在本地保存图像(从外部库中检索) - Angular? [英] Saving an image (retrieved from external library) locally - Angular?

问题描述

我对 Angular 和其他方面真的很陌生.所以我从一个库(angularx-qrcode)生成器中得到了一个二维码图像.

这是获取图像的代码:

 </qrcode>

现在我想要一个按钮，允许用户在本地保存上面的图像.我怎样才能做到这一点?

对于不同的 Angular 版本(例如 2 与 7)，语法是否也不同?

非常感谢！！任何帮助将不胜感激:)

解决方案

现在我想要一个按钮，允许用户保存上面的图像本地.我怎样才能做到这一点?

<小时>

因此，您想将二维码图像下载到本地设备中

<块引用>

检查 WORKING STACKBLITZ

这是我的做法！

<块引用>

• 首先需要从生成的图片中获取base64图片数据
• 将 base 64 编码的图像转换为 blob 数据
• 添加一个按钮来下载图片

你的 component.html 可以是这样的:~

<qrcode #parent [qrdata]="qrdata" [size]="256" [level]="'M'"></qrcode><br><button (click)="saveAsImage(parent)">下载二维码图片</button>

你的 component.ts 可以是这样的:~

import { Component } from '@angular/core';@成分({选择器:'我的应用'，templateUrl: './app.component.html',styleUrls: ['./app.component.css']})导出类 AppComponent {qrdata = '初始二维码数据串';saveAsImage(父){//从图像中获取 base 64 日期const parentElement = parent.el.nativeElement.querySelector("img").src;//将 base 64 编码的图像转换为 blobData让 blobData = this.convertBase64ToBlob(parentElement);//保存为图片if (window.navigator && window.navigator.msSaveOrOpenBlob) {//IEwindow.navigator.msSaveOrOpenBlob(blobData, '二维码');} else {//铬const blob = new Blob([blobData], { type: "image/png" });const url = window.URL.createObjectURL(blob);//window.open(url);const link = document.createElement('a');链接.href = url;link.download = '二维码';链接.点击()；}}私人 convertBase64ToBlob(Base64Image: any) {//分成两部分const 部分 = Base64Image.split(';base64,');//保留内容类型const imageType = part[0].split(':')[1];//解码 BASE64 字符串const decodedData = window.atob(parts[1]);//创建大小与行数据长度相同的 UNIT8ARRAYconst uInt8Array = new Uint8Array(decodedData.length);//将所有字符代码插入 UINT8ARRAYfor (let i = 0; i 

<小时>

另外，如果你想保存二维码中的文本，请检查下面的这个:~

<块引用>

检查 WORKING STACKBLITZ

I'm really really new to Angular and all. So I've gotten a QR code image from a library (angularx-qrcode) generator.

Here's the code to get the image:

     <qrcode [qrdata]="'Your QR code data string'" [size]="256" [level]="'M'"></qrcode> 

Now I wanna have a button that allows the user to save the above image locally. How can I achieve this?

Also is the syntax different for different Angular versions (e.g. 2 vs 7)?

Thank you so much!! any help would be appreciated:)

解决方案

Now I wanna have a button that allows the user to save the above image locally. How can I achieve this?

---

So, you want to download the Qr code image into your local device

CHECK WORKING STACKBLITZ

This is my approach on how I did it!

• First, you need to get the base64 image data from the generated image
• Convert the base 64 encoded image into blob data
• Add a button to download the image

Your component.html can be something like this:~

<qrcode #parent [qrdata]="qrdata" [size]="256" [level]="'M'"></qrcode>
<br>
<button (click)="saveAsImage(parent)">Download QR Code Image</button>

Your component.ts can be something like this:~

import { Component } from '@angular/core';

@Component({
  selector: 'my-app',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css']
})
export class AppComponent {
  qrdata = 'Initial QR code data string';

  saveAsImage(parent) {
    // fetches base 64 date from image
    const parentElement = parent.el.nativeElement.querySelector("img").src;

    // converts base 64 encoded image to blobData
    let blobData = this.convertBase64ToBlob(parentElement);

    // saves as image
    if (window.navigator && window.navigator.msSaveOrOpenBlob) { //IE
      window.navigator.msSaveOrOpenBlob(blobData, 'Qrcode');
    } else { // chrome
      const blob = new Blob([blobData], { type: "image/png" });
      const url = window.URL.createObjectURL(blob);
      // window.open(url);
      const link = document.createElement('a');
      link.href = url;
      link.download = 'Qrcode';
      link.click();
    }

  }

  private convertBase64ToBlob(Base64Image: any) {
    // SPLIT INTO TWO PARTS
    const parts = Base64Image.split(';base64,');
    // HOLD THE CONTENT TYPE
    const imageType = parts[0].split(':')[1];
    // DECODE BASE64 STRING
    const decodedData = window.atob(parts[1]);
    // CREATE UNIT8ARRAY OF SIZE SAME AS ROW DATA LENGTH
    const uInt8Array = new Uint8Array(decodedData.length);
    // INSERT ALL CHARACTER CODE INTO UINT8ARRAY
    for (let i = 0; i < decodedData.length; ++i) {
      uInt8Array[i] = decodedData.charCodeAt(i);
    }
    // RETURN BLOB IMAGE AFTER CONVERSION
    return new Blob([uInt8Array], { type: imageType });
  }

}

---

Also, if you want to save the text inside the QRCode check this one below:~

CHECK WORKING STACKBLITZ

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