From 5d95205bae4e6b279d6eb99c3b5f81f95c9b031e Mon Sep 17 00:00:00 2001 From: Eirik Aavitsland Date: Fri, 28 Oct 2022 10:56:00 +0200 Subject: [PATCH] PDF writer: implement support for document internal links QPdfEngine already supported links to external URIs, but not internal links for navigation in a document. For internal links, PDF supports "named destinations" instead of direct coordinates. That way, we avoid the need for a two-pass implementation. Instead, we just store the name and position of all anchors as we enounter them. At document finishing time, we export the list of named destinations in a PDF "name tree" structure. The PDF named destinations feature uses the same main catalog item ("Names") as the attached files feature. Hence, this commit must slightly change the implementation of file attachment support also, so that the structure supports both. Now, we always add a reference to a Names object in the catalog when we start the document. When we finish, we write that object, making it reference the attached files-structure and/or the named destinations-structure, as needed. Fixes: QTBUG-83458 Change-Id: I9c43e7b423062d3f21965ab8a0d81a53c4dd72cb Reviewed-by: Shawn Rutledge --- src/gui/painting/qpdf.cpp | 133 +++++++++++++++++++++++++++----------- src/gui/painting/qpdf_p.h | 13 +++- 2 files changed, 107 insertions(+), 39 deletions(-) diff --git a/src/gui/painting/qpdf.cpp b/src/gui/painting/qpdf.cpp index 1a6770c29ae..8d2e6aabc98 100644 --- a/src/gui/painting/qpdf.cpp +++ b/src/gui/painting/qpdf.cpp @@ -1505,8 +1505,9 @@ bool QPdfEngine::begin(QPaintDevice *pdev) d->xrefPositions.clear(); d->pageRoot = 0; - d->embeddedfilesRoot = 0; d->namesRoot = 0; + d->destsRoot = 0; + d->attachmentsRoot = 0; d->catalog = 0; d->info = 0; d->graphicsState = 0; @@ -1543,6 +1544,7 @@ bool QPdfEngine::end() d->outDevice = nullptr; } + d->destCache.clear(); d->fileCache.clear(); setActive(false); @@ -1591,10 +1593,7 @@ void QPdfEnginePrivate::writeHeader() catalog = addXrefEntry(-1); pageRoot = requestObject(); - if (!fileCache.isEmpty()) { - namesRoot = requestObject(); - embeddedfilesRoot = requestObject(); - } + namesRoot = requestObject(); // catalog { @@ -1602,11 +1601,8 @@ void QPdfEnginePrivate::writeHeader() QPdf::ByteStream s(&catalog); s << "<<\n" << "/Type /Catalog\n" - << "/Pages " << pageRoot << "0 R\n"; - - // Embedded files, if any - if (!fileCache.isEmpty()) - s << "/Names " << embeddedfilesRoot << "0 R\n"; + << "/Pages " << pageRoot << "0 R\n" + << "/Names " << namesRoot << "0 R\n"; if (pdfVersion == QPdfEngine::Version_A1b || !xmpDocumentMetadata.isEmpty()) s << "/Metadata " << metaDataObj << "0 R\n"; @@ -1620,12 +1616,6 @@ void QPdfEnginePrivate::writeHeader() write(catalog); } - if (!fileCache.isEmpty()) { - addXrefEntry(embeddedfilesRoot); - xprintf("<>\n" - "endobj\n", namesRoot); - } - // graphics state graphicsState = addXrefEntry(-1); xprintf("<<\n" @@ -1793,6 +1783,39 @@ void QPdfEnginePrivate::writePageRoot() "endobj\n"); } +void QPdfEnginePrivate::writeDestsRoot() +{ + if (destCache.isEmpty()) + return; + + QHash destObjects; + QByteArray xs, ys; + for (const DestInfo &destInfo : qAsConst(destCache)) { + int destObj = addXrefEntry(-1); + xs.setNum(static_cast(destInfo.coords.x()), 'f'); + ys.setNum(static_cast(destInfo.coords.y()), 'f'); + xprintf("[%d 0 R /XYZ %s %s 0]\n", destInfo.pageObj, xs.constData(), ys.constData()); + xprintf("endobj\n"); + destObjects.insert(destInfo.anchor, destObj); + } + + // names + destsRoot = addXrefEntry(-1); + QStringList anchors = destObjects.keys(); + anchors.sort(); + xprintf("<<\n/Limits ["); + printString(anchors.constFirst()); + xprintf(" "); + printString(anchors.constLast()); + xprintf("]\n/Names [\n"); + for (const QString &anchor : qAsConst(anchors)) { + printString(anchor); + xprintf(" %d 0 R\n", destObjects[anchor]); + } + xprintf("]\n>>\n" + "endobj\n"); +} + void QPdfEnginePrivate::writeAttachmentRoot() { if (fileCache.isEmpty()) @@ -1832,7 +1855,7 @@ void QPdfEnginePrivate::writeAttachmentRoot() } // names - addXrefEntry(namesRoot); + attachmentsRoot = addXrefEntry(-1); xprintf("<>\n"); + xprintf("endobj\n"); +} + void QPdfEnginePrivate::embedFont(QFontSubset *font) { //qDebug() << "embedFont" << font->object_id; @@ -2099,7 +2137,9 @@ void QPdfEnginePrivate::writeTail() writePage(); writeFonts(); writePageRoot(); + writeDestsRoot(); writeAttachmentRoot(); + writeNamesRoot(); addXrefEntry(xrefPositions.size(),false); xprintf("xref\n" @@ -2951,7 +2991,9 @@ void QPdfEnginePrivate::drawTextItem(const QPointF &p, const QTextItemInt &ti) { Q_Q(QPdfEngine); - if (ti.charFormat.hasProperty(QTextFormat::AnchorHref)) { + const bool isLink = ti.charFormat.hasProperty(QTextFormat::AnchorHref); + const bool isAnchor = ti.charFormat.hasProperty(QTextFormat::AnchorName); + if (isLink || isAnchor) { qreal size = ti.fontEngine->fontDef.pixelSize; int synthesized = ti.fontEngine->synthesized(); qreal stretch = synthesized & QFontEngine::SynthesizedStretch ? ti.fontEngine->fontDef.stretch/100. : 1.; @@ -2971,32 +3013,47 @@ void QPdfEnginePrivate::drawTextItem(const QPointF &p, const QTextItemInt &ti) trans.map(0, 0, &x1, &y1); trans.map(ti.width.toReal()/size, (ti.ascent.toReal()-ti.descent.toReal())/size, &x2, &y2); - uint annot = addXrefEntry(-1); - QByteArray x1s, y1s, x2s, y2s; - x1s.setNum(static_cast(x1), 'f'); - y1s.setNum(static_cast(y1), 'f'); - x2s.setNum(static_cast(x2), 'f'); - y2s.setNum(static_cast(y2), 'f'); - QByteArray rectData = x1s + ' ' + y1s + ' ' + x2s + ' ' + y2s; - xprintf("<<\n/Type /Annot\n/Subtype /Link\n"); + if (isLink) { + uint annot = addXrefEntry(-1); + QByteArray x1s, y1s, x2s, y2s; + x1s.setNum(static_cast(x1), 'f'); + y1s.setNum(static_cast(y1), 'f'); + x2s.setNum(static_cast(x2), 'f'); + y2s.setNum(static_cast(y2), 'f'); + QByteArray rectData = x1s + ' ' + y1s + ' ' + x2s + ' ' + y2s; + xprintf("<<\n/Type /Annot\n/Subtype /Link\n"); - if (pdfVersion == QPdfEngine::Version_A1b) - xprintf("/F 4\n"); // enable print flag, disable all other + if (pdfVersion == QPdfEngine::Version_A1b) + xprintf("/F 4\n"); // enable print flag, disable all other - xprintf("/Rect ["); - xprintf(rectData.constData()); + xprintf("/Rect ["); + xprintf(rectData.constData()); #ifdef Q_DEBUG_PDF_LINKS - xprintf("]\n/Border [16 16 1]\n/A <<\n"); + xprintf("]\n/Border [16 16 1]\n"); #else - xprintf("]\n/Border [0 0 0]\n/A <<\n"); + xprintf("]\n/Border [0 0 0]\n"); #endif - xprintf("/Type /Action\n/S /URI\n/URI (%s)\n", - ti.charFormat.anchorHref().toLatin1().constData()); - xprintf(">>\n>>\n"); - xprintf("endobj\n"); + const QString link = ti.charFormat.anchorHref(); + const bool isInternal = link.startsWith(QLatin1Char('#')); + if (!isInternal) { + xprintf("/A <<\n"); + xprintf("/Type /Action\n/S /URI\n/URI (%s)\n", link.toLatin1().constData()); + xprintf(">>\n"); + } else { + xprintf("/Dest "); + printString(link.sliced(1)); + xprintf("\n"); + } + xprintf(">>\n"); + xprintf("endobj\n"); - if (!currentPage->annotations.contains(annot)) { - currentPage->annotations.append(annot); + if (!currentPage->annotations.contains(annot)) { + currentPage->annotations.append(annot); + } + } else { + const QString anchor = ti.charFormat.anchorNames().constFirst(); + const uint curPage = pages.last(); + destCache.append(DestInfo({ anchor, curPage, QPointF(x1, y2) })); } } diff --git a/src/gui/painting/qpdf_p.h b/src/gui/painting/qpdf_p.h index 4c6a570e76f..2c70ddf6645 100644 --- a/src/gui/painting/qpdf_p.h +++ b/src/gui/painting/qpdf_p.h @@ -271,7 +271,9 @@ private: int writeXmpDcumentMetaData(); int writeOutputIntent(); void writePageRoot(); + void writeDestsRoot(); void writeAttachmentRoot(); + void writeNamesRoot(); void writeFonts(); void embedFont(QFontSubset *font); qreal calcUserUnit() const; @@ -305,11 +307,20 @@ private: QString mimeType; }; + struct DestInfo + { + QString anchor; + uint pageObj; + QPointF coords; + }; + // various PDF objects - int pageRoot, embeddedfilesRoot, namesRoot, catalog, info, graphicsState, patternColorSpace; + int pageRoot, namesRoot, destsRoot, attachmentsRoot, catalog, info; + int graphicsState, patternColorSpace; QList pages; QHash imageCache; QHash, uint > alphaCache; + QList destCache; QList fileCache; QByteArray xmpDocumentMetadata; };