construct offset based on constraints

web/app/3d/cad-utils.js

@@ -348,20 +348,8 @@ export function normalOfCCWSeqTHREE(ccwSequence) {
   return b.sub(a).cross(c.sub(a)).normalize();
 }
 
-
-// http://en.wikipedia.org/wiki/Shoelace_formula
-export function area(contour) {
-  var n = contour.length;
-  var a = 0.0;
-  for ( var p = n - 1, q = 0; q < n; p = q ++ ) {
-    a += contour[ p ].x * contour[ q ].y - contour[ q ].x * contour[ p ].y;
-  }
-  return a * 0.5;
-}
-
-export function isCCW(path2D) {
-  return area(path2D) >= 0;
-}
+export const area = math.area;
+export const isCCW = math.isCCW;
 
 export function calculateExtrudedLid(sourcePolygon, normal, direction, expansionFactor) {
   var lid = [];

web/app/math/math.js

@@ -175,4 +175,18 @@ export function isPointInsidePolygon( inPt, inPolygon ) {
   return	inside;
 }
 
+// http://en.wikipedia.org/wiki/Shoelace_formula
+export function area(contour) {
+  var n = contour.length;
+  var a = 0.0;
+  for ( var p = n - 1, q = 0; q < n; p = q ++ ) {
+    a += contour[ p ].x * contour[ q ].y - contour[ q ].x * contour[ p ].y;
+  }
+  return a * 0.5;
+}
+
+export function isCCW(path2D) {
+  return area(path2D) >= 0;
+}
+
 export const sq = (a) => a * a;

web/app/sketcher/constr/constraints.js

@@ -9,6 +9,8 @@ function createByConstraintName(name, params, values) {
       return new Equal(params);
     case "equalsTo":
       return new EqualsTo(params, values[0]);
+    case "Diff":
+      return new Diff(params, values[0]);
     case "MinLength":
       return new MinLength(params, values[0]);
     case "perpendicular":
@@ -201,6 +203,21 @@ function EqualsTo(params, value) {
   };
 }
 
+function Diff(params, value) {
+
+  this.params = params;
+  this.value = value;
+
+  this.error = function() {
+    return this.params[0].get() - this.params[1].get() - this.value;
+  };
+
+  this.gradient = function(out) {
+    out[0] =  1;
+    out[1] = -1;
+  };
+}
+
 /** @constructor */
 function P2LDistance(params, distance) {
 

web/app/sketcher/parametric.js

@@ -402,7 +402,7 @@ ParametricManager.prototype.radius = function(objs, promptCallback) {
   }
 };
 
-ParametricManager.prototype.linkObjects = function(objs) {
+ParametricManager.prototype._linkObjects = function(objs) {
   var i;
   var masterIdx = -1;
   for (i = 0; i < objs.length; ++i) {
@@ -423,6 +423,10 @@ ParametricManager.prototype.linkObjects = function(objs) {
     var c = new Constraints.Coincident(objs[i], objs[masterIdx]);
     this._add(c);
   }
+};
+
+ParametricManager.prototype.linkObjects = function(objs) {
+  this._linkObjects(objs);
   this.notify();
 };
 
@@ -888,6 +892,38 @@ Constraints.Coincident.prototype.getObjects = function() {
 
 // ------------------------------------------------------------------------------------------------------------------ //
 
+/** @constructor */
+Constraints.RadiusOffset = function(arc1, arc2, offset) {
+  this.arc1 = arc1;
+  this.arc2 = arc2;
+  this.offset = offset;
+};
+
+Constraints.RadiusOffset.prototype.NAME = 'RadiusOffset';
+Constraints.RadiusOffset.prototype.UI_NAME = 'Radius Offset';
+
+Constraints.RadiusOffset.prototype.getSolveData = function() {
+  return [
+    ['Diff', [this.arc1.r, this.arc2.r], [this.offset]]
+  ];
+};
+
+Constraints.RadiusOffset.prototype.serialize = function() {
+  return [this.NAME, [this.arc1.id, this.arc2.id, this.offset]];
+};
+
+Constraints.Factory[Constraints.RadiusOffset.prototype.NAME] = function(refs, data) {
+  return new Constraints.RadiusOffset(refs(data[0]), refs(data[1]), data[2]);
+};
+
+Constraints.RadiusOffset.prototype.getObjects = function() {
+  return [this.arc1, this.arc2];
+};
+
+Constraints.RadiusOffset.prototype.SettableFields = {'offset' : "Enter the offset"};
+
+// ------------------------------------------------------------------------------------------------------------------ //
+
 /** @constructor */
 Constraints.Lock = function(p, c) {
   this.p = p;

web/app/sketcher/tools/loop-pick.js

@@ -9,12 +9,14 @@ export class LoopPickTool extends Tool {
     this.loops = new Map();
     this.marked = new Set();
     this.pickedLoop = null;
-  }
+    this.pointToObject = new Map();
+  }  
 
   restart() {
     this.sendHint('pick a polygon');
     this.reindexLoops();
     this.marked.clear();
+    this.pointToObject.clear();
     this.pickedLoop = null;
   };
 
@@ -56,8 +58,8 @@ export class LoopPickTool extends Tool {
     const graph = {
 
       connections : (p) => {
-        const conns = [this.otherEnd(p)];
-        p.linked.forEach(l => conns.push(this.otherEnd(l)));
+        const conns = p.linked.slice();
+        conns.push(this.otherEnd(p));
         return conns;
       },
 
@@ -69,22 +71,37 @@ export class LoopPickTool extends Tool {
         return points.length;
       }
     };
-    const loops = Graph.findAllLoops(graph, (p) => p.id, (a, b) => a.id == b.id);
+    const loopPoints = Graph.findAllLoops(graph, (p) => p.id, (a, b) => a.id == b.id);
+    const loops = loopPoints.map(l => this.cleanLoop(l));
     for (let loop of loops) {
-      for (let point of loop) {
+      for (let point of loop.points) {
         this.loops.set(point, loop);
       }
     }
   }
 
+  cleanLoop(loop) {
+    const points = [];
+    const edges = [];
+    for (var i = 0; i < loop.length; i++) {
+      const a = loop[i];
+      const b = loop[(i + 1) % loop.length];
+      if (a.parent == b.parent) {
+        points.push(a);
+        edges.push(b.parent);
+      }
+    }
+    return {points, edges};
+  }
+  
   mousemove(e) {
     this.clearMarked();
     this.pickedLoop = null;
     const p = this.viewer.screenToModel(e);
     this.pickedLoop = this.pickLoop(p);
     if (this.pickedLoop != null) {
-      for (let p of this.pickedLoop) {
-        this.mark(p.parent);
+      for (let obj of this.pickedLoop.edges) {
+        this.mark(obj);
       }
     }
     this.viewer.refresh();
@@ -115,3 +132,17 @@ export class LoopPickTool extends Tool {
   onMousedown(e) {};
 
 }
+
+function getEdgeFor(a, b) {
+  if (isEdgeFor(a.parent, a, b)) {
+    return a.parent
+  } else if (isEdgeFor(b.parent, a, b)) {
+    return b.parent;
+  } else {
+    return null;
+  }
+}
+
+function isEdgeFor(obj, a, b) {
+  return (obj.a.id == a.id && obj.b.id == b.id) || (obj.a.id == b.id && obj.b.id == b.id)
+}

web/app/sketcher/tools/offset.js

@@ -1,5 +1,11 @@
 import {LoopPickTool} from './loop-pick'
+import {Constraints} from '../parametric'
 import * as math from '../../math/math';
+import Vector from '../../math/vector';
+import {swap} from '../../utils/utils'
+import ClipperLib from '../../../lib/clipper'
+import {EndPoint} from '../shapes/point'
+import {Arc} from '../shapes/arc'
 
 export class OffsetTool extends LoopPickTool {
 
@@ -8,20 +14,103 @@ export class OffsetTool extends LoopPickTool {
   }
 
   onMousedown(e) {
-    const delta = prompt('offset distance?');
-    const offsetPolygon = math.polygonOffsetByDelta(this.pickedLoop, parseInt(delta));
-    const length = offsetPolygon.length;
-    const segments = [];
-    for (let p = length - 1, q = 0; q < length; p = q++) {
-      const a = offsetPolygon[p];
-      const b = offsetPolygon[q];
-      const segment = this.viewer.addSegment(a.x, a.y, b.x, b.y, this.viewer.activeLayer);
-      segments.push(segment);
+    const loopPoints = this.pickedLoop.points;
+    const loopEdges = this.pickedLoop.edges;
+    const length = loopPoints.length;
+
+    for (let obj of loopEdges) {
+      if (!SUPPORTED_OBJECTS.has(obj._class)) {
+        alert(obj._class + " isn't supported for offsets");
+        return;
+      }
     }
-    for (var i = 0; i < segments.length; i++) {
-      this.viewer.parametricManager.linkObjects([segments[i].b, segments[(i + 1) % segments.length].a]);
+    let delta = parseInt(prompt('offset distance?', 100));
+    const absDelta = Math.abs(delta);
+    
+    const edges = [];
+    const startPoint = findLowestPoint(loopPoints);
+    const start = loopPoints.indexOf(startPoint);
+    if (start == -1) {
+      return;
     }
+
+    function pos(i) {
+      return (i + start) % length;
+    }
+
+    if (!math.isCCW([loopPoints[pos(0)], loopPoints[pos(1)], loopPoints[pos(length - 1)]])) {
+      delta *= -1;
+    }
+    
+    const arcs = [];
+    
+    for (let i = 0; i < length; ++i) {
+      const a = loopPoints[pos(i)];
+      const b = loopPoints[pos(i + 1)];
+      const normal = new Vector(-(b.y - a.y), (b.x - a.x))._normalize();
+      const offVector = normal._multiply(delta);
+      const origEdge = loopEdges[pos(i)];
+      const aOffX = a.x + offVector.x;
+      const aOffY = a.y + offVector.y;
+      const bOffX = b.x + offVector.x;
+      const bOffY = b.y + offVector.y;
+      if (origEdge._class == 'TCAD.TWO.Segment') {
+        const segment = this.viewer.addSegment(aOffX, aOffY, 
+                                               bOffX, bOffY, this.viewer.activeLayer);
+        this.viewer.parametricManager._add(new Constraints.Parallel(origEdge, segment));
+        this.viewer.parametricManager._add(new Constraints.P2LDistance(a, segment, absDelta));
+        edges.push(segment);
+      } else if (origEdge._class == 'TCAD.TWO.Arc') {
+        const arc = new Arc(
+          new EndPoint(aOffX, aOffY),
+          new EndPoint(bOffX, bOffY),
+          new EndPoint(origEdge.c.x + offVector.x, origEdge.c.y + offVector.y)
+        );
+        arc.stabilize(this.viewer);
+        this.viewer.parametricManager._linkObjects([origEdge.c, arc.c]);
+        this.viewer.parametricManager._add(new Constraints.RadiusOffset(origEdge, arc, delta));
+        this.viewer.activeLayer.add(arc);
+        edges.push(arc);
+        arcs.push(arc);
+      }
+    }
+
+    arcs.forEach(e => e.c.aux = true);
+    for (let i = 0; i < edges.length; i++) {
+      this.viewer.parametricManager._linkObjects([edges[i].b, edges[(i + 1) % edges.length].a]);
+    }
+    loopEdges.forEach(e => e.aux = true);
+    this.viewer.parametricManager.refresh();
+    loopEdges.forEach(e => e.aux = false);
+    arcs.forEach(e => e.c.aux = false);
     this.viewer.toolManager.releaseControl();
-    this.viewer.refresh();
   }
 }
+
+
+function segmentToVector(segment) {
+  return new Vector(segment.b.x - segment.a.x, segment.b.y - segment.a.y);
+}
+
+const SUPPORTED_OBJECTS = new Set();
+SUPPORTED_OBJECTS.add('TCAD.TWO.Segment');
+SUPPORTED_OBJECTS.add('TCAD.TWO.Arc');
+
+function SimpleSegment(a, b) {
+  this.a = a;
+  this.b = b;
+}
+
+function findLowestPoint(poly) {
+  let hero = {x: Number.MAX_VALUE, y: Number.MAX_VALUE};
+  for (let point of poly) {
+    if (point.y < hero.y) {
+      hero = point;
+    } else if (hero.y == hero.y) {
+      if (point.x < hero.x) {
+        hero = point;
+      }
+    }
+  }  
+  return hero;
+}