ImageCompressionUtils.java

package com.nwt.myhealthcarefordoctors.utils;

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.media.ExifInterface;
import android.os.Environment;
import android.util.Log;

import com.esafirm.imagepicker.model.Image;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

import okhttp3.MediaType;
import okhttp3.MultipartBody;
import okhttp3.RequestBody;

/**
 * Created by SMM on 5/11/2018.
 */

public class ImageCompressionUtils {

    public static List<MultipartBody.Part> getCompressedImages(List<Image> originalImages) {
        List<MultipartBody.Part> partList = new ArrayList<>(originalImages.size());
        File imageFile = null;
        for (int i = 0; i < originalImages.size(); i++) {
            imageFile = new File(compressImage(originalImages.get(i).getPath()));
            RequestBody requestFile =
                    RequestBody.create(
                            MediaType.parse("image/*"),
                            imageFile
                    );
            partList.add(MultipartBody.Part.createFormData("file", imageFile.getName(), requestFile));
        }
        return partList;
    }


    public static String compressImage(String filePath) {

        Bitmap scaledBitmap = null;
        BitmapFactory.Options options = new BitmapFactory.Options();
//      by setting this field as true, the actual bitmap pixels are not loaded in the memory. Just the bounds are loaded. If
//      you try the use the bitmap here, you will get null.
        options.inJustDecodeBounds = true;
        Bitmap bmp = BitmapFactory.decodeFile(filePath, options);
        int actualHeight = options.outHeight;
        int actualWidth = options.outWidth;
//      max Height and width values of the compressed image is taken as 816x612
        float maxHeight = 816.0f;
        float maxWidth = 612.0f;
        float imgRatio = actualWidth / actualHeight;
        float maxRatio = maxWidth / maxHeight;
//      width and height values are set maintaining the aspect ratio of the image
        if (actualHeight > maxHeight || actualWidth > maxWidth) {
            if (imgRatio < maxRatio) {
                imgRatio = maxHeight / actualHeight;
                actualWidth = (int) (imgRatio * actualWidth);
                actualHeight = (int) maxHeight;
            } else if (imgRatio > maxRatio) {
                imgRatio = maxWidth / actualWidth;
                actualHeight = (int) (imgRatio * actualHeight);
                actualWidth = (int) maxWidth;
            } else {
                actualHeight = (int) maxHeight;
                actualWidth = (int) maxWidth;
            }
        }
//      setting inSampleSize value allows to load a scaled down version of the original image
        options.inSampleSize = calculateInSampleSize(options, actualWidth, actualHeight);
//      inJustDecodeBounds set to false to load the actual bitmap
        options.inJustDecodeBounds = false;
//      this options allow android to claim the bitmap memory if it runs low on memory
        options.inPurgeable = true;
        options.inInputShareable = true;
        options.inTempStorage = new byte[16 * 1024];
        try {
//          load the bitmap from its path
            bmp = BitmapFactory.decodeFile(filePath, options);
        } catch (OutOfMemoryError exception) {
            exception.printStackTrace();

        }
        try {
            scaledBitmap = Bitmap.createBitmap(actualWidth, actualHeight, Bitmap.Config.ARGB_8888);
        } catch (OutOfMemoryError exception) {
            exception.printStackTrace();
        }

        float ratioX = actualWidth / (float) options.outWidth;
        float ratioY = actualHeight / (float) options.outHeight;
        float middleX = actualWidth / 2.0f;
        float middleY = actualHeight / 2.0f;

        Matrix scaleMatrix = new Matrix();
        scaleMatrix.setScale(ratioX, ratioY, middleX, middleY);

        Canvas canvas = new Canvas(scaledBitmap);
        canvas.setMatrix(scaleMatrix);
        canvas.drawBitmap(bmp, middleX - bmp.getWidth() / 2, middleY - bmp.getHeight() / 2, new Paint(Paint.FILTER_BITMAP_FLAG));

//      check the rotation of the image and display it properly
        ExifInterface exif;
        try {
            exif = new ExifInterface(filePath);

            int orientation = exif.getAttributeInt(
                    ExifInterface.TAG_ORIENTATION, 0);
            Log.d("EXIF", "Exif: " + orientation);
            Matrix matrix = new Matrix();
            if (orientation == 6) {
                matrix.postRotate(90);
                Log.d("EXIF", "Exif: " + orientation);
            } else if (orientation == 3) {
                matrix.postRotate(180);
                Log.d("EXIF", "Exif: " + orientation);
            } else if (orientation == 8) {
                matrix.postRotate(270);
                Log.d("EXIF", "Exif: " + orientation);
            }
            scaledBitmap = Bitmap.createBitmap(scaledBitmap, 0, 0,
                    scaledBitmap.getWidth(), scaledBitmap.getHeight(), matrix,
                    true);
        } catch (IOException e) {
            e.printStackTrace();
        }

        FileOutputStream out = null;
        String filename = getFilename();
        try {
            out = new FileOutputStream(filename);
//          write the compressed bitmap at the destination specified by filename.
            scaledBitmap.compress(Bitmap.CompressFormat.JPEG, 100, out);

        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
        return filename;
    }


    private static String getFilename() {
        File file = getFileDirectory();
        String uriSting = (file.getAbsolutePath() + "/" + System.currentTimeMillis() + ".jpg");
        return uriSting;
    }

    public static File getFileDirectory(){
        File file = new File(Environment.getExternalStorageDirectory().getPath(), "MyHealthcare/.tmp");
        if (!file.exists()) {
            file.mkdirs();
        }
        return file;
    }

   public static void deleteImages(File fileOrDirectory) {
        if (fileOrDirectory.isDirectory())
            for (File child : fileOrDirectory.listFiles())
                deleteImages(child);

        fileOrDirectory.delete();
    }


    private static int calculateInSampleSize(BitmapFactory.Options options, int reqWidth, int reqHeight) {
        final int height = options.outHeight;
        final int width = options.outWidth;
        int inSampleSize = 1;
        if (height > reqHeight || width > reqWidth) {
            final int heightRatio = Math.round((float) height / (float) reqHeight);
            final int widthRatio = Math.round((float) width / (float) reqWidth);
            inSampleSize = heightRatio < widthRatio ? heightRatio : widthRatio;
        }
        final float totalPixels = width * height;
        final float totalReqPixelsCap = reqWidth * reqHeight * 2;
        while (totalPixels / (inSampleSize * inSampleSize) > totalReqPixelsCap) {
            inSampleSize++;
        }
        return inSampleSize;
    }
}