Make QPdfLinkModel public and use in QPdfView

Now you can click links on pages in PDF documents in QPdfView.

Task-number: QTBUG-77511
Fixes: QTBUG-102760
Change-Id: I348dcfd906be088aa3fcbe53aec4628b521cc2f3
Reviewed-by: Axel Spoerl <axel.spoerl@qt.io>

3 files changed, 88 insertions, 1 deletions

diff --git a/src/pdfwidgets/qpdfview.cpp b/src/pdfwidgets/qpdfview.cpp
index 831b51515..ce49245e9 100644
--- a/src/pdfwidgets/qpdfview.cpp
+++ b/src/pdfwidgets/qpdfview.cpp
@@ -8,6 +8,7 @@
 #include "qpdfpagerenderer.h"
 
 #include <QGuiApplication>
+#include <QLoggingCategory>
 #include <QPainter>
 #include <QPaintEvent>
 #include <QPdfDocument>
@@ -18,6 +19,9 @@
 
 QT_BEGIN_NAMESPACE
 
+Q_LOGGING_CATEGORY(qLcLink, "qt.pdf.links")
+//#define DEBUG_LINKS
+
 QPdfViewPrivate::QPdfViewPrivate(QPdfView *q)
     : q_ptr(q)
     , m_document(nullptr)
@@ -241,6 +245,12 @@ qreal QPdfViewPrivate::yPositionForPage(int pageNumber) const
     return (*it).y();
 }
 
+QTransform QPdfViewPrivate::screenScaleTransform() const
+{
+    const qreal scale = m_screenResolution * m_zoomFactor;
+    return QTransform::fromScale(scale, scale);
+}
+
 void QPdfViewPrivate::updateDocumentLayout()
 {
     m_documentLayout = calculateDocumentLayout();
@@ -282,7 +292,7 @@ QPdfView::QPdfView(QWidget *parent)
     horizontalScrollBar()->setSingleStep(20);
 
     QScroller::grabGesture(this);
-
+    setMouseTracking(true);
     d->calculateViewport();
 }
 
@@ -317,6 +327,7 @@ void QPdfView::setDocument(QPdfDocument *document)
                         [d](){ d->documentStatusChanged(); });
 
     d->m_pageRenderer->setDocument(d->m_document);
+    d->m_linkModel.setDocument(d->m_document);
 
     d->documentStatusChanged();
 }
@@ -510,6 +521,29 @@ void QPdfView::paintEvent(QPaintEvent *event)
             } else {
                 d->m_pageRenderer->requestPage(page, pageGeometry.size() * devicePixelRatioF());
             }
+
+#ifdef DEBUG_LINKS
+            const QTransform scaleTransform = d->screenScaleTransform();
+            const QString fmt = u"page %1 @ %2, %3"_s;
+            d->m_linkModel.setPage(page);
+            const int linkCount = d->m_linkModel.rowCount({});
+            for (int i = 0; i < linkCount; ++i) {
+                const QRectF linkBounds = scaleTransform.mapRect(
+                            d->m_linkModel.data(d->m_linkModel.index(i),
+                                                int(QPdfLinkModel::Role::Rect)).toRectF())
+                        .translated(pageGeometry.topLeft());
+                painter.setPen(Qt::blue);
+                painter.drawRect(linkBounds);
+                painter.setPen(Qt::red);
+                const QPoint loc = d->m_linkModel.data(d->m_linkModel.index(i),
+                                                       int(QPdfLinkModel::Role::Location)).toPoint();
+                // TODO maybe draw destination URL if that's what it is
+                painter.drawText(linkBounds.bottomLeft() + QPoint(2, -2),
+                                 fmt.arg(d->m_linkModel.data(d->m_linkModel.index(i),
+                                                             int(QPdfLinkModel::Role::Page)).toInt())
+                                 .arg(loc.x()).arg(loc.y()));
+            }
+#endif
         }
     }
 }
@@ -533,6 +567,50 @@ void QPdfView::scrollContentsBy(int dx, int dy)
     d->calculateViewport();
 }
 
+void QPdfView::mousePressEvent(QMouseEvent *event)
+{
+    Q_ASSERT(event->isAccepted());
+}
+
+void QPdfView::mouseMoveEvent(QMouseEvent *event)
+{
+    Q_D(QPdfView);
+    const QTransform screenInvTransform = d->screenScaleTransform().inverted();
+    for (auto it = d->m_documentLayout.pageGeometries.cbegin(); it != d->m_documentLayout.pageGeometries.cend(); ++it) {
+        const int page = it.key();
+        const QRect pageGeometry = it.value();
+        if (pageGeometry.contains(event->position().toPoint())) {
+            const QPointF posInPoints = screenInvTransform.map(event->position() - pageGeometry.topLeft());
+            d->m_linkModel.setPage(page);
+            auto dest = d->m_linkModel.linkAt(posInPoints);
+            setCursor(dest.isValid() ? Qt::PointingHandCursor : Qt::ArrowCursor);
+            if (dest.isValid())
+                qCDebug(qLcLink) << event->position() << ":" << posInPoints << "pt ->" << dest;
+        }
+    }
+}
+
+void QPdfView::mouseReleaseEvent(QMouseEvent *event)
+{
+    Q_D(QPdfView);
+    const QTransform screenInvTransform = d->screenScaleTransform().inverted();
+    for (auto it = d->m_documentLayout.pageGeometries.cbegin(); it != d->m_documentLayout.pageGeometries.cend(); ++it) {
+        const int page = it.key();
+        const QRect pageGeometry = it.value();
+        if (pageGeometry.contains(event->position().toPoint())) {
+            const QPointF posInPoints = screenInvTransform.map(event->position() - pageGeometry.topLeft());
+            d->m_linkModel.setPage(page);
+            auto dest = d->m_linkModel.linkAt(posInPoints);
+            if (dest.isValid()) {
+                qCDebug(qLcLink) << event << ": jumping to" << dest;
+                d->m_pageNavigator->jump(dest.page(), dest.location(), dest.zoom());
+                // TODO scroll and zoom to where the link tells us to
+            }
+            return;
+        }
+    }
+}
+
 QT_END_NAMESPACE
 
 #include "moc_qpdfview.cpp"
diff --git a/src/pdfwidgets/qpdfview.h b/src/pdfwidgets/qpdfview.h
index 5a4d7ed38..886ed697f 100644
--- a/src/pdfwidgets/qpdfview.h
+++ b/src/pdfwidgets/qpdfview.h
@@ -4,6 +4,8 @@
 #ifndef QPDFVIEW_H
 #define QPDFVIEW_H
 
+#include <QtPdf/qpdfdocument.h>
+#include <QtPdf/qpdflink.h>
 #include <QtPdfWidgets/qtpdfwidgetsglobal.h>
 #include <QtWidgets/qabstractscrollarea.h>
 
@@ -78,6 +80,9 @@ protected:
     void paintEvent(QPaintEvent *event) override;
     void resizeEvent(QResizeEvent *event) override;
     void scrollContentsBy(int dx, int dy) override;
+    void mousePressEvent(QMouseEvent *event) override;
+    void mouseMoveEvent(QMouseEvent *event) override;
+    void mouseReleaseEvent(QMouseEvent *event) override;
 
 private:
     Q_DECLARE_PRIVATE(QPdfView)
diff --git a/src/pdfwidgets/qpdfview_p.h b/src/pdfwidgets/qpdfview_p.h
index 23e83e8eb..97dc3de4f 100644
--- a/src/pdfwidgets/qpdfview_p.h
+++ b/src/pdfwidgets/qpdfview_p.h
@@ -16,6 +16,7 @@
 //
 
 #include "qpdfview.h"
+#include "qpdflinkmodel.h"
 
 #include <QHash>
 #include <QPointer>
@@ -44,6 +45,8 @@ public:
 
     qreal yPositionForPage(int page) const;
 
+    QTransform screenScaleTransform() const; // points to pixels
+
     struct DocumentLayout
     {
         QSize documentSize;
@@ -57,6 +60,7 @@ public:
     QPointer<QPdfDocument> m_document;
     QPdfPageNavigator* m_pageNavigator;
     QPdfPageRenderer *m_pageRenderer;
+    QPdfLinkModel m_linkModel;
 
     QPdfView::PageMode m_pageMode;
     QPdfView::ZoomMode m_zoomMode;