529 lines
18 KiB
Vue
529 lines
18 KiB
Vue
<template>
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<view class="canvas">
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<view ref="Content" class="theContent">
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<slot></slot>
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</view>
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<canvas canvas-id="myCanvas" id="myCanvas" @onReady="onCanvasReady"
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:style="{ width: width + 'px', height: height + 'px' }"></canvas>
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</view>
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</template>
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<!--
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list参数说明：
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图片渲染：
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type: 'image',
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x: X轴位置,
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y: Y轴位置,
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path: 图片路径,
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width: 图片宽度,
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height: 图片高度,
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rotate: 旋转角度
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mode:'center' 居中自适应
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shape: 形状，默认无，可选值：circle 圆形 如果是number,则生成圆角矩形
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area: {x,y,width,height} // 绘制范围，超出该范围会被剪裁掉 该属性与shape暂时无法同时使用，area存在时，shape失效
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矩形渲染：
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type: 'square',
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x: X轴位置,
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y: Y轴位置,
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width: 图片宽度,
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height: 图片高度,
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rotate: 旋转角度
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shape: 形状，默认无，可选值：circle 圆形 如果是number,则生成圆角矩形
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fillStyle:填充的背景样式
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area: {x,y,width,height} // 绘制范围，超出该范围会被剪裁掉 该属性与shape暂时无法同时使用，area存在时，shape失效
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文字渲染：
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type: 'text',
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x: X轴位置,
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y: Y轴位置,
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text: 文本内容,
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size: 字体大小,
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textBaseline： 基线 默认top 可选值：'top'、'bottom'、'middle'、'normal'
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color: 颜色
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多行文字渲染：
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type: 'textarea',
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x: X轴位置,
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y: Y轴位置,
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width：换行的宽度
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height: 高度，溢出会展示“...”
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lineSpace: 行间距
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text: 文本内容,
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size: 字体大小,
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textBaseline： 基线 默认top 可选值：'top'、'bottom'、'middle'、'normal'
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color: 颜色
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-->
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<script>
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let timer = null;
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export default {
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name: "Poster",
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props: {
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// 绘制队列
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list: {
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type: Array,
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required: true,
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},
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// 海报宽度(默认设备宽度放大两倍) 建议都放大两倍
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width: {
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type: [Number, String],
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default: uni.getSystemInfoSync().windowWidth * 2,
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},
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// 海报高度(默认设备高度放大两倍)
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height: {
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type: [Number, String],
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default: uni.getSystemInfoSync().windowHeight * 2,
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},
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//背景颜色
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backgroundColor: {
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type: String,
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default: "rgba(0,0,0,0)",
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},
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},
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data() {
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return {
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posterUrl: "",
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renderList: [],
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ctx: null, //画布上下文
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counter: -1, //计数器
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drawPathQueue: [], //画图路径队列
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};
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},
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watch: {
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drawPathQueue(newVal, oldVal) {
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// 绘制单行文字
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const fillText = (textOptions) => {
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this.ctx.setFillStyle(textOptions.color);
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this.ctx.setFontSize(textOptions.size);
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this.ctx.setTextBaseline(textOptions.textBaseline || "top");
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this.ctx.fillText(textOptions.text, textOptions.x, textOptions.y);
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};
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// 绘制段落
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const fillParagraph = (textOptions) => {
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this.ctx.setFontSize(textOptions.size);
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let tempOptions = JSON.parse(JSON.stringify(textOptions));
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// 如果没有指定行间距则设置默认值
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tempOptions.lineSpace = tempOptions.lineSpace ? tempOptions.lineSpace : 10;
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// 获取字符串
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let str = textOptions.text;
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// 计算指定高度可以输出的最大行数
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let lineCount = Math.floor((tempOptions.height + tempOptions.lineSpace) / (tempOptions.size +
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tempOptions.lineSpace));
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// 初始化单行宽度
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let lineWidth = 0;
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let lastSubStrIndex = 0; //每次开始截取的字符串的索引
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// 构建一个打印数组
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let strArr = str.split("");
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let drawArr = [];
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let text = "";
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while (strArr.length) {
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let word = strArr.shift();
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text += word;
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let textWidth = this.ctx.measureText(text).width;
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if (textWidth > textOptions.width) {
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// 因为超出宽度 所以要截取掉最后一个字符
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text = text.substr(0, text.length - 1);
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drawArr.push(text);
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text = "";
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// 最后一个字还给strArr
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strArr.unshift(word);
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} else if (!strArr.length) {
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drawArr.push(text);
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}
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}
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if (drawArr.length > lineCount) {
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// 超出最大行数
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drawArr.length = lineCount;
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let pointWidth = this.ctx.measureText("...").width;
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let wordWidth = 0;
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let wordArr = drawArr[drawArr.length - 1].split("");
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let words = "";
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while (pointWidth > wordWidth) {
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words += wordArr.pop();
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wordWidth = this.ctx.measureText(words).width;
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}
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drawArr[drawArr.length - 1] = wordArr.join("") + "...";
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}
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// 打印
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for (let i = 0; i < drawArr.length; i++) {
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let _h = i > 0 ? tempOptions.size + tempOptions.lineSpace : 0;
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tempOptions.y = tempOptions.y + _h; // y的位置
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tempOptions.text = drawArr[i]; // 绘制的文本
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fillText(tempOptions);
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}
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};
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const roundRect = (x, y, w, h, r) => {
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// 开始绘制
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this.ctx.beginPath();
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// 因为边缘描边存在锯齿，最好指定使用 transparent 填充
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// 这里是使用 fill 还是 stroke都可以，二选一即可
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this.ctx.setFillStyle("transparent");
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// ctx.setStrokeStyle('transparent')
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// 左上角
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this.ctx.arc(x + r, y + r, r, Math.PI, Math.PI * 1.5);
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// border-top
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this.ctx.moveTo(x + r, y);
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this.ctx.lineTo(x + w - r, y);
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this.ctx.lineTo(x + w, y + r);
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// 右上角
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this.ctx.arc(x + w - r, y + r, r, Math.PI * 1.5, Math.PI * 2);
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// border-right
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this.ctx.lineTo(x + w, y + h - r);
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this.ctx.lineTo(x + w - r, y + h);
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// 右下角
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this.ctx.arc(x + w - r, y + h - r, r, 0, Math.PI * 0.5);
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// border-bottom
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this.ctx.lineTo(x + r, y + h);
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this.ctx.lineTo(x, y + h - r);
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// 左下角
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this.ctx.arc(x + r, y + h - r, r, Math.PI * 0.5, Math.PI);
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// border-left
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this.ctx.lineTo(x, y + r);
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this.ctx.lineTo(x + r, y);
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// 这里是使用 fill 还是 stroke都可以，二选一即可，但是需要与上面对应
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this.ctx.fill();
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// ctx.stroke()
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this.ctx.closePath();
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// 剪切
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this.ctx.clip();
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};
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// 图片自适应
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const adaptiveImg = (img, x, y, mode) => {
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const {
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imgW: w,
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imgH: h,
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width: dWidth,
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height: dHeight
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} = img;
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let dw = dWidth / w; //canvas与图片的宽比
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let dh = dHeight / h; //canvas与图片的高比
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// 裁剪图片中间部分
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if ((w > dWidth && h > dHeight) || (w < dWidth && h < dHeight)) {
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if (dw > dh) {
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this.ctx.drawImage(img.path, 0, (h - dHeight / dw) / 2, w, dHeight / dw, x, y, dWidth,
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dHeight);
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} else {
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this.ctx.drawImage(img.path, (w - dWidth / dh) / 2, 0, dWidth / dh, h, x, y, dWidth,
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dHeight);
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}
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} else {
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// 拉伸图片
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if (w < dWidth) {
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this.ctx.drawImage(img.path, 0, (h - dHeight / dw) / 2, w, dHeight / dw, x, y, dWidth,
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dHeight);
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} else {
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this.ctx.drawImage(img.path, (w - dWidth / dh) / 2, 0, dWidth / dh, h, x, y, dWidth,
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dHeight);
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}
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}
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// 裁剪图片中间部分
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// this.ctx.drawImage(img.path, sx, sy, sWidth, sHeight, x, y, dWidth, dHeight);
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// this.ctx.drawImage(img.path, x, y, temp.dWidth, temp.dHeight);
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};
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// 绘制背景
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this.ctx.setFillStyle(this.backgroundColor);
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this.ctx.fillRect(0, 0, this.width, this.height);
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/* 所有元素入队则开始绘制 */
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if (newVal.length === this.renderList.length) {
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if (newVal.length == 0) {
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this.$emit("on-error", {
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msg: "数据为空",
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});
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return;
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}
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try {
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// console.log('生成的队列：' + JSON.stringify(newVal));
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console.log("开始绘制...");
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for (let i = 0; i < this.drawPathQueue.length; i++) {
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for (let j = 0; j < this.drawPathQueue.length; j++) {
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let current = this.drawPathQueue[j];
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/* 按顺序绘制 */
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if (current.index === i) {
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/* 文本绘制 */
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if (current.type === "text") {
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console.log("开始绘制...text");
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fillText(current);
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this.counter--;
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}
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/* 多行文本 */
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if (current.type === "textarea") {
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console.log("开始绘制...textarea");
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fillParagraph(current);
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this.counter--;
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}
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/* 多行文本 */
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if (current.type === "square") {
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console.log("开始绘制...square");
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this.ctx.save(); // 保存上下文，绘制后恢复
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this.ctx.beginPath(); //开始绘制
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//画好了圆 剪切 原始画布中剪切任意形状和尺寸。一旦剪切了某个区域，则所有之后的绘图都会被限制在被剪切的区域内 这也是我们要save上下文的原因
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// 设置旋转中心
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let offsetX = current.x + Number(current.width) / 2;
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let offsetY = current.y + Number(current.height) / 2;
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this.ctx.translate(offsetX, offsetY);
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let degrees = current.rotate ? Number(current.rotate) % 360 : 0;
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this.ctx.rotate((degrees * Math.PI) / 180);
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this.ctx.fillStyle = current.fillStyle;
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this.ctx.fillRect(current.x - offsetX, current.y - offsetY, current.width, current
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.height);
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this.ctx.closePath();
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this.ctx.restore(); // 恢复之前保存的上下文
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this.counter--;
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}
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/* 图片绘制 */
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if (current.type === "image") {
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console.log("开始绘制...image");
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if (current.area) {
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// 绘制绘图区域
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this.ctx.save();
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this.ctx.beginPath(); //开始绘制
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this.ctx.rect(current.area.x, current.area.y, current.area.width, current.area
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.height);
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this.ctx.clip();
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// 设置旋转中心
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let offsetX = current.x + Number(current.width) / 2;
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let offsetY = current.y + Number(current.height) / 2;
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this.ctx.translate(offsetX, offsetY);
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let degrees = current.rotate ? Number(current.rotate) % 360 : 0;
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this.ctx.rotate((degrees * Math.PI) / 180);
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this.ctx.drawImage(current.path, current.x - offsetX, current.y - offsetY,
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current.width, current.height);
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this.ctx.closePath();
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this.ctx.restore(); // 恢复之前保存的上下文
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} else if (current.shape == "circle") {
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this.ctx.save(); // 保存上下文，绘制后恢复
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this.ctx.beginPath(); //开始绘制
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//先画个圆 前两个参数确定了圆心 （x,y） 坐标 第三个参数是圆的半径 四参数是绘图方向 默认是false，即顺时针
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let width = current.width / 2 + current.x;
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let height = current.height / 2 + current.y;
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let r = current.width / 2;
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this.ctx.arc(width, height, r, 0, Math.PI * 2);
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this.ctx.lineTo(current.x, current.y);
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this.ctx.fill();
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//画好了圆 剪切 原始画布中剪切任意形状和尺寸。一旦剪切了某个区域，则所有之后的绘图都会被限制在被剪切的区域内 这也是我们要save上下文的原因
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this.ctx.clip();
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// 设置旋转中心
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let offsetX = current.x + Number(current.width) / 2;
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let offsetY = current.y + Number(current.height) / 2;
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this.ctx.translate(offsetX, offsetY);
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let degrees = current.rotate ? Number(current.rotate) % 360 : 0;
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this.ctx.rotate((degrees * Math.PI) / 180);
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current.mode ?
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adaptiveImg(current, current.x - offsetX, current.y - offsetY, current
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.mode) :
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this.ctx.drawImage(current.path, current.x - offsetX, current.y - offsetY,
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current.width, current.height);
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this.ctx.closePath();
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this.ctx.restore(); // 恢复之前保存的上下文
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} else if (typeof current.shape == "number") {
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this.ctx.save(); // 保存上下文，绘制后恢复
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this.ctx.beginPath(); //开始绘制
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roundRect(current.x, current.y, current.width, current.height, current.shape);
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//画好了圆 剪切 原始画布中剪切任意形状和尺寸。一旦剪切了某个区域，则所有之后的绘图都会被限制在被剪切的区域内 这也是我们要save上下文的原因
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// 设置旋转中心
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let offsetX = current.x + Number(current.width) / 2;
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let offsetY = current.y + Number(current.height) / 2;
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this.ctx.translate(offsetX, offsetY);
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let degrees = current.rotate ? Number(current.rotate) % 360 : 0;
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this.ctx.rotate((degrees * Math.PI) / 180);
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current.mode ?
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adaptiveImg(current, current.x - offsetX, current.y - offsetY, current
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.mode) :
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this.ctx.drawImage(current.path, current.x - offsetX, current.y - offsetY,
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current.width, current.height);
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this.ctx.closePath();
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this.ctx.restore(); // 恢复之前保存的上下文
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} else {
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this.ctx.drawImage(current.path, current.x, current.y, current.width, current
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.height);
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}
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this.counter--;
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}
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}
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}
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}
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} catch (err) {
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console.log(err);
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this.$emit("on-error", err);
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}
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}
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},
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counter(newVal, oldVal) {
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if (newVal === 0) {
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this.ctx.draw(false, (draw) => {
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uni.canvasToTempFilePath({
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canvasId: "myCanvas",
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success: (res) => {
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// 在H5平台下，tempFilePath 为 base64
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console.log("图片已保存至本地：", res.tempFilePath);
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this.posterUrl = res.tempFilePath;
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this.$emit("on-success", res.tempFilePath);
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},
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fail: (error) => {
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this.$emit("on-error", error);
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},
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},
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this
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);
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});
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}
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},
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},
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mounted() {
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// this.generateImg();
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// console.log('mounted');
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},
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methods: {
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onCanvasReady() {
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// #ifdef MP-ALIPAY
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const query = my.createSelectorQuery();
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query
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.select("#myCanvas")
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.node()
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.exec((res) => {
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const canvas = res[0].node;
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const ctx = canvas.getContext("2d");
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});
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// #endif
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},
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/**
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* @param {*} elClass 元素名称
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* @param {*} slot 是否采用slot方式
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* @param {*} startX X偏移
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* @param {*} startY Y偏移
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* @return {*}
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*/
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createForElRect(elClass = "Poster", slot = true, startX = 0, startY = 0) {
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uni
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.createSelectorQuery()
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.selectAll("." + elClass)
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.fields({
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dataset: true,
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size: true,
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rect: true,
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value: true,
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scrollOffset: true,
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properties: ["src", "mode"],
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computedStyle: ["margin", "padding", "backgroundColor", "fontSize", "color", "fontWeight",
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"borderRadius"
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],
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context: true,
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},
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(res) => {
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let list = [];
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const sys = uni.getSystemInfoSync();
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let multiple = sys.windowWidth / this.width;
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res.forEach((val, index) => {
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let src = val.src || val.dataset.enode || "";
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let type = val.src ? "image" : val.dataset.etype || "text";
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let text = val.dataset.enode || "";
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let size = val.fontSize.replace("px", "") || 13;
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let shape = val.borderRadius == "50%" ? "circle" : val.borderRadius.replace("px",
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"") * 2;
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let x = (startX + val.left - (slot ? sys.screenWidth : 0)) / multiple;
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let y = (startY + val.top) / multiple;
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y = (startY + val.top - (slot ? 50 : 0)) / multiple;
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// #ifdef H5
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y = (startY + val.top) / multiple;
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// #endif
|
||
list.push({
|
||
type: type,
|
||
shape,
|
||
text,
|
||
mode: "center",
|
||
x,
|
||
y,
|
||
path: src,
|
||
width: val.width / multiple,
|
||
height: val.height / multiple,
|
||
size: size / multiple,
|
||
color: val.color,
|
||
});
|
||
});
|
||
let canvas = uni.createCanvasContext("myCanvas", this);
|
||
this.ctx = canvas;
|
||
this.renderList = [...this.list, ...list];
|
||
this.generateImg();
|
||
}
|
||
)
|
||
.exec();
|
||
},
|
||
create() {
|
||
let canvas = uni.createCanvasContext("myCanvas", this);
|
||
this.ctx = canvas;
|
||
this.renderList = this.list;
|
||
this.generateImg();
|
||
},
|
||
async generateImg() {
|
||
console.log("generateimg");
|
||
this.counter = this.renderList.length;
|
||
this.drawPathQueue = [];
|
||
const getImgInfo = async (current) => {
|
||
// console.log("current", current);
|
||
return new Promise((resolve, reject) => {
|
||
uni.getImageInfo ?
|
||
uni.getImageInfo({
|
||
src: current.path,
|
||
success: (res) => {
|
||
current.path = res.path;
|
||
current.imgW = res.width;
|
||
current.imgH = res.height;
|
||
// this.drawPathQueue.push(current);
|
||
resolve(current);
|
||
},
|
||
}) :
|
||
resolve(current);
|
||
});
|
||
};
|
||
const delayedLog = async (v, i) => {
|
||
let current = this.renderList[i];
|
||
current.index = i;
|
||
/* 如果是文本直接放入队列 */
|
||
if (current.type === "text" || current.type === "textarea" || current.type === "square") {
|
||
// this.drawPathQueue.push(current);
|
||
return current;
|
||
} else {
|
||
return await getImgInfo(current);
|
||
/* 图片需获取本地缓存path放入队列 */
|
||
}
|
||
};
|
||
const processArray = async (array) => {
|
||
// map array to promises
|
||
const promises = array.map((v, i) => delayedLog(v, i));
|
||
// wait until all promises are resolved
|
||
const allData = await Promise.all(promises);
|
||
console.log("Done!", allData);
|
||
return allData;
|
||
};
|
||
this.drawPathQueue = await processArray(this.renderList);
|
||
},
|
||
saveImg() {
|
||
uni.canvasToTempFilePath({
|
||
canvasId: "myCanvas",
|
||
success: (res) => {
|
||
// 在H5平台下，tempFilePath 为 base64
|
||
uni.saveImageToPhotosAlbum({
|
||
filePath: res.tempFilePath,
|
||
success: () => {
|
||
console.log("save success");
|
||
},
|
||
});
|
||
},
|
||
},
|
||
this
|
||
);
|
||
},
|
||
},
|
||
};
|
||
</script>
|
||
|
||
<style lang="scss" scoped>
|
||
.canvas {
|
||
position: fixed;
|
||
top: 100rpx;
|
||
left: 750rpx;
|
||
width: 100vw;
|
||
}
|
||
|
||
.theContent {}
|
||
</style> |