diff options
| -rw-r--r-- | src/quicktemplates2/qquicktumbler.cpp | 17 | ||||
| -rw-r--r-- | tests/auto/controls/data/tst_tumbler.qml | 27 |
2 files changed, 38 insertions, 6 deletions
diff --git a/src/quicktemplates2/qquicktumbler.cpp b/src/quicktemplates2/qquicktumbler.cpp index 8b702c60..85c70b1b 100644 --- a/src/quicktemplates2/qquicktumbler.cpp +++ b/src/quicktemplates2/qquicktumbler.cpp @@ -949,9 +949,20 @@ void QQuickTumblerAttachedPrivate::calculateDisplacement() const qreal contentY = tumblerPrivate->viewContentY; const qreal delegateH = delegateHeight(tumbler); const qreal preferredHighlightBegin = tumblerPrivate->view->property("preferredHighlightBegin").toReal(); - // Tumbler's displacement goes from negative at the top to positive towards the bottom, so we must switch this around. - const qreal reverseDisplacement = (contentY + preferredHighlightBegin) / delegateH; - displacement = reverseDisplacement - index; + const qreal itemY = qobject_cast<QQuickItem*>(parent)->y(); + qreal currentItemY = 0; + auto currentItem = tumblerPrivate->view->property("currentItem").value<QQuickItem*>(); + if (currentItem) + currentItemY = currentItem->y(); + // Start from the y position of the current item. + const qreal topOfCurrentItemInViewport = currentItemY - contentY; + // Then, calculate the distance between it and the preferredHighlightBegin. + const qreal relativePositionToPreferredHighlightBegin = topOfCurrentItemInViewport - preferredHighlightBegin; + // Next, calculate the distance between us and the current item. + const qreal distanceFromCurrentItem = currentItemY - itemY; + const qreal displacementInPixels = distanceFromCurrentItem - relativePositionToPreferredHighlightBegin; + // Convert it from pixels to a floating point index. + displacement = displacementInPixels / delegateH; } emitIfDisplacementChanged(previousDisplacement, displacement); diff --git a/tests/auto/controls/data/tst_tumbler.qml b/tests/auto/controls/data/tst_tumbler.qml index c9cc10d7..5b3ef6e3 100644 --- a/tests/auto/controls/data/tst_tumbler.qml +++ b/tests/auto/controls/data/tst_tumbler.qml @@ -1,6 +1,6 @@ /**************************************************************************** ** -** Copyright (C) 2017 The Qt Company Ltd. +** Copyright (C) 2019 The Qt Company Ltd. ** Contact: https://www.qt.io/licensing/ ** ** This file is part of the test suite of the Qt Toolkit. @@ -54,8 +54,8 @@ import QtQuick.Controls 2.12 TestCase { id: testCase - width: 200 - height: 200 + width: 300 + height: 300 visible: true when: windowShown name: "Tumbler" @@ -513,6 +513,7 @@ TestCase { Text { text: parent.displacement.toFixed(2) anchors.right: parent.right + anchors.verticalCenter: parent.verticalCenter } property real displacement: Tumbler.displacement @@ -1236,4 +1237,24 @@ TestCase { // 5 - 2 = 3 compare(tumbler.currentIndex, 3); } + + function test_displacementAfterResizing() { + createTumbler({ + width: 200, + wrap: false, + delegate: displacementDelegate, + model: 30, + visibleItemCount: 7, + currentIndex: 15 + }) + + var delegate = findChild(tumblerView, "delegate15") + verify(delegate) + + tryCompare(delegate, "displacement", 0) + + // Resizing the Tumbler shouldn't affect the displacement. + tumbler.height *= 1.4 + tryCompare(delegate, "displacement", 0) + } } |