Angularで画像をトリミングする方法

.
├── app-routing.module.ts
├── app.component.html
├── app.component.scss
├── app.component.spec.ts
├── app.component.ts
├── app.module.ts
├── explore-container
│   ├── explore-container.component.html
│   ├── explore-container.component.scss
│   ├── explore-container.component.spec.ts
│   ├── explore-container.component.ts
│   └── explore-container.module.ts
├── tab1
│   ├── tab1-routing.module.ts
│   ├── tab1.module.ts
│   ├── tab1.page.html
│   ├── tab1.page.scss
│   ├── tab1.page.spec.ts
│   └── tab1.page.ts
├── tab2
│   ├── tab2-routing.module.ts
│   ├── tab2.module.ts
│   ├── tab2.page.html
│   ├── tab2.page.scss
│   ├── tab2.page.spec.ts
│   └── tab2.page.ts
├── tab3
│   ├── tab3-routing.module.ts
│   ├── tab3.module.ts
│   ├── tab3.page.html
│   ├── tab3.page.scss
│   ├── tab3.page.spec.ts
│   └── tab3.page.ts
└── tabs
├── tabs-routing.module.ts
├── tabs.module.ts
├── tabs.page.html
├── tabs.page.scss
├── tabs.page.spec.ts
└── tabs.page.ts

npm install ngx-image-cropper --save

import { IonicModule } from '@ionic/angular';
import { NgModule } from '@angular/core';
import { CommonModule } from '@angular/common';
import { FormsModule } from '@angular/forms';
import { Tab1Page } from './tab1.page';
import { ExploreContainerComponentModule } from '../explore-container/explore-container.module';
import { ImageCropperModule } from 'ngx-image-cropper';

import { Tab1PageRoutingModule } from './tab1-routing.module';

@NgModule({
  imports: [
    IonicModule,
    CommonModule,
    FormsModule,
    ExploreContainerComponentModule,
    Tab1PageRoutingModule,
    ImageCropperModule
  ],
  declarations: [Tab1Page]
})
export class Tab1PageModule {}

<input type="file" (change)="fileChangeEvent($event)" />

<image-cropper
    [imageChangedEvent]="imageChangedEvent"
    [maintainAspectRatio]="true"
    [aspectRatio]="4 / 3"
    format="png"
    (imageCropped)="imageCropped($event)"
    (imageLoaded)="imageLoaded()"
    (cropperReady)="cropperReady()"
    (loadImageFailed)="loadImageFailed()"
></image-cropper>

<img [src]="croppedImage" />

import { Component } from '@angular/core';
import { ImageCroppedEvent } from 'ngx-image-cropper';

@Component({
  selector: 'app-tab1',
  templateUrl: 'tab1.page.html',
  styleUrls: ['tab1.page.scss']
})
export class Tab1Page {
    imageChangedEvent: any = '';
    croppedImage: any = '';

    constructor(
    ) {}

    fileChangeEvent(event: any): void {
        this.imageChangedEvent = event;
    }
    imageCropped(event: ImageCroppedEvent) {
        this.croppedImage = event.base64;
    }
    imageLoaded(image: HTMLImageElement) {
        // show cropper
    }
    cropperReady() {
        // cropper ready
    }
    loadImageFailed() {
        // show message
    }

}

<ion-content [fullscreen]="true">
  <ion-header collapse="condense">
    <ion-toolbar>
      <ion-title size="large">Tab 1</ion-title>
    </ion-toolbar>
  </ion-header>

  <ion-item>
    <input type="file" accept='image/*'  (change)="fileChangeEvent($event)" />
  </ion-item>

  <ion-progress-bar type="indeterminate" *ngIf="show" reversed="true"></ion-progress-bar>
  <!--プログレスバーの追加です-->

  <image-cropper
  [imageChangedEvent]="imageChangedEvent"
  [maintainAspectRatio]="false"
  [aspectRatio]="5/ 3"
  format="jpeg"
  (imageCropped)="imageCropped($event)"
  (imageLoaded)="imageLoaded()"
  (cropperReady)="cropperReady()"
  (loadImageFailed)="loadImageFailed()"
  imageQuality=25
></image-cropper>

  <img [src]="croppedImage" />

  <ion-button expand='block' (click)="onButtonClicked()" shape='round'>Get cropped image</ion-button>

</ion-content>

import { LoadingController } from '@ionic/angular';
import { Observable } from 'rxjs';

'
'
  constructor(
    public loadingController: LoadingController,
  ) {}

export class Tab1Page {
  imageChangedEvent: any = '';
  originalImgName:string;
  buffCroppedImageBase64:string;
  croppedImageBase64: any = '';
  croppedFileObject:any;
  show:any=false;

  fileChangeEvent(event: any): void {
    this.show = true;
    this.read(event).subscribe(()=>{
      console.log('done');
      this.show = false;
    });
  }

  read(event: any):Observable<any> {
    return new Observable(observer => {
      setTimeout(() => {
        this.imageChangedEvent = event;
        this.originalImgName = event.target.files[0].name;
        observer.next('e');
      }, 500);
    })
  }

  imageCropped(event: ImageCroppedEvent) {
      this.buffCroppedImageBase64 = event.base64;
  }

  onButtonClicked(){
    this.croppedImageBase64 = this.buffCroppedImageBase64;
    console.log(this.croppedImageBase64,'this.croppedImageBase64');

    var bin = atob(this.buffCroppedImageBase64.replace(/^.*,/, ''));
    // バイナリデータ化
    var buffer = new Uint8Array(bin.length);
    for (var i = 0; i < bin.length; i++) {
        buffer[i] = bin.charCodeAt(i);
    }
    this.croppedFileObject = new File([buffer.buffer], "heihei.jpg",{type: "image/jpeg"});
    console.log(this.croppedFileObject,'this.croppedFileObject');
  }

import { Component } from '@angular/core';
import { ImageCroppedEvent } from 'ngx-image-cropper';
import { LoadingController } from '@ionic/angular';
import { Observable } from 'rxjs';

@Component({
  selector: 'app-tab1',
  templateUrl: 'tab1.page.html',
  styleUrls: ['tab1.page.scss']
})
export class Tab1Page {
  imageChangedEvent: any = '';
  originalImgName:string;
  buffCroppedImageBase64:string;
  croppedImageBase64: any = '';
  show:any=false;

  constructor(
    public loadingController: LoadingController,
  ) {}

  fileChangeEvent(event: any): void {
    console.log(event,'abcde');
    this.show = true;
    this.read(event).subscribe(()=>{
      console.log('done');
      this.show = false;
    });
  }

  read(event: any):Observable<any> {
    return new Observable(observer => {
      setTimeout(() => {
        this.imageChangedEvent = event;
        this.originalImgName = event.target.files[0].name;
        observer.next('e');
      }, 500);
    })
  }


  imageCropped(event: ImageCroppedEvent) {
      this.buffCroppedImageBase64 = event.base64;
  }
  imageLoaded(image: HTMLImageElement) {
      // show cropper
  }
  cropperReady() {
      // cropper ready
  }
  loadImageFailed() {
      // show message
  }

  onButtonClicked(){
    this.croppedImageBase64 = this.buffCroppedImageBase64;
    console.log(this.croppedImageBase64,'this.croppedImageBase64');

    var bin = atob(this.buffCroppedImageBase64.replace(/^.*,/, ''));
    // バイナリデータ化
    var buffer = new Uint8Array(bin.length);
    for (var i = 0; i < bin.length; i++) {
        buffer[i] = bin.charCodeAt(i);
    }
    this.croppedFileObject = new File([buffer.buffer], "heihei.jpg",{type: "image/jpeg"});
    console.log(this.croppedFileObject,'this.croppedFileObject');
  }


}