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100 lines
2.7 KiB
JavaScript
100 lines
2.7 KiB
JavaScript
import JsPDF from 'jspdf'
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// 导出PDF插件，需要通过Export插件使用
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class ExportPDF {
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// 构造函数
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constructor(opt) {
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this.mindMap = opt.mindMap
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}
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// 导出为pdf
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pdf(name, img, useMultiPageExport = false) {
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if (useMultiPageExport) {
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this.multiPageExport(name, img)
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} else {
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this.onePageExport(name, img)
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}
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}
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// 单页导出
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onePageExport(name, img) {
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let pdf = new JsPDF('', 'pt', 'a4')
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let a4Width = 595
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let a4Height = 841
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let a4Ratio = a4Width / a4Height
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let image = new Image()
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image.onload = () => {
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let imageWidth = image.width
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let imageHeight = image.height
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let imageRatio = imageWidth / imageHeight
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let w, h
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if (imageWidth <= a4Width && imageHeight <= a4Height) {
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// 使用图片原始宽高
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w = imageWidth
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h = imageHeight
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} else if (a4Ratio > imageRatio) {
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// 以a4Height为高度，缩放图片宽度
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w = imageRatio * a4Height
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h = a4Height
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} else {
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// 以a4Width为宽度，缩放图片高度
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w = a4Width
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h = a4Width / imageRatio
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}
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pdf.addImage(img, 'PNG', (a4Width - w) / 2, (a4Height - h) / 2, w, h)
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pdf.save(name)
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}
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image.src = img
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}
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// 多页导出
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multiPageExport(name, img) {
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let image = new Image()
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const a4Width = 592.28
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const a4Height = 841.89
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image.onload = () => {
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let imageWidth = image.width
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let imageHeight = image.height
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// 一页pdf显示高度
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let pageHeight = (imageWidth / a4Width) * a4Height
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// 未生成pdf的高度
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let leftHeight = imageHeight
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// 偏移
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let position = 0
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// a4纸的尺寸[595.28,841.89]，图片在pdf中图片的宽高
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let imgWidth = a4Width
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let imgHeight = (a4Width / imageWidth) * imageHeight
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let pdf = new JsPDF('', 'pt', 'a4')
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// 有两个高度需要区分，一个是图片的实际高度，和生成pdf的页面高度(841.89)
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// 当内容未超过pdf一页显示的范围，无需分页
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if (leftHeight < pageHeight) {
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pdf.addImage(
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img,
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'PNG',
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(a4Width - imgWidth) / 2,
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(a4Height - imgHeight) / 2,
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imgWidth,
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imgHeight
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)
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} else {
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// 分页
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while (leftHeight > 0) {
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pdf.addImage(img, 'PNG', 0, position, imgWidth, imgHeight)
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leftHeight -= pageHeight
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position -= a4Height
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// 避免添加空白页
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if (leftHeight > 0) {
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pdf.addPage()
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}
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}
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}
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pdf.save(name)
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}
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image.src = img
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}
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}
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ExportPDF.instanceName = 'doExportPDF'
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export default ExportPDF
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