BrightAndContrast

package com.kaidul.contrastandbrightness;

import android.app.Activity;
import android.content.Intent;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.ColorMatrix;
import android.graphics.ColorMatrixColorFilter;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.net.Uri;
import android.os.Bundle;
import android.util.Log;
import android.view.Display;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ImageView;

public class MainActivity extends Activity implements OnClickListener {
  ImageView chosenImageView;
  Button choosePicture;
  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    chosenImageView = (ImageView) this.findViewById(R.id.ChosenImageView);
    choosePicture = (Button) this.findViewById(R.id.ChoosePictureButton);

    choosePicture.setOnClickListener(this);
  }

  public void onClick(View v) {
    Intent choosePictureIntent = new Intent(Intent.ACTION_PICK,
        android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
    startActivityForResult(choosePictureIntent, 0);
  }

  protected void onActivityResult(int requestCode, int resultCode,
      Intent intent) {
    super.onActivityResult(requestCode, resultCode, intent);

    if (resultCode == RESULT_OK) {
      Uri imageFileUri = intent.getData();

      Display currentDisplay = getWindowManager().getDefaultDisplay();
      int dw = currentDisplay.getWidth();
      int dh = currentDisplay.getHeight() / 2 - 100;

      try {

        BitmapFactory.Options bmpFactoryOptions = new BitmapFactory.Options();
        bmpFactoryOptions.inJustDecodeBounds = true;
        Bitmap bmp = BitmapFactory
            .decodeStream(getContentResolver().openInputStream(
                imageFileUri), null, bmpFactoryOptions);

        int heightRatio = (int) Math.ceil(bmpFactoryOptions.outHeight
            / (float) dh);
        int widthRatio = (int) Math.ceil(bmpFactoryOptions.outWidth
            / (float) dw);

        if (heightRatio > 1 && widthRatio > 1) {
          if (heightRatio > widthRatio) {
            bmpFactoryOptions.inSampleSize = heightRatio;
          } else {
            bmpFactoryOptions.inSampleSize = widthRatio;
          }
        }
        bmpFactoryOptions.inJustDecodeBounds = false;
        bmp = BitmapFactory.decodeStream(getContentResolver().openInputStream(imageFileUri), null, bmpFactoryOptions);
        Bitmap alteredBitmap = Bitmap.createBitmap(bmp.getWidth(), bmp
            .getHeight(), bmp.getConfig());
        Canvas canvas = new Canvas(alteredBitmap);
        Paint paint = new Paint();
        ColorMatrix cm = new ColorMatrix();
        // Increase Contrast, Slightly Reduce Brightness
        float contrast = 3;
        float brightness = 3;
        cm.set(new float[] { contrast, 0, 0, 0, brightness, 0,
            contrast, 0, 0, brightness, 0, 0, contrast, 0,
            brightness, 0, 0, 0, 1, 0 });

        paint.setColorFilter(new ColorMatrixColorFilter(cm));
        Matrix matrix = new Matrix();
        canvas.drawBitmap(bmp, matrix, paint);
        ImageView alteredImageView = (ImageView) this
            .findViewById(R.id.AlteredImageView);
        alteredImageView.setImageBitmap(alteredBitmap);
        chosenImageView.setImageBitmap(bmp);
      } catch (Exception e) {
        Log.v("ERROR", e.toString());
      }
    }
  }
}