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jwl-applet/src/pages/index/components/ggl/scraping.vue

280 lines
7.6 KiB

<template>
<view class="scraping-happy" id="container">
<canvas canvas-id="scraping-happy" class="scraping__canvas" :disable-scroll="true" @touchstart="touchstart"
@touchmove="touchmove" @touchend="touchend" />
<cover-view class="scraping__view">
{{ showText }}
</cover-view>
<slot></slot>
</view>
</template>
<script>
/** @name 水印配置默认值 **/
const WATERMARK = {
text: '刮一刮',
fontSize: 14,
color: '#C5C5C5',
}
/** @name 标题配置默认值 **/
const TITLE = {
text: '刮一刮',
fontSize: 16,
color: '#333',
}
/**
* @name 涂层配置默认值
* @property { string } color 涂层颜色
* @property { number } drawSize 清除涂层的画笔大小
*/
const MASK = {
color: '#DDDDDD',
drawSize: 20,
}
/** @name 容错值,解决部分机型涂层没有覆盖满的情况,主要原因是由于像素尺寸不同导致的,应尽可能让width与height保持整数 **/
const TOLERANT = 3;
let ctx = null;
export default {
props: {
/** @name 涂层设置 **/
mask: {
type: [String, Object],
},
/** @name 水印设置 **/
watermark: {
type: [String, Object],
},
/** @name 提示文字 **/
title: {
type: [String, Object],
},
/** @name 刮开百分之多少直接消除图层,为0的时候不消除 **/
percentage: {
type: Number,
default: 40,
},
result: {
type: String,
default: ''
}
},
data() {
return {
width: 0,
height: 0,
touchX: 0,
touchY: 0,
showText: ''
}
},
computed: {
maskSetting() {
return {
...MASK,
...(typeof this.mask === 'object' ? this.mask : {
text: this.mask
}),
}
},
watermarkSetting() {
return {
...WATERMARK,
...(typeof this.watermark === 'object' ? this.watermark : {
text: this.watermark
}),
};
},
titleSetting() {
return {
...TITLE,
...(typeof this.title === 'object' ? this.title : {
text: this.title
}),
};
}
},
mounted() {
// 获取画布实例
ctx = uni.createCanvasContext('scraping-happy', this);
this.init();
},
methods: {
/** @name 初始化 **/
init() {
const query = uni.createSelectorQuery().in(this);
query
.select('#container')
.boundingClientRect(({
width,
height
}) => {
this.width = width;
this.height = height;
setTimeout(() => {
this.initCanvas();
this.showText = this.result
}, 20)
})
.exec();
},
/** @name 初始化canvas状态 **/
initCanvas() {
const {
width,
height
} = this;
// 清空矩形内容
ctx.clearRect(0, 0, width, height);
// 设置画笔颜色
ctx.setFillStyle(this.maskSetting.color);
// 绘制矩形
ctx.fillRect(0, 0, width, height + TOLERANT);
// 绘制水印
this.drawWatermark();
// 绘制提示文字
this.drawTitle();
// 绘制到canvas身上
ctx.draw();
},
/** @name 绘制水印 **/
drawWatermark() {
if (!this.watermarkSetting.text) return;
// 保存当前的绘图上下文
ctx.save();
// 旋转
ctx.rotate((-10 * Math.PI) / 180);
// 水印具体绘制过程
const {
width,
height
} = this;
const watermarkWidth = this.watermarkSetting.text.length * this.watermarkSetting.fontSize;
let x = 0;
let y = 0;
let i = 0;
while ((x <= width * 5 || y <= height * 5) && i < 300) {
ctx.setFillStyle(this.watermarkSetting.color);
ctx.setFontSize(this.watermarkSetting.fontSize);
ctx.fillText(this.watermarkSetting.text, x, y);
x += watermarkWidth + watermarkWidth * 1.6;
if (x > width && y <= height) {
x = -Math.random() * 100;
y += this.watermarkSetting.fontSize * 3;
}
i++;
}
ctx.restore();
},
/** @name 绘制提示文字 **/
drawTitle() {
if (!this.titleSetting.text) return;
ctx.setTextAlign('center');
ctx.setTextBaseline('middle');
ctx.setFillStyle(this.titleSetting.color);
ctx.setFontSize(this.titleSetting.fontSize);
ctx.fillText(this.titleSetting.text, this.width / 2, this.height / 3);
},
/** @name 触摸事件 **/
touchstart(e) {
this.touchX = e.touches[0].x;
this.touchY = e.touches[0].y;
},
async touchmove(e) {
// 把画笔到画布中的指定点
ctx.moveTo(this.touchX, this.touchY);
// 清除涂层
ctx.clearRect(this.touchX, this.touchY, this.maskSetting.drawSize, this.maskSetting.drawSize);
ctx.draw(true);
// 记录移动点位
this.touchX = e.touches[0].x;
this.touchY = e.touches[0].y;
// if (this.percentage > 0) {
// const clearPercent = await this.getClearMaskPercent();
// }
},
async touchend() {
if (this.percentage > 0) {
const clearPercent = await this.getClearMaskPercent();
if (clearPercent >= this.percentage) {
ctx.moveTo(0, 0);
ctx.clearRect(0, 0, this.width, this.height);
ctx.stroke();
ctx.draw(true);
this.$emit('complete')
}
}
},
/** @name 计算被清除的涂层百分比 **/
getClearMaskPercent() {
return new Promise(resolve => {
uni.canvasGetImageData({
canvasId: 'scraping-happy',
x: 0,
y: 0,
width: this.width,
height: this.height,
success: res => {
// 区域内所有点的像素信息,它是一个数组,数组中每 "4" 项表示一个点的 rgba 值
const allPointPixels = res.data;
// 储存被清除的点-点的透明度
const clearPoint = [];
// 取透明度来判断,如果透明度值小于一半,则判断为该点已经被清除
for (let i = 0; i < allPointPixels.length; i += 4) {
if (allPointPixels[i + 3] < 128) {
clearPoint.push(allPointPixels[i + 3]);
}
}
// 已被清除的百分比 = 清除的点 / 全部的点
const percent = (
(clearPoint.length / (allPointPixels.length / 4)) *
100
).toFixed(2);
resolve(percent);
},
fail: e => {
console.log('canvasGetImageData', e);
},
}, this);
});
},
/** @name 重置 **/
reset() {
this.initCanvas();
this.touchX = 0;
this.touchY = 0;
}
}
};
</script>
<style>
.scraping-happy {
width: 100%;
height: 200rpx;
position: relative;
display: flex;
justify-content: center;
align-items: center;
}
.scraping__canvas {
width: 100%;
height: 100%;
position: absolute;
z-index: 10;
/* background-color: red; */
display: inline-block;
}
.scraping__view {
position: absolute;
z-index: 1;
color: #f29100;
font-size: 20px;
font-weight: bold;
letter-spacing: 8px;
}
</style>