
case RectHeightStyle::kIncludeLineSpacingBottom: {
clip.fBottom = this->height();
clip.fTop = this->sizes().delta();
auto verticalShift = this->sizes().rawAscent() - this->sizes().ascent();
clip.offset(0, verticalShift);
if (isLastLine()) {
clip.fBottom -= verticalShift;
}
break;
}
case RectHeightStyle::kStrut: {
const auto& strutStyle = paragraphStyle.getStrutStyle();
if (strutStyle.getStrutEnabled()
&& strutStyle.getFontSize() > 0) {
auto strutMetrics = fOwner->strutMetrics();
auto top = this->baseline();
clip.fTop = top + strutMetrics.ascent();
clip.fBottom = top + strutMetrics.descent();
}
}
break;
case RectHeightStyle::kTight: {
if (run->fHeightMultiplier <= 0) {
break;
}
const auto effectiveBaseline = this->baseline() + this->sizes().delta();
clip.fTop = effectiveBaseline + run->ascent();
clip.fBottom = effectiveBaseline + run->descent();
}
break;
default:
SkASSERT(false);
break;
}
// Separate trailing spaces and move them in the default order of the paragraph
// in case the run order and the paragraph order don't match
SkRect trailingSpaces = SkRect::MakeEmpty();
if (this->trimmedText().end <this->textWithNewlines().end && // Line has trailing space
this->textWithNewlines().end == intersect.end && // Range is at the end of the line
this->trimmedText().end > intersect.start) // Range has more than just spaces
{
auto delta = this->spacesWidth();
trailingSpaces = SkRect::MakeXYWH(0, 0, 0, 0);
// There are trailing spaces in this run
if (paragraphStyle.getTextAlign() == TextAlign::kJustify && isLastLine())
{
// TODO: this is just a patch. Make it right later (when it's clear what and how)
trailingSpaces = clip;
if(run->leftToRight()) {
trailingSpaces.fLeft = this->width();
clip.fRight = this->width();
} else {
trailingSpaces.fRight = 0;
clip.fLeft = 0;
}
} else if (paragraphStyle.getTextDirection() == TextDirection::kRtl &&
!run->leftToRight())
{
// Split
trailingSpaces = clip;
trailingSpaces.fLeft = - delta;
trailingSpaces.fRight = 0;
clip.fLeft += delta;
} else if (paragraphStyle.getTextDirection() == TextDirection::kLtr &&
run->leftToRight())
{
// Split
trailingSpaces = clip;
trailingSpaces.fLeft = this->width();
trailingSpaces.fRight = trailingSpaces.fLeft + delta;
clip.fRight -= delta;
}
}
clip.offset(this->offset());
if (trailingSpaces.width() > 0) {
trailingSpaces.offset(this->offset());
}
// Check if we can merge two boxes instead of adding a new one
auto merge = [&lastRun, &context, &boxes](SkRect clip) {
bool mergedBoxes = false;
if (!boxes.empty() &&
lastRun != nullptr &&
context.run->leftToRight() == lastRun->leftToRight() &&
lastRun->placeholderStyle() == nullptr &&
context.run->placeholderStyle() == nullptr &&
nearlyEqual(lastRun->heightMultiplier(),
context.run->heightMultiplier()) &&
lastRun->font() == context.run->font())
{
auto& lastBox = boxes.back();
if (nearlyEqual(lastBox.rect.fTop, clip.fTop) &&
nearlyEqual(lastBox.rect.fBottom, clip.fBottom) &&
(nearlyEqual(lastBox.rect.fLeft, clip.fRight) ||
nearlyEqual(lastBox.rect.fRight, clip.fLeft)))
{
lastBox.rect.fLeft = std::min(lastBox.rect.fLeft, clip.fLeft);
lastBox.rect.fRight = std::max(lastBox.rect.fRight, clip.fRight);
mergedBoxes = true;
}
}
lastRun = context.run;
return mergedBoxes;
};
if (!merge(clip)) {
boxes.emplace_back(clip, context.run->getTextDirection());
}
if (!nearlyZero(trailingSpaces.width()) && !merge(trailingSpaces)) {
boxes.emplace_back(trailingSpaces, paragraphStyle.getTextDirection());
}
if (rectWidthStyle == RectWidthStyle::kMax && !isLastLine()) {
// Align the very left/right box horizontally
auto lineStart = this->offset().fX;
auto lineEnd = this->offset().fX + this->width();
auto left = boxes[startBox];
auto right = boxes.back();
if (left.rect.fLeft > lineStart && left.direction == TextDirection::kRtl) {
left.rect.fRight = left.rect.fLeft;
left.rect.fLeft = 0;
boxes.insert(boxes.begin() + startBox + 1, left);
}
if (right.direction == TextDirection::kLtr &&
right.rect.fRight >= lineEnd &&
right.rect.fRight < fOwner->widthWithTrailingSpaces()) {
right.rect.fLeft = right.rect.fRight;
right.rect.fRight = fOwner->widthWithTrailingSpaces();
boxes.emplace_back(right);
}
}
return true;
});
return true;
});
if (fOwner->getApplyRoundingHack()) {
for (auto& r : boxes) {
r.rect.fLeft = littleRound(r.rect.fLeft);
r.rect.fRight = littleRound(r.rect.fRight);
r.rect.fTop = littleRound(r.rect.fTop);
r.rect.fBottom = littleRound(r.rect.fBottom);
}
}
}
PositionWithAffinity TextLine::getGlyphPositionAtCoordinate(SkScalar dx) {
if (SkScalarNearlyZero(this->width()) && SkScalarNearlyZero(this->spacesWidth())) {
// TODO: this is one of the flutter changes that have to go away eventually
// Empty line is a special case in txtlib (but only when there are no spaces, too)
auto utf16Index = fOwner->getUTF16Index(this->fTextExcludingSpaces.end);
return { SkToS32(utf16Index) , kDownstream };
}
PositionWithAffinity result(0, Affinity::kDownstream);
this->iterateThroughVisualRuns(true,
[this, dx, &result]
(const Run* run, SkScalar runOffsetInLine, TextRange textRange, SkScalar* runWidthInLine) {
if (run->isEllipsis()) {
auto utf16Index = fOwner->getUTF16Index(this->fText.end);
result = { SkToS32(utf16Index) , kDownstream };
return false;
}
bool keepLooking = true;
*runWidthInLine = this->iterateThroughSingleRunByStyles(
TextAdjustment::GraphemeGluster, run, runOffsetInLine, textRange, StyleType::kNone,
[this, run, dx, &result, &keepLooking]
(TextRange textRange, const TextStyle& style, const TextLine::ClipContext& context0) {
SkScalar offsetX = this->offset().fX;
ClipContext context = context0;
// Correct the clip size because libtxt counts trailing spaces
if (run->leftToRight()) {
context.clip.fRight += context.fExcludedTrailingSpaces; // extending clip to the right
} else {
// Clip starts from 0; we cannot extend it to the left from that
}
// However, we need to offset the clip
context.clip.offset(offsetX, 0.0f);
// This patch will help us to avoid a floating point error
if (SkScalarNearlyEqual(context.clip.fRight, dx, 0.01f)) {
context.clip.fRight = dx;
}
if (dx <= context.clip.fLeft) {
// All the other runs are placed right of this one
auto utf16Index = fOwner->getUTF16Index(context.run->globalClusterIndex(context.pos));
if (run->leftToRight()) {
result = { SkToS32(utf16Index), kDownstream};
keepLooking = false;
} else {
result = { SkToS32(utf16Index + 1), kUpstream};
// If we haven't reached the end of the run we need to keep looking
keepLooking = context.pos != 0;
}
// For RTL we go another way
return !run->leftToRight();
}
if (dx >= context.clip.fRight) {
// We have to keep looking ; just in case keep the last one as the closest
auto utf16Index = fOwner->getUTF16Index(context.run->globalClusterIndex(context.pos + context.size));
if (run->leftToRight()) {
result = {SkToS32(utf16Index), kUpstream};
} else {
result = {SkToS32(utf16Index), kDownstream};
}
// For RTL we go another way
return run->leftToRight();
}
// So we found the run that contains our coordinates
// Find the glyph position in the run that is the closest left of our point
// TODO: binary search
size_t found = context.pos;
for (size_t index = context.pos; index < context.pos + context.size; ++index) {
// TODO: this rounding is done to match Flutter tests. Must be removed..
auto end = context.run->positionX(index) + context.fTextShift + offsetX;
if (fOwner->getApplyRoundingHack()) {
end = littleRound(end);
}
if (end > dx) {
break;
} else if (end == dx && !context.run->leftToRight()) {
// When we move RTL variable end points to the beginning of the code point which is included
found = index;
break;
}
found = index;
}
SkScalar glyphemePosLeft = context.run->positionX(found) + context.fTextShift + offsetX;
SkScalar glyphemesWidth = context.run->positionX(found + 1) - context.run->positionX(found);
// Find the grapheme range that contains the point
auto clusterIndex8 = context.run->globalClusterIndex(found);
auto clusterEnd8 = context.run->globalClusterIndex(found + 1);
auto graphemes = fOwner->countSurroundingGraphemes({clusterIndex8, clusterEnd8});
SkScalar center = glyphemePosLeft + glyphemesWidth / 2;
if (graphemes.size() > 1) {
// Calculate the position proportionally based on grapheme count
SkScalar averageGraphemeWidth = glyphemesWidth / graphemes.size();
SkScalar delta = dx - glyphemePosLeft;
int graphemeIndex = SkScalarNearlyZero(averageGraphemeWidth)
? 0
: SkScalarFloorToInt(delta / averageGraphemeWidth);
// Justification shifts coordinates beyond glyph bounds;
// clamp to valid graphemes
graphemeIndex = std::clamp(graphemeIndex, 0, SkToInt(graphemes.size()) - 1);
auto graphemeCenter = glyphemePosLeft + graphemeIndex * averageGraphemeWidth +
averageGraphemeWidth / 2;
auto graphemeUtf8Index = graphemes[graphemeIndex];
if ((dx < graphemeCenter) == context.run->leftToRight()) {
size_t utf16Index = fOwner->getUTF16Index(graphemeUtf8Index);
result = { SkToS32(utf16Index), kDownstream };
} else {
size_t utf16Index = fOwner->getUTF16Index(graphemeUtf8Index + 1);
result = { SkToS32(utf16Index), kUpstream };
}
// Keep UTF16 index as is
} else if ((dx < center) == context.run->leftToRight()) {
size_t utf16Index = fOwner->getUTF16Index(clusterIndex8);
result = { SkToS32(utf16Index), kDownstream };
} else {
size_t utf16Index = context.run->leftToRight()
? fOwner->getUTF16Index(clusterEnd8)
: fOwner->getUTF16Index(clusterIndex8) + 1;
result = { SkToS32(utf16Index), kUpstream };
}
return keepLooking = false;
});
return keepLooking;
}
);
return result;
}
void TextLine::getRectsForPlaceholders(std::vector<TextBox>& boxes) {
std::vector<std::pair<TextIndex, TextBox>> placeholders;
this->iterateThroughVisualRuns(
true,
[&placeholders, this](
const Run* run, SkScalar runOffset, TextRange textRange, SkScalar* width) {
auto context = this->measureTextInsideOneRun(
textRange, run, runOffset, 0, true, TextAdjustment::GraphemeGluster);
*width = context.clip.width();
if (textRange.width() == 0) {
return true;
}
if (!run->isPlaceholder()) {
return true;
}
SkRect clip = context.clip;
clip.offset(this->offset());
if (fOwner->getApplyRoundingHack()) {
clip.fLeft = littleRound(clip.fLeft);
clip.fRight = littleRound(clip.fRight);
clip.fTop = littleRound(clip.fTop);
clip.fBottom = littleRound(clip.fBottom);
}
placeholders.emplace_back(run->textRange().start,
TextBox(clip, run->getTextDirection()));
return true;
});
// Measure in visual order, but return boxes in the order placeholders were added.
// Sorting by their text offsets also handles mixed-direction runs within a line.
std::sort(placeholders.begin(), placeholders.end(), [](const auto& a, const auto& b) {
return a.first < b.first;
});
for (const auto& placeholder : placeholders) {
boxes.push_back(placeholder.second);
}
}
} // namespace textlayout
} // namespace skia