Adjustments to attempt to make swing and allemande a bit smoother.

www/js/animation.ts

@@ -89,7 +89,7 @@ export class LinearAnimationSegment extends AnimationSegment {
 export interface AnimationTransitionFlags {
   rotation?: boolean;
   hands?: boolean;
-  handsDuring?: "Actual" | "None" | "Start" | "End";
+  handsDuring?: "Actual" | "None" | "Start" | "End" | Map<Hand, Offset>;
 }
 export class TransitionAnimationSegment extends AnimationSegment {
   private readonly actualAnimation: AnimationSegment;
@@ -122,32 +122,33 @@ export class TransitionAnimationSegment extends AnimationSegment {
       const transitionEnd = this.actualAnimation.interpolateRotation(1 - this.endTransitionProgress);
 
       if (actualEnd > actualStart) {
-        while (transitionStart < this.startRotation) {
+        while (transitionStart <= this.startRotation - 180) {
           this.startRotation -= 360;
         }
-        while (transitionEnd > this.endRotation) {
+        while (transitionEnd >= this.endRotation + 180) {
           this.endRotation += 360;
         }
       } else if (actualEnd < actualStart) {
-        while (transitionStart > this.startRotation) {
+        while (transitionStart >= this.startRotation + 180) {
           this.startRotation += 360;
         }
-        while (transitionEnd < this.endRotation) {
+        while (transitionEnd <= this.endRotation - 180) {
           this.endRotation -= 360;
         }
-      } else {
-        while (transitionStart - this.startRotation < 180) {
-          this.startRotation -= 360;
-        }
-        while (transitionStart - this.startRotation > 180) {
-          this.startRotation += 360;
-        }
-        while (transitionEnd - this.endRotation < 180) {
-          this.endRotation -= 360;
-        }
-        while (transitionEnd - this.endRotation > 180) {
-          this.endRotation += 360;
-        }
+      }
+
+      // Transitions should be short adjustments, not spins.
+      while (transitionStart - this.startRotation < -180) {
+        this.startRotation -= 360;
+      }
+      while (transitionStart - this.startRotation > 180) {
+        this.startRotation += 360;
+      }
+      while (transitionEnd - this.endRotation < -180) {
+        this.endRotation -= 360;
+      }
+      while (transitionEnd - this.endRotation > 180) {
+        this.endRotation += 360;
       }
     }
   }
@@ -185,6 +186,8 @@ export class TransitionAnimationSegment extends AnimationSegment {
       ? startHand
       : this.flags.handsDuring === "End"
       ? endHand
+      : this.flags.handsDuring instanceof Map
+      ? this.flags.handsDuring.get(hand)
       : (() => { throw "Unexpected handsDuring: " + this.flags.handsDuring; })();
 
     if (this.flags.hands) {
@@ -238,8 +241,9 @@ export class RotationAnimationSegment extends AnimationSegment {
   private readonly startFacing: Rotation;
   private readonly closer?: Closer;
   private readonly hands: Map<Hand, HandAnimation>;
+  private readonly centerRelativeTo: number;
 
-  constructor({ beats, startPosition, endPosition, rotation, around, facing, closer, hands }: {
+  constructor({ beats, startPosition, endPosition, rotation, around, facing, closer, hands, centerRelativeTo }: {
     beats: number;
     startPosition: DancerSetPosition;
     endPosition: DancerSetPosition;
@@ -248,6 +252,7 @@ export class RotationAnimationSegment extends AnimationSegment {
     facing: RotationAnimationFacing;
     closer?: CloserDuringRotation;
     hands?: Map<Hand, HandAnimation>;
+    centerRelativeTo?: number;
   }) {
     super(beats, startPosition, endPosition);
 
@@ -268,6 +273,7 @@ export class RotationAnimationSegment extends AnimationSegment {
     }
     this.startRotation = positionToDegrees(startPosition.position);
     this.startFacing = startPosition.rotation;
+    this.centerRelativeTo = centerRelativeTo ?? this.startFacing;
     const actualRotation = normalizeRotation(positionToDegrees(endPosition.position) - this.startRotation,
       rotation);
     this.endRotation = this.startRotation + actualRotation;
@@ -311,14 +317,13 @@ export class RotationAnimationSegment extends AnimationSegment {
       return super.interpolateRotation(progress);
     } else {
       const degrees = interpolateLinear(progress, this.startRotation, this.endRotation);
-      let rotation : number;
       switch (this.facing) {
         case RotationAnimationFacing.Start:
           return this.startFacing;
         case RotationAnimationFacing.Center:
           return degrees - 90;
         case RotationAnimationFacing.CenterRelative:
-          return degrees - this.startRotation + this.startFacing;
+          return degrees - this.startRotation + this.centerRelativeTo;
         case RotationAnimationFacing.Forward:
           return degrees + 180;
         case RotationAnimationFacing.Backward:

www/js/interpreter.ts

@@ -697,7 +697,7 @@ function moveAsLowLevelMoves({ move, nextMove, startingPos, numProgessions }: {
             return combine([
               prevEnd => ({
                 beats: meltdownBeats,
-                endPosition: prevEnd,
+                endPosition: {...prevEnd, dancerDistance: DancerDistance.Compact },
                 movementPattern: {
                   kind: SemanticAnimationKind.RotateAround,
                   minAmount: 360,

www/js/interpreterCommon.ts

@@ -324,5 +324,5 @@ export type SemanticPosition = {
   facing: Facing,
   hands?: Map<Hand, HandConnection>,
   balance?: BalanceWeight,
-  dancerDistance?: DancerDistance.Normal | DancerDistance.SwingLark | DancerDistance.SwingRobin,
+  dancerDistance?: DancerDistance,
 };

www/js/lowLevelMove.ts

@@ -170,6 +170,30 @@ function CenterOf(sideOrCenter: CircleSideOrCenter, setOffset?: number, lineOffs
   return { x: setCenter.x + xOffset, y: setCenter.y + yOffset };
 }
 
+function swingHandPosition(role: DancerDistance.SwingLark | DancerDistance.SwingRobin, hand: Hand): Offset {
+  if (role === DancerDistance.SwingLark) {
+    if (hand === Hand.Left) {
+      return { x: 0, y: Math.sqrt(1 / 2) };
+    }
+    else {
+      return { x: 0.8, y: 0.5 };
+    }
+  } else /* role === DancerDistance.SwingRobin */ {
+    if (hand === Hand.Left) {
+      return { x: -0.8, y: 0.5 };
+    }
+    else {
+      return { x: 0, y: Math.sqrt(1 / 2) };
+    };
+  }
+}
+function swingHandPositions(role: DancerDistance.SwingLark | DancerDistance.SwingRobin): Map<Hand, Offset> {
+  return new Map<Hand, Offset>([
+    [Hand.Left, swingHandPosition(role, Hand.Left)],
+    [Hand.Right, swingHandPosition(role, Hand.Right)],
+  ]);
+}
+
 function SemanticToSetPosition(semantic: SemanticPosition): DancerSetPosition {
 
   let rotation: number;
@@ -211,8 +235,6 @@ function SemanticToSetPosition(semantic: SemanticPosition): DancerSetPosition {
           yAmount = 1;
           break;
         case DancerDistance.Compact:
-          yAmount = 0.75;
-          break;
         case DancerDistance.SwingLark:
         case DancerDistance.SwingRobin:
           yAmount = 0.5;
@@ -286,8 +308,8 @@ function SemanticToSetPosition(semantic: SemanticPosition): DancerSetPosition {
       position = OffsetPlus(position, balanceOffset, setOffset);
 
       const isFacingUpOrDown = semantic.facing === Facing.Up || semantic.facing === Facing.Down;
-      if (semantic.dancerDistance === DancerDistance.SwingLark) {
-        if (isFacingUpOrDown) {
+      if (semantic.dancerDistance === DancerDistance.SwingLark || semantic.dancerDistance == DancerDistance.SwingRobin) {
+        if (isFacingUpOrDown == (semantic.dancerDistance === DancerDistance.SwingLark)) {
           rotation -= 45;
         } else {
           rotation += 45;
@@ -296,21 +318,8 @@ function SemanticToSetPosition(semantic: SemanticPosition): DancerSetPosition {
         return {
           position,
           rotation,
-          leftArmEnd: { x: 0, y: Math.sqrt(1/2)},
-          rightArmEnd: { x: 0.8, y: 0.5 },
-        };
-      } else if (semantic.dancerDistance === DancerDistance.SwingRobin) {
-        if (isFacingUpOrDown) {
-          rotation += 45;
-        } else {
-          rotation -= 45;
-        }
-
-        return {
-          position,
-          rotation,
-          leftArmEnd: { x: -0.8, y: 0.5 },
-          rightArmEnd: { x: 0, y: Math.sqrt(1/2) },
+          leftArmEnd: swingHandPosition(semantic.dancerDistance, Hand.Left),
+          rightArmEnd: swingHandPosition(semantic.dancerDistance, Hand.Right),
         };
       }
 
@@ -325,10 +334,11 @@ function SemanticToSetPosition(semantic: SemanticPosition): DancerSetPosition {
           case HandTo.DancerRight:
             return OffsetPlus({ x: +1, y: 0 }, balanceHandAdjustment);
           case HandTo.DancerForward:
+            const armLength = yAmount + (semantic.balance === BalanceWeight.Backward ? balanceAmount : 0);
             if (hand === connection.hand) {
-              return { x: 0, y: +0.5 };
+              return { x: 0, y: +armLength/2 };
             } else {
-              return { x: dancerWidth / 2 * (hand === Hand.Left ? -1 : +1), y: +1 };
+              return { x: dancerWidth / 2 * (hand === Hand.Left ? -1 : +1), y: +armLength };
             }
           case HandTo.LeftInCircle:
           case HandTo.RightInCircle:
@@ -572,13 +582,13 @@ export function animateLowLevelMove(move: LowLevelMove): animation.AnimationSegm
               rotation: move.movementPattern.minAmount,
               around: {
                 center: rotateCenter,
-                width: setWidth / 5,
-                height: setHeight / 5,
+                width: 1,
+                height: 1,
               },
-              facing: animation.RotationAnimationFacing.Center,
+              facing: animation.RotationAnimationFacing.Forward,
               closer: move.movementPattern.close ? {
                 transitionBeats: 1,
-                minDistance: setWidth,
+                minDistance: 1,
               } : undefined,
               hands
             }),
@@ -611,22 +621,31 @@ export function animateLowLevelMove(move: LowLevelMove): animation.AnimationSegm
         });
 
         return [
-          new animation.LinearAnimationSegment({
-            beats: 1,
-            startPosition: startSetPosition,
-            endPosition: swingStart,
-          }),
-          new animation.RotationAnimationSegment({
-            beats: move.beats - 3,
-            startPosition: swingStart,
-            endPosition: beforeUnfold,
-            rotation: move.movementPattern.minAmount,
-            around: {
-              center: rotateSwingCenter,
-              width: setWidth / 5,
-              height: setHeight / 5,
+          new animation.TransitionAnimationSegment({
+            actualAnimation: new animation.RotationAnimationSegment({
+              beats: move.beats - 2,
+              startPosition: startSetPosition,
+              endPosition: beforeUnfold,
+              rotation: move.movementPattern.minAmount,
+              around: {
+                center: rotateSwingCenter,
+                width: 1,
+                height: 1,
+              },
+              closer: {
+                minDistance: 1,
+                transitionBeats: 1,
+              },
+              facing: animation.RotationAnimationFacing.CenterRelative,
+              centerRelativeTo: startSetPosition.rotation + ((move.startPosition.facing === Facing.Up || move.startPosition.facing === Facing.Down) === (dancerDistance === DancerDistance.SwingLark) ? -45 : +45)
+            }),
+            flags: {
+              rotation: true,
+              hands: true,
+              handsDuring: swingHandPositions(dancerDistance),
             },
-            facing: animation.RotationAnimationFacing.CenterRelative
+            startTransitionBeats: 1,
+            endTransitionBeats: 0,
           }),
           new animation.LinearAnimationSegment({
             beats: 1,