How to create Image Reflection in Android?

By | January 8, 2012

Reflection in Android

This simple Activity creates a reflection of the provided image.

package com.coderzheaven.imagereflection;

import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.Bitmap.Config;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.LinearGradient;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.PorterDuff.Mode;
import android.graphics.PorterDuffXfermode;
import android.graphics.Shader.TileMode;
import android.os.Bundle;
import android.view.Menu;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.LinearLayout.LayoutParams;

public class ImageReflection extends Activity {

	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		// setContentView(R.layout.activity_image_reflection);

		Bitmap originalImage = BitmapFactory.decodeResource(getResources(),
				R.drawable.coderzheaven_logo);

		// Create an Image view and add our bitmap with reflection to it
		ImageView imageView = new ImageView(this);
		imageView.setImageBitmap(getRefelection(originalImage));

		// Add the image to a linear layout and display it
		LinearLayout linLayout = new LinearLayout(this);
		linLayout.addView(imageView, new LinearLayout.LayoutParams(
				LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT));

                linLayout.setBackgroundColor(Color.BLACK);
		// set LinearLayout as ContentView
		setContentView(linLayout);
	}


	public Bitmap getRefelection(Bitmap image) {
		// The gap we want between the reflection and the original image
		final int reflectionGap = 4;

		// Get you bit map from drawable folder
		Bitmap originalImage = image;

		int width = originalImage.getWidth();
		int height = originalImage.getHeight();

		// This will not scale but will flip on the Y axis
		Matrix matrix = new Matrix();
		matrix.preScale(1, -1);

		// Create a Bitmap with the flip matix applied to it.
		// We only want the bottom half of the image
		Bitmap reflectionImage = Bitmap.createBitmap(originalImage, 0,
				height / 2, width, height / 2, matrix, false);

		// Create a new bitmap with same width but taller to fit reflection
		Bitmap bitmapWithReflection = Bitmap.createBitmap(width,
				(height + height / 2), Config.ARGB_8888);

		// Create a new Canvas with the bitmap that's big enough for
		// the image plus gap plus reflection
		Canvas canvas = new Canvas(bitmapWithReflection);
		// Draw in the original image
		canvas.drawBitmap(originalImage, 0, 0, null);
		//Draw the reflection Image
		canvas.drawBitmap(reflectionImage, 0, height + reflectionGap, null);

		// Create a shader that is a linear gradient that covers the reflection
		Paint paint = new Paint();
		LinearGradient shader = new LinearGradient(0,
				originalImage.getHeight(), 0, bitmapWithReflection.getHeight()
						+ reflectionGap, 0x70ffffff, 0x00ffffff, TileMode.CLAMP);
		// Set the paint to use this shader (linear gradient)
		paint.setShader(shader);
		// Set the Transfer mode to be porter duff and destination in
		paint.setXfermode(new PorterDuffXfermode(Mode.DST_IN));
		// Draw a rectangle using the paint with our linear gradient
		canvas.drawRect(0, height, width, bitmapWithReflection.getHeight()
				+ reflectionGap, paint);
		return bitmapWithReflection;
	}

}

Download the complete source code for above example from here.

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