adding snapping code between ink strokes. added some componentView API functions to convert local (eg ink) points to/from screen space and for snapping

1 files changed, 26 insertions, 0 deletions

diff --git a/src/client/views/InkingStroke.tsx b/src/client/views/InkingStroke.tsx
index 24c2d7651..b258ea741 100644
--- a/src/client/views/InkingStroke.tsx
+++ b/src/client/views/InkingStroke.tsx
@@ -124,6 +124,32 @@ export class InkingStroke extends ViewBoxBaseComponent<FieldViewProps, InkDocume
         }
     }
 
+    ptFromScreen = (scrPt: { X: number, Y: number }) => {
+        const { inkScaleX, inkScaleY, inkStrokeWidth, inkTop, inkLeft } = this.inkScaledData();
+        const docPt = this.props.ScreenToLocalTransform().transformPoint(scrPt.X, scrPt.Y);
+        const inkPt = {
+            X: (docPt[0] - inkStrokeWidth / 2) / inkScaleX + inkStrokeWidth / 2 + inkLeft,
+            Y: (docPt[1] - inkStrokeWidth / 2) / inkScaleY + inkStrokeWidth / 2 + inkTop,
+        }
+        return inkPt;
+    }
+    ptToScreen = (inkPt: { X: number, Y: number }) => {
+        const { inkScaleX, inkScaleY, inkStrokeWidth, inkTop, inkLeft } = this.inkScaledData();
+        const docPt = {
+            X: (inkPt.X - inkLeft - inkStrokeWidth / 2) * inkScaleX + inkStrokeWidth / 2,
+            Y: (inkPt.Y - inkTop - inkStrokeWidth / 2) * inkScaleY + inkStrokeWidth / 2
+        };
+        const scrPt = this.props.ScreenToLocalTransform().inverse().transformPoint(docPt.X, docPt.Y);
+        return { X: scrPt[0], Y: scrPt[1] };
+    }
+
+    snapPt = (scrPt: { X: number, Y: number }) => {
+        const { inkData } = this.inkScaledData();
+        const inkPt = this.ptFromScreen(scrPt);
+        const { nearestPt, distance } = InkStrokeProperties.nearestPtToStroke(inkData, inkPt, []);
+        return { nearestPt, distance: distance * this.props.ScreenToLocalTransform().inverse().Scale };
+    }
+
     inkScaledData = () => {
         const inkData = Cast(this.dataDoc[this.fieldKey], InkField)?.inkData ?? [];
         const inkStrokeWidth = NumCast(this.rootDoc.strokeWidth, 1);