cocos creator 鼠标画笔|画线

cocos creator 版本使用 至少适配版本2.3.2以上
案例:

简要思路:MOUSE_MOVE事件和Graphics组件实现
前端也可以通过canvas和mousemove事件实现，原理一致

具体步骤如下：

1.添加节点Node
2.在Node节点上绑定组件Graphics
3.添加下方脚本drawcontroll.ts
4.注意Node节点的锚点和位置（如果不想要这个方法，可以看最下方解决方案）

drawcontroll.ts全部代码

import { _decorator, Component, Color, Node, Graphics, Vec3, UITransform } from 'cc';
const { ccclass, property } = _decorator;

@ccclass('drawcontroll')
export class drawcontroll extends Component {
    graphics=null;
    isDrawing = false;
    array = [];

    start() {
        this.graphics = this.getComponent(Graphics);
        this.graphics.lineWidth = 5;
        this.graphics.strokeColor = Color.RED;
        this.node.on(Node.EventType.MOUSE_DOWN, this.onMouseDown, this);
        this.node.on(Node.EventType.MOUSE_MOVE, this.onMouseMove, this);
        this.node.on(Node.EventType.MOUSE_UP, this.onMouseUp, this);
    }
        onMouseDown (event) {
            this.isDrawing = true;
            this.graphics.moveTo(event.getLocation().x,event.getLocation().y);
        }
        onMouseMove (event) {
            if (this.isDrawing) {
                this.graphics.lineTo(event.getLocation().x,event.getLocation().y);
                this.graphics.stroke();
            }
        }
        onMouseUp (event) {
            this.isDrawing = false;
        }
}

注意事项：
当如果发现鼠标画出来的线和鼠标轨迹有很大偏移，有两种方法

1. 浏览器是否是缩小放大状态 -----调整为百分之百
2. 锚点和位置设置的问题

创建的Node脚本的锚点和位置在不变的情况下(锚点0.5,0.5,位置0，0)

那么只需要将上面drawcontroll.ts代码替换即可

		onMouseDown (event) {
            this.isDrawing = true;
            const moveToPoint = this.node.parent.getComponent(UITransform).convertToNodeSpaceAR(new Vec3(event.getLocation().x,event.getLocation().y,0));
            this.graphics.moveTo(moveToPoint.x,moveToPoint.y);
        }
        onMouseMove (event) {
            if (this.isDrawing) {
                const lineToPoint = this.node.parent.getComponent(UITransform).convertToNodeSpaceAR(new Vec3(event.getLocation().x,event.getLocation().y,0));
                this.graphics.lineTo(lineToPoint.x,lineToPoint.y);
                this.graphics.stroke();
            }
        }

convertToNodeSpaceAR方法解说如下：

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关键词：
cocos creator 鼠标画笔|画线， cocos creator画线 ， cocos creator 画笔， cocos creator 画形状， cocos creator 画图