Hue Filter Effect on image in ImageView (Android)

Before Hue Filter Effect

After Hue Filter Effect

hue level 2

hue level 6

Create new Android Project

Project Name: PlayingwithBitmaps

Build Target: Android 2.3.3   //or greater than that

Application Name: PlayingwithBitmaps

Package Name: com.hamad.playingwithbitmaps

Create Activity: Main

Min SDK: 10 // or greater than that

  1.create main layout:

• One image view to display the image.

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#000000"
    android:id="@+id/rlMain" >

    <ImageView
        android:id="@+id/imViewAndroid"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"
        android:src="@drawable/car" />

</RelativeLayout>

 2. code of main activity:

 
package com.shaikhhamadali.blogspot.playingwithbitmaps;

import android.os.Bundle;
import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Color;
import android.widget.ImageView;

public class Main extends Activity {
 ImageView imViewAndroid;
 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  imViewAndroid = (ImageView) findViewById(R.id.imViewAndroid);
  imViewAndroid.setImageBitmap(applyHueFilterEffect(BitmapFactory.decodeResource(getResources(), R.drawable.beautiful),3));
 }
 public Bitmap applyHueFilterEffect(Bitmap source, int level) {
  // get original image size
  int width = source.getWidth();
  int height = source.getHeight();
  int[] pixels = new int[width * height];
  float[] HSV = new float[3];
  // get pixel array from source image
  source.getPixels(pixels, 0, width, 0, 0, width, height);

  int index = 0;
  // iteration through pixels
  for(int y = 0; y < height; ++y) {
   for(int x = 0; x < width; ++x) {
    // get current index in 2D-matrix
    index = y * width + x;              
    // convert to HSV
    Color.colorToHSV(pixels[index], HSV);
    // increase Saturation level
    HSV[0] *= level;
    HSV[0] = (float) Math.max(0.0, Math.min(HSV[0], 360.0));
    // take color back
    pixels[index] |= Color.HSVToColor(HSV);
   }
  }
  // output bitmap                
  Bitmap bmOut = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
  bmOut.setPixels(pixels, 0, width, 0, 0, width, height);
  return bmOut;       
 }
} 

  3. note that:

• For better understanding i will post an other one on saturation filter soon.
• you can also refer this link for better understanding HueFilter.
• With the help of this,applyHueFilterEffect() method you can apply Hue Filter Effect on image on click,on action_down etc.

  4. conclusion:

• Some deep information about Hue Filter effect .
• Know how to apply Hue Filter  effect on image bitmap from drawables.

  5. About the post:

•  The code seems to explain itself due to comments, and is very easy to understand.
•  Don’t mind to write a comment whatever you like to ask, to know,to suggest or recommend.
•  Hope you enjoy it!

6. Source Code:

        you can download the source code here

Cheers,

Hamad Ali Shaikh