开始

ionic start ionic3-image-crop blank
cd ionic3-image-crop

安装插件与第三方库

• Apache Cordova Camera plugin
• ng2-img-cropper node package

ionic cordova plugin add cordova-plugin-camera
npm install @ionic-native/camera --save 
npm install ng2-img-cropper --save 

生成服务

ionic g provider photo

先生成一个服务，稍后我们将使用它来处理与 Camera plugin 的交互的服务。

配置

编辑文件 src/app/app.module.ts:

import { BrowserModule } from '@angular/platform-browser';
import { ErrorHandler, NgModule } from '@angular/core';
import { IonicApp, IonicErrorHandler, IonicModule } from 'ionic-angular';
import { SplashScreen } from '@ionic-native/splash-screen';
import { StatusBar } from '@ionic-native/status-bar';

import { MyApp } from './app.component';
import { HomePage } from '../pages/home/home';
import { PhotoProvider } from '../providers/photo/photo';
import { Camera } from '@ionic-native/camera';
import { ImageCropperModule } from "ng2-img-cropper/index";

@NgModule({
  declarations: [
    MyApp,
    HomePage
  ],
  imports: [
    BrowserModule,
    ImageCropperModule,
    IonicModule.forRoot(MyApp)
  ],
  bootstrap: [IonicApp],
  entryComponents: [
    MyApp,
    HomePage
  ],
  providers: [
    StatusBar,
    SplashScreen,
    Camera,
    {provide: ErrorHandler, useClass: IonicErrorHandler},
    PhotoProvider
  ]
})
export class AppModule {}

实现具体的服务

编辑文件 src/providers/photo/photo.ts，实现一个单一的方法 - selectImage - 用于处理设备 photolibrary 的打开，选择所需的图片并将其作为 base64 编码字符串返回:

import { Injectable } from '@angular/core';
import { Camera, CameraOptions } from '@ionic-native/camera';

@Injectable()
export class PhotoProvider {

  constructor(private _CAMERA: Camera) { }

  selectImage() {
    return new Promise(resolve => {
      let cameraOptions: CameraOptions = {
        sourceType: this._CAMERA.PictureSourceType.PHOTOLIBRARY,
        destinationType: this._CAMERA.DestinationType.DATA_URL,
        quality: 100,
        targetWidth: 320,
        targetHeight: 240,
        encodingType: this._CAMERA.EncodingType.JPEG,
        correctOrientation: true
      };
      this._CAMERA.getPicture(cameraOptions).then(data => {
        let cameraImage = "data:image/jpeg;base64," + data;
        resolve(cameraImage);
      })
    });
  }

}

Home

src/pages/home/home.ts:

import { PhotoProvider } from './../../providers/photo/photo';
import { Component, ViewChild } from '@angular/core';
import { ImageCropperComponent, CropperSettings, Bounds } from 'ng2-img-cropper';

@Component({
  selector: 'page-home',
  templateUrl: 'home.html'
})
export class HomePage {
  @ViewChild('cropper') ImageCropper: ImageCropperComponent;

  data: any;
  cropperSettings: CropperSettings;
  croppedWidth: number;
  croppedHeight: number;

  constructor(private _PHOTO: PhotoProvider) {
    this.cropperSettings = new CropperSettings();

    // Hide the default file input for image selection (we'll be using the Camera plugin instead)
    this.cropperSettings.noFileInput = true;

    // Create a new cropped image object when the cropping tool is resized
    this.cropperSettings.cropOnResize = true;

    // We want to convert the file type for a cropped image to a JPEG format
    this.cropperSettings.fileType = 'image/jpeg';

    this.cropperSettings.rounded = true;

    // We want to be able to adjust the size of the cropping tool by dragging from any corner in any direction
    // Cannot set keepAspect to false on rounded cropper
    this.cropperSettings.keepAspect = true;

    // Create an object to store image related cropping data
    this.data = {};
  }

  selectImage() {
    this._PHOTO.selectImage()
      .then((data: any) => {
        // Create an Image object, assign retrieved base64 image from the device photo library
        let image: any = new Image();
        image.src = data;

        // Assign the Image object to the ImageCropper component
        this.ImageCropper.setImage(image);
      })
      .catch((error: any) => {
        console.dir(error);
      });
  }

  cropped(bounds: Bounds) {
    this.croppedHeight = bounds.bottom - bounds.top;
    this.croppedWidth = bounds.right - bounds.left;
  }

}

src/pages/home/home.html:

<ion-header>
  <ion-navbar>
    <ion-title>
      Image Cropper
    </ion-title>
  </ion-navbar>
</ion-header>

<ion-content padding>
  <!-- Select image from device photolibrary -->
  <button ion-button block color="primary" (click)="selectImage()">Select an Image</button>

  <!-- Declare image cropper with following aspects:

       1. Template reference variable to allow component
          class to 'hook' into the cropper tool in DOM
       2. Set image from the component class's data object
       3. Apply settings from the component class's cropperSettings object
       4. Call the cropped method in the image cropper's onCrop event
   -->
  <img-cropper #cropper [image]="data" [settings]="cropperSettings" (onCrop)="cropped($event)"></img-cropper>

  <!-- Display the cropped image -->
  <div *ngIf="data.image" [class.rounded]="cropperSettings.rounded">
    <img [src]="data.image" [width]="croppedWidth" [height]="croppedHeight">
  </div>

</ion-content>

src/pages/home/home.scss:

.rounded>img {
  border-radius: 100px;
}