tei/MapLibreParticleLab
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Cleaning up line breaking code.

Browse Source 
* Don't include trailing spacing (as opposed to whitespace) in lineLength
* Modify BiDi interface to require initial bidi layout and linebreaking to happen in one call.
* Code style changes suggested by @kkaefer
This commit is contained in:
Chris Loer
2016-12-14 10:18:37 -08:00
parent f55a6e2b7a
commit f68449aeb8
4 changed files with 72 additions and 79 deletions
Download Patch File Download Diff File Expand all files Collapse all files

79
platform/default/bidi.cpp
View File

@@ -8,20 +8,30 @@ namespace mbgl {
class BiDiImpl {
public:
BiDiImpl() : bidiText(ubidi_open()), bidiLine(ubidi_open()) {}
~BiDiImpl() { ubidi_close(bidiText); ubidi_close(bidiLine); }
BiDiImpl() : bidiText(ubidi_open()), bidiLine(ubidi_open()) {
}
~BiDiImpl() {
ubidi_close(bidiText);
ubidi_close(bidiLine);
}
UBiDi* bidiText = nullptr;
UBiDi* bidiLine = nullptr;
};
BiDi::BiDi() : impl(std::make_unique<BiDiImpl>())
{
}
BiDi::~BiDi() {
}
// Takes UTF16 input in logical order and applies Arabic shaping to the input while maintaining
// logical order
// Output won't be intelligible until the bidirectional algorithm is applied
// logical order. Output won't be intelligible until the bidirectional algorithm is applied
std::u16string applyArabicShaping(const std::u16string& input) {
UErrorCode errorCode = U_ZERO_ERROR;
int32_t outputLength =
const int32_t outputLength =
u_shapeArabic(input.c_str(), static_cast<int32_t>(input.size()), NULL, 0,
(U_SHAPE_LETTERS_SHAPE & U_SHAPE_LETTERS_MASK) |
(U_SHAPE_TEXT_DIRECTION_LOGICAL & U_SHAPE_TEXT_DIRECTION_MASK),
@@ -30,7 +40,7 @@ std::u16string applyArabicShaping(const std::u16string& input) {
// Pre-flighting will always set U_BUFFER_OVERFLOW_ERROR
errorCode = U_ZERO_ERROR;
std::unique_ptr<UChar[]> outputText = std::make_unique<UChar[]>(outputLength);
auto outputText = std::make_unique<UChar[]>(outputLength);
u_shapeArabic(input.c_str(), static_cast<int32_t>(input.size()), outputText.get(), outputLength,
(U_SHAPE_LETTERS_SHAPE & U_SHAPE_LETTERS_MASK) |
(U_SHAPE_TEXT_DIRECTION_LOGICAL & U_SHAPE_TEXT_DIRECTION_MASK),
@@ -43,75 +53,66 @@ std::u16string applyArabicShaping(const std::u16string& input) {
return std::u16string(outputText.get(), outputLength);
}
ProcessedBiDiText::ProcessedBiDiText(BiDi& p_bidi) : bidi(p_bidi) {
}
void ProcessedBiDiText::mergeParagraphLineBreaks(std::set<int32_t>& lineBreakPoints) {
int32_t paragraphCount = ubidi_countParagraphs(bidi.impl->bidiText);
void BiDi::mergeParagraphLineBreaks(std::set<int32_t>& lineBreakPoints) {
int32_t paragraphCount = ubidi_countParagraphs(impl->bidiText);
for (int32_t i = 0; i < paragraphCount; i++) {
UErrorCode errorCode = U_ZERO_ERROR;
int32_t paragraphEndIndex;
ubidi_getParagraphByIndex(bidi.impl->bidiText, i, NULL, &paragraphEndIndex, NULL, &errorCode);
ubidi_getParagraphByIndex(impl->bidiText, i, NULL, &paragraphEndIndex, NULL, &errorCode);
if (U_FAILURE(errorCode))
if (U_FAILURE(errorCode)) {
throw std::runtime_error(std::string("ProcessedBiDiText::mergeParagraphLineBreaks: ") +
u_errorName(errorCode));
}
lineBreakPoints.insert(paragraphEndIndex);
}
}
std::vector<std::u16string>
ProcessedBiDiText::applyLineBreaking(std::set<int32_t> lineBreakPoints) {
std::vector<std::u16string> BiDi::applyLineBreaking(std::set<int32_t> lineBreakPoints) {
// BiDi::getLine will error if called across a paragraph boundary, so we need to ensure that all
// paragraph
// boundaries are included in the set of line break points. The calling code might not include
// the line break because it
// didn't need to wrap at that point, or because the text was separated with a more exotic code
// point such as (U+001C)
// paragraph boundaries are included in the set of line break points. The calling code might not
// include the line break because it didn't need to wrap at that point, or because the text was
// separated with a more exotic code point such as (U+001C)
mergeParagraphLineBreaks(lineBreakPoints);
std::vector<std::u16string> transformedLines;
int32_t start = 0;
for (int32_t lineBreakPoint : lineBreakPoints) {
transformedLines.push_back(bidi.getLine(start, lineBreakPoint));
transformedLines.push_back(getLine(start, lineBreakPoint));
start = lineBreakPoint;
}
return transformedLines;
}
BiDi::BiDi() : impl(std::make_unique<BiDiImpl>())
{
}
BiDi::~BiDi() {
}
ProcessedBiDiText BiDi::processText(const std::u16string& input) {
std::vector<std::u16string> BiDi::processText(const std::u16string& input,
std::set<int32_t> lineBreakPoints) {
UErrorCode errorCode = U_ZERO_ERROR;
ubidi_setPara(impl->bidiText, input.c_str(), static_cast<int32_t>(input.size()), UBIDI_DEFAULT_LTR,
NULL, &errorCode);
ubidi_setPara(impl->bidiText, input.c_str(), static_cast<int32_t>(input.size()),
UBIDI_DEFAULT_LTR, NULL, &errorCode);
if (U_FAILURE(errorCode))
if (U_FAILURE(errorCode)) {
throw std::runtime_error(std::string("BiDi::processText: ") + u_errorName(errorCode));
}
return ProcessedBiDiText(*this);
return applyLineBreaking(lineBreakPoints);
}
std::u16string BiDi::getLine(int32_t start, int32_t end) {
UErrorCode errorCode = U_ZERO_ERROR;
ubidi_setLine(impl->bidiText, start, end, impl->bidiLine, &errorCode);
if (U_FAILURE(errorCode))
if (U_FAILURE(errorCode)) {
throw std::runtime_error(std::string("BiDi::getLine (setLine): ") + u_errorName(errorCode));
}
// Because we set UBIDI_REMOVE_BIDI_CONTROLS, the output may be smaller than what we reserve
// Setting UBIDI_INSERT_LRM_FOR_NUMERIC would require
// ubidi_getLength(pBiDi)+2*ubidi_countRuns(pBiDi)
int32_t outputLength = ubidi_getProcessedLength(impl->bidiLine);
std::unique_ptr<UChar[]> outputText = std::make_unique<UChar[]>(outputLength);
const int32_t outputLength = ubidi_getProcessedLength(impl->bidiLine);
auto outputText = std::make_unique<UChar[]>(outputLength);
// UBIDI_DO_MIRRORING: Apply unicode mirroring of characters like parentheses
// UBIDI_REMOVE_BIDI_CONTROLS: Now that all the lines are set, remove control characters so that
@@ -119,8 +120,10 @@ std::u16string BiDi::getLine(int32_t start, int32_t end) {
ubidi_writeReordered(impl->bidiLine, outputText.get(), outputLength,
UBIDI_DO_MIRRORING | UBIDI_REMOVE_BIDI_CONTROLS, &errorCode);
if (U_FAILURE(errorCode))
throw std::runtime_error(std::string("BiDi::getLine (writeReordered): ") + u_errorName(errorCode));
if (U_FAILURE(errorCode)) {
throw std::runtime_error(std::string("BiDi::getLine (writeReordered): ") +
u_errorName(errorCode));
}
return std::u16string(outputText.get(), outputLength);
}

11
platform/qt/src/bidi.cpp
View File

@@ -16,15 +16,12 @@ std::u16string applyArabicShaping(const std::u16string& input) {
return utf16string.toStdU16String();
}
ProcessedBiDiText::ProcessedBiDiText(BiDi& p_bidi) : bidi(p_bidi) {
}
void ProcessedBiDiText::mergeParagraphLineBreaks(std::set<int32_t>& lineBreakPoints) {
void BiDi::mergeParagraphLineBreaks(std::set<int32_t>& lineBreakPoints) {
lineBreakPoints.insert(bidi.impl->string.length());
}
std::vector<std::u16string>
ProcessedBiDiText::applyLineBreaking(std::set<int32_t> lineBreakPoints) {
BiDi::applyLineBreaking(std::set<int32_t> lineBreakPoints) {
mergeParagraphLineBreaks(lineBreakPoints);
std::vector<std::u16string> transformedLines;
@@ -44,9 +41,9 @@ BiDi::BiDi() : impl(std::make_unique<BiDiImpl>())
BiDi::~BiDi() {
}
ProcessedBiDiText BiDi::processText(const std::u16string& input) {
std::vector<std::u16string> BiDi::processText(const std::u16string& input, std::set<int32_t> lineBreakPoints) {
impl->string = QString::fromStdU16String(input);
return ProcessedBiDiText(*this);
return applyLineBreaking(lineBreakPoints);
}
std::u16string BiDi::getLine(int32_t start, int32_t end) {

20
src/mbgl/text/bidi.hpp
View File

@@ -14,30 +14,16 @@ class BiDiImpl;
std::u16string applyArabicShaping(const std::u16string&);
class ProcessedBiDiText {
public:
ProcessedBiDiText(BiDi&);
std::vector<std::u16string> applyLineBreaking(std::set<int32_t>);
private:
void mergeParagraphLineBreaks(std::set<int32_t>&);
BiDi& bidi;
};
class BiDi : private util::noncopyable {
public:
BiDi();
~BiDi();
// Calling processText resets internal state, invalidating any existing ProcessedBiDiText
// objects
ProcessedBiDiText processText(const std::u16string&);
friend class ProcessedBiDiText;
std::vector<std::u16string> processText(const std::u16string&, std::set<int32_t>);
private:
void mergeParagraphLineBreaks(std::set<int32_t>&);
std::vector<std::u16string> applyLineBreaking(std::set<int32_t>);
std::u16string getLine(int32_t start, int32_t end);
std::unique_ptr<BiDiImpl> impl;

41
src/mbgl/text/glyph_set.cpp
View File

@@ -48,10 +48,9 @@ const Shaping GlyphSet::getShaping(const std::u16string& logicalInput,
// different from the glyphs that get shown
Shaping shaping(translate.x * 24, translate.y * 24, logicalInput);
ProcessedBiDiText processedText = bidi.processText(logicalInput);
std::vector<std::u16string> reorderedLines =
processedText.applyLineBreaking(determineLineBreaks(logicalInput, spacing, maxWidth));
bidi.processText(logicalInput,
determineLineBreaks(logicalInput, spacing, maxWidth));
shapeLines(shaping, reorderedLines, spacing, lineHeight, horizontalAlign, verticalAlign,
justify, translate);
@@ -84,8 +83,9 @@ void justifyLine(std::vector<PositionedGlyph>& positionedGlyphs,
uint32_t start,
uint32_t end,
float justify) {
if (!justify)
if (!justify) {
return;
}
PositionedGlyph& glyph = positionedGlyphs[end];
auto it = sdfs.find(glyph.glyph);
@@ -105,14 +105,13 @@ float GlyphSet::determineIdeographicLineWidth(const std::u16string& logicalInput
float totalWidth = 0;
// totalWidth doesn't include the last character for magical tuning reasons. This makes the
// algorithm a little
// more agressive about trying to fit the text into fewer lines, taking advantage of the
// tolerance for going a little
// over maxWidth
// algorithm a little more agressive about trying to fit the text into fewer lines, taking
// advantage of the tolerance for going a little over maxWidth
for (uint32_t i = 0; i < logicalInput.size() - 1; i++) {
auto it = sdfs.find(logicalInput[i]);
if (it != sdfs.end())
if (it != sdfs.end()) {
totalWidth += it->second.metrics.advance + spacing;
}
}
int32_t lineCount = std::fmax(1, std::ceil(totalWidth / maxWidth));
@@ -124,14 +123,17 @@ float GlyphSet::determineIdeographicLineWidth(const std::u16string& logicalInput
std::set<int32_t> GlyphSet::determineLineBreaks(const std::u16string& logicalInput,
const float spacing,
float maxWidth) const {
if (!maxWidth)
if (!maxWidth) {
return {};
}
if (logicalInput.empty())
if (logicalInput.empty()) {
return {};
}
if (util::i18n::allowsIdeographicBreaking(logicalInput))
if (util::i18n::allowsIdeographicBreaking(logicalInput)) {
maxWidth = determineIdeographicLineWidth(logicalInput, spacing, maxWidth);
}
std::set<int32_t> lineBreakPoints;
float currentX = 0;
@@ -140,8 +142,9 @@ std::set<int32_t> GlyphSet::determineLineBreaks(const std::u16string& logicalInp
for (uint32_t i = 0; i < logicalInput.size(); i++) {
auto it = sdfs.find(logicalInput[i]);
if (it == sdfs.end())
if (it == sdfs.end()) {
continue;
}
const SDFGlyph& glyph = it->second;
@@ -186,24 +189,28 @@ void GlyphSet::shapeLines(Shaping& shaping,
// Collapse whitespace so it doesn't throw off justification
boost::algorithm::trim_if(line, boost::algorithm::is_any_of(u" \t\n\v\f\r"));
if (line.empty())
if (line.empty()) {
continue;
}
uint32_t lineStartIndex = static_cast<uint32_t>(shaping.positionedGlyphs.size());
for (char16_t chr : line) {
auto it = sdfs.find(chr);
if (it == sdfs.end())
if (it == sdfs.end()) {
continue;
}
const SDFGlyph& glyph = it->second;
shaping.positionedGlyphs.emplace_back(chr, x, y);
x += glyph.metrics.advance + spacing;
}
if (static_cast<uint32_t>(shaping.positionedGlyphs.size()) == lineStartIndex)
if (static_cast<uint32_t>(shaping.positionedGlyphs.size()) == lineStartIndex) {
continue;
}
maxLineLength = util::max(x, maxLineLength);
float lineLength = x - spacing; // Don't count trailing spacing
maxLineLength = util::max(lineLength, maxLineLength);
justifyLine(shaping.positionedGlyphs, sdfs, lineStartIndex,
static_cast<uint32_t>(shaping.positionedGlyphs.size()) - 1, justify);