Use HRotationAnimator instead of HNumberAnimation

src/qml/Base/HButtonContent.qml

@@ -18,47 +18,42 @@ HRowLayout {
 
     Behavior on opacity { HOpacityAnimator {} }
 
+    Item {
+        id: iconWrapper
 
-    HIcon {
+        Layout.preferredWidth: icon.width
-        property bool loading: button.loading || false
+        Layout.preferredHeight: icon.height
-
-        id: icon
-        svgName: button.icon.name
-        colorize: enabled ? button.icon.color: theme.icons.disabledColorize
-        cache: button.icon.cache
-
-        onLoadingChanged: if (! loading) resetAnimations.start()
-
-        Layout.fillHeight: true
-        Layout.alignment: Qt.AlignCenter
-
 
         ParallelAnimation {
             id: resetAnimations
-            HOpacityAnimator { target: icon; to: 1 }
+            HOpacityAnimator { target: iconWrapper; to: 1 }
-            HNumberAnimation { target: icon; property: "rotation"; to: 0 }
+            HRotationAnimator { target: iconWrapper; to: 0 }
         }
 
-
+        HOpacityAnimator {
-        HNumberAnimation on opacity {
             id: blink
+            target: iconWrapper
             from: 1
             to: 0.5
             factor: 2
             running: button.loading || false
-            onFinished: { [from, to] = [to, from]; start() }
+            onFinished: {
+                if (button.loading) { [from, to] = [to, from]; start() }
+            }
         }
 
         SequentialAnimation {
             running: button.loading || false
             loops: Animation.Infinite
+            onStopped: resetAnimations.start()
 
             HPauseAnimation { factor: blink.factor * 8 }
 
-            HNumberAnimation {
+            // These don't work directly on HIcon, hence why we wrap it in
+            // an Item. Qt bug? (5.13.1_1)
+            HRotationAnimator {
                 id: rotation1
-                target: icon
+                target: iconWrapper
-                property: "rotation"
                 from: 0
                 to: 180
                 factor: blink.factor
@@ -66,14 +61,26 @@ HRowLayout {
 
             HPauseAnimation { factor: blink.factor * 8 }
 
-            HNumberAnimation {
+            HRotationAnimator {
                 target: rotation1.target
-                property: rotation1.property
                 from: rotation1.to
                 to: 360
                 factor: rotation1.factor
+                direction: RotationAnimator.Clockwise
             }
         }
+
+        HIcon {
+            property bool loading: button.loading || false
+
+            id: icon
+            svgName: button.icon.name
+            colorize: enabled ? button.icon.color: theme.icons.disabledColorize
+            cache: button.icon.cache
+
+            Layout.fillHeight: true
+            Layout.alignment: Qt.AlignCenter
+        }
     }
 
     HLabel {

src/qml/Base/HRotationAnimator.qml

@@ -0,0 +1,7 @@
+import QtQuick 2.12
+
+RotationAnimator {
+    duration: theme.animationDuration * factor
+
+    property real factor: 1.0
+}