Fix discontinuity with successive pinch-zoom in PdfMultiPageView

pinch.persistentScale is settable since 6.5 (qtdeclarative
a432970b258edb9ff041d221b2155df30cad4799): we need that to tell
PinchHandler to start over from 1 after we have also set the rendered
scale back to 1, because PinchHandler does not read the scale property
for itself.

This cherry-pick includes 48ebac59b1ec5bbafa1c64adbdbc44b0cf3f302a
to avoid a crash on exit by waiting for the rendering to be done, and
a4e64baef027fb407b8c1491c444ed58edd15529 to disable touch compression.

Fixes: QTBUG-115502
Task-number: QTBUG-120245
Task-number: QTBUG-121502
Fixes: QTBUG-121564
Pick-to: 6.5
Change-Id: I21951c447bf33e5942b6a1635488d5474ec8f293
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
(cherry picked from commit c0524da14d92a957b4607fb5867dba5d23eea6d9)
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>
(cherry picked from commit 8c27ae33f80440d20f578fa404c454c8d7bfdf19)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

2 files changed, 80 insertions, 1 deletions

diff --git a/src/pdfquick/PdfMultiPageView.qml b/src/pdfquick/PdfMultiPageView.qml
index 10683f55d..84c3e3181 100644
--- a/src/pdfquick/PdfMultiPageView.qml
+++ b/src/pdfquick/PdfMultiPageView.qml
@@ -408,12 +408,16 @@ Item {
                             const centroidInFlickable = tableView.mapFromItem(paper, pinch.centroid.position.x, pinch.centroid.position.y)
                             const newSourceWidth = image.sourceSize.width * paper.scale
                             const ratio = newSourceWidth / image.sourceSize.width
-                            console.log(lcMPV, "pinch ended on page", index, "with centroid", pinch.centroid.position, centroidInPoints, "wrt flickable", centroidInFlickable,
+                            console.log(lcMPV, "pinch ended on page", index,
+                                        "with scale", paper.scale.toFixed(3), "ratio", ratio.toFixed(3),
+                                        "centroid", pinch.centroid.position, centroidInPoints,
+                                        "wrt flickable", centroidInFlickable,
                                         "page at", pageHolder.x.toFixed(2), pageHolder.y.toFixed(2),
                                         "contentX/Y were", tableView.contentX.toFixed(2), tableView.contentY.toFixed(2))
                             if (ratio > 1.1 || ratio < 0.9) {
                                 const centroidOnPage = Qt.point(centroidInPoints.x * root.renderScale * ratio, centroidInPoints.y * root.renderScale * ratio)
                                 paper.scale = 1
+                                pinch.persistentScale = 1
                                 paper.x = 0
                                 paper.y = 0
                                 root.renderScale *= ratio
diff --git a/tests/auto/pdfquick/multipageview/tst_multipageview.cpp b/tests/auto/pdfquick/multipageview/tst_multipageview.cpp
index 9cd8e3e2d..9067fdbe3 100644
--- a/tests/auto/pdfquick/multipageview/tst_multipageview.cpp
+++ b/tests/auto/pdfquick/multipageview/tst_multipageview.cpp
@@ -6,6 +6,7 @@
 #include <QtCore/QLoggingCategory>
 #include <QtGui/QClipboard>
 #include <QtGui/QPointingDevice>
+#include <QtGui/QStyleHints>
 #include <QtQuick/QQuickView>
 #include <QtPdfQuick/private/qquickpdflinkmodel_p.h>
 #include <QtPdfQuick/private/qquickpdfsearchmodel_p.h>
@@ -28,6 +29,7 @@ private Q_SLOTS:
     void password();
     void selectionAndClipboard();
     void search();
+    void pinchDragPinch();
 
 public:
     enum NavigationAction {
@@ -355,5 +357,78 @@ void tst_MultiPageView::search()
     QVERIFY(movements > 4);
 }
 
+void tst_MultiPageView::pinchDragPinch()
+{
+    qputenv("QML_NO_TOUCH_COMPRESSION", "1");
+    QQuickView window;
+    QVERIFY(showView(window, testFileUrl("multiPageView.qml")));
+    QQuickItem *pdfView = window.rootObject();
+    QVERIFY(pdfView);
+    pdfView->setProperty("source", testFileUrl("bookmarksAndLinks.pdf"));
+    QTRY_COMPARE(pdfView->property("currentPageRenderingStatus").toInt(), QQuickPdfPageImage::Ready);
+    QQuickItem *table = static_cast<QQuickItem *>(findFirstChild(pdfView, "QQuickTableView"));
+    QVERIFY(table);
+    QQuickItem *firstPage = tableViewItemAtCell(table, 0, 0);
+    QVERIFY(firstPage);
+    QQuickItem *paper = firstPage->childAt(10, 10);
+    QVERIFY(paper);
+    QQuickPdfPageImage *image = firstPage->findChild<QQuickPdfPageImage *>();
+    QVERIFY(image);
+
+    auto pinch = [&window, paper, this]() {
+        const int threshold = QGuiApplication::styleHints()->startDragDistance();
+        const int movement = 100;
+        QCOMPARE_GT(movement, threshold);
+        const qreal initialScale = paper->scale();
+        QPoint p0(100, 200);
+        QPoint p1(200, 200);
+        QTest::QTouchEventSequence seq = QTest::touchEvent(&window, touchscreen.get());
+        seq.press(0, p0, &window).commit();
+        seq.stationary(0).press(1, p1, &window).commit();
+        p1.setX(p1.x() + movement);
+        QSignalSpy frameSwappedSpy(&window, &QQuickWindow::frameSwapped);
+        seq.stationary(0).move(1, p1, &window).commit();
+        // after a frame is rendered, the PinchHandler ought to be active
+        // (but verifying it would require private API)
+        QTRY_VERIFY(frameSwappedSpy.size() > 0);
+        QTRY_COMPARE(paper->scale(), initialScale);
+
+        for (int i = 1; i <= 2; ++i) {
+            p1.setX(p1.x() + movement);
+            seq.stationary(0).move(1, p1, &window).commit();
+            QTRY_COMPARE(paper->scale(), initialScale + i * 0.5);
+        }
+        seq.release(0, p0, &window).release(1, p1, &window).commit();
+    };
+
+    auto drag = [&window, table, this]() {
+        const int movement = 100;
+        QPoint p0(200, 200);
+        QTest::QTouchEventSequence seq = QTest::touchEvent(&window, touchscreen.get());
+        seq.press(0, p0, &window).commit();
+        p0.setY(p0.y() + movement);
+        seq.move(0, p0, &window).commit();
+        p0.setY(p0.y() + movement);
+        seq.move(0, p0, &window).commit();
+        seq.release(0, p0, &window).commit();
+        QTRY_COMPARE(table->property("moving"), false);
+    };
+
+    pinch();
+    qCDebug(lcTests) << "new scale" << pdfView->property("renderScale").toReal();
+    QTRY_COMPARE(pdfView->property("renderScale").toReal(), 2);
+
+    drag();
+    QCOMPARE(pdfView->property("renderScale").toReal(), 2);
+
+    pinch();
+    qCDebug(lcTests) << "new scale" << pdfView->property("renderScale").toReal();
+    QTRY_COMPARE(pdfView->property("renderScale").toReal(), 4);
+
+    // wait for rendering to be done before we exit: if we delete the document
+    // prematurely, QPdfIOHandler might access a dangling pointer
+    QTRY_COMPARE(image->status(), QQuickPdfPageImage::Ready);
+}
+
 QTEST_MAIN(tst_MultiPageView)
 #include "tst_multipageview.moc"