Angular使用 ng-img-max 调整浏览器中的图片的示例代码

$ npm install ng2-img-max blueimp-canvas-to-blob --save

# or Yarn :
$ yarn add ng2-img-max blueimp-canvas-to-blob

//: .angular-cli.json

...
"scripts": [
 "../node_modules/blueimp-canvas-to-blob/js/canvas-to-blob.min.js"
],
//...

//: app.module.ts

//...
import { Ng2ImgMaxModule } from 'ng2-img-max';

@NgModule({
 declarations: [ AppComponent ],
 imports: [
  //...
  ng2ImgMaxModule
 ],
 providers: [],
 bootstrap: [ AppComponent ]
})
export class AppModule {}

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

import { Ng2ImgMaxService } from 'ng2-img-max';

@Component({ ... })
export class AppComponent {
 constructor(private ng2ImgMax: Ng2ImgMaxService ) {}
}

<input type='file' (change)="onImageChange($event)" accept="image/*" />

updateImage: Blob;

constructor(private ng2ImgMax: Ng2ImgMaxService) {}

onImageChange(event){
 let image = event.target.files[0];
 
 this.ng2ImgMax.resizeImage(image,400,300).subscribe(result=> {
  this.uploadImage = result;
 },
 error=> {
  console.log('error:',error);
 })
}

//: app.component.ts

uploadedImage: File;
constructor(private ng2ImgMax: Ng2ImgMaxService) {}
onImageChange(event){
 let image = event.target.files[0];
 
 this.ng2ImgMax.resizeImage(image,400,300).subscribe(result=> {
  this.uploadedImage = new File([result],result.name);
 },
 error=> {
  console.log('error',error);
 })
}

//...
onImageChange(event) {
 let image = event.target.files[0];
 this.ng2ImgMax.resizeImage(image,10000,300).subscribe(result=> {
  this.uploadedImage = new File([result],result.name);
 },
 error=> {
  console.log('error:',error);
 });
}

onImageChange(event) {
 let image = event.target.files[0];

 this.ng2ImgMax.compressImage(image, 0.075).subscribe(
  result => {
   this.uploadedImage = new File([result], result.name);
   this.getImagePreview(this.uploadedImage);
  },
  error => {
   console.log('😢 Oh no!', error);
  }
 );
}

//: app.component.ts

import { Component } from '@angular/core';
import { Ng2ImgMaxService } from 'ng2-img-max';
import { DomSanitizer } from '@angular/platform-browser';

@Component({ ... })
export class AppComponent {
 uploadedImage: File;
 imagePreview: string;

 constructor(
  private ng2ImgMax: Ng2ImgMaxService,
  public sanitizer: DomSanitizer
 ) {}

 onImageChange(event) {
  let image = event.target.files[0];

  this.ng2ImgMax.resizeImage(image, 10000, 375).subscribe(
   result => {
    this.uploadedImage = new File([result], result.name);
    this.getImagePreview(this.uploadedImage);
   },
   error => {
    console.log('😢 Oh no!', error);
   }
  );
 }

 getImagePreview(file: File) {
  const reader: FileReader = new FileReader();
  reader.readAsDataURL(file);
  reader.onload = () => {
   this.imagePreview = reader.result;
  };
 }
}

//: app.component.html

<img
  *ngIf="imagePreview"
  [src]="sanitizer.bypassSecurityTrustUrl(imagePreview)">