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skia / skia / 7880a8f62967bc8cd953538ba057d614e4e76a91 / . / modules / skparagraph / src / ParagraphImpl.cpp
blob: 166173dfed1000d51a39428dfbe114a953d908e7 [file] [log] [blame]
// Copyright 2019 Google LLC.
#include "include/core/SkCanvas.h"
#include "include/core/SkFontMetrics.h"
#include "include/core/SkMatrix.h"
#include "include/core/SkPictureRecorder.h"
#include "include/core/SkSpan.h"
#include "include/core/SkTypeface.h"
#include "include/private/base/SkTFitsIn.h"
#include "include/private/base/SkTo.h"
#include "modules/skparagraph/include/Metrics.h"
#include "modules/skparagraph/include/Paragraph.h"
#include "modules/skparagraph/include/ParagraphPainter.h"
#include "modules/skparagraph/include/ParagraphStyle.h"
#include "modules/skparagraph/include/TextStyle.h"
#include "modules/skparagraph/src/OneLineShaper.h"
#include "modules/skparagraph/src/ParagraphImpl.h"
#include "modules/skparagraph/src/ParagraphPainterImpl.h"
#include "modules/skparagraph/src/Run.h"
#include "modules/skparagraph/src/TextLine.h"
#include "modules/skparagraph/src/TextWrapper.h"
#include "src/base/SkUTF.h"
#include <math.h>
#include <algorithm>
#include <utility>
namespace skia {
namespace textlayout {
namespace {
SkScalar littleRound(SkScalar a) {
// This rounding is done to match Flutter tests. Must be removed..
auto val = std::fabs(a);
if (val < 10000) {
return SkScalarRoundToScalar(a * 100.0)/100.0;
} else if (val < 100000) {
return SkScalarRoundToScalar(a * 10.0)/10.0;
} else {
return SkScalarFloorToScalar(a);
}
}
} // namespace
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;
}
Paragraph::Paragraph(ParagraphStyle style, sk_sp<FontCollection> fonts)
: fFontCollection(std::move(fonts))
, fParagraphStyle(std::move(style))
, fAlphabeticBaseline(0)
, fIdeographicBaseline(0)
, fHeight(0)
, fWidth(0)
, fMaxIntrinsicWidth(0)
, fMinIntrinsicWidth(0)
, fLongestLine(0)
, fExceededMaxLines(0)
{ }
ParagraphImpl::ParagraphImpl(const SkString& text,
ParagraphStyle style,
SkTArray<Block, true> blocks,
SkTArray<Placeholder, true> placeholders,
sk_sp<FontCollection> fonts,
std::shared_ptr<SkUnicode> unicode)
: Paragraph(std::move(style), std::move(fonts))
, fTextStyles(std::move(blocks))
, fPlaceholders(std::move(placeholders))
, fText(text)
, fState(kUnknown)
, fUnresolvedGlyphs(0)
, fPicture(nullptr)
, fStrutMetrics(false)
, fOldWidth(0)
, fOldHeight(0)
, fUnicode(std::move(unicode))
, fHasLineBreaks(false)
, fHasWhitespacesInside(false)
, fTrailingSpaces(0)
{
SkASSERT(fUnicode);
}
ParagraphImpl::ParagraphImpl(const std::u16string& utf16text,
ParagraphStyle style,
SkTArray<Block, true> blocks,
SkTArray<Placeholder, true> placeholders,
sk_sp<FontCollection> fonts,
std::shared_ptr<SkUnicode> unicode)
: ParagraphImpl(SkString(),
std::move(style),
std::move(blocks),
std::move(placeholders),
std::move(fonts),
std::move(unicode))
{
SkASSERT(fUnicode);
fText = SkUnicode::convertUtf16ToUtf8(utf16text);
}
ParagraphImpl::~ParagraphImpl() = default;
int32_t ParagraphImpl::unresolvedGlyphs() {
if (fState < kShaped) {
return -1;
}
return fUnresolvedGlyphs;
}
void ParagraphImpl::layout(SkScalar rawWidth) {
// TODO: This rounding is done to match Flutter tests. Must be removed...
auto floorWidth = SkScalarFloorToScalar(rawWidth);
if ((!SkScalarIsFinite(rawWidth) || fLongestLine <= floorWidth) &&
fState >= kLineBroken &&
fLines.size() == 1 && fLines.front().ellipsis() == nullptr) {
// Most common case: one line of text (and one line is never justified, so no cluster shifts)
// We cannot mark it as kLineBroken because the new width can be bigger than the old width
fWidth = floorWidth;
fState = kShaped;
} else if (fState >= kLineBroken && fOldWidth != floorWidth) {
// We can use the results from SkShaper but have to do EVERYTHING ELSE again
fState = kShaped;
} else {
// Nothing changed case: we can reuse the data from the last layout
}
if (fState < kShaped) {
// Check if we have the text in the cache and don't need to shape it again
if (!fFontCollection->getParagraphCache()->findParagraph(this)) {
if (fState < kIndexed) {
// This only happens once at the first layout; the text is immutable
// and there is no reason to repeat it
if (this->computeCodeUnitProperties()) {
fState = kIndexed;
}
}
this->fRuns.clear();
this->fClusters.clear();
this->fClustersIndexFromCodeUnit.clear();
this->fClustersIndexFromCodeUnit.push_back_n(fText.size() + 1, EMPTY_INDEX);
if (!this->shapeTextIntoEndlessLine()) {
this->resetContext();
// TODO: merge the two next calls - they always come together
this->resolveStrut();
this->computeEmptyMetrics();
this->fLines.clear();
// Set the important values that are not zero
fWidth = floorWidth;
fHeight = fEmptyMetrics.height();
if (fParagraphStyle.getStrutStyle().getStrutEnabled() &&
fParagraphStyle.getStrutStyle().getForceStrutHeight()) {
fHeight = fStrutMetrics.height();
}
fAlphabeticBaseline = fEmptyMetrics.alphabeticBaseline();
fIdeographicBaseline = fEmptyMetrics.ideographicBaseline();
fLongestLine = FLT_MIN - FLT_MAX; // That is what flutter has
fMinIntrinsicWidth = 0;
fMaxIntrinsicWidth = 0;
this->fOldWidth = floorWidth;
this->fOldHeight = this->fHeight;
return;
} else {
// Add the paragraph to the cache
fFontCollection->getParagraphCache()->updateParagraph(this);
}
}
fState = kShaped;
}
if (fState == kShaped) {
this->resetContext();
this->resolveStrut();
this->computeEmptyMetrics();
this->fLines.clear();
this->breakShapedTextIntoLines(floorWidth);
fState = kLineBroken;
}
if (fState == kLineBroken) {
// Build the picture lazily not until we actually have to paint (or never)
this->resetShifts();
this->formatLines(fWidth);
fState = kFormatted;
}
this->fOldWidth = floorWidth;
this->fOldHeight = this->fHeight;
// TODO: This rounding is done to match Flutter tests. Must be removed...
fMinIntrinsicWidth = littleRound(fMinIntrinsicWidth);
fMaxIntrinsicWidth = littleRound(fMaxIntrinsicWidth);
// TODO: This is strictly Flutter thing. Must be factored out into some flutter code
if (fParagraphStyle.getMaxLines() == 1 ||
(fParagraphStyle.unlimited_lines() && fParagraphStyle.ellipsized())) {
fMinIntrinsicWidth = fMaxIntrinsicWidth;
}
// TODO: Since min and max are calculated differently it's possible to get a rounding error
// that would make min > max. Sort it out later, make it the same for now
if (fMaxIntrinsicWidth < fMinIntrinsicWidth) {
fMaxIntrinsicWidth = fMinIntrinsicWidth;
}
//SkDebugf("layout('%s', %f): %f %f\n", fText.c_str(), rawWidth, fMinIntrinsicWidth, fMaxIntrinsicWidth);
}
void ParagraphImpl::paint(SkCanvas* canvas, SkScalar x, SkScalar y) {
CanvasParagraphPainter painter(canvas);
paint(&painter, x, y);
}
void ParagraphImpl::paint(ParagraphPainter* painter, SkScalar x, SkScalar y) {
for (auto& line : fLines) {
line.paint(painter, x, y);
}
}
void ParagraphImpl::resetContext() {
fAlphabeticBaseline = 0;
fHeight = 0;
fWidth = 0;
fIdeographicBaseline = 0;
fMaxIntrinsicWidth = 0;
fMinIntrinsicWidth = 0;
fLongestLine = 0;
fMaxWidthWithTrailingSpaces = 0;
fExceededMaxLines = false;
}
// shapeTextIntoEndlessLine is the thing that calls this method
bool ParagraphImpl::computeCodeUnitProperties() {
if (nullptr == fUnicode) {
return false;
}
// Get bidi regions
auto textDirection = fParagraphStyle.getTextDirection() == TextDirection::kLtr
? SkUnicode::TextDirection::kLTR
: SkUnicode::TextDirection::kRTL;
if (!fUnicode->getBidiRegions(fText.c_str(), fText.size(), textDirection, &fBidiRegions)) {
return false;
}
// Collect all spaces and some extra information
// (and also substitute \t with a space while we are at it)
if (!fUnicode->computeCodeUnitFlags(&fText[0],
fText.size(),
this->paragraphStyle().getReplaceTabCharacters(),
&fCodeUnitProperties)) {
return false;
}
// Get some information about trailing spaces / hard line breaks
fTrailingSpaces = fText.size();
TextIndex firstWhitespace = EMPTY_INDEX;
for (int i = 0; i < fCodeUnitProperties.size(); ++i) {
auto flags = fCodeUnitProperties[i];
if (SkUnicode::isPartOfWhiteSpaceBreak(flags)) {
if (fTrailingSpaces == fText.size()) {
fTrailingSpaces = i;
}
if (firstWhitespace == EMPTY_INDEX) {
firstWhitespace = i;
}
} else {
fTrailingSpaces = fText.size();
}
if (SkUnicode::isHardLineBreak(flags)) {
fHasLineBreaks = true;
}
}
if (firstWhitespace < fTrailingSpaces) {
fHasWhitespacesInside = true;
}
return true;
}
static bool is_ascii_7bit_space(int c) {
SkASSERT(c >= 0 && c <= 127);
// Extracted from https://en.wikipedia.org/wiki/Whitespace_character
//
enum WS {
kHT = 9,
kLF = 10,
kVT = 11,
kFF = 12,
kCR = 13,
kSP = 32, // too big to use as shift
};
#define M(shift) (1 << (shift))
constexpr uint32_t kSpaceMask = M(kHT) | M(kLF) | M(kVT) | M(kFF) | M(kCR);
// we check for Space (32) explicitly, since it is too large to shift
return (c == kSP) || (c <= 31 && (kSpaceMask & M(c)));
#undef M
}
Cluster::Cluster(ParagraphImpl* owner,
RunIndex runIndex,
size_t start,
size_t end,
SkSpan<const char> text,
SkScalar width,
SkScalar height)
: fOwner(owner)
, fRunIndex(runIndex)
, fTextRange(text.begin() - fOwner->text().begin(), text.end() - fOwner->text().begin())
, fGraphemeRange(EMPTY_RANGE)
, fStart(start)
, fEnd(end)
, fWidth(width)
, fHeight(height)
, fHalfLetterSpacing(0.0) {
size_t whiteSpacesBreakLen = 0;
size_t intraWordBreakLen = 0;
const char* ch = text.begin();
if (text.end() - ch == 1 && *(unsigned char*)ch <= 0x7F) {
// I am not even sure it's worth it if we do not save a unicode call
if (is_ascii_7bit_space(*ch)) {
++whiteSpacesBreakLen;
}
} else {
for (auto i = fTextRange.start; i < fTextRange.end; ++i) {
if (fOwner->codeUnitHasProperty(i, SkUnicode::CodeUnitFlags::kPartOfWhiteSpaceBreak)) {
++whiteSpacesBreakLen;
}
if (fOwner->codeUnitHasProperty(i, SkUnicode::CodeUnitFlags::kPartOfIntraWordBreak)) {
++intraWordBreakLen;
}
}
}
fIsWhiteSpaceBreak = whiteSpacesBreakLen == fTextRange.width();
fIsIntraWordBreak = intraWordBreakLen == fTextRange.width();
fIsHardBreak = fOwner->codeUnitHasProperty(fTextRange.end,
SkUnicode::CodeUnitFlags::kHardLineBreakBefore);
}
SkScalar Run::calculateWidth(size_t start, size_t end, bool clip) const {
SkASSERT(start <= end);
// clip |= end == size(); // Clip at the end of the run?
auto correction = 0.0f;
if (end > start && !fJustificationShifts.empty()) {
// This is not a typo: we are using Point as a pair of SkScalars
correction = fJustificationShifts[end - 1].fX -
fJustificationShifts[start].fY;
}
return posX(end) - posX(start) + correction;
}
// In some cases we apply spacing to glyphs first and then build the cluster table, in some we do
// the opposite - just to optimize the most common case.
void ParagraphImpl::applySpacingAndBuildClusterTable() {
// Check all text styles to see what we have to do (if anything)
size_t letterSpacingStyles = 0;
bool hasWordSpacing = false;
for (auto& block : fTextStyles) {
if (block.fRange.width() > 0) {
if (!SkScalarNearlyZero(block.fStyle.getLetterSpacing())) {
++letterSpacingStyles;
}
if (!SkScalarNearlyZero(block.fStyle.getWordSpacing())) {
hasWordSpacing = true;
}
}
}
if (letterSpacingStyles == 0 && !hasWordSpacing) {
// We don't have to do anything about spacing (most common case)
this->buildClusterTable();
return;
}
if (letterSpacingStyles == 1 && !hasWordSpacing && fTextStyles.size() == 1 &&
fTextStyles[0].fRange.width() == fText.size() && fRuns.size() == 1) {
// We have to letter space the entire paragraph (second most common case)
auto& run = fRuns[0];
auto& style = fTextStyles[0].fStyle;
run.addSpacesEvenly(style.getLetterSpacing());
this->buildClusterTable();
// This is something Flutter requires
for (auto& cluster : fClusters) {
cluster.setHalfLetterSpacing(style.getLetterSpacing()/2);
}
return;
}
// The complex case: many text styles with spacing (possibly not adjusted to glyphs)
this->buildClusterTable();
// Walk through all the clusters in the direction of shaped text
// (we have to walk through the styles in the same order, too)
SkScalar shift = 0;
for (auto& run : fRuns) {
// Skip placeholder runs
if (run.isPlaceholder()) {
continue;
}
bool soFarWhitespacesOnly = true;
bool wordSpacingPending = false;
Cluster* lastSpaceCluster = nullptr;
run.iterateThroughClusters([this, &run, &shift, &soFarWhitespacesOnly, &wordSpacingPending, &lastSpaceCluster](Cluster* cluster) {
// Shift the cluster (shift collected from the previous clusters)
run.shift(cluster, shift);
// Synchronize styles (one cluster can be covered by few styles)
Block* currentStyle = fTextStyles.begin();
while (!cluster->startsIn(currentStyle->fRange)) {
currentStyle++;
SkASSERT(currentStyle != fTextStyles.end());
}
SkASSERT(!currentStyle->fStyle.isPlaceholder());
// Process word spacing
if (currentStyle->fStyle.getWordSpacing() != 0) {
if (cluster->isWhitespaceBreak() && cluster->isSoftBreak()) {
if (!soFarWhitespacesOnly) {
lastSpaceCluster = cluster;
wordSpacingPending = true;
}
} else if (wordSpacingPending) {
SkScalar spacing = currentStyle->fStyle.getWordSpacing();
run.addSpacesAtTheEnd(spacing, lastSpaceCluster);
run.shift(cluster, spacing);
shift += spacing;
wordSpacingPending = false;
}
}
// Process letter spacing
if (currentStyle->fStyle.getLetterSpacing() != 0) {
shift += run.addSpacesEvenly(currentStyle->fStyle.getLetterSpacing(), cluster);
}
if (soFarWhitespacesOnly && !cluster->isWhitespaceBreak()) {
soFarWhitespacesOnly = false;
}
});
}
}
// Clusters in the order of the input text
void ParagraphImpl::buildClusterTable() {
// It's possible that one grapheme includes few runs; we cannot handle it
// so we break graphemes by the runs instead
// It's not the ideal solution and has to be revisited later
int cluster_count = 1;
for (auto& run : fRuns) {
cluster_count += run.isPlaceholder() ? 1 : run.size();
fCodeUnitProperties[run.fTextRange.start] |= SkUnicode::CodeUnitFlags::kGraphemeStart;
fCodeUnitProperties[run.fTextRange.start] |= SkUnicode::CodeUnitFlags::kGlyphClusterStart;
}
if (!fRuns.empty()) {
fCodeUnitProperties[fRuns.back().textRange().end] |= SkUnicode::CodeUnitFlags::kGraphemeStart;
fCodeUnitProperties[fRuns.back().textRange().end] |= SkUnicode::CodeUnitFlags::kGlyphClusterStart;
}
fClusters.reserve_back(cluster_count);
// Walk through all the run in the direction of input text
for (auto& run : fRuns) {
auto runIndex = run.index();
auto runStart = fClusters.size();
if (run.isPlaceholder()) {
// Add info to cluster indexes table (text -> cluster)
for (auto i = run.textRange().start; i < run.textRange().end; ++i) {
fClustersIndexFromCodeUnit[i] = fClusters.size();
}
// There are no glyphs but we want to have one cluster
fClusters.emplace_back(this, runIndex, 0ul, 1ul, this->text(run.textRange()), run.advance().fX, run.advance().fY);
fCodeUnitProperties[run.textRange().start] |= SkUnicode::CodeUnitFlags::kSoftLineBreakBefore;
fCodeUnitProperties[run.textRange().end] |= SkUnicode::CodeUnitFlags::kSoftLineBreakBefore;
} else {
// Walk through the glyph in the direction of input text
run.iterateThroughClustersInTextOrder([runIndex, this](size_t glyphStart,
size_t glyphEnd,
size_t charStart,
size_t charEnd,
SkScalar width,
SkScalar height) {
SkASSERT(charEnd >= charStart);
// Add info to cluster indexes table (text -> cluster)
for (auto i = charStart; i < charEnd; ++i) {
fClustersIndexFromCodeUnit[i] = fClusters.size();
}
SkSpan<const char> text(fText.c_str() + charStart, charEnd - charStart);
fClusters.emplace_back(this, runIndex, glyphStart, glyphEnd, text, width, height);
fCodeUnitProperties[charStart] |= SkUnicode::CodeUnitFlags::kGlyphClusterStart;
});
}
fCodeUnitProperties[run.textRange().start] |= SkUnicode::CodeUnitFlags::kGlyphClusterStart;
run.setClusterRange(runStart, fClusters.size());
fMaxIntrinsicWidth += run.advance().fX;
}
fClustersIndexFromCodeUnit[fText.size()] = fClusters.size();
fClusters.emplace_back(this, EMPTY_RUN, 0, 0, this->text({fText.size(), fText.size()}), 0, 0);
}
bool ParagraphImpl::shapeTextIntoEndlessLine() {
if (fText.size() == 0) {
return false;
}
fFontSwitches.clear();
OneLineShaper oneLineShaper(this);
auto result = oneLineShaper.shape();
fUnresolvedGlyphs = oneLineShaper.unresolvedGlyphs();
this->applySpacingAndBuildClusterTable();
return result;
}
void ParagraphImpl::breakShapedTextIntoLines(SkScalar maxWidth) {
if (!fHasLineBreaks &&
!fHasWhitespacesInside &&
fPlaceholders.size() == 1 &&
fRuns.size() == 1 && fRuns[0].fAdvance.fX <= maxWidth) {
// This is a short version of a line breaking when we know that:
// 1. We have only one line of text
// 2. It's shaped into a single run
// 3. There are no placeholders
// 4. There are no linebreaks (which will format text into multiple lines)
// 5. There are no whitespaces so the minIntrinsicWidth=maxIntrinsicWidth
// (To think about that, the last condition is not quite right;
// we should calculate minIntrinsicWidth by soft line breaks.
// However, it's how it's done in Flutter now)
auto& run = this->fRuns[0];
auto advance = run.advance();
auto textRange = TextRange(0, this->text().size());
auto textExcludingSpaces = TextRange(0, fTrailingSpaces);
InternalLineMetrics metrics(this->strutForceHeight());
metrics.add(&run);
auto disableFirstAscent = this->paragraphStyle().getTextHeightBehavior() &
TextHeightBehavior::kDisableFirstAscent;
auto disableLastDescent = this->paragraphStyle().getTextHeightBehavior() &
TextHeightBehavior::kDisableLastDescent;
if (disableFirstAscent) {
metrics.fAscent = metrics.fRawAscent;
}
if (disableLastDescent) {
metrics.fDescent = metrics.fRawDescent;
}
if (this->strutEnabled()) {
this->strutMetrics().updateLineMetrics(metrics);
}
ClusterIndex trailingSpaces = fClusters.size();
do {
--trailingSpaces;
auto& cluster = fClusters[trailingSpaces];
if (!cluster.isWhitespaceBreak()) {
++trailingSpaces;
break;
}
advance.fX -= cluster.width();
} while (trailingSpaces != 0);
advance.fY = metrics.height();
auto clusterRange = ClusterRange(0, trailingSpaces);
auto clusterRangeWithGhosts = ClusterRange(0, this->clusters().size() - 1);
this->addLine(SkPoint::Make(0, 0), advance,
textExcludingSpaces, textRange, textRange,
clusterRange, clusterRangeWithGhosts, run.advance().x(),
metrics);
fLongestLine = nearlyZero(advance.fX) ? run.advance().fX : advance.fX;
fHeight = advance.fY;
fWidth = maxWidth;
fMaxIntrinsicWidth = run.advance().fX;
fMinIntrinsicWidth = advance.fX;
fAlphabeticBaseline = fLines.empty() ? fEmptyMetrics.alphabeticBaseline() : fLines.front().alphabeticBaseline();
fIdeographicBaseline = fLines.empty() ? fEmptyMetrics.ideographicBaseline() : fLines.front().ideographicBaseline();
fExceededMaxLines = false;
return;
}
TextWrapper textWrapper;
textWrapper.breakTextIntoLines(
this,
maxWidth,
[&](TextRange textExcludingSpaces,
TextRange text,
TextRange textWithNewlines,
ClusterRange clusters,
ClusterRange clustersWithGhosts,
SkScalar widthWithSpaces,
size_t startPos,
size_t endPos,
SkVector offset,
SkVector advance,
InternalLineMetrics metrics,
bool addEllipsis) {
// TODO: Take in account clipped edges
auto& line = this->addLine(offset, advance, textExcludingSpaces, text, textWithNewlines, clusters, clustersWithGhosts, widthWithSpaces, metrics);
if (addEllipsis) {
line.createEllipsis(maxWidth, this->getEllipsis(), true);
}
fLongestLine = std::max(fLongestLine, nearlyZero(advance.fX) ? widthWithSpaces : advance.fX);
});
fHeight = textWrapper.height();
fWidth = maxWidth;
fMaxIntrinsicWidth = textWrapper.maxIntrinsicWidth();
fMinIntrinsicWidth = textWrapper.minIntrinsicWidth();
fAlphabeticBaseline = fLines.empty() ? fEmptyMetrics.alphabeticBaseline() : fLines.front().alphabeticBaseline();
fIdeographicBaseline = fLines.empty() ? fEmptyMetrics.ideographicBaseline() : fLines.front().ideographicBaseline();
fExceededMaxLines = textWrapper.exceededMaxLines();
}
void ParagraphImpl::formatLines(SkScalar maxWidth) {
auto effectiveAlign = fParagraphStyle.effective_align();
const bool isLeftAligned = effectiveAlign == TextAlign::kLeft
|| (effectiveAlign == TextAlign::kJustify && fParagraphStyle.getTextDirection() == TextDirection::kLtr);
if (!SkScalarIsFinite(maxWidth) && !isLeftAligned) {
// Special case: clean all text in case of maxWidth == INF & align != left
// We had to go through shaping though because we need all the measurement numbers
fLines.clear();
return;
}
for (auto& line : fLines) {
line.format(effectiveAlign, maxWidth);
}
}
void ParagraphImpl::resolveStrut() {
auto strutStyle = this->paragraphStyle().getStrutStyle();
if (!strutStyle.getStrutEnabled() || strutStyle.getFontSize() < 0) {
return;
}
std::vector<sk_sp<SkTypeface>> typefaces = fFontCollection->findTypefaces(strutStyle.getFontFamilies(), strutStyle.getFontStyle(), std::nullopt);
if (typefaces.empty()) {
SkDEBUGF("Could not resolve strut font\n");
return;
}
SkFont font(typefaces.front(), strutStyle.getFontSize());
SkFontMetrics metrics;
font.getMetrics(&metrics);
if (strutStyle.getHeightOverride()) {
auto strutHeight = metrics.fDescent - metrics.fAscent;
auto strutMultiplier = strutStyle.getHeight() * strutStyle.getFontSize();
fStrutMetrics = InternalLineMetrics(
(metrics.fAscent / strutHeight) * strutMultiplier,
(metrics.fDescent / strutHeight) * strutMultiplier,
strutStyle.getLeading() < 0 ? 0 : strutStyle.getLeading() * strutStyle.getFontSize(),
metrics.fAscent, metrics.fDescent, metrics.fLeading);
} else {
fStrutMetrics = InternalLineMetrics(
metrics.fAscent,
metrics.fDescent,
strutStyle.getLeading() < 0 ? 0 : strutStyle.getLeading() * strutStyle.getFontSize());
}
fStrutMetrics.setForceStrut(this->paragraphStyle().getStrutStyle().getForceStrutHeight());
}
BlockRange ParagraphImpl::findAllBlocks(TextRange textRange) {
BlockIndex begin = EMPTY_BLOCK;
BlockIndex end = EMPTY_BLOCK;
for (int index = 0; index < fTextStyles.size(); ++index) {
auto& block = fTextStyles[index];
if (block.fRange.end <= textRange.start) {
continue;
}
if (block.fRange.start >= textRange.end) {
break;
}
if (begin == EMPTY_BLOCK) {
begin = index;
}
end = index;
}
if (begin == EMPTY_INDEX || end == EMPTY_INDEX) {
// It's possible if some text is not covered with any text style
// Not in Flutter but in direct use of SkParagraph
return EMPTY_RANGE;
}
return { begin, end + 1 };
}
TextLine& ParagraphImpl::addLine(SkVector offset,
SkVector advance,
TextRange textExcludingSpaces,
TextRange text,
TextRange textIncludingNewLines,
ClusterRange clusters,
ClusterRange clustersWithGhosts,
SkScalar widthWithSpaces,
InternalLineMetrics sizes) {
// Define a list of styles that covers the line
auto blocks = findAllBlocks(textExcludingSpaces);
return fLines.emplace_back(this, offset, advance, blocks,
textExcludingSpaces, text, textIncludingNewLines,
clusters, clustersWithGhosts, widthWithSpaces, sizes);
}
// Returns a vector of bounding boxes that enclose all text between
// start and end glyph indexes, including start and excluding end
std::vector<TextBox> ParagraphImpl::getRectsForRange(unsigned start,
unsigned end,
RectHeightStyle rectHeightStyle,
RectWidthStyle rectWidthStyle) {
std::vector<TextBox> results;
if (fText.isEmpty()) {
if (start == 0 && end > 0) {
// On account of implied "\n" that is always at the end of the text
//SkDebugf("getRectsForRange(%d, %d): %f\n", start, end, fHeight);
results.emplace_back(SkRect::MakeXYWH(0, 0, 0, fHeight), fParagraphStyle.getTextDirection());
}
return results;
}
this->ensureUTF16Mapping();
if (start >= end || start > SkToSizeT(fUTF8IndexForUTF16Index.size()) || end == 0) {
return results;
}
// Adjust the text to grapheme edges
// Apparently, text editor CAN move inside graphemes but CANNOT select a part of it.
// I don't know why - the solution I have here returns an empty box for every query that
// does not contain an end of a grapheme.
// Once a cursor is inside a complex grapheme I can press backspace and cause trouble.
// To avoid any problems, I will not allow any selection of a part of a grapheme.
// One flutter test fails because of it but the editing experience is correct
// (although you have to press the cursor many times before it moves to the next grapheme).
TextRange text(fText.size(), fText.size());
// TODO: This is probably a temp change that makes SkParagraph work as TxtLib
// (so we can compare the results). We now include in the selection box only the graphemes
// that belongs to the given [start:end) range entirely (not the ones that intersect with it)
if (start < SkToSizeT(fUTF8IndexForUTF16Index.size())) {
auto utf8 = fUTF8IndexForUTF16Index[start];
// If start points to a trailing surrogate, skip it
if (start > 0 && fUTF8IndexForUTF16Index[start - 1] == utf8) {
utf8 = fUTF8IndexForUTF16Index[start + 1];
}
text.start = this->findNextGraphemeBoundary(utf8);
}
if (end < SkToSizeT(fUTF8IndexForUTF16Index.size())) {
auto utf8 = this->findPreviousGraphemeBoundary(fUTF8IndexForUTF16Index[end]);
text.end = utf8;
}
//SkDebugf("getRectsForRange(%d,%d) -> (%d:%d)\n", start, end, text.start, text.end);
for (auto& line : fLines) {
auto lineText = line.textWithNewlines();
auto intersect = lineText * text;
if (intersect.empty() && lineText.start != text.start) {
continue;
}
line.getRectsForRange(intersect, rectHeightStyle, rectWidthStyle, results);
}
/*
SkDebugf("getRectsForRange(%d, %d)\n", start, end);
for (auto& r : results) {
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);
SkDebugf("[%f:%f * %f:%f]\n", r.rect.fLeft, r.rect.fRight, r.rect.fTop, r.rect.fBottom);
}
*/
return results;
}
std::vector<TextBox> ParagraphImpl::getRectsForPlaceholders() {
std::vector<TextBox> boxes;
if (fText.isEmpty()) {
return boxes;
}
if (fPlaceholders.size() == 1) {
// We always have one fake placeholder
return boxes;
}
for (auto& line : fLines) {
line.getRectsForPlaceholders(boxes);
}
/*
SkDebugf("getRectsForPlaceholders('%s'): %d\n", fText.c_str(), boxes.size());
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);
SkDebugf("[%f:%f * %f:%f] %s\n", r.rect.fLeft, r.rect.fRight, r.rect.fTop, r.rect.fBottom,
(r.direction == TextDirection::kLtr ? "left" : "right"));
}
*/
return boxes;
}
// TODO: Optimize (save cluster <-> codepoint connection)
PositionWithAffinity ParagraphImpl::getGlyphPositionAtCoordinate(SkScalar dx, SkScalar dy) {
if (fText.isEmpty()) {
return {0, Affinity::kDownstream};
}
this->ensureUTF16Mapping();
for (auto& line : fLines) {
// Let's figure out if we can stop looking
auto offsetY = line.offset().fY;
if (dy >= offsetY + line.height() && &line != &fLines.back()) {
// This line is not good enough
continue;
}
// This is so far the the line vertically closest to our coordinates
// (or the first one, or the only one - all the same)
auto result = line.getGlyphPositionAtCoordinate(dx);
//SkDebugf("getGlyphPositionAtCoordinate(%f, %f): %d %s\n", dx, dy, result.position,
// result.affinity == Affinity::kUpstream ? "up" : "down");
return result;
}
return {0, Affinity::kDownstream};
}
// Finds the first and last glyphs that define a word containing
// the glyph at index offset.
// By "glyph" they mean a character index - indicated by Minikin's code
SkRange<size_t> ParagraphImpl::getWordBoundary(unsigned offset) {
if (fWords.empty()) {
if (!fUnicode->getWords(fText.c_str(), fText.size(), nullptr, &fWords)) {
return {0, 0 };
}
}
int32_t start = 0;
int32_t end = 0;
for (size_t i = 0; i < fWords.size(); ++i) {
auto word = fWords[i];
if (word <= offset) {
start = word;
end = word;
} else if (word > offset) {
end = word;
break;
}
}
//SkDebugf("getWordBoundary(%d): %d - %d\n", offset, start, end);
return { SkToU32(start), SkToU32(end) };
}
void ParagraphImpl::getLineMetrics(std::vector<LineMetrics>& metrics) {
metrics.clear();
for (auto& line : fLines) {
metrics.emplace_back(line.getMetrics());
}
}
SkSpan<const char> ParagraphImpl::text(TextRange textRange) {
SkASSERT(textRange.start <= fText.size() && textRange.end <= fText.size());
auto start = fText.c_str() + textRange.start;
return SkSpan<const char>(start, textRange.width());
}
SkSpan<Cluster> ParagraphImpl::clusters(ClusterRange clusterRange) {
SkASSERT(clusterRange.start < SkToSizeT(fClusters.size()) &&
clusterRange.end <= SkToSizeT(fClusters.size()));
return SkSpan<Cluster>(&fClusters[clusterRange.start], clusterRange.width());
}
Cluster& ParagraphImpl::cluster(ClusterIndex clusterIndex) {
SkASSERT(clusterIndex < SkToSizeT(fClusters.size()));
return fClusters[clusterIndex];
}
Run& ParagraphImpl::runByCluster(ClusterIndex clusterIndex) {
auto start = cluster(clusterIndex);
return this->run(start.fRunIndex);
}
SkSpan<Block> ParagraphImpl::blocks(BlockRange blockRange) {
SkASSERT(blockRange.start < SkToSizeT(fTextStyles.size()) &&
blockRange.end <= SkToSizeT(fTextStyles.size()));
return SkSpan<Block>(&fTextStyles[blockRange.start], blockRange.width());
}
Block& ParagraphImpl::block(BlockIndex blockIndex) {
SkASSERT(blockIndex < SkToSizeT(fTextStyles.size()));
return fTextStyles[blockIndex];
}
void ParagraphImpl::setState(InternalState state) {
if (fState <= state) {
fState = state;
return;
}
fState = state;
switch (fState) {
case kUnknown:
SkASSERT(false);
/*
// The text is immutable and so are all the text indexing properties
// taken from SkUnicode
fCodeUnitProperties.reset();
fWords.clear();
fBidiRegions.clear();
fUTF8IndexForUTF16Index.reset();
fUTF16IndexForUTF8Index.reset();
*/
[[fallthrough]];
case kIndexed:
fRuns.clear();
fClusters.clear();
[[fallthrough]];
case kShaped:
fLines.clear();
[[fallthrough]];
case kLineBroken:
fPicture = nullptr;
[[fallthrough]];
default:
break;
}
}
void ParagraphImpl::computeEmptyMetrics() {
// The empty metrics is used to define the height of the empty lines
// Unfortunately, Flutter has 2 different cases for that:
// 1. An empty line inside the text
// 2. An empty paragraph
// In the first case SkParagraph takes the metrics from the default paragraph style
// In the second case it should take it from the current text style
bool emptyParagraph = fRuns.empty();
TextStyle textStyle = paragraphStyle().getTextStyle();
if (emptyParagraph && !fTextStyles.empty()) {
textStyle = fTextStyles.back().fStyle;
}
auto typefaces = fontCollection()->findTypefaces(
textStyle.getFontFamilies(), textStyle.getFontStyle(), textStyle.getFontArguments());
auto typeface = typefaces.empty() ? nullptr : typefaces.front();
SkFont font(typeface, textStyle.getFontSize());
fEmptyMetrics = InternalLineMetrics(font, paragraphStyle().getStrutStyle().getForceStrutHeight());
if (!paragraphStyle().getStrutStyle().getForceStrutHeight() &&
textStyle.getHeightOverride()) {
const auto intrinsicHeight = fEmptyMetrics.height();
const auto strutHeight = textStyle.getHeight() * textStyle.getFontSize();
if (paragraphStyle().getStrutStyle().getHalfLeading()) {
fEmptyMetrics.update(
fEmptyMetrics.ascent(),
fEmptyMetrics.descent(),
fEmptyMetrics.leading() + strutHeight - intrinsicHeight);
} else {
const auto multiplier = strutHeight / intrinsicHeight;
fEmptyMetrics.update(
fEmptyMetrics.ascent() * multiplier,
fEmptyMetrics.descent() * multiplier,
fEmptyMetrics.leading() * multiplier);
}
}
if (emptyParagraph) {
// For an empty text we apply both TextHeightBehaviour flags
// In case of non-empty paragraph TextHeightBehaviour flags will be applied at the appropriate place
// We have to do it here because we skip wrapping for an empty text
auto disableFirstAscent = (paragraphStyle().getTextHeightBehavior() & TextHeightBehavior::kDisableFirstAscent) == TextHeightBehavior::kDisableFirstAscent;
auto disableLastDescent = (paragraphStyle().getTextHeightBehavior() & TextHeightBehavior::kDisableLastDescent) == TextHeightBehavior::kDisableLastDescent;
fEmptyMetrics.update(
disableFirstAscent ? fEmptyMetrics.rawAscent() : fEmptyMetrics.ascent(),
disableLastDescent ? fEmptyMetrics.rawDescent() : fEmptyMetrics.descent(),
fEmptyMetrics.leading());
}
if (fParagraphStyle.getStrutStyle().getStrutEnabled()) {
fStrutMetrics.updateLineMetrics(fEmptyMetrics);
}
}
SkString ParagraphImpl::getEllipsis() const {
auto ellipsis8 = fParagraphStyle.getEllipsis();
auto ellipsis16 = fParagraphStyle.getEllipsisUtf16();
if (!ellipsis8.isEmpty()) {
return ellipsis8;
} else {
return SkUnicode::convertUtf16ToUtf8(fParagraphStyle.getEllipsisUtf16());
}
}
void ParagraphImpl::updateFontSize(size_t from, size_t to, SkScalar fontSize) {
SkASSERT(from == 0 && to == fText.size());
auto defaultStyle = fParagraphStyle.getTextStyle();
defaultStyle.setFontSize(fontSize);
fParagraphStyle.setTextStyle(defaultStyle);
for (auto& textStyle : fTextStyles) {
textStyle.fStyle.setFontSize(fontSize);
}
fState = std::min(fState, kIndexed);
fOldWidth = 0;
fOldHeight = 0;
}
void ParagraphImpl::updateTextAlign(TextAlign textAlign) {
fParagraphStyle.setTextAlign(textAlign);
if (fState >= kLineBroken) {
fState = kLineBroken;
}
}
void ParagraphImpl::updateForegroundPaint(size_t from, size_t to, SkPaint paint) {
SkASSERT(from == 0 && to == fText.size());
auto defaultStyle = fParagraphStyle.getTextStyle();
defaultStyle.setForegroundColor(paint);
fParagraphStyle.setTextStyle(defaultStyle);
for (auto& textStyle : fTextStyles) {
textStyle.fStyle.setForegroundColor(paint);
}
}
void ParagraphImpl::updateBackgroundPaint(size_t from, size_t to, SkPaint paint) {
SkASSERT(from == 0 && to == fText.size());
auto defaultStyle = fParagraphStyle.getTextStyle();
defaultStyle.setBackgroundColor(paint);
fParagraphStyle.setTextStyle(defaultStyle);
for (auto& textStyle : fTextStyles) {
textStyle.fStyle.setBackgroundColor(paint);
}
}
SkTArray<TextIndex> ParagraphImpl::countSurroundingGraphemes(TextRange textRange) const {
textRange = textRange.intersection({0, fText.size()});
SkTArray<TextIndex> graphemes;
if ((fCodeUnitProperties[textRange.start] & SkUnicode::CodeUnitFlags::kGraphemeStart) == 0) {
// Count the previous partial grapheme
graphemes.emplace_back(textRange.start);
}
for (auto index = textRange.start; index < textRange.end; ++index) {
if ((fCodeUnitProperties[index] & SkUnicode::CodeUnitFlags::kGraphemeStart) != 0) {
graphemes.emplace_back(index);
}
}
return graphemes;
}
TextIndex ParagraphImpl::findPreviousGraphemeBoundary(TextIndex utf8) const {
while (utf8 > 0 &&
(fCodeUnitProperties[utf8] & SkUnicode::CodeUnitFlags::kGraphemeStart) == 0) {
--utf8;
}
return utf8;
}
TextIndex ParagraphImpl::findNextGraphemeBoundary(TextIndex utf8) const {
while (utf8 < fText.size() &&
(fCodeUnitProperties[utf8] & SkUnicode::CodeUnitFlags::kGraphemeStart) == 0) {
++utf8;
}
return utf8;
}
TextIndex ParagraphImpl::findNextGlyphClusterBoundary(TextIndex utf8) const {
while (utf8 < fText.size() &&
(fCodeUnitProperties[utf8] & SkUnicode::CodeUnitFlags::kGlyphClusterStart) == 0) {
++utf8;
}
return utf8;
}
TextIndex ParagraphImpl::findPreviousGlyphClusterBoundary(TextIndex utf8) const {
while (utf8 > 0 &&
(fCodeUnitProperties[utf8] & SkUnicode::CodeUnitFlags::kGlyphClusterStart) == 0) {
--utf8;
}
return utf8;
}
void ParagraphImpl::ensureUTF16Mapping() {
fillUTF16MappingOnce([&] {
fUnicode->extractUtfConversionMapping(
this->text(),
[&](size_t index) { fUTF8IndexForUTF16Index.emplace_back(index); },
[&](size_t index) { fUTF16IndexForUTF8Index.emplace_back(index); });
});
}
void ParagraphImpl::visit(const Visitor& visitor) {
int lineNumber = 0;
for (auto& line : fLines) {
line.ensureTextBlobCachePopulated();
for (auto& rec : line.fTextBlobCache) {
SkTextBlob::Iter iter(*rec.fBlob);
SkTextBlob::Iter::ExperimentalRun run;
SkSTArray<128, uint32_t> clusterStorage;
const Run* R = rec.fVisitor_Run;
const uint32_t* clusterPtr = &R->fClusterIndexes[0];
if (R->fClusterStart > 0) {
int count = R->fClusterIndexes.size();
clusterStorage.reset(count);
for (int i = 0; i < count; ++i) {
clusterStorage[i] = R->fClusterStart + R->fClusterIndexes[i];
}
clusterPtr = &clusterStorage[0];
}
clusterPtr += rec.fVisitor_Pos;
while (iter.experimentalNext(&run)) {
const Paragraph::VisitorInfo info = {
run.font,
rec.fOffset,
rec.fClipRect.fRight,
run.count,
run.glyphs,
run.positions,
clusterPtr,
0, // flags
};
visitor(lineNumber, &info);
clusterPtr += run.count;
}
}
visitor(lineNumber, nullptr); // signal end of line
lineNumber += 1;
}
}
int ParagraphImpl::getLineNumberAt(TextIndex codeUnitIndex) const {
for (auto i = 0; i < fLines.size(); ++i) {
auto& line = fLines[i];
if (line.text().contains({codeUnitIndex, codeUnitIndex})) {
return i;
}
}
return -1;
}
bool ParagraphImpl::getLineMetricsAt(int lineNumber, LineMetrics* lineMetrics) const {
if (lineNumber < 0 || lineNumber >= fLines.size()) {
return false;
}
auto& line = fLines[lineNumber];
if (lineMetrics) {
*lineMetrics = line.getMetrics();
}
return true;
}
TextRange ParagraphImpl::getActualTextRange(int lineNumber, bool includeSpaces) const {
if (lineNumber < 0 || lineNumber >= fLines.size()) {
return EMPTY_TEXT;
}
auto& line = fLines[lineNumber];
return includeSpaces ? line.text() : line.trimmedText();
}
bool ParagraphImpl::getGlyphClusterAt(TextIndex codeUnitIndex, GlyphClusterInfo* glyphInfo) {
for (auto i = 0; i < fLines.size(); ++i) {
auto& line = fLines[i];
if (!line.text().contains({codeUnitIndex, codeUnitIndex})) {
continue;
}
for (auto c = line.clustersWithSpaces().start; c < line.clustersWithSpaces().end; ++c) {
auto& cluster = fClusters[c];
if (cluster.contains(codeUnitIndex)) {
std::vector<TextBox> boxes;
line.getRectsForRange(cluster.textRange(),
RectHeightStyle::kTight,
RectWidthStyle::kTight,
boxes);
if (boxes.size() > 0) {
if (glyphInfo) {
*glyphInfo = {boxes[0].rect, cluster.textRange(), boxes[0].direction};
}
return true;
}
}
}
return false;
}
return false;
}
bool ParagraphImpl::getClosestGlyphClusterAt(SkScalar dx,
SkScalar dy,
GlyphClusterInfo* glyphInfo) {
auto res = this->getGlyphPositionAtCoordinate(dx, dy);
auto textIndex = res.position + (res.affinity == Affinity::kDownstream ? 0 : 1);
GlyphClusterInfo gci;
if (this->getGlyphClusterAt(textIndex, glyphInfo ? glyphInfo : &gci)) {
return true;
} else {
return false;
}
}
SkFont ParagraphImpl::getFontAt(TextIndex codeUnitIndex) const {
for (auto& run : fRuns) {
if (run.textRange().contains({codeUnitIndex, codeUnitIndex})) {
return run.font();
}
}
return SkFont();
}
std::vector<Paragraph::FontInfo> ParagraphImpl::getFonts() const {
std::vector<FontInfo> results;
for (auto& run : fRuns) {
results.emplace_back(run.font(), run.textRange());
}
return results;
}
} // namespace textlayout
} // namespace skia