修复:偏移算法,在圆弧被压成0长度圆弧时,精度问题导致的圆弧变成全圆,从而导致偏移错误

__test__/Polyline/__snapshots__/offset3.test.ts.snap

@@ -0,0 +1,5 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`圆弧被压扁时 1`] = `1`;
+
+exports[`圆弧被压扁时 2`] = `"1260.08305"`;

__test__/Polyline/offset.test.ts

@@ -21,7 +21,7 @@ function EntityToMatchSnapshot(ens: Curve[])
     }
 }
 
-function testOffset(pl: Curve, dis)
+function testOffset(pl: Curve, dis: number)
 {
     let cus = pl.GetOffsetCurves(dis);
     EntityToMatchSnapshot(cus);

__test__/Polyline/offset3.test.ts

@@ -0,0 +1,36 @@
+import { Factory } from "../../src/DatabaseServices/CADFactory";
+import { Curve } from "../../src/DatabaseServices/Entity/Curve";
+import { Polyline } from "../../src/DatabaseServices/Entity/Polyline";
+import "../Utils/jest.util";
+import { LoadEntityFromFileData } from "../Utils/LoadEntity.util";
+
+Factory(Polyline);
+
+function loadFile(data)
+{
+    return LoadEntityFromFileData(data) as Curve[];
+}
+
+function EntityToMatchSnapshot(ens: Curve[])
+{
+    expect(ens.length).toMatchSnapshot();
+    for (let c of ens)
+    {
+        expect(c.Length).toMatchNumberSnapshot();
+    }
+}
+
+function testOffset(pl: Curve, dis: number)
+{
+    let cus = pl.GetOffsetCurves(dis);
+    EntityToMatchSnapshot(cus);
+}
+
+test('圆弧被压扁时', () =>
+{
+    let pl = loadFile(
+        { "file": [1, "Polyline", 8, 2, 154, false, 1, 7, 0, [1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 377.4539113436276, 1247.0593462341237, 0, 1], 0, 0, true, [1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1], 0, 2, 6, [0, 0], 0, [19.763395114298646, 0], 0, [19.763395114298646, -77.16333081989751], 0, [620.8495708336222, 2], 0, [12.422828246409608, 2], 0.07998201834820468, [0, 0], 0, false], "basePt": { "x": 377.4539113436276, "y": 1169.8960154142262, "z": 0 }, "ucs": [1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1] }
+    )[0] as Polyline;
+
+    testOffset(pl, -1);
+});

src/GraphicsSystem/OffsetPolyline.ts

@@ -10,7 +10,7 @@ import { Curve } from "../DatabaseServices/Entity/Curve";
 import { Line } from "../DatabaseServices/Entity/Line";
 import { Polyline } from "../DatabaseServices/Entity/Polyline";
 import { IntersectsBox } from "../Geometry/Box";
-import { CurveMap, Vertice, Route } from "../Geometry/CurveMap";
+import { CurveMap, Route, Vertice } from "../Geometry/CurveMap";
 import { angle, equaln, equalv2, equalv3, IdentityMtx4, SelectNearP } from "../Geometry/GeUtils";
 import { SortEntityByBox } from "../Geometry/SortEntityByBox";
 import { IntersectOption } from "../GraphicsSystem/IntersectWith";
@@ -388,6 +388,19 @@ export class OffsetPolyline
             }
             if (d.sp) cu2.StartPoint = d.sp;
             if (d.ep) cu2.EndPoint = d.ep;
+
+            //这是极端情况,圆弧被压缩成0长度圆弧,本质是空圆弧(我们会在下面判断它)(因为精度的问题)
+            //因为精度的问题,这种0圆心角的圆弧会被当成全圆,但是偏移算法中,应该不可能出现全圆弧的圆弧,所以我们压扁它
+            if (cu2 instanceof Arc
+                && equaln(cu2.StartAngle, cu2.EndAngle, 1e-6)
+                // && !equaln((<Arc>this._SubCurves[d.index]).AllAngle, Math.PI * 2, 1e-3) 应该不会出现
+            )
+            {
+                if (cu2.IsClockWise)
+                    cu2.StartAngle = cu2.EndAngle + 1e-6;
+                else
+                    cu2.EndAngle = cu2.StartAngle + 1e-6;
+            }
         }
         for (let d of this._SubOffsetedCurves)
         {
@@ -456,7 +469,7 @@ export class OffsetPolyline
             if (l1Intact && d.preArc && d.preArc instanceof Arc)
             {
                 let a = d.preArc;
-                if (Math.sign(a.Bul) !== this._OffsetDistSign)
+                if (Math.sign(a.Bul) !== this._OffsetDistSign && a.AllAngle > 1e-6)
                 {
                     let ipts = a.IntersectWith(l1, IntersectOption.OnBothOperands);
                     if (ipts.length === 2)
@@ -471,7 +484,7 @@ export class OffsetPolyline
             if (l2Intact && d.nextArc && d.nextArc instanceof Arc)
             {
                 let a = d.nextArc;
-                if (Math.sign(a.Bul) !== this._OffsetDistSign)
+                if (Math.sign(a.Bul) !== this._OffsetDistSign && a.AllAngle > 1e-6)
                 {
                     let ipts = a.IntersectWith(l2, IntersectOption.OnBothOperands);
                     if (ipts.length === 2)