fixed hide before/after in trails. move ink mask to developer. fixed tangent dragging on some curves that have no initial tangent. fixed tree view highlights when dragging.

1 files changed, 3 insertions, 2 deletions

diff --git a/src/client/views/InkStrokeProperties.ts b/src/client/views/InkStrokeProperties.ts
index abc4381a6..13bd12361 100644
--- a/src/client/views/InkStrokeProperties.ts
+++ b/src/client/views/InkStrokeProperties.ts
@@ -12,6 +12,7 @@ import { DocumentManager } from '../util/DocumentManager';
 import { undoBatch } from '../util/UndoManager';
 import { InkingStroke } from './InkingStroke';
 import { DocumentView } from './nodes/DocumentView';
+import _ = require('lodash');
 
 export class InkStrokeProperties {
     static _Instance: InkStrokeProperties | undefined;
@@ -262,7 +263,7 @@ export class InkStrokeProperties {
                 var endDir = { x: 0, y: 0 };
                 for (var i = 0; i < nearestSeg / 4 + 1; i++) {
                     const bez = new Bezier(splicedPoints.slice(i * 4, i * 4 + 4).map(p => ({ x: p.X, y: p.Y })));
-                    if (i === 0) startDir = bez.derivative(0);
+                    if (i === 0) startDir = bez.derivative(_.isEqual(bez.derivative(0), { x: 0, y: 0, t: 0 }) ? 1e-8 : 0);
                     if (i === nearestSeg / 4) endDir = bez.derivative(nearestT);
                     for (var t = 0; t < (i === nearestSeg / 4 ? nearestT + 0.05 : 1); t += 0.05) {
                         const pt = bez.compute(i !== nearestSeg / 4 ? t : Math.min(nearestT, t));
@@ -273,7 +274,7 @@ export class InkStrokeProperties {
                 for (var i = nearestSeg / 4; i < splicedPoints.length / 4; i++) {
                     const bez = new Bezier(splicedPoints.slice(i * 4, i * 4 + 4).map(p => ({ x: p.X, y: p.Y })));
                     if (i === nearestSeg / 4) startDir = bez.derivative(nearestT);
-                    if (i === splicedPoints.length / 4 - 1) endDir = bez.derivative(1);
+                    if (i === splicedPoints.length / 4 - 1) endDir = bez.derivative(_.isEqual(bez.derivative(1), { x: 0, y: 0, t: 1 }) ? 1 - 1e-8 : 1);
                     for (var t = i === nearestSeg / 4 ? nearestT : 0; t < (i === nearestSeg / 4 ? 1 + 0.05 + 1e-7 : 1 + 1e-7); t += 0.05) {
                         const pt = bez.compute(Math.min(1, t));
                         samplesRight.push(new Point(pt.x, pt.y));