# 小程序bug

## 1.canvas 自动增加了display:none 属性--OK

增加了canvas-id就会展示了。

## 2. 拖拽延迟

[https://developers.weixin.qq.com/blogdetail?action=get\_post\_info\&docid=000c043a28c2e819bd36628d75b000\&highline=旋转 缩放\&token=1894067750\&lang=zh\_CN](https://developers.weixin.qq.com/blogdetail?action=get_post_info\&docid=000c043a28c2e819bd36628d75b000\&highline=旋转%20缩放\&token=1894067750\&lang=zh_CN)

* 节流函数
* 移动量大于一定值得时候再setData()
* 使用动画API处理

原来这个原因：

```javascript
/**
   * 触摸小配件中
   */
  partTouchMove: function (e) {
    //获取当前小配件的partTouchData
    //let partTouchData = e.currentTarget.dataset.item.partTouchData;
    //获取当前小配件的id
    let id = e.currentTarget.dataset.item.id;
    let partTouchData = this.data.showDogs[id].partTouchData
```

把

```javascript
let partTouchData = e.currentTarget.dataset.item.partTouchData;
```

改为

```javascript
let partTouchData = this.data.showDogs[id].partTouchData
```

完美解决！！！

可能是通过data-绑定了复杂数据，不断循环获取的时候，会严重影响性能。

## 3. Canvas中如果先fill，clip会失效，需求是保存白底图片

因为要用fill画背景颜色，这个时候再剪切的话就会失效。

**解决方法：**

要使保存的canvas背景色是白色，可以在canvasToTempFilePath中加上一个参数， fileType: 'jpg'即可解决。

但是在Android上这样也不行，可以使用异步处理一下就OK了，好像clip和fillRect也不冲突。

```javascript
context.fillStyle = "#fff";
context.fillRect(0, 0, width, height);
```

## 4. Canvas保存的图片像素太低

将目标图片的长和高\*2

参考：<https://www.cnblogs.com/wmhuang/p/6477223.html>

## 5.


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