klp-oa/klp-ui/src/views/wms/coil/panels/LabelRender/index.vue

<template>
  <div class="label-render-container">
    <!-- 标签预览容器 -->
    <div class="preview-container" id="label-preview-container" ref="labelRef">
      <ProductionTagPreview v-if="labelType === '2'" :content="content" />
      <OuterTagPreview v-if="labelType === '3'" :content="content" />
      <SampleTagPreview v-if="labelType === '4'" :content="content" />
      <ForgeTagPreview v-if="labelType === '5'" :content="content" />
      <SaltSprayTagPreview v-if="labelType === '6'" :content="content" />
    </div>
    <div class="action-buttons">
      <el-button type="primary" @click="downloadLabelAsImage">下载标签图片</el-button>
      <el-button type="primary" @click="printLabel" style="margin-left: 10px;">打印标签</el-button>
    </div>
  </div>
</template>

<script>
import domToImage from 'dom-to-image';
import printJS from 'print-js';
import html2canvas from 'html2canvas'; // 新增：引入高清渲染库
import { Message } from 'element-ui';

import ProductionTagPreview from './ProductionTagPreview.vue';
import OuterTagPreview from './OuterTagPreview.vue';
import SampleTagPreview from './SampleTagPreview.vue';
import ForgeTagPreview from './ForgeTagPreview.vue';
import SaltSprayTagPreview from './SaltSprayTagPreview.vue';

export default {
  name: 'LabelRender',
  components: {
    ProductionTagPreview,
    OuterTagPreview,
    SampleTagPreview,
    ForgeTagPreview,
    SaltSprayTagPreview,
  },
  props: {
    labelType: {
      type: String,
      required: true,
    },
    content: {
      type: Object,
      required: true,
    },
  },
  methods: {
    // -------- 图片下载方法（保留，可按需替换为html2canvas） --------
    async downloadLabelAsImage() {
      const labelContainer = document.getElementById('label-preview-container');
      if (!labelContainer) {
        Message.error('未找到标签容器，无法下载');
        return;
      }

      try {
        // 可选：也替换为html2canvas提升下载清晰度
        // const canvas = await html2canvas(labelContainer, { scale: 3, backgroundColor: '#ffffff', allowTaint: true, taintTest: false });
        // const dataUrl = canvas.toDataURL('image/png', 1.0);
        const dataUrl = await domToImage.toPng(labelContainer);
        
        const downloadLink = document.createElement('a');
        downloadLink.href = dataUrl;
        downloadLink.download = `标签_${new Date().getTime()}.png`;
        document.body.appendChild(downloadLink);
        downloadLink.click();
        document.body.removeChild(downloadLink);
      } catch (error) {
        console.error('标签图片下载失败：', error);
        Message.error('标签图片下载失败，请重试');
      }
    },

    // -------- 重构后的打印方法（核心优化） --------
    async printLabel() {
      // 1. 获取标签容器DOM
      const labelContainer = document.querySelector('.label-container');
      if (!labelContainer) {
        Message.error('未找到标签容器，无法打印');
        return;
      }

      try {
        Message.info('正在准备打印内容，请稍等...');
        
        // 2. 等待二维码/字体等资源加载完成（复用之前的等待逻辑）
        await this.waitForAllResources(labelContainer);

        // 3. 用html2canvas生成高清Canvas（解决文字模糊+二维码丢失）
        const canvas = await html2canvas(labelContainer, {
          scale: 1.5, // 3倍高清渲染（核心）
          backgroundColor: '#ffffff', // 强制白色背景，避免打印时背景透明
          useCORS: true, // 支持跨域图片
          allowTaint: true, // 允许渲染canvas（二维码）
          taintTest: false, // 关闭canvas污染检测
          windowWidth: labelContainer.offsetWidth * 1.5, // 适配缩放后的宽度
          windowHeight: labelContainer.offsetHeight * 1.5, // 适配缩放后的高度
          logging: false,
        });

        // 4. 创建临时打印容器（避免影响原DOM）
        const printContainerId = 'temp-print-container-' + new Date().getTime();
        const tempPrintContainer = document.createElement('div');
        tempPrintContainer.id = printContainerId;
        // 将高清Canvas插入临时容器
        tempPrintContainer.appendChild(canvas);
        // document.body.appendChild(tempPrintContainer);

        // 5. 调用printJS打印高清Canvas（而非原HTML）
        printJS({
          printable: tempPrintContainer, // 打印临时容器
          type: 'html',
          header: null,
          footer: null,
          scanStyles: false, // 禁用自动扫描样式，手动控制
          // 自定义打印样式：确保Canvas适配纸张、无多余边距
          style: `
            #${printContainerId} {
              width: 100%;
              height: auto;
              margin: 0;
              padding: 0;
            }
            #${printContainerId} canvas {
              max-width: 100%;
              height: auto;
              border: none;
            }
            @media print {
              body * { visibility: hidden; }
              #${printContainerId}, #${printContainerId} * { visibility: visible; }
              #${printContainerId} { position: absolute; top: 0; left: 0; }
            }
          `,
          printContainer: true,
          onAfterPrint: () => {
            // 6. 打印完成后清理临时容器
            document.body.removeChild(tempPrintContainer);
            Message.success('打印准备完成，请在打印预览中确认打印');
          },
          onError: (error) => {
            // 异常时也清理临时容器
            document.body.removeChild(tempPrintContainer);
            console.error('打印失败:', error);
            Message.error('打印失败，请重试');
          }
        });

        // document.removeChild(tempPrintContainer);
      } catch (error) {
        console.error('打印准备失败:', error);
        Message.error('打印内容准备失败，请重试');
      }
    },

    // -------- 辅助方法：等待所有资源加载（图片+字体+二维码） --------
    async waitForAllResources(element) {
      // 等待图片加载
      const images = element.querySelectorAll('img');
      const imgPromises = Array.from(images).map(img => 
        img.complete ? Promise.resolve() : new Promise(resolve => {
          img.onload = resolve;
          img.onerror = resolve;
        })
      );
      await Promise.all(imgPromises);

      // 等待字体加载
      await document.fonts.ready;

      // 等待二维码Canvas渲染
      await this.waitForQRCodeRender(element);

      // 最终等待样式稳定
      await new Promise(resolve => setTimeout(resolve, 300));
    },

    // -------- 辅助方法：等待二维码Canvas渲染完成 --------
    async waitForQRCodeRender(element) {
      const qrCanvasList = element.querySelectorAll('canvas');
      if (qrCanvasList.length === 0) return;

      const qrLoadPromises = Array.from(qrCanvasList).map(canvas => {
        return new Promise(resolve => {
          const checkInterval = setInterval(() => {
            const ctx = canvas.getContext('2d');
            if (!ctx) {
              clearInterval(checkInterval);
              resolve();
              return;
            }
            const imageData = ctx.getImageData(0, 0, canvas.width, canvas.height);
            const hasContent = imageData.data.some(value => value !== 0);
            if (hasContent || Date.now() - (ctx.startTime || 0) > 2000) {
              clearInterval(checkInterval);
              resolve();
            }
          }, 100);
        });
      });
      await Promise.all(qrLoadPromises);
    }
  },
};
</script>

<style scoped>
.label-render-container {
  width: 100%;
  display: flex;
  flex-direction: column;
  justify-content: flex-start;
  align-items: center;
  /* padding: 1rem; */
  box-sizing: border-box;
}

.action-buttons {
  margin-top: 1rem;
}

.preview-container {
  background-color: #fff;
  color: #000;
  /* padding: 1.5rem; */
  width: fit-content;
  /* min-width: 200px; */
  box-shadow: 0 0 60px rgba(255, 255, 255, 0.2);
  /* border: 1px solid rgba(255, 255, 255, 0.1); */
  overflow: hidden;
  transition: all 0.3s ease;
}

.preview-container:hover {
  box-shadow: 0 0 80px rgba(255, 255, 255, 0.3);
  transform: translateY(-2px);
}

/* 强制二维码Canvas可见，避免渲染丢失 */
:deep(canvas) {
  display: block;
  visibility: visible;
  opacity: 1;
}

/* 字体平滑，提升文字清晰度 */
:deep(.preview-container) {
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  font-smooth: always;
}
</style>