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authorChris Loer <chris.loer@gmail.com>2018-09-19 15:20:03 -0700
committerChris Loer <chris.loer@mapbox.com>2018-10-15 13:15:46 -0700
commitbc718257748f1ad87658e85f8c31b574afca57a9 (patch)
tree10ca9f0b762362102482d0614e2d04feab419730 /platform/default
parentfed55418f21719149e510a6c49836ba58a5da2c2 (diff)
downloadqtlocation-mapboxgl-bc718257748f1ad87658e85f8c31b574afca57a9.tar.gz
[core] Bidi support for styled text.
Remove use of QString from non-ICU Qt stub bidi implementation since we weren't making use of it.
Diffstat (limited to 'platform/default')
-rw-r--r--platform/default/bidi.cpp102
1 files changed, 102 insertions, 0 deletions
diff --git a/platform/default/bidi.cpp b/platform/default/bidi.cpp
index d475c387b3..f972e43cc1 100644
--- a/platform/default/bidi.cpp
+++ b/platform/default/bidi.cpp
@@ -100,6 +100,108 @@ std::vector<std::u16string> BiDi::processText(const std::u16string& input,
return applyLineBreaking(lineBreakPoints);
}
+
+std::vector<StyledText> BiDi::processStyledText(const StyledText& input, std::set<std::size_t> lineBreakPoints) {
+ std::vector<StyledText> lines;
+ const auto& inputText = input.first;
+ const auto& styleIndices = input.second;
+
+ UErrorCode errorCode = U_ZERO_ERROR;
+
+ ubidi_setPara(impl->bidiText, mbgl::utf16char_cast<const UChar*>(inputText.c_str()), static_cast<int32_t>(inputText.size()),
+ UBIDI_DEFAULT_LTR, nullptr, &errorCode);
+
+ if (U_FAILURE(errorCode)) {
+ throw std::runtime_error(std::string("BiDi::processStyledText: ") + u_errorName(errorCode));
+ }
+
+ mergeParagraphLineBreaks(lineBreakPoints);
+
+ std::size_t lineStartIndex = 0;
+
+ for (std::size_t lineBreakPoint : lineBreakPoints) {
+ StyledText line;
+ line.second.reserve(lineBreakPoint - lineStartIndex);
+
+ errorCode = U_ZERO_ERROR;
+ ubidi_setLine(impl->bidiText, static_cast<int32_t>(lineStartIndex), static_cast<int32_t>(lineBreakPoint), impl->bidiLine, &errorCode);
+ if (U_FAILURE(errorCode)) {
+ throw std::runtime_error(std::string("BiDi::processStyledText (setLine): ") + u_errorName(errorCode));
+ }
+
+ errorCode = U_ZERO_ERROR;
+ uint32_t runCount = ubidi_countRuns(impl->bidiLine, &errorCode);
+ if (U_FAILURE(errorCode)) {
+ throw std::runtime_error(std::string("BiDi::processStyledText (countRuns): ") + u_errorName(errorCode));
+ }
+
+ for (uint32_t runIndex = 0; runIndex < runCount; runIndex++) {
+ int32_t runLogicalStart;
+ int32_t runLength;
+ UBiDiDirection direction = ubidi_getVisualRun(impl->bidiLine, runIndex, &runLogicalStart, &runLength);
+ const bool isReversed = direction == UBIDI_RTL;
+
+ std::size_t logicalStart = lineStartIndex + runLogicalStart;
+ std::size_t logicalEnd = logicalStart + runLength;
+ if (isReversed) {
+ // Within this reversed section, iterate logically backwards
+ // Each time we see a change in style, render a reversed chunk
+ // of everything since the last change
+ std::size_t styleRunStart = logicalEnd;
+ uint8_t currentStyleIndex = styleIndices.at(styleRunStart - 1);
+ for (std::size_t i = logicalEnd - 1; i >= logicalStart; i--) {
+ if (currentStyleIndex != styleIndices.at(i) || i == logicalStart) {
+ std::size_t styleRunEnd = i == logicalStart ? i : i + 1;
+ std::u16string reversed = writeReverse(inputText, styleRunEnd, styleRunStart);
+ line.first += reversed;
+ for (std::size_t j = 0; j < reversed.size(); j++) {
+ line.second.push_back(currentStyleIndex);
+ }
+ currentStyleIndex = styleIndices.at(i);
+ styleRunStart = styleRunEnd;
+ }
+ if (i == 0) {
+ break;
+ }
+ }
+
+ } else {
+ line.first += input.first.substr(logicalStart, runLength);
+ line.second.insert(line.second.end(), styleIndices.begin() + logicalStart, styleIndices.begin() + logicalStart + runLength);
+ }
+ }
+
+ lines.push_back(line);
+ lineStartIndex = lineBreakPoint;
+ }
+
+ return lines;
+}
+
+std::u16string BiDi::writeReverse(const std::u16string& input, std::size_t logicalStart, std::size_t logicalEnd) {
+ UErrorCode errorCode = U_ZERO_ERROR;
+ int32_t logicalLength = static_cast<int32_t>(logicalEnd - logicalStart);
+ std::u16string outputText(logicalLength + 1, 0);
+
+ // 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
+ // they don't show up on screen (some fonts have glyphs representing them)
+ int32_t outputLength =
+ ubidi_writeReverse(mbgl::utf16char_cast<const UChar*>(&input[logicalStart]),
+ logicalLength,
+ mbgl::utf16char_cast<UChar*>(&outputText[0]),
+ logicalLength + 1, // Extra room for null terminator, although we don't really need to have ICU write it for us
+ UBIDI_DO_MIRRORING | UBIDI_REMOVE_BIDI_CONTROLS,
+ &errorCode);
+
+ if (U_FAILURE(errorCode)) {
+ throw std::runtime_error(std::string("BiDi::writeReverse: ") + u_errorName(errorCode));
+ }
+
+ outputText.resize(outputLength); // REMOVE_BIDI_CONTROLS may have shrunk the string
+
+ return outputText;
+}
std::u16string BiDi::getLine(std::size_t start, std::size_t end) {
UErrorCode errorCode = U_ZERO_ERROR;