rotate-scale

本文回答：旋转 = entity.rotate(basePoint, angle)，basePoint 用 new Point2D(x, y)，angle 是弧度；缩放 = entity.scale(basePoint, factor)。命令版 ROTATE / SCALE，支持 R（参考）模式，ROTATE 还支持 C 复制旋转。

一、旋转

const rect = createRect(40, 40, 40, 20);
rect.color = 1;
Engine.addEntities(rect);

const basePoint = new Point2D(60, 50);

const rect45 = rect.clone();
rect45.rotate(basePoint, Math.PI / 4);
rect45.color = 2;

const rect90 = rect.clone();
rect90.rotate(basePoint, Math.PI / 2);
rect90.color = 3;

Engine.addEntities([rect45, rect90]);
Engine.regen();

MCP 参考：vjcad/example/edit/03rotate.js。

angle 是弧度：Math.PI / 2 ↔ 90°；正值逆时针；负值顺时针。

二、缩放

const basePoint = new Point2D(0, 0);

const c = new CircleEnt([50, 50], 20);
c.setDefaults();
c.color = 1;
Engine.addEntities(c);

const half = c.clone();
half.scale(basePoint, 0.5);
half.color = 2;

const big  = c.clone();
big.scale(basePoint, 1.5);
big.color = 3;

Engine.addEntities([half, big]);
Engine.regen();

MCP 参考：vjcad/example/edit/04scale.js。

三、命令版

Engine.editor.executerWithOp('ROTATE');
Engine.editor.executerWithOp('SCALE');

ROTATE 命令选项：

SCALE 命令选项：

MCP 参考：vjcad/doc/edit/edit-commands.md。

反例

• entity.rotate(basePoint, 45) 把 45 当度数：是弧度。用 Math.PI / 4。
• basePoint 传 [x, y] 数组：示例用 Point2D，但[x,y] 数组同样生效（内部转 Point2D），scale([0,0],0.5) 与 scale(new Point2D(0,0),0.5) 结果一致。
• 没 Engine.regen()：屏幕看不到变化。

参考（官方文档 MCP）

• 文档：vjcad/doc/edit/index.md、vjcad/doc/edit/edit-commands.md
• 示例：vjcad/example/edit/03rotate.js、vjcad/example/edit/04scale.js