BITMap 倒影

public static Bitmap createReflectedImage(Bitmap originalImage) {        // The gap we want between the reflection and the original image        final int reflectionGap = 4;        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 matrix 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 in the gap        Paint defaultPaint = new Paint();        canvas.drawRect(0, height, width, height + reflectionGap, defaultPaint);        // Draw in the reflection        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;    }