vue-pdf打印出现方字块乱码问题

今天分享vue-pdf预览显示没有问题，但是打印时出现乱码问题。话不多说先上乱码图。今天主要是分享给大家两种方法。亲测有效!!!!!!!!乱码问题是因为我们安装vue-pdf的版本问题，它的这个源码因为版本更新已经改变了，下面这个地址详细的介绍了源码的改变。红色区域的'-'号表明是已经删除了的，绿色区域的加号是新加的。上一页然后在你绑定的打印按钮的方法中直接使用。......

H-rosy

3504人浏览 · 2022-08-06 10:50:27

H-rosy · 2022-08-06 10:50:27 发布

问题：

今天分享vue-pdf预览显示没有问题，但是打印时出现乱码问题。话不多说先上乱码图。今天主要是分享给大家两种方法。亲测有效!!!!!!!!

第一：在你使用vue-pdf的组件中使用<iframe>标签,如果对iframe不熟悉也没有关系，你就知道iframe 元素会创建包含另外一个文档的内联框架就OK了。

第一种：

把iframe标签放入组件中，这里我是放在pdf标签下方的

<iframe id="printIframe" :src="src" frameborder="0" style="display:none"></iframe>

iframe里面的' :src '是其本身的属性，"src"这个src是一个字符串，也是我PDF文件的地址，我这里是写了一个固定地址是放在我们component文件中的。直接在data里面的return中声明一个src变量并对它赋值就可以了
然后在你绑定的打印按钮的方法中直接使用

document.getElementById('printIframe').contentWindow.print();

替代原来的方法 //this.$refs.mypdf.print()就可以了

代码如下：

<template>

<el-dialog

title="合同内容"

:visible.sync="dialogVisible"

width="70%"

:before-close="handleClose">



<el-button @click="num--" v-if="num>=1">上一页</el-button>

<el-button @click="num++" v-if="num<=pageCount">下一页</el-button>

<el-button @click="print">打印合同</el-button>

{{currentPage}}/{{pageCount}}

<pdf

:src=src :page="num"

@num-pages="pageCount = $event"

@page-loaded="currentPage=$event"

style="display:inline-block;width:500px"

ref="mypdf"

></pdf>

<iframe id="printIframe" :src="src" frameborder="0" style="display:none"></iframe>

<span slot="footer" class="dialog-footer">

<el-button @click="dialogVisible = false">取消</el-button>

<el-button type="primary" @click="dialogVisible = false">确定</el-button>

</span>

</el-dialog>

</template>

<script>

import pdf from 'vue-pdf'

export default {

name: 'VuePdf',

components: {pdf},

data () {

return {

dialogVisible: false,

currentPage:0,

pageCount:0,

num:1,

src:'./test.pdf',

}

},

methods:{

print(){

//打印合同的方法

//this.$refs.mypdf.print()

document.getElementById('printIframe').contentWindow.print();

},

handleClose(done) {

this.$confirm('确认关闭？')

.then(()=> {

done();

})

.catch(()=> {});

}

}

}

</script>

<style>

</style>

第二种方法：

第二种方法是改变原码的方式，在node_modules下的vue-pdf下的src下的pdfjsWrapper.js中。

乱码问题是因为我们安装vue-pdf的版本问题，它的这个源码因为版本更新已经改变了，下面这个地址详细的介绍了源码的改变。红色区域的'-'号表明是已经删除了的，绿色区域的加号是新加的。

使用方法就是你把红色区域的注释掉，并加上绿色区域的！！！！

github网址：https://github.com/FranckFreiburger/vue-pdf/pull/130/commits/253f6186ff0676abf9277786087dda8d95dd8ea7

部分内容：

需要注意的是里面的行数会有一些区别，可以Ctrl+H搜索关键字定位

下卖以我的代码行数为例：

首先找到上图中显示的78行位置，我是在91行：注释掉它，并且在下方加入绿色的两行！~~~~~好了就是按照这样改就好啦。

好吧，改的真麻烦直接给改完后的代码：

import { PDFLinkService } from 'pdfjs-dist/es5/web/pdf_viewer';
 
var pendingOperation = Promise.resolve();
 
export default function(PDFJS) {
 
	function isPDFDocumentLoadingTask(obj) {
 
		return typeof(obj) === 'object' && obj !== null && obj.__PDFDocumentLoadingTask === true;
		// or: return obj.constructor.name === 'PDFDocumentLoadingTask';
	}
 
	function createLoadingTask(src, options) {
 
		var source;
		if ( typeof(src) === 'string' )
			source = { url: src };
		else if ( src instanceof Uint8Array )
			source = { data: src };
		else if ( typeof(src) === 'object' && src !== null )
			source = Object.assign({}, src);
		else
			throw new TypeError('invalid src type');
 
		// source.verbosity = PDFJS.VerbosityLevel.INFOS;
		// source.pdfBug = true;
		// source.stopAtErrors = true;
 
		if ( options && options.withCredentials )
			source.withCredentials = options.withCredentials;
 
		var loadingTask = PDFJS.getDocument(source);
		loadingTask.__PDFDocumentLoadingTask = true; // since PDFDocumentLoadingTask is not public
 
		if ( options && options.onPassword )
			loadingTask.onPassword = options.onPassword;
 
		if ( options && options.onProgress )
			loadingTask.onProgress = options.onProgress;
 
		return loadingTask;
	}
 
 
	function PDFJSWrapper(canvasElt, annotationLayerElt, emitEvent) {
 
		var pdfDoc = null;
		var pdfPage = null;
		var pdfRender = null;
		var canceling = false;
 
		canvasElt.getContext('2d').save();
 
		function clearCanvas() {
 
			canvasElt.getContext('2d').clearRect(0, 0, canvasElt.width, canvasElt.height);
		}
 
		function clearAnnotations() {
 
			while ( annotationLayerElt.firstChild )
				annotationLayerElt.removeChild(annotationLayerElt.firstChild);
		}
 
		this.destroy = function() {
 
			if ( pdfDoc === null )
				return;
 
			// Aborts all network requests and destroys worker.
			pendingOperation = pdfDoc.destroy();
			pdfDoc = null;
		}
 
		this.getResolutionScale = function() {
 
			return canvasElt.offsetWidth / canvasElt.width;
		}
 
		this.printPage = function(dpi, pageNumberOnly) {
 
			if ( pdfPage === null )
				return;
 
			// 1in == 72pt
			// 1in == 96px
			var PRINT_RESOLUTION = dpi === undefined ? 150 : dpi;
			var PRINT_UNITS = PRINT_RESOLUTION / 72.0;
			var CSS_UNITS = 96.0 / 72.0;
 
 
			var printContainerElement = document.createElement('div');
			printContainerElement.setAttribute('id', 'print-container')
			
 
			function removePrintContainer() {
				printContainerElement.parentNode.removeChild(printContainerElement);
			}
 
			new Promise(function(resolve, reject) {
 
				printContainerElement.frameBorder = '0';
				printContainerElement.scrolling = 'no';
				printContainerElement.width = '0px;'
				printContainerElement.height = '0px;'
				printContainerElement.style.cssText = 'position: absolute; top: 0; left: 0';
 
				window.document.body.appendChild(printContainerElement);
				resolve(window)
			})
			.then(function(win) {
 
				win.document.title = '';
 
				return pdfDoc.getPage(1)
				.then(function(page) {
					var viewport = page.getViewport({ scale: 1 });
					printContainerElement.appendChild(win.document.createElement('style')).textContent =
						'@supports ((size:A4) and (size:1pt 1pt)) {' +
							'@page { margin: 1pt; size: ' + ((viewport.width * PRINT_UNITS) / CSS_UNITS) + 'pt ' + ((viewport.height * PRINT_UNITS) / CSS_UNITS) + 'pt; }' +
						'}' +
 
						'@media print {' +
							'body { margin: 0 }' +
							'#print-canvas { page-break-before: avoid; page-break-after: always; page-break-inside: avoid; display: block }' +
							'body > *:not(#print-container) { display: none; }' +
						'}'+
 
						'@media screen {' +
							'body { margin: 0 }' +
						'}'
					return win;
				})
			})
			.then(function(win) {
 
				var allPages = [];
 
				for ( var pageNumber = 1; pageNumber <= pdfDoc.numPages; ++pageNumber ) {
 
					if ( pageNumberOnly !== undefined && pageNumberOnly.indexOf(pageNumber) === -1 )
						continue;
 
					allPages.push(
						pdfDoc.getPage(pageNumber)
						.then(function(page) {
 
							var viewport = page.getViewport({ scale: 1 });
 
							var printCanvasElt = printContainerElement.appendChild(win.document.createElement('canvas'));
							printCanvasElt.setAttribute('id', 'print-canvas')
							printCanvasElt.width = (viewport.width * PRINT_UNITS);
							printCanvasElt.height = (viewport.height * PRINT_UNITS);
 
							return page.render({
								canvasContext: printCanvasElt.getContext('2d'),
								transform: [ // Additional transform, applied just before viewport transform.
									PRINT_UNITS, 0, 0,
									PRINT_UNITS, 0, 0
								],
								viewport: viewport,
								intent: 'print'
							}).promise;
						})
					);
				}
 
				Promise.all(allPages)
				.then(function() {
					win.focus(); // Required for IE
					if (win.document.queryCommandSupported('print')) {
						win.document.execCommand('print', false, null);
						} else {
						win.print();
						}
						removePrintContainer();
				})
				.catch(function(err) {
 
					
					removePrintContainer();
					emitEvent('error', err);
				})
			})
		}
 
		this.renderPage = function(rotate) {
			if ( pdfRender !== null ) {
 
				if ( canceling )
					return;
				canceling = true;
				pdfRender.cancel().catch(function(err) {
					emitEvent('error', err);
				});
				return;
			}
 
			if ( pdfPage === null )
				return;
 
			var pageRotate = (pdfPage.rotate === undefined ? 0 : pdfPage.rotate) + (rotate === undefined ? 0 : rotate);
 
			var scale = canvasElt.offsetWidth / pdfPage.getViewport({ scale: 1 }).width * (window.devicePixelRatio || 1);
			var viewport = pdfPage.getViewport({ scale: scale, rotation:pageRotate });
 
			emitEvent('page-size', viewport.width, viewport.height, scale);
 
			canvasElt.width = viewport.width;
			canvasElt.height = viewport.height;
 
			pdfRender = pdfPage.render({
				canvasContext: canvasElt.getContext('2d'),
				viewport: viewport
			});
 
			annotationLayerElt.style.visibility = 'hidden';
			clearAnnotations();
 
			var viewer = {
				scrollPageIntoView: function(params) {
					emitEvent('link-clicked', params.pageNumber)
				},
			};
 
			var linkService = new PDFLinkService();
			linkService.setDocument(pdfDoc);
			linkService.setViewer(viewer);
 
			pendingOperation = pendingOperation.then(function() {
 
				var getAnnotationsOperation =
				pdfPage.getAnnotations({ intent: 'display' })
				.then(function(annotations) {
 
					PDFJS.AnnotationLayer.render({
						viewport: viewport.clone({ dontFlip: true }),
						div: annotationLayerElt,
						annotations: annotations,
						page: pdfPage,
						linkService: linkService,
						renderInteractiveForms: false
					});
				});
 
				var pdfRenderOperation =
				pdfRender.promise
				.then(function() {
 
					annotationLayerElt.style.visibility = '';
					canceling = false;
					pdfRender = null;
				})
				.catch(function(err) {
 
					pdfRender = null;
					if ( err instanceof PDFJS.RenderingCancelledException ) {
 
						canceling = false;
						this.renderPage(rotate);
						return;
					}
					emitEvent('error', err);
				}.bind(this))
 
				return Promise.all([getAnnotationsOperation, pdfRenderOperation]);
			}.bind(this));
		}
 
 
		this.forEachPage = function(pageCallback) {
 
			var numPages = pdfDoc.numPages;
 
			(function next(pageNum) {
 
				pdfDoc.getPage(pageNum)
				.then(pageCallback)
				.then(function() {
 
					if ( ++pageNum <= numPages )
						next(pageNum);
				})
			})(1);
		}
 
 
		this.loadPage = function(pageNumber, rotate) {
 
			pdfPage = null;
 
			if ( pdfDoc === null )
				return;
 
			pendingOperation = pendingOperation.then(function() {
 
				return pdfDoc.getPage(pageNumber);
			})
			.then(function(page) {
 
				pdfPage = page;
				this.renderPage(rotate);
				emitEvent('page-loaded', page.pageNumber);
			}.bind(this))
			.catch(function(err) {
 
				clearCanvas();
				clearAnnotations();
				emitEvent('error', err);
			});
		}
 
		this.loadDocument = function(src) {
 
			pdfDoc = null;
			pdfPage = null;
 
			emitEvent('num-pages', undefined);
 
			if ( !src ) {
 
				canvasElt.removeAttribute('width');
				canvasElt.removeAttribute('height');
				clearAnnotations();
				return;
			}
 
			// wait for pending operation ends
			pendingOperation = pendingOperation.then(function() {
 
				var loadingTask;
				if ( isPDFDocumentLoadingTask(src) ) {
 
					if ( src.destroyed ) {
 
						emitEvent('error', new Error('loadingTask has been destroyed'));
						return
					}
 
					loadingTask = src;
				} else {
 
					loadingTask = createLoadingTask(src, {
						onPassword: function(updatePassword, reason) {
 
							var reasonStr;
							switch (reason) {
								case PDFJS.PasswordResponses.NEED_PASSWORD:
									reasonStr = 'NEED_PASSWORD';
									break;
								case PDFJS.PasswordResponses.INCORRECT_PASSWORD:
									reasonStr = 'INCORRECT_PASSWORD';
									break;
							}
							emitEvent('password', updatePassword, reasonStr);
						},
						onProgress: function(status) {
 
							var ratio = status.loaded / status.total;
							emitEvent('progress', Math.min(ratio, 1));
						}
					});
				}
 
				return loadingTask.promise;
			})
			.then(function(pdf) {
 
				pdfDoc = pdf;
				emitEvent('num-pages', pdf.numPages);
				emitEvent('loaded');
			})
			.catch(function(err) {
 
				clearCanvas();
				clearAnnotations();
				emitEvent('error', err);
			})
		}
 
		annotationLayerElt.style.transformOrigin = '0 0';
	}
 
	return {
		createLoadingTask: createLoadingTask,
		PDFJSWrapper: PDFJSWrapper,
	}
}

最终效果：

总结：

第一种看起来真的很简单快捷，但是第二种可以了解为什么会出现乱码问题，看看哪种方法适合你吧，如果有用欢迎点赞评论收藏一波哟

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