Android给bitmap图加上倒影效果

Android给bitmap图加上倒影效果:

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;
}