Fix ScrollBars with paddings

Padding was not taken into account when calculating the new position,
which caused there to be small offset between the mouse press and the
resulting handle position by the amount of padding used.

Task-number: QTBUG-52233
Change-Id: Ibd8c4375b030a27a6124aefc4bc9af570d14d3a9
Reviewed-by: Mitch Curtis <mitch.curtis@theqtcompany.com>

5 files changed, 25 insertions, 9 deletions

diff --git a/src/imports/controls/ScrollBar.qml b/src/imports/controls/ScrollBar.qml
index 55d53191..b9ebd634 100644
--- a/src/imports/controls/ScrollBar.qml
+++ b/src/imports/controls/ScrollBar.qml
@@ -60,8 +60,8 @@ T.ScrollBar {
         opacity: 0.0
 
         readonly property bool horizontal: control.orientation === Qt.Horizontal
-        x: control.leftPadding + (horizontal ? control.position * control.width : 0)
-        y: control.topPadding + (horizontal ? 0 : control.position * control.height)
+        x: control.leftPadding + (horizontal ? control.position * control.availableWidth : 0)
+        y: control.topPadding + (horizontal ? 0 : control.position * control.availableHeight)
         width: horizontal ? control.size * control.availableWidth : implicitWidth
         height: horizontal ? implicitHeight : control.size * control.availableHeight
 
diff --git a/src/imports/controls/material/ScrollBar.qml b/src/imports/controls/material/ScrollBar.qml
index 539b9243..72130c63 100644
--- a/src/imports/controls/material/ScrollBar.qml
+++ b/src/imports/controls/material/ScrollBar.qml
@@ -60,8 +60,8 @@ T.ScrollBar {
         opacity: 0.0
 
         readonly property bool horizontal: control.orientation === Qt.Horizontal
-        x: control.leftPadding + (horizontal ? control.position * control.width : 0)
-        y: control.topPadding + (horizontal ? 0 : control.position * control.height)
+        x: control.leftPadding + (horizontal ? control.position * control.availableWidth : 0)
+        y: control.topPadding + (horizontal ? 0 : control.position * control.availableHeight)
         width: horizontal ? control.size * control.availableWidth : implicitWidth
         height: horizontal ? implicitHeight : control.size * control.availableHeight
 
diff --git a/src/imports/controls/universal/ScrollBar.qml b/src/imports/controls/universal/ScrollBar.qml
index b1bc8f6a..dd0a81ca 100644
--- a/src/imports/controls/universal/ScrollBar.qml
+++ b/src/imports/controls/universal/ScrollBar.qml
@@ -58,8 +58,8 @@ T.ScrollBar {
         opacity: 0.0
 
         readonly property bool horizontal: control.orientation === Qt.Horizontal
-        x: control.leftPadding + (horizontal ? control.position * control.width : 0)
-        y: control.topPadding + (horizontal ? 0 : control.position * control.height)
+        x: control.leftPadding + (horizontal ? control.position * control.availableWidth : 0)
+        y: control.topPadding + (horizontal ? 0 : control.position * control.availableHeight)
         width: horizontal ? control.size * control.availableWidth : implicitWidth
         height: horizontal ? implicitHeight : control.size * control.availableHeight
     }
diff --git a/src/templates/qquickscrollbar.cpp b/src/templates/qquickscrollbar.cpp
index 86d4e290..b3679bf8 100644
--- a/src/templates/qquickscrollbar.cpp
+++ b/src/templates/qquickscrollbar.cpp
@@ -285,9 +285,9 @@ qreal QQuickScrollBar::positionAt(const QPoint &point) const
 {
     Q_D(const QQuickScrollBar);
     if (d->orientation == Qt::Horizontal)
-        return point.x() / width();
+        return (point.x() - leftPadding()) / availableWidth();
     else
-        return point.y() / height();
+        return (point.y() - topPadding()) / availableHeight();
 }
 
 #ifndef QT_NO_ACCESSIBILITY
diff --git a/tests/auto/controls/data/tst_scrollbar.qml b/tests/auto/controls/data/tst_scrollbar.qml
index 55f31e12..6e021ccf 100644
--- a/tests/auto/controls/data/tst_scrollbar.qml
+++ b/tests/auto/controls/data/tst_scrollbar.qml
@@ -57,7 +57,7 @@ TestCase {
 
     Component {
         id: scrollBar
-        ScrollBar { }
+        ScrollBar { padding: 0 }
     }
 
     Component {
@@ -210,4 +210,20 @@ TestCase {
 
         control.destroy()
     }
+
+    function test_padding_data() {
+        return [
+            { tag: "horizontal", properties: { visible: true, orientation: Qt.Horizontal, width: testCase.width, leftPadding: testCase.width * 0.1 } },
+            { tag: "vertical", properties: { visible: true, orientation: Qt.Vertical, height: testCase.height, topPadding: testCase.height * 0.1 } }
+        ]
+    }
+
+    function test_padding(data) {
+        var control = scrollBar.createObject(testCase, data.properties)
+
+        mousePress(control, control.leftPadding + control.availableWidth * 0.5, control.topPadding + control.availableHeight * 0.5, Qt.LeftButton)
+        mouseRelease(control, control.leftPadding + control.availableWidth * 0.5, control.topPadding + control.availableHeight * 0.5, Qt.LeftButton)
+
+        compare(control.position, 0.5)
+    }
 }