Improve Control::background automatic resizing

- width follows only if x and width are both not specified
- height follows only if y and height are both not specified

Change-Id: Ib881daa9da339baac53f7f9d4de6e5bdad7723e2
Reviewed-by: J-P Nurmi <jpnurmi@theqtcompany.com>

2 files changed, 48 insertions, 2 deletions

diff --git a/src/controls/qquickcontrol.cpp b/src/controls/qquickcontrol.cpp
index 26e68b9f..ac4c257d 100644
--- a/src/controls/qquickcontrol.cpp
+++ b/src/controls/qquickcontrol.cpp
@@ -127,11 +127,11 @@ void QQuickControlPrivate::resizeBackground()
     Q_Q(QQuickControl);
     if (background) {
         QQuickItemPrivate *p = QQuickItemPrivate::get(background);
-        if (!p->widthValid) {
+        if (!p->widthValid && qFuzzyIsNull(background->x())) {
             background->setWidth(q->width());
             p->widthValid = false;
         }
-        if (!p->heightValid) {
+        if (!p->heightValid && qFuzzyIsNull(background->y())) {
             background->setHeight(q->height());
             p->heightValid = false;
         }
diff --git a/tests/auto/controls/data/tst_control.qml b/tests/auto/controls/data/tst_control.qml
index 3d46ff16..da0a979c 100644
--- a/tests/auto/controls/data/tst_control.qml
+++ b/tests/auto/controls/data/tst_control.qml
@@ -129,4 +129,50 @@ TestCase {
 
         control.destroy()
     }
+
+    function test_background() {
+        var control = component.createObject(testCase)
+
+        control.background = component.createObject(control)
+
+        // background has no x or width set, so its width follows control's width
+        control.width = 320
+        compare(control.background.width, control.width)
+
+        // background has no y or height set, so its height follows control's height
+        compare(control.background.height, control.height)
+        control.height = 240
+
+        // has width => width does not follow
+        control.background.width /= 2
+        control.width += 20
+        verify(control.background.width !== control.width)
+
+        // reset width => width follows again
+        control.background.width = undefined
+        control.width += 20
+        compare(control.background.width, control.width)
+
+        // has x => width does not follow
+        control.background.x = 10
+        control.width += 20
+        verify(control.background.width !== control.width)
+
+        // has height => height does not follow
+        control.background.height /= 2
+        control.height -= 20
+        verify(control.background.height !== control.height)
+
+        // reset height => height follows again
+        control.background.height = undefined
+        control.height -= 20
+        compare(control.background.height, control.height)
+
+        // has y => height does not follow
+        control.background.y = 10
+        control.height -= 20
+        verify(control.background.height !== control.height)
+
+        control.destroy()
+    }
 }