這篇文章主要介紹多段線實現布爾運算的方法

先上代碼

function getOperatedCurves(sourceCurs: Curve[], targetCus: Curve[])  {    let source: Polyline | Circle = (sourceCurs[0] instanceof Circle) ? sourceCurs[0] as Circle : new Polyline().Combine(sourceCurs)[0];    let target: Polyline | Circle = (targetCus[0] instanceof Circle) ? targetCus[0] as Circle : new Polyline().Combine(targetCus)[0];    try    {      if (!source.IsClose || !target.IsClose) throw new Error("不是封閉曲線");    }    catch (err)    {      console.log(err);    }    let interPts = source.IntersectWith(target, IntersectOption.OnBothOperands);    let sourceContainerTarget = isTargetCurInSourceCur(source, target);    let targetContainerSource = isTargetCurInSourceCur(target, source);    let isContainer = sourceContainerTarget || targetContainerSource;    let intersectionList: Curve[] = []; //交集    let unionList: Curve[] = []; //并集    let subList: Curve[] = []; //補集    /*    *兩封閉區域有交點并且不是包含關系,則通過交點把區域分割    */    if (interPts.length && !isContainer)    {      let pars1 = interPts.map(p => source.GetParamAtPoint(p)).sort((a, b) => a - b);      let pars2 = interPts.map(p => target.GetParamAtPoint(p)).sort((a, b) => a - b);      let cus1: Array<Polyline | Arc> = source.GetSplitCurves(pars1);      cus1.forEach(pl =>      {        if (isTargetCurInSourceCur(target, pl))        {          intersectionList.push(pl);        }        else        {          subList.push(pl);          unionList.push(pl);        }      })      let cus2: Array<Polyline | Arc> = target.GetSplitCurves(pars2);      cus2.forEach(pl =>      {        if (isTargetCurInSourceCur(source, pl))        {          intersectionList.push(pl);          subList.push(pl);        }        else        {          unionList.push(pl);        }      })    }    else    {      if (isContainer)      {        if (sourceContainerTarget)        {          intersectionList.push(target);          subList.push(source, target);          unionList.push(source);        }        else        {          unionList.push(target);          intersectionList.push(source);        }      }      else      {        unionList.push(source, target)        subList.push(source);      }    }    return {      intersectionList, unionList, subList    }  }

由于一些曲線類實現方法不一，這里主要說一些實現布爾運算的思路

判斷2封閉曲線是否是被包含的關系 獲取2封閉曲線的所有交點，這里交點可能是圓和線，線和線，圓和圓的，求交點的方法網上應該很多，以后有時間也會寫寫用JavaScript實現方式 根據所有的交點把2封閉曲線分割為多個部分 對分割后的線段進行整理，其中相交部分是曲線在對方曲線內部的部分，合并是互不在對方曲線內部的部分，相減類似不想說了，具體看代碼，如果是被包含狀態則更加就簡單了