自定义实体
在 mxcad 中，我们支持用户自定义实体，可以根据具体的需求来创建和管理自定义实体。我们可以通过从自定义实体类 McDbCustomEntity() 中继承实体的名称、属性、方法等，也可结合自身需求对自定义实体类中的属性或方法进行重写。下面以自定义一条直线为例：
通过重写 dwgInFields() 函数读取自定义实体数据，dwgOutFields() 函数写入自定义实体数据（在从文件读取实体或把实体写入文件时，复制实体等地方都会调用这两个函数）。
getGripPoints() 方法是在点击这个渲染好的图形时提供一个操作点位，即返回自定义的编辑夹点，并在点击操作点移动的回调函数moveGripPointsAt() 中处理夹点编辑结果。
动态绘制 worldDraw() 方法能够绘制自定义实体的显示效果。
每次触发动态绘制worldDraw，就会将原本的实例对象删掉(同时也会删除渲染的three.js物体对象)，通过create方法重新创建实例。
点击 McDbCustomEntity 查看详细属性和方法说明。
ts
import { IMcDbDwgFiler, McDbCustomEntity, McDbLine, McGePoint3d, McGePoint3dArray, MxCADUiPrPoint, MxCADWorldDraw, MxCpp } from "mxcad";
import { MxFun } from "mxdraw";
class McDbTestLineCustomEntity extends McDbCustomEntity {
private pt1: McGePoint3d = new McGePoint3d();
private pt2: McGePoint3d = new McGePoint3d();
constructor(imp?: any) {
super(imp);
}
public create(imp: any) {
return new McDbTestLineCustomEntity(imp)
}
public getTypeName(): string {
return "McDbTestLineCustomEntity";
}
public dwgInFields(filter: IMcDbDwgFiler): boolean {
this.pt1 = filter.readPoint("pt1").val;
this.pt2 = filter.readPoint("pt2").val;
return true;
}
public dwgOutFields(filter: IMcDbDwgFiler): boolean {
filter.writePoint("pt1", this.pt1);
filter.writePoint("pt2", this.pt2);
return true;
}
public moveGripPointsAt(iIndex: number, dXOffset: number, dYOffset: number, dZOffset: number) {
this.assertWrite();
if (iIndex == 0) {
this.pt1.x += dXOffset;
this.pt1.y += dYOffset;
this.pt1.z += dZOffset;
}
else if (iIndex == 1) {
this.pt2.x += dXOffset;
this.pt2.y += dYOffset;
this.pt2.z += dZOffset;
}
};
public getGripPoints(): McGePoint3dArray {
let ret = new McGePoint3dArray()
ret.append(this.pt1);
ret.append(this.pt2);
return ret;
};
public worldDraw(draw: MxCADWorldDraw): void {
let tmpline = new McDbLine(this.pt1, this.pt2);
draw.drawEntity(tmpline);
}
public setPoint1(pt1: McGePoint3d) {
this.assertWrite();
this.pt1 = pt1.clone();
}
public setPoint2(pt2: McGePoint3d) {
this.assertWrite();
this.pt2 = pt2.clone();
}
public getPoint1() {
return this.pt1;
}
public getPoint2() {
return this.pt2;
}
}
async function MxTest_DrawCustomEntity() {
let mxcad = MxCpp.getCurrentMxCAD();
const getPoint = new MxCADUiPrPoint();
getPoint.setMessage("\n指定一点:");
let pt1 = (await getPoint.go());
if (!pt1) return;
getPoint.setBasePt(pt1);
getPoint.setUseBasePt(true);
getPoint.setMessage("\n指定二点:");
let pt2 = (await getPoint.go());
if (!pt2) return;
let myline = new McDbTestLineCustomEntity();
new McDbTestLineCustomEntity().rxInit();
myline.setPoint1(pt1);
myline.setPoint2(pt2);
mxcad.drawEntity(myline);
}
MxTest_DrawCustomEntity()