dihedral angle label fix

src/mol-repr/shape/loci/dihedral.ts

@@ -306,7 +306,7 @@ function buildText(data: DihedralData, props: DihedralProps, text?: Text): Text
         Vec3.setMagnitude(tmpVec, tmpVec, tmpState.radius);
         Vec3.add(tmpVec, tmpState.arcCenter, tmpVec);
 
-        const angle = Math.abs(radToDeg(tmpState.angle)).toFixed(2);
+        const angle = radToDeg(tmpState.angle).toFixed(2);
         const label =  props.customText || `${angle}\u00B0`;
         const radius = Math.max(2, tmpState.sphereA.radius, tmpState.sphereB.radius, tmpState.sphereC.radius, tmpState.sphereD.radius);
         const scale = radius / 2;

src/mol-theme/label.ts

@@ -330,7 +330,7 @@ export function angleLabel(triple: Loci.Bundle<3>, options: Partial<LabelOptions
 export function dihedralLabel(quad: Loci.Bundle<4>, options: Partial<LabelOptions & { measureOnly: boolean }> = {}) {
     const o = { ...DefaultLabelOptions, measureOnly: false, ...options };
     const [cA, cB, cC, cD] = quad.loci.map(l => Loci.getCenter(l)!);
-    const dihedral = `${Math.abs(radToDeg(Vec3.dihedralAngle(cA, cB, cC, cD))).toFixed(2)}\u00B0`;
+    const dihedral = `${radToDeg(Vec3.dihedralAngle(cA, cB, cC, cD)).toFixed(2)}\u00B0`;
     if (o.measureOnly) return dihedral;
     const label = bundleLabel(quad, o);
     return o.condensed ? `${dihedral} | ${label}` : `Dihedral ${dihedral}</br>${label}`;