Custom ImageView with drop shadow

Okay, I've been reading and searching around, and am now banging my head against the wall trying to figure this out. Here's what I have so far:

package com.pockdroid.sandbox;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Rect;
import android.widget.ImageView;

public class ShadowImageView extends ImageView {

private Rect mRect;
private Paint mPaint;

public ShadowImageView(Context context)
{
	super(context);
	mRect = new Rect();
	mPaint = new Paint();
	mPaint.setAntiAlias(true);
	mPaint.setShadowLayer(2f, 1f, 1f, Color.BLACK);
}

@Override
protected void onDraw(Canvas canvas) 
{
	Rect r = mRect;
	Paint paint = mPaint;
	
	canvas.drawRect(r, paint);
	super.onDraw(canvas);
}

@Override
protected void onMeasure(int w, int h)
{
	super.onMeasure(w,h);
	int mH, mW;
	mW = getSuggestedMinimumWidth() < getMeasuredWidth()? getMeasuredWidth() : getSuggestedMinimumWidth();
	mH = getSuggestedMinimumHeight() < getMeasuredHeight()? getMeasuredHeight() : getSuggestedMinimumHeight();
	setMeasuredDimension(mW + 5, mH + 5);
}

}

The "+5" in the measurements are there as temporary; From what I understand I'll need to do some math to determine the size that the drop shadow adds to the canvas, right?

But when I use this:

public View getView(int position, View convertView, ViewGroup parent) {
    ShadowImageView sImageView;
    if (convertView == null) {
        sImageView = new ShadowImageView(mContext);
        GridView.LayoutParams lp = new GridView.LayoutParams(85, 85);
        sImageView.setLayoutParams(lp);
        
        sImageView.setScaleType(ImageView.ScaleType.CENTER);
        sImageView.setPadding(5,5,5,5);
    } else {
        sImageView = (ShadowImageView) convertView;
    }

    sImageView.setImageBitmap(bitmapList.get(position));
    return sImageView;
}

in my ImageView, I still get just a normal ImageView when I run the program.

Any thoughts? Thanks.

EDIT: So I spoke with RomainGuy some in the IRC channel, and I have it working now for plain rectangular images with the below code. It still won't draw the shadow directly to my bitmap's transparency though, so I'm still working on that.

@Override
protected void onDraw(Canvas canvas) 
{
	Bitmap bmp = BitmapFactory.decodeResource(getResources(), R.drawable.omen);
	Paint paint = new Paint();
	paint.setAntiAlias(true);
	paint.setShadowLayer(5.5f, 6.0f, 6.0f, Color.BLACK);
	canvas.drawColor(Color.GRAY);
	canvas.drawRect(50, 50, 50 + bmp.getWidth(), 50 + bmp.getHeight(), paint);
	canvas.drawBitmap(bmp, 50, 50, null);		
}

Okay, I don't foresee any more answers on this one, so what I ended up going with for now is just a solution for rectangular images. I've used the following NinePatch:



along with the appropriate padding in XML:

<ImageView
		android:id="@+id/image_test"
		android:background="@drawable/drop_shadow"
		android:layout_width="wrap_content"
		android:layout_height="wrap_content"
		android:paddingLeft="6px"
		android:paddingTop="4px"
		android:paddingRight="8px"
		android:paddingBottom="9px"
		android:src="@drawable/pic1"
		/>

to get a fairly good result:



Not ideal, but it'll do.

This is taken from Romain Guy's presentation at Devoxx, pdf found here.

Paint mShadow = new Paint(); 
// radius=10, y-offset=2, color=black 
mShadow.setShadowLayer(10.0f, 0.0f, 2.0f, 0xFF000000); 
// in onDraw(Canvas) 
canvas.drawBitmap(bitmap, 0.0f, 0.0f, mShadow);

Hope this helps.

NOTES

1. Don't forget for Honeycomb and above you need to invoke setLayerType(LAYER_TYPE_SOFTWARE, mShadow), otherwise you will not see your shadow! (@Dmitriy_Boichenko)
2. SetShadowLayer does not work with hardware acceleration unfortunately so it greatly reduces performances (@Matt Wear) [1] [2]

I believe this answer from UIFuel

<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">

     <!-- Drop Shadow Stack -->
     <item>
        <shape>
            <padding android:top="1dp" android:right="1dp" android:bottom="1dp" android:left="1dp" />
            <solid android:color="#00CCCCCC" />
        </shape>
    </item>
     <item>
        <shape>
            <padding android:top="1dp" android:right="1dp" android:bottom="1dp" android:left="1dp" />
            <solid android:color="#10CCCCCC" />
        </shape>
    </item>
     <item>
        <shape>
            <padding android:top="1dp" android:right="1dp" android:bottom="1dp" android:left="1dp" />
            <solid android:color="#20CCCCCC" />
        </shape>
    </item>
     <item>
        <shape>
            <padding android:top="1dp" android:right="1dp" android:bottom="1dp" android:left="1dp" />
            <solid android:color="#30CCCCCC" />
        </shape>
    </item>
    <item>
        <shape>
            <padding android:top="1dp" android:right="1dp" android:bottom="1dp" android:left="1dp" />
            <solid android:color="#50CCCCCC" />
        </shape>
    </item>

    <!-- Background -->
    <item>
	<shape>
            <solid android:color="@color/white" />
	    <corners android:radius="3dp" />
	</shape>
    </item>
</layer-list>

My dirty solution:

private static Bitmap getDropShadow3(Bitmap bitmap) {

    if (bitmap==null) return null;
    int think = 6;
    int w = bitmap.getWidth();
    int h = bitmap.getHeight();

    int newW = w - (think);
    int newH = h - (think);

    Bitmap.Config conf = Bitmap.Config.ARGB_8888;
    Bitmap bmp = Bitmap.createBitmap(w, h, conf);
    Bitmap sbmp = Bitmap.createScaledBitmap(bitmap, newW, newH, false);

    Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
    Canvas c = new Canvas(bmp);

    // Right
    Shader rshader = new LinearGradient(newW, 0, w, 0, Color.GRAY, Color.LTGRAY, Shader.TileMode.CLAMP);
    paint.setShader(rshader);
    c.drawRect(newW, think, w, newH, paint);

    // Bottom
    Shader bshader = new LinearGradient(0, newH, 0, h, Color.GRAY, Color.LTGRAY, Shader.TileMode.CLAMP);
    paint.setShader(bshader);
    c.drawRect(think, newH, newW  , h, paint);

    //Corner
    Shader cchader = new LinearGradient(0, newH, 0, h, Color.LTGRAY, Color.LTGRAY, Shader.TileMode.CLAMP);
    paint.setShader(cchader);
    c.drawRect(newW, newH, w  , h, paint);


    c.drawBitmap(sbmp, 0, 0, null);

    return bmp;
}

result:

Here you are. Set source of ImageView statically in xml or dynamically in code.

Shadow is here white.

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="wrap_content" android:layout_height="wrap_content">

    <View android:layout_width="wrap_content" android:layout_height="wrap_content"
	    android:background="@android:color/white" android:layout_alignLeft="@+id/image"
		android:layout_alignRight="@id/image" android:layout_alignTop="@id/image"
	    android:layout_alignBottom="@id/image" android:layout_marginLeft="10dp"
	    android:layout_marginBottom="10dp" />

	<ImageView android:id="@id/image" android:layout_width="wrap_content"
	    android:layout_height="wrap_content" android:src="..."
	    android:padding="5dp" />

</RelativeLayout>

I manage to apply gradient border using this code..

public static Bitmap drawShadow(Bitmap bitmap, int leftRightThk, int bottomThk, int padTop) {
	int w = bitmap.getWidth();
	int h = bitmap.getHeight();
	
	int newW = w - (leftRightThk * 2);
	int newH = h - (bottomThk + padTop);
	
	Bitmap.Config conf = Bitmap.Config.ARGB_8888;
	Bitmap bmp = Bitmap.createBitmap(w, h, conf);
	Bitmap sbmp = Bitmap.createScaledBitmap(bitmap, newW, newH, false);
	
	Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
	Canvas c = new Canvas(bmp);
			
	// Left
	int leftMargin = (leftRightThk + 7)/2;
	Shader lshader = new LinearGradient(0, 0, leftMargin, 0, Color.TRANSPARENT, Color.BLACK, TileMode.CLAMP);
	paint.setShader(lshader);
	c.drawRect(0, padTop, leftMargin, newH, paint);	
	
	// Right
	Shader rshader = new LinearGradient(w - leftMargin, 0, w, 0, Color.BLACK, Color.TRANSPARENT, TileMode.CLAMP);
	paint.setShader(rshader);
	c.drawRect(newW, padTop, w, newH, paint);
	
	// Bottom
	Shader bshader = new LinearGradient(0, newH, 0, bitmap.getHeight(), Color.BLACK, Color.TRANSPARENT, TileMode.CLAMP);
	paint.setShader(bshader);
	c.drawRect(leftMargin -3, newH, newW + leftMargin + 3, bitmap.getHeight(), paint);
	c.drawBitmap(sbmp, leftRightThk, 0, null);
	
	return bmp;
}

hope this helps !

This works for me ...

public class ShadowImage extends Drawable {

Bitmap bm;

@Override
public void draw(Canvas canvas) {

	Paint mShadow = new Paint();
	Rect rect = new Rect(0,0,bm.getWidth(), bm.getHeight());
	
	mShadow.setAntiAlias(true);
	mShadow.setShadowLayer(5.5f, 4.0f, 4.0f, Color.BLACK);

	canvas.drawRect(rect, mShadow);
	canvas.drawBitmap(bm, 0.0f, 0.0f, null);

}

public ShadowImage(Bitmap bitmap) {
	super();
	this.bm = bitmap;
} ... }

Here the Implementation of Paul Burkes answer:

public class ShadowImageView extends ImageView {

	public ShadowImageView(Context context, AttributeSet attrs, int defStyle) {
		super(context, attrs, defStyle);
	}

	public ShadowImageView(Context context, AttributeSet attrs) {
		super(context, attrs);
	}

	public ShadowImageView(Context context) {
		super(context);
	}

	private Paint createShadow() {
		Paint mShadow = new Paint();

		float radius = 10.0f;
		float xOffset = 0.0f;
		float yOffset = 2.0f;

		// color=black
		int color = 0xFF000000;
		mShadow.setShadowLayer(radius, xOffset, yOffset, color);


		return mShadow;
	}

	@Override
	protected void onDraw(Canvas canvas) {
		Paint mShadow = createShadow();
		Drawable d = getDrawable();
		if (d != null){
		    setLayerType(LAYER_TYPE_SOFTWARE, mShadow);
			Bitmap bitmap = ((BitmapDrawable) getDrawable()).getBitmap();
			canvas.drawBitmap(bitmap, 0.0f, 0.0f, mShadow);
		} else {
			super.onDraw(canvas);
		}

	};

}

TODO: execute setLayerType(LAYER_TYPE_SOFTWARE, mShadow); only if API Level is > 10

I've built upon the answer above - https://stackoverflow.com/a/11155031/2060486 - to create a shadow around ALL sides..

 private static final int GRAY_COLOR_FOR_SHADE = Color.argb(50, 79, 79, 79);

// this method takes a bitmap and draws around it 4 rectangles with gradient to create a
// shadow effect.
public static Bitmap addShadowToBitmap(Bitmap origBitmap) {
    int shadowThickness = 13; // can be adjusted as needed
    int bmpOriginalWidth = origBitmap.getWidth();
    int bmpOriginalHeight = origBitmap.getHeight();
    int bigW = bmpOriginalWidth + shadowThickness * 2; // getting dimensions for a bigger bitmap with margins
    int bigH = bmpOriginalHeight + shadowThickness * 2;
    Bitmap containerBitmap = Bitmap.createBitmap(bigW, bigH, Bitmap.Config.ARGB_8888);
    Bitmap copyOfOrigBitmap = Bitmap.createScaledBitmap(origBitmap, bmpOriginalWidth, bmpOriginalHeight, false);
    Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
    Canvas canvas = new Canvas(containerBitmap); // drawing the shades on the bigger bitmap
    //right shade - direction of gradient is positive x (width)
    Shader rightShader = new LinearGradient(bmpOriginalWidth, 0, bigW, 0, GRAY_COLOR_FOR_SHADE,
            Color.TRANSPARENT, Shader.TileMode.CLAMP);
    paint.setShader(rightShader);
    canvas.drawRect(bigW - shadowThickness, shadowThickness, bigW, bigH - shadowThickness, paint);
    //bottom shade - direction is positive y (height)
    Shader bottomShader = new LinearGradient(0, bmpOriginalHeight, 0, bigH, GRAY_COLOR_FOR_SHADE,
            Color.TRANSPARENT, Shader.TileMode.CLAMP);
    paint.setShader(bottomShader);
    canvas.drawRect(shadowThickness, bigH - shadowThickness, bigW - shadowThickness, bigH, paint);
    //left shade - direction is negative x
    Shader leftShader = new LinearGradient(shadowThickness, 0, 0, 0, GRAY_COLOR_FOR_SHADE,
            Color.TRANSPARENT, Shader.TileMode.CLAMP);
    paint.setShader(leftShader);
    canvas.drawRect(0, shadowThickness, shadowThickness, bigH - shadowThickness, paint);
    //top shade - direction is negative y
    Shader topShader = new LinearGradient(0, shadowThickness, 0, 0, GRAY_COLOR_FOR_SHADE,
            Color.TRANSPARENT, Shader.TileMode.CLAMP);
    paint.setShader(topShader);
    canvas.drawRect(shadowThickness, 0, bigW - shadowThickness, shadowThickness, paint);
    // starting to draw bitmap not from 0,0 to get margins for shade rectangles
    canvas.drawBitmap(copyOfOrigBitmap, shadowThickness, shadowThickness, null);
    return containerBitmap;
}

Change the color in the const as you see fit.

Use this class to draw shadow on bitmaps

public class ShadowGenerator {

    // Percent of actual icon size
    private static final float HALF_DISTANCE = 0.5f;
    public static final float BLUR_FACTOR = 0.5f/48;

    // Percent of actual icon size
    private static final float KEY_SHADOW_DISTANCE = 1f/48;
    public static final int KEY_SHADOW_ALPHA = 61;

    public static final int AMBIENT_SHADOW_ALPHA = 30;

    private static final Object LOCK = new Object();
    // Singleton object guarded by {@link #LOCK}
    private static ShadowGenerator sShadowGenerator;

    private  int mIconSize;

    private final Canvas mCanvas;
    private final Paint mBlurPaint;
    private final Paint mDrawPaint;
    private final Context mContext;

    private ShadowGenerator(Context context) {
        mContext = context;
        mIconSize = Utils.convertDpToPixel(context,63);
        mCanvas = new Canvas();
        mBlurPaint = new Paint(Paint.ANTI_ALIAS_FLAG | Paint.FILTER_BITMAP_FLAG);
        mBlurPaint.setMaskFilter(new BlurMaskFilter(mIconSize * BLUR_FACTOR, Blur.NORMAL));
        mDrawPaint = new Paint(Paint.ANTI_ALIAS_FLAG | Paint.FILTER_BITMAP_FLAG);
    }

    public synchronized Bitmap recreateIcon(Bitmap icon) {
        mIconSize = Utils.convertDpToPixel(mContext,3)+icon.getWidth();
        int[] offset = new int[2];
        Bitmap shadow = icon.extractAlpha(mBlurPaint, offset);
        Bitmap result = Bitmap.createBitmap(mIconSize, mIconSize, Config.ARGB_8888);
        mCanvas.setBitmap(result);

        // Draw ambient shadow
        mDrawPaint.setAlpha(AMBIENT_SHADOW_ALPHA);
        mCanvas.drawBitmap(shadow, offset[0], offset[1], mDrawPaint);

        // Draw key shadow
        mDrawPaint.setAlpha(KEY_SHADOW_ALPHA);
        mCanvas.drawBitmap(shadow, offset[0], offset[1] + KEY_SHADOW_DISTANCE * mIconSize, mDrawPaint);

        // Draw the icon
        mDrawPaint.setAlpha(255);
        mCanvas.drawBitmap(icon, 0, 0, mDrawPaint);

        mCanvas.setBitmap(null);
        return result;
    }



    public static ShadowGenerator getInstance(Context context) {

        synchronized (LOCK) {
            if (sShadowGenerator == null) {
                sShadowGenerator = new ShadowGenerator(context);
            }
        }
        return sShadowGenerator;
    }
    
}

If you want to use the custom imageView, I suggest you use this one

View look perfect and dont't use any nine path image