pdf/engine/src/document/document_builder.cpp

#include "pdfengine/document/document_builder.hpp"
#include <algorithm>
#include <cmath>

namespace pdfengine::document {

PageModel DocumentBuilder::buildFromOCR(const RawOCRPage& rawPage) const {
    PageModel model;
    model.pageIndex = rawPage.pageIndex;
    model.width = rawPage.pageWidth;
    model.height = rawPage.pageHeight;

    if (rawPage.lines.empty()) {
        return model;
    }

    // Standard baseline clustering to group lines into Paragraphs
    std::vector<Paragraph> paragraphs;
    Paragraph currentPara;
    double lastLineY = -1.0;
    double lastLineH = 0.0;

    for (size_t lIdx = 0; lIdx < rawPage.lines.size(); ++lIdx) {
        const auto& rawLine = rawPage.lines[lIdx];

        TextLine line;
        line.x = rawLine.x;
        line.y = rawLine.y;
        line.w = rawLine.width;
        line.h = rawLine.height;
        line.baselineY = rawLine.baselineY;
        line.angle = 0.0;

        TextRun run;
        run.text = rawLine.text;
        run.fontName = rawLine.fontName.empty() ? "Helvetica" : rawLine.fontName;

        bool isBold = rawLine.isBold || rawLine.fontWeight >= 600;
        bool isItalic = rawLine.isItalic || rawLine.fontStyle == "italic";

        run.flags = (isBold ? 2 : 0) | (isItalic ? 1 : 0);
        run.fontWeight = rawLine.fontWeight > 0 ? rawLine.fontWeight : (isBold ? 700 : 400);
        run.fontStyle = !rawLine.fontStyle.empty() ? rawLine.fontStyle : (isItalic ? "italic" : "normal");

        if (!rawLine.fontFace.empty()) {
            run.fontFace = rawLine.fontFace;
        } else if (isBold && isItalic) {
            run.fontFace = run.fontName + "-BoldItalic";
        } else if (isBold) {
            run.fontFace = run.fontName + "-Bold";
        } else if (isItalic) {
            run.fontFace = run.fontName + "-Italic";
        } else {
            run.fontFace = run.fontName;
        }

        run.internalFontId = !rawLine.fontId.empty()
            ? rawLine.fontId
            : (run.fontName + "_TrueType_" + std::to_string(run.fontWeight));

        run.fontSize = rawLine.fontSize > 0.0 ? rawLine.fontSize : (rawLine.height * 0.72);
        run.x = rawLine.x;
        run.y = rawLine.y;
        run.w = rawLine.width;
        run.h = rawLine.height;
        run.fillColor = "#000000";
        run.fontFidelity = "exact";

        // Generate Glyphs
        if (!rawLine.words.empty()) {
            for (const auto& w : rawLine.words) {
                double charW = w.width / std::max<size_t>(1, w.text.size());
                double currX = w.x;
                for (char ch : w.text) {
                    Glyph g;
                    g.text = std::string(1, ch);
                    g.unicode = static_cast<uint32_t>(static_cast<unsigned char>(ch));
                    g.fontName = run.fontName;
                    g.fontSize = run.fontSize;
                    g.flags = run.flags;
                    g.originX = currX;
                    g.originY = rawLine.baselineY;
                    g.bboxX = currX;
                    g.bboxY = w.y;
                    g.bboxW = charW;
                    g.bboxH = w.height;
                    run.glyphs.push_back(g);
                    line.glyphs.push_back(g);
                    currX += charW;
                }
            }
        } else {
            double charW = rawLine.width / std::max<size_t>(1, rawLine.text.size());
            double currX = rawLine.x;
            for (char ch : rawLine.text) {
                Glyph g;
                g.text = std::string(1, ch);
                g.unicode = static_cast<uint32_t>(static_cast<unsigned char>(ch));
                g.fontName = run.fontName;
                g.fontSize = run.fontSize;
                g.flags = run.flags;
                g.originX = currX;
                g.originY = rawLine.baselineY;
                g.bboxX = currX;
                g.bboxY = rawLine.y;
                g.bboxW = charW;
                g.bboxH = rawLine.height;
                run.glyphs.push_back(g);
                line.glyphs.push_back(g);
                currX += charW;
            }
        }

        line.runs.push_back(run);

        // Check paragraph break (vertical gap > 1.5x line height)
        bool isNewPara = false;
        if (lastLineY >= 0.0) {
            double gap = rawLine.y - (lastLineY + lastLineH);
            if (gap > lastLineH * 1.5 || gap < -lastLineH * 0.5) {
                isNewPara = true;
            }
        }

        if (isNewPara && !currentPara.lines.empty()) {
            // Finalize current paragraph bounds
            double pX1 = currentPara.lines.front().x;
            double pY1 = currentPara.lines.front().y;
            double pX2 = pX1 + currentPara.lines.front().w;
            double pY2 = pY1 + currentPara.lines.front().h;

            for (const auto& l : currentPara.lines) {
                pX1 = std::min(pX1, l.x);
                pY1 = std::min(pY1, l.y);
                pX2 = std::max(pX2, l.x + l.w);
                pY2 = std::max(pY2, l.y + l.h);
            }

            currentPara.x = pX1;
            currentPara.y = pY1;
            currentPara.w = pX2 - pX1;
            currentPara.h = pY2 - pY1;

            paragraphs.push_back(currentPara);
            currentPara = Paragraph();
        }

        currentPara.lines.push_back(line);
        lastLineY = rawLine.y;
        lastLineH = rawLine.height;
    }

    if (!currentPara.lines.empty()) {
        double pX1 = currentPara.lines.front().x;
        double pY1 = currentPara.lines.front().y;
        double pX2 = pX1 + currentPara.lines.front().w;
        double pY2 = pY1 + currentPara.lines.front().h;

        for (const auto& l : currentPara.lines) {
            pX1 = std::min(pX1, l.x);
            pY1 = std::min(pY1, l.y);
            pX2 = std::max(pX2, l.x + l.w);
            pY2 = std::max(pY2, l.y + l.h);
        }

        currentPara.x = pX1;
        currentPara.y = pY1;
        currentPara.w = pX2 - pX1;
        currentPara.h = pY2 - pY1;

        paragraphs.push_back(currentPara);
    }

    model.paragraphs = std::move(paragraphs);
    return model;
}

} // namespace pdfengine::document