Settle the eyes down while walking

Two things made the eyes jump. The body bobbed two units per step and the head
rode along with it, and each eye ran its own random blink timer, so the cat
winked one eye at a time at intervals of its own choosing.

The bob is now a property on the cat rather than an animation owning torso.y,
the amplitude is softer, and the head translates against it by 75 percent, the
way a walking cat keeps its head level. Measured on a 240 px cat, the eye's
vertical travel per step went from 4.0 px to 0.8 px.

Both eyes now share one eyelid, driven by a single timer and a single
animation. That also removes the Behavior that was fighting the blink animation
for the same property, and the mid-blink flicker to the drawn closed-eye arch,
which now only appears when the eyes are really shut.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

qml/Cat.qml

@@ -16,6 +16,11 @@ Item {
     property bool showCodes: true
     property real sipDip: 0
 
+    // Vertical travel of the body during a step. The head cancels most of it
+    // again, because a walking cat keeps its head almost level and the eyes
+    // are what the eye follows.
+    property real bob: 0
+
     // The cat announces what it is doing in the machine's own language.
     readonly property string moodCode: mood === "running" || mood === "chasing" ? "G00"
                                      : mood === "walking"    ? "G01"
@@ -98,6 +103,7 @@ Item {
             id: torso
             width: 100
             height: 90
+            y: cat.bob
 
             // tail
             Shape {
@@ -238,6 +244,7 @@ Item {
                 x: 46; y: 12
                 width: 50; height: 44
                 transformOrigin: Item.Bottom
+                transform: Translate { y: -cat.bob * 0.75 }
 
                 Behavior on x { NumberAnimation { duration: 450; easing.type: Easing.InOutQuad } }
                 Behavior on y { NumberAnimation { duration: 450; easing.type: Easing.InOutQuad } }
@@ -311,34 +318,31 @@ Item {
                     Item {
                         id: eye
                         required property int index
-                        property real open: 1
                         x: (index === 0 ? 12 : 29) + cat.look.x * 2.2
                         y: 17 + cat.look.y * 1.6
                         width: 9.5; height: 12
 
-                        Behavior on open { NumberAnimation { duration: 110 } }
-
                         Rectangle {
                             id: eyeBall
                             anchors.horizontalCenter: parent.horizontalCenter
                             anchors.verticalCenter: parent.verticalCenter
                             width: eye.width * (cat.mood === "alert" || cat.mood === "batting" ? 1.15 : 1)
-                            height: eye.height * eye.open * (cat.mood === "alert" || cat.mood === "batting" ? 1.15 : 1)
+                            height: eye.height * cat.eyeOpen * (cat.mood === "alert" || cat.mood === "batting" ? 1.15 : 1)
                             radius: width / 2
                             color: cat.eyeColor
-                            visible: eye.open > 0.08
+                            visible: !cat.eyesShut && cat.eyeOpen > 0.02
                             antialiasing: true
 
                             Rectangle { // highlight
                                 x: parent.width * 0.5; y: parent.height * 0.14
-                                width: 3.4; height: 3.4 * eye.open
+                                width: 3.4; height: 3.4 * cat.eyeOpen
                                 radius: 1.7
                                 color: "white"
                                 antialiasing: true
                             }
                             Rectangle {
                                 x: parent.width * 0.22; y: parent.height * 0.6
-                                width: 1.6; height: 1.6 * eye.open
+                                width: 1.6; height: 1.6 * cat.eyeOpen
                                 radius: 0.8
                                 color: "white"
                                 antialiasing: true
@@ -347,7 +351,7 @@ Item {
 
                         Shape { // closed eye: happy arch or sleepy curve
                             anchors.fill: parent
-                            visible: eye.open <= 0.08
+                            visible: cat.eyesShut
                             preferredRendererType: Shape.CurveRenderer
                             ShapePath {
                                 strokeColor: cat.ink
@@ -363,23 +367,6 @@ Item {
                             }
                         }
 
-                        Timer { // blink
-                            interval: 2600 + Math.random() * 3800
-                            running: !cat.sleeping && !cat.happy && cat.mood !== "alert"
-                            repeat: true
-                            onTriggered: { interval = 2600 + Math.random() * 3800; blinkAnim.start() }
-                        }
-                        SequentialAnimation {
-                            id: blinkAnim
-                            NumberAnimation { target: eye; property: "open"; to: 0; duration: 80 }
-                            NumberAnimation { target: eye; property: "open"; to: 1; duration: 120 }
-                        }
-
-                        states: State {
-                            name: "closed"
-                            when: cat.sleeping || cat.happy
-                            PropertyChanges { eye.open: 0 }
-                        }
                     }
                 }
 
@@ -450,14 +437,6 @@ Item {
                 }
             }
 
-            // walking bob
-            SequentialAnimation on y {
-                running: cat.moving
-                loops: Animation.Infinite
-                alwaysRunToEnd: true
-                NumberAnimation { to: cat.running ? -4 : -2; duration: cat.running ? 130 : 240; easing.type: Easing.InOutSine }
-                NumberAnimation { to: 0; duration: cat.running ? 130 : 240; easing.type: Easing.InOutSine }
-            }
 
             // purr wiggle while petted / loving
             SequentialAnimation on rotation {
@@ -543,6 +522,48 @@ Item {
 
     onMoodCodeChanged: if (showCodes && moodCode.length > 0) codeFlash.restart()
 
+    SequentialAnimation {
+        running: cat.moving
+        loops: Animation.Infinite
+        alwaysRunToEnd: true
+        NumberAnimation { target: cat; property: "bob"; to: cat.running ? -3 : -1.6; duration: cat.running ? 130 : 240; easing.type: Easing.InOutSine }
+        NumberAnimation { target: cat; property: "bob"; to: 0; duration: cat.running ? 130 : 240; easing.type: Easing.InOutSine }
+    }
+
+    // One pair of eyelids for both eyes. Two independent blink timers made the
+    // cat wink at random, which read as the eyes jittering.
+    readonly property bool eyesShut: sleeping || happy
+    property real eyeOpen: 1
+
+    onEyesShutChanged: {
+        blinkSeq.stop()
+        lidAnim.to = eyesShut ? 0 : 1
+        lidAnim.restart()
+    }
+
+    NumberAnimation {
+        id: lidAnim
+        target: cat
+        property: "eyeOpen"
+        duration: 140
+        easing.type: Easing.InOutQuad
+    }
+
+    SequentialAnimation {
+        id: blinkSeq
+        NumberAnimation { target: cat; property: "eyeOpen"; to: 0.06; duration: 90; easing.type: Easing.InQuad }
+        NumberAnimation { target: cat; property: "eyeOpen"; to: 1; duration: 140; easing.type: Easing.OutQuad }
+    }
+
+    Timer {
+        id: blinkTimer
+        interval: 3600
+        running: !cat.eyesShut && !cat.lifted
+        repeat: true
+        onTriggered: { interval = 3200 + Math.random() * 4200; blinkSeq.start() }
+        Component.onCompleted: interval = 2000 + Math.random() * 4000
+    }
+
     // Head dips into the mug, holds, comes back up.
     SequentialAnimation {
         running: cat.mood === "drinking" && !cat.lifted