如何利用matrix实现图片倒影效果

利用matrix可以实现各种图片的特效，比如图片的旋转、缩放、移动，甚至是图片倒影效果，这篇文章为大家介绍了matrix实现图片倒影的代码，感兴趣的小伙伴们可以参考一下

本文主要内容就是用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：