Thursday 3 March 2016

Image Compression without affecting Image quality in Android

Hello Friends,

Today i am going to brief you about how you can upload large size image in compressed form like whatsapp.

The images captured by the recent cameras often exceed 2 MB. Using such images frequently results in OutOfMemoryError. Also, due to landscape/portrait orientation, the images often are displayed as rotated. To deal with these issues we need to compress the image and give proper rotation before loading it to memory. The following method compresses image (similar to whatsapp), while maintaining its aspect ratio and also preventing significant loss to its quality.

I have also implemented demo which contains image selection using camera and gallery also. It reduces size of an image without affecting its quality.

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package com.demo.imagecompressiondemo;

import android.app.Activity;
import android.content.Context;
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.view.inputmethod.InputMethodManager;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;

/**
 * Created by Grishma on 14/3/16.
 */
public class CommonUtils {
    private static final float maxHeight = 1280.0f;
    private static final float maxWidth = 1280.0f;

    public 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;
    }


    /**
     * Reduces the size of an image without affecting its quality.
     *
     * @param imagePath -Path of an image
     * @return
     */
    public static String compressImage(String imagePath) {
        Bitmap scaledBitmap = null;
        BitmapFactory.Options options = new BitmapFactory.Options();
        options.inJustDecodeBounds = true;
        Bitmap bmp = BitmapFactory.decodeFile(imagePath, options);

        int actualHeight = options.outHeight;
        int actualWidth = options.outWidth;

        float imgRatio = (float) actualWidth / (float) actualHeight;
        float maxRatio = maxWidth / maxHeight;

        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;
            }
        }
        options.inSampleSize = calculateInSampleSize(options, actualWidth, actualHeight);
        options.inJustDecodeBounds = false;
        options.inDither = false;
        options.inPurgeable = true;
        options.inInputShareable = true;
        options.inTempStorage = new byte[16 * 1024];
        try {
            bmp = BitmapFactory.decodeFile(imagePath, options);
        } catch (OutOfMemoryError exception) {
            exception.printStackTrace();
        }
        try {
            scaledBitmap = Bitmap.createBitmap(actualWidth, actualHeight, Bitmap.Config.RGB_565);
        } 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));
        if (bmp != null) {
            bmp.recycle();
        }
        ExifInterface exif;
        try {
            exif = new ExifInterface(imagePath);
            int orientation = exif.getAttributeInt(ExifInterface.TAG_ORIENTATION, 0);
            Matrix matrix = new Matrix();
            if (orientation == 6) {
                matrix.postRotate(90);
            } else if (orientation == 3) {
                matrix.postRotate(180);
            } else if (orientation == 8) {
                matrix.postRotate(270);
            }
            scaledBitmap = Bitmap.createBitmap(scaledBitmap, 0, 0, scaledBitmap.getWidth(), scaledBitmap.getHeight(), matrix, true);
        } catch (IOException e) {
            e.printStackTrace();
        }
        FileOutputStream out = null;
        String filepath = MainActivity.imageFilePath;//getFilename();
        try {
            //new File(imageFilePath).delete();
            out = new FileOutputStream(filepath);

            //write the compressed bitmap at the destination specified by filename.
            scaledBitmap.compress(Bitmap.CompressFormat.JPEG, 80, out);

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

        return filepath;
    }

    public static String getFilename() {
        File mediaStorageDir = new File(Environment.getExternalStorageDirectory()
                  + "/ImageCompApp/Images");

        // Create the storage directory if it does not exist
        if (!mediaStorageDir.exists()) {
            mediaStorageDir.mkdirs();
        }

        String mImageName = "IMG_" + String.valueOf(System.currentTimeMillis()) + ".jpg";
        String uriString = (mediaStorageDir.getAbsolutePath() + "/" + mImageName);
        return uriString;
    }

    public static void hideKeyboard(Activity context) {
        try {
            if (context == null) return;
            InputMethodManager imm = (InputMethodManager) context.getSystemService(Context.INPUT_METHOD_SERVICE);
            imm.hideSoftInputFromWindow(context.getWindow().getCurrentFocus().getWindowToken(), 0);
        } catch (Exception e) {
        }
    }
}
The method getFilename():: It creates a folder in the SDCard used to store the images.
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public static String getFilename() {
        File mediaStorageDir = new File(Environment.getExternalStorageDirectory()
                  + "/ImageCompApp/Images");

        // Create the storage directory if it does not exist
        if (!mediaStorageDir.exists()) {
            mediaStorageDir.mkdirs();
        }

        String mImageName = "IMG_" + String.valueOf(System.currentTimeMillis()) + ".jpg";
        String uriString = (mediaStorageDir.getAbsolutePath() + "/" + mImageName);
        return uriString;
    }
The method calculateInSampleSize:: calculates a proper value for inSampleSize based on the actual and required dimensions:

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 public 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;
    }
A demo project implementing this compression can be downloaded from Here.


Note:In this approach, the max height and width of the output image is maintained at around 960px and 1280px respectively [float maxHeight = 1280.0f; float maxWidth = 1280.0f;] The final height and width are decided depending upon the aspect ratio(width:height) of the image. The extent of compression required to achieve this ia calculated by the method “calculateInSampleSize”. The method returns an integer value “inSampleSize”. This “inSampleSize” decides the extent of compression. For example if inSampleSize=1, the image will be compressed to half; inSampleSize = 4 means the image the will be compressed to one-fourth. So when we are loading the image from the path, it loads a scaled down version.




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5 comments:

  1. Unknown9 January 2020 at 04:23

    Very Help Full

    ReplyDelete
  2. Shubham17 August 2020 at 20:11

    Very helpful project, I have listed best image compressor Android apps here: Image compressor apps

    ReplyDelete
  3. Shrutika25 November 2020 at 03:37

    While compressing is the file width and height is reduced.

    ReplyDelete
  4. Unknown15 January 2021 at 22:45

    Its only for compressing already saved images what abt captured image compression????

    ReplyDelete
  5. Prabha23 March 2021 at 23:14

    inPurgeable and inInputShareable deprecated

    any solution

    ReplyDelete

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