利用Matrix实现图片倒影效果

利用matrix可以实现各种图片的特效，今天就用marix加上渐变色实现图片倒影的效果，步骤如下：

1. 获取需要倒影效果的图片，这里取原图片的一半

2. 添加颜色渐变到倒影图片上

具体的实现如下面代码所述，我们以一种自定义view的形式给出效果图，代码如下：

package com.flection.view;

import com.flection.main.R;

import android.annotation.SuppressLint;

import android.content.Context;

import android.graphics.Bitmap;

import android.graphics.Bitmap.Config;

import android.graphics.BitmapFactory;

import android.graphics.Canvas;

import android.graphics.Color;

import android.graphics.LinearGradient;

import android.graphics.Matrix;

import android.graphics.Paint;

import android.graphics.PorterDuffXfermode;

import android.graphics.Shader.TileMode;

import android.graphics.drawable.BitmapDrawable;

import android.util.AttributeSet;

import android.view.View;

public class FlectionView extends View {

Context mContext=null;

public FlectionView(Context context) {

super(context);

}

public FlectionView(Context context, AttributeSet attrs) {

super(context, attrs);

this.mContext=context;

}

@SuppressLint("DrawAllocation")

@Override

protected void onDraw(Canvas canvas) {

//设置背景色

this.setBackgroundColor(Color.parseColor("#8B8378"));

Bitmap oldBitmap = BitmapFactory.decodeResource(mContext.getResources(),R.drawable.dropbox);

Bitmap newBitmap = createFlectionBitmap(oldBitmap);

canvas.drawBitmap(newBitmap,newBitmap.getWidth() ,newBitmap.getHeight(), new Paint());

this.invalidate();

}

//获取原图+倒影图的bitmap

private Bitmap createFlectionBitmap(Bitmap oldBitmap) {

int mWidth = oldBitmap.getWidth();

int mHeight = oldBitmap.getHeight();

//原图和倒影图之间的缝隙

int gap = 2;

Matrix matrix = new Matrix();

matrix.preScale(1, -1);

Bitmap flection = Bitmap.createBitmap(oldBitmap, 0, mHeight / 2,

mWidth, mHeight / 2, matrix, false);

Bitmap background = Bitmap.createBitmap(mWidth, mHeight+gap+mHeight/2, Config.ARGB_8888);

Canvas canvas = new Canvas(background);

Paint p1 = new Paint();

//画出原图

canvas.drawBitmap(oldBitmap, 0, 0, p1);

//画出倒影图

canvas.drawBitmap(flection, 0, mHeight+gap, p1);

Paint shaderPaint = new Paint();

LinearGradient shader = new LinearGradient(0, mHeight, 0,

flection.getHeight(), 0x70ffffff, 0x00ffffff, TileMode.MIRROR);

shaderPaint.setShader(shader);

shaderPaint.setXfermode(new PorterDuffXfermode(android.graphics.PorterDuff.Mode.DST_IN));

//画出渐变颜色

canvas.drawRect(0, mHeight+gap, mWidth, background.getHeight(), shaderPaint);

return background;

}

}

实现的效果如下图：