Support allemande from long lines to short lines.

www/js/animation.ts

@@ -99,6 +99,7 @@ export class LinearAnimationSegment extends AnimationSegment {
 export interface AnimationTransitionFlags {
   rotation?: boolean;
   rotationDuring?: "Actual" | "Start" | "End";
+  rotationDirection?: Hand;
   hands?: boolean;
   handsDuring?: "Actual" | "None" | "Start" | "End" | Map<Hand, Offset>;
 }
@@ -126,20 +127,30 @@ export class TransitionAnimationSegment extends AnimationSegment {
     this.startRotation = this.startPosition.rotation;
     this.endRotation = this.endPosition.rotation;
     if (this.flags.rotation) {
-      const actualStart = this.actualAnimation.interpolateRotation(0);
+      let rotationDirection = flags.rotationDirection;
-      const actualEnd = this.actualAnimation.interpolateRotation(1);
+
+      if (!flags.rotationDirection) {
+        const actualStart = this.actualAnimation.interpolateRotation(0);
+        const actualEnd = this.actualAnimation.interpolateRotation(1);
+
+        if (actualEnd > actualStart) {
+          rotationDirection = Hand.Right;
+        } else if (actualEnd < actualStart) {
+          rotationDirection = Hand.Left;
+        }
+      }
 
       const transitionStart = this.actualAnimation.interpolateRotation(this.startTransitionProgress);
       const transitionEnd = this.actualAnimation.interpolateRotation(1 - this.endTransitionProgress);
 
-      if (actualEnd > actualStart) {
+      if (rotationDirection === Hand.Right) {
         while (transitionStart <= this.startRotation - 180) {
           this.startRotation -= 360;
         }
         while (transitionEnd >= this.endRotation + 180) {
           this.endRotation += 360;
         }
-      } else if (actualEnd < actualStart) {
+      } else if (rotationDirection === Hand.Left) {
         while (transitionStart >= this.startRotation + 180) {
           this.startRotation += 360;
         }
@@ -148,18 +159,21 @@ export class TransitionAnimationSegment extends AnimationSegment {
         }
       }
 
-      // Transitions should be short adjustments, not spins.
+      if (!this.flags.rotationDirection) {
-      while (transitionStart - this.startRotation < -180) {
+        // Transitions should be short adjustments, not spins...
-        this.startRotation -= 360;
+        //  ... unless a direction is explicitly specified.
-      }
+        while (transitionStart - this.startRotation < -180) {
-      while (transitionStart - this.startRotation > 180) {
+          this.startRotation -= 360;
-        this.startRotation += 360;
+        }
-      }
+        while (transitionStart - this.startRotation > 180) {
-      while (transitionEnd - this.endRotation < -180) {
+          this.startRotation += 360;
-        this.endRotation -= 360;
+        }
-      }
+        while (transitionEnd - this.endRotation < -180) {
-      while (transitionEnd - this.endRotation > 180) {
+          this.endRotation -= 360;
-        this.endRotation += 360;
+        }
+        while (transitionEnd - this.endRotation > 180) {
+          this.endRotation += 360;
+        }
       }
     }
   }

www/js/interpreter.ts

@@ -884,18 +884,20 @@ function moveAsLowLevelMoves({ move, nextMove, startingPos, numProgessions }: {
           if (startPos.kind === PositionKind.ShortLines) {
             if (around === CircleSide.Left || around === CircleSide.Right) {
               // Fix startPos if necessary. Needed because pass through always swaps but sometimes shouldn't.
+              let startWhich = startPos.which;
               if ((startPos.facing === Facing.Up || startPos.facing === Facing.Down) &&
                 ((byHandOrShoulder === Hand.Right)
                   !== (startPos.facing === Facing.Up)
-                  !== (startPos.which === ShortLinesPosition.FarLeft || startPos.which === ShortLinesPosition.MiddleRight))) {
+                  !== startPos.which.isLeftOfSide())) {
+                startWhich = startPos.which.swapOnSide()
                 startingPos = {
                   ...startPos,
-                  which: startPos.which.swapOnSide()
+                  which: startWhich,
                 };
               }
 
               const endWhich = CirclePosition.fromSides(startingPos.which.leftRightSide(),
-                (startingPos.which === ShortLinesPosition.FarLeft || startingPos.which === ShortLinesPosition.MiddleRight)
+                startWhich.isLeftOfSide()
                   !== (byHandOrShoulder === Hand.Right)
                   !== (intoWavePositions === 1)
                   ? CircleSide.Top
@@ -924,9 +926,15 @@ function moveAsLowLevelMoves({ move, nextMove, startingPos, numProgessions }: {
                 setOffset: startPos.setOffset,
                 lineOffset: startPos.lineOffset,
               }
-
             } else {
-              throw new Error("Allemande from circle to short lines is unsupported.");
+              const endWhich = startPos.which.toShortLines(intoWavePositions === 1 ? Hand.Right : Hand.Left);
+              endPosition = {
+                kind: PositionKind.ShortLines,
+                which: endWhich,
+                facing: endWhich.isLeftOfSide() === (byHandOrShoulder === Hand.Left) ? Facing.Up : Facing.Down,
+                setOffset: startPos.setOffset,
+                lineOffset: startPos.lineOffset,
+              }
             }
           }
         }

www/js/interpreterCommon.ts

@@ -286,6 +286,11 @@ export class ShortLinesPosition {
     return this.leftRightSide() === CircleSide.Left;
   }
 
+  // Of the two positions on the same leftRightSide() is this the one further to the left?
+  public isLeftOfSide() : boolean {
+    return this.enumValue === ShortLinesPositionEnum.FarLeft || this.enumValue === ShortLinesPositionEnum.MiddleRight;
+  }
+
   public facingSide() : Facing.Left | Facing.Right {
     return this.isLeft() === this.isMiddle() ? Facing.Left : Facing.Right;
   }

www/js/lowLevelMove.ts

@@ -832,6 +832,7 @@ function animateLowLevelMoveWithoutSlide(move: LowLevelMove): animation.Animatio
             flags: {
               hands: true,
               rotation: true,
+              rotationDirection: move.movementPattern.side,
             },
             startTransitionBeats: 0.5,
           })