SplitView: fix resized item jumping in size when an item is hidden

The logic that handles the item to the left of the handle being resized
incorrectly used a hidden handle as the leftEdge. This would cause the
item to get more space than it should because it thought it had more
space to consume.

Before the fix, leftEdge is 10 and accumulated is 0, so:

    //          390         400    0             10
    const qreal rightStop = size - accumulated - pressedHandleSize;

    //    110             10        110
    qreal leftStop = qMax(leftEdge, pressedHandlePos);

    //          110                   110       110               390
    const qreal newHandlePos = qBound(leftStop, pressedHandlePos, rightStop);

    //          100           110            10
    const qreal newItemSize = newHandlePos - leftEdge;

After the fix, leftEdge is 60 and accumulated is 0, so:

    //          390         400    0             10
    const qreal rightStop = size - accumulated - pressedHandleSize;

    //    110             60        110
    qreal leftStop = qMax(leftEdge, pressedHandlePos);

    //          110                   110       110               390
    const qreal newHandlePos = qBound(leftStop, pressedHandlePos, rightStop);

    //          50            110            60
    const qreal newItemSize = newHandlePos - leftEdge;

Fixes: QTBUG-125049
Pick-to: 6.5 6.7
Change-Id: I3cdf57693c71c1f367780eda0ff6794fea02d546
Reviewed-by: Kaj Grönholm <kaj.gronholm@qt.io>

1 files changed, 91 insertions, 8 deletions

diff --git a/tests/auto/quickcontrols/controls/data/tst_splitview.qml b/tests/auto/quickcontrols/controls/data/tst_splitview.qml
index 3bcf9a53c6..aed303689a 100644
--- a/tests/auto/quickcontrols/controls/data/tst_splitview.qml
+++ b/tests/auto/quickcontrols/controls/data/tst_splitview.qml
@@ -74,20 +74,19 @@ TestCase {
             // Note that the indices mentioned here account for handles; they do not
             // match the indices reported by QQuickSplitView's logging categories.
             compare(item.x, expectedGeometry.x, "Mismatch in actual vs expected x value of "
-                + itemType + " at index " + typeSpecificIndex + context)
+                + itemType + " " + item + " at index " + typeSpecificIndex + context)
             compare(item.y, expectedGeometry.y, "Mismatch in actual vs expected y value of "
-                + itemType + " at index " + typeSpecificIndex + context)
+                + itemType + " " + item + " at index " + typeSpecificIndex + context)
             compare(item.width, expectedGeometry.width, "Mismatch in actual vs expected width value of "
-                + itemType + " at index " + typeSpecificIndex + context)
+                + itemType + " " + item + " at index " + typeSpecificIndex + context)
             compare(item.height, expectedGeometry.height, "Mismatch in actual vs expected height value of "
-                + itemType + " at index " + typeSpecificIndex + context)
+                + itemType + " " + item + " at index " + typeSpecificIndex + context)
         }
     }
 
     property real defaultHorizontalHandleWidth: 10
     property real defaultVerticalHandleHeight: 10
 
-
     Component {
         id: signalSpyComponent
         SignalSpy {}
@@ -96,14 +95,14 @@ TestCase {
     Component {
         id: handleComponent
         Rectangle {
-            objectName: "handle"
+            objectName: `handle ${x},${y} ${width}x${height} visible: ${visible}`
             implicitWidth: defaultHorizontalHandleWidth
             implicitHeight: defaultVerticalHandleHeight
             color: "#444"
 
             Text {
-                objectName: "handleText_" + text
-                text: parent.x + "," + parent.y + " " + parent.width + "x" + parent.height
+                objectName: text + "_Text"
+                text: parent.objectName
                 color: "white"
                 anchors.centerIn: parent
                 rotation: 90
@@ -2678,4 +2677,88 @@ TestCase {
         verify(!firstHandle.SplitHandle.pressed)
         compare(firstItem.width, 125)
     }
+
+    Component {
+        id: hiddenItemComponent
+
+        SplitView {
+            anchors.fill: parent
+            handle: handleComponent
+            orientation: Qt.Horizontal
+
+            component SplitItem: Rectangle {
+                objectName: labelText
+
+                SplitView.preferredWidth: 50
+                SplitView.fillHeight: true
+
+                required property string labelText
+
+                Text {
+                    anchors.fill: parent
+                    wrapMode: Text.Wrap
+                    horizontalAlignment: Text.AlignHCenter
+                    verticalAlignment: Text.AlignVCenter
+                    text: `${parent.labelText} - width: ${parent.width.toFixed(2)}`
+                }
+            }
+
+            SplitItem {
+                color: "blue"
+                labelText: "View 1"
+            }
+            SplitItem {
+                color: "red"
+                labelText: "View 2 (hidden)"
+                visible: false
+            }
+            SplitItem {
+                color: "purple"
+                labelText: "View 3"
+            }
+            SplitItem {
+                color: "yellow"
+                labelText: "View 4"
+            }
+        }
+    }
+
+    function test_resizeHiddenItem() {
+        let control = createTemporaryObject(hiddenItemComponent, testCase)
+        verify(control)
+
+        const standardItemWidth = 50
+        let expectedGeometries = [
+            // First item.
+            { x: 0, y: 0, width: standardItemWidth, height: control.height },
+            // First handle.
+            { x: standardItemWidth, y: 0, width: defaultHorizontalHandleWidth, height: control.height },
+            // The second item and its handle are hidden.
+            { hidden: true },
+            { hidden: true },
+            // Third item.
+            { x: standardItemWidth + defaultHorizontalHandleWidth, y: 0, width: standardItemWidth, height: control.height },
+            // Third handle.
+            { x: (standardItemWidth * 2) + defaultHorizontalHandleWidth, y: 0, width: defaultHorizontalHandleWidth, height: control.height },
+            // Fourth item.
+            { x: (standardItemWidth * 2) + (defaultHorizontalHandleWidth * 2), y: 0,
+                width: control.width - (standardItemWidth * 2) - (defaultHorizontalHandleWidth * 2), height: control.height }
+        ]
+        compareSizes(control, expectedGeometries, "before dragging handle")
+
+        // Drag the third handle to the right.
+        let handles = findHandles(control)
+        let thirdHandle = handles[2]
+        // The third (index 4 here) item should get one pixel bigger, and the fourth one pixel smaller.
+        ++expectedGeometries[4].width
+        ++expectedGeometries[5].x // handle
+        ++expectedGeometries[6].x
+        --expectedGeometries[6].width
+        // Use individual events rather than mouseDrag because that will move it past the drag threshold,
+        // which we don't want, since we only want to move by 1 pixel.
+        mousePress(thirdHandle)
+        mouseMove(thirdHandle, thirdHandle.width / 2 + 1, thirdHandle.height / 2, 16)
+        mouseRelease(thirdHandle)
+        compareSizes(control, expectedGeometries, "after dragging handle")
+    }
 }