图片倒影的实现

public Bitmap getReflectedImage(Bitmap originalImage) {  
        final int reflectionGap = 0;  
 
        int width = originalImage.getWidth();  
        int height = originalImage.getHeight();  
 
        Matrix matrix = new Matrix();  
        matrix.preScale(1, -1);  
 
        Bitmap reflectionImage = Bitmap.createBitmap(originalImage, 0,  
                height / 2, width, height / 2, matrix, false);  
 
        Bitmap bitmapWithReflection = Bitmap.createBitmap(width,  
                (height + height / 2), Config.ARGB_8888);  
 
        Canvas canvas = new Canvas(bitmapWithReflection);  
        canvas.drawBitmap(originalImage, 0, 0, null);  
        Paint defaultPaint = new Paint();  
        canvas.drawRect(0, height, width, height + reflectionGap, defaultPaint);  
 
        canvas.drawBitmap(reflectionImage, 0, height + reflectionGap, null);  
 
        Paint paint = new Paint();  
        LinearGradient shader = new LinearGradient(0,  
                originalImage.getHeight(), 0, bitmapWithReflection.getHeight()  
                        + reflectionGap, 0x70ffffff, 0x00ffffff, TileMode.CLAMP);  
        paint.setShader(shader);  
        paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.MULTIPLY)); 
        canvas.drawRect(0, height, width, bitmapWithReflection.getHeight()  
                + reflectionGap, paint);  
 
        defaultPaint.setColor(Color.LTGRAY);  
        width--;  
 
        try {  
            if (!originalImage.isRecycled())  
                originalImage.recycle();  
        } catch (Exception e) {  
            Log.e(TAG, e.getMessage(), e);  
        }  
 
        return bitmapWithReflection;  
    }