Method UpdateLineSpans

external/zep/src/window.cpp:487–709

This is the most expensive part of window update; applying line span generation for wrapped text and unicode character sizes which may vary in byte count and physical pixel width It can take about a millisecond to do during editing on release buildj; but this is fast enough for now. There are several ways in which this function can be optimized: - Only regenerate spans which have changed, since on

    // - Have a no-wrap text mode and save a lot of the wrapping work.
    // - Do some threading
    void ZepWindow::UpdateLineSpans() {
        TIME_SCOPE(UpdateLineSpans);

        m_maxDisplayLines = (long)std::max(0.0f, std::floor(m_textRegion->rect.Height() / m_defaultLineSize));

        const auto& textBuffer = m_pBuffer->GetWorkingBuffer();

        long bufferLine = 0;
        long spanLine = 0;
        float bufferPosYPx = 0.0f;
        float xOffset = m_xPad;

        bool isMarkdown = m_pBuffer->GetFileExtension() == ".md";

        // Nuke the existing spans
        // In future we can in-place modify for speed
        std::for_each(m_windowLines.begin(), m_windowLines.end(), [](SpanInfo* pInfo) { delete pInfo; });
        m_windowLines.clear();

        auto widgetMarkers = m_pBuffer->GetRangeMarkers(RangeMarkerType::Widget);
        auto itrWidgetMarkers = widgetMarkers.begin();

        // Process every buffer line
        for (;;) {
            // We haven't processed this line yet, so we can't display anything
            // else
            if (m_pBuffer->GetLineCount() <= bufferLine)
                break;

            if (m_pBuffer->IsLineHiddenByFold(bufferLine)) {
                bufferLine++;
                continue;
            }

            ByteRange lineByteRange;
            if (!m_pBuffer->GetLineOffsets(bufferLine, lineByteRange))
                break;

            const FoldRange* foldedRange = m_pBuffer->GetFoldStartingOnLine(bufferLine);

            // Padding at the top of the line
            NVec2f topPadding = NVec2f(DPI_Y((float)GetEditor().GetConfig().lineMargins.x), DPI_Y((float)GetEditor().GetConfig().lineMargins.y));

            auto markersOnLine = m_pBuffer->GetRangeMarkersOnLine(RangeMarkerType::All, bufferLine);
            auto lineWidgetHeight = ArrangeLineMarkers(markersOnLine);

            // Move the line down by the height of the widget
            bufferPosYPx += lineWidgetHeight.x;

            // TODO: Find a clean way to do this extra work during layout for extensions that need it
            ZepTextType type = ZepTextType::Text;
            if (isMarkdown) {
                uint32_t headerCount = 0;
                // Markdown experiment
                for (auto ch = lineByteRange.first; ch < lineByteRange.second; ch += utf8_codepoint_length(textBuffer[ch])) {
                    if (textBuffer[ch] != '#')
                        break;
                    headerCount++;