Increase Contrast, Reduce Brightness : Color « 2D Graphics « Android






  1. Android
  2. 2D Graphics
  3. Color

Increase Contrast, Reduce Brightness

  
package app.test;

import java.io.FileNotFoundException;
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 Test extends Activity implements OnClickListener {
  ImageView chosenImageView;
  Button choosePicture;
  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.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 = -5;
        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());
      }
    }
  }
}

//main.xml


<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
<Button
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="Choose Picture" android:id="@+id/ChoosePictureButton"/>

<ImageView android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/ChosenImageView"></ImageView>
<ImageView android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/AlteredImageView"></ImageView>
</LinearLayout>








Related examples in the same category

1.Using solid color to paint
2.Set color for Paint
3.Create Color from RGB value
4.Load Color from resource xml file
5.Using View to display color
6.Change check box color
7.Color Filters
8.Color Matrix Sample
9.HSV To Color
10.RGB To Color
11.lighten Color
12.Get Random Location and Colors
13.Returns the complimentary (opposite) color.
14.brighter a color
15.darker a color
16.extends View to create ColorCircle
17.Increase Red
18.Decrease Saturation