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图片无限放大,不模糊,图片移动,仿微信图片放大

简介:
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备注:本文关键内容是“OOM(Out Of Memory)异常",跟 “移动截图起点规则”内容,其他部分没看也可以看的懂


写此程序背景

        看到微信的图片浏览的强大功能,于是自己写了一个。原则上可以无限放大,但是放大部分     像素必须有原图片的1个像素,最小也不能小于1*1像素。

思路:

   功能解剖:

       缩放:微信的缩放能缩放到用户满意的范围。(放大不会超过max倍,缩小不会超过min)

       移动:当图片高与宽小于屏幕时,能移动图片到任意位置。当高或宽大于屏幕时,移动图片则会截取图片某一模块放大满屏显示。

   最重要的一点就是图片放大时看不出来图片变模糊


   解剖雏形:

       假设用系统自带Matrix函数来控制放大缩小。

       缩小:    可以缩小很小倍,当不易控制倍数(如1.25倍,但Matrix不会那么精确)

       放大:但放大超出屏幕时,Bitmap.createBitmap会在内存中创建一个很大的图(或内存超出系统设定的值或宽高超出屏幕),导致显存或内存不足。

       因为上条放大会出现问题所以本方案绝对不行。


   解剖过度:

   那么要有那么一种缩放方法满足下面条件

       一、能几乎精确的缩小到某一个倍数

       二、放大时内存不会溢出

       基于缩放的截取方法想出以下移动方案

       一、当放大时移动时计算某个参考点在图上移动的位置所占比列(x,y),高宽为屏幕高度/倍数

       二、当缩小的图在屏幕范围之内,那么移动的效果通过移动ImageView的位置实现

   方案:因为缩放的关键是放大,所以可以考虑放大时用截取一段图*n倍不会溢出的图

   截图方案: 一、看到截取就想到用画布canvas解决(于是创建了一个MyBitMap类)能截永远不会内存溢出的放大图。并且图像不会模糊(canvas优秀之处)。

补充:OOM(Out Of Memory)异常

1.放大时不模糊的实现:利用canvas获取放大后的图,就能解决安常规放大后模糊的现状。

   2.图片不溢出的实现:在canvas放大时限制图片的大小不超出屏幕就行。

溢出的情况

   一、图片的高或宽超出了屏幕。所以在canvas放大时限制图片的大小不超出屏幕就行。

   二、某一个bitmap超出了系统对单张图片的限制大小5MB(5MB根据系统不同会有差别)。利用canve截图到的图才几十kb。如果利用常规的Matrix在原来的图基础上来放大(放大后的图片大小为原图大小*当前倍数的平方),就会有超限(5MB)溢出。


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import android.graphics.Bitmap;
import android.graphics.Bitmap.Config;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Rect;
import android.widget.ImageView.ScaleType;
/**
 *此处函数是得到剪切的图片
 * @author ZhangJianLin
 *
 */
public class MyBitMap {
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  
    public MyBitMap() {
    // TODO Auto-generated constructor stub
}
    /**
     *
     * @param unscaledBitmap the bitmap of source
     * @param dstWidth what width you want to set
     * @param dstHeight What width you want to set
     * @param scalingLogic it is ScaleType
     * @return the scaled bitmap
     */
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  
    public static Bitmap createScaledBitmap(Bitmap unscaledBitmap, int dstWidth, int dstHeight, ScaleType scalingLogic) {
          Rect srcRect = calculateSrcRect(unscaledBitmap.getWidth(), unscaledBitmap.getHeight(), dstWidth, dstHeight, scalingLogic);
          Rect dstRect = calculateDstRect(unscaledBitmap.getWidth(), unscaledBitmap.getHeight(), dstWidth, dstHeight, scalingLogic);
          Bitmap scaledBitmap = Bitmap.createBitmap(dstRect.width(), dstRect.height(), Config.ARGB_8888);
          Canvas canvas = new Canvas(scaledBitmap);
          canvas.drawBitmap(unscaledBitmap, srcRect, dstRect, new Paint(Paint.FILTER_BITMAP_FLAG));
          return scaledBitmap;
          }
    //根据dstWOrH计算原图应该截取的截图合适的高宽比例图
    public static Rect calculateSrcRect(int srcWidth, int srcHeight, int dstWidth, int dstHeight, ScaleType scalingLogic) {
          if (scalingLogic == ScaleType.CENTER_CROP) {
            final float srcAspect = (float)srcWidth / (float)srcHeight;
            final float dstAspect = (float)dstWidth / (float)dstHeight;
            if (srcAspect > dstAspect) {
              final int srcRectWidth = (int)(srcHeight * dstAspect);
              final int srcRectLeft = (srcWidth - srcRectWidth) / 2;
              return new Rect(srcRectLeft, 0, srcRectLeft + srcRectWidth, srcHeight);
            else {
              final int srcRectHeight = (int)(srcWidth / dstAspect);
              final int scrRectTop = (int)(srcHeight - srcRectHeight) / 2;
              return new Rect(0, scrRectTop, srcWidth, scrRectTop + srcRectHeight);
            }
          else {
            return new Rect(00, srcWidth, srcHeight);
          }
        }
    //根据dstWOrH计算原图应该截取的期望图合适的高宽比例图
        public static Rect calculateDstRect(int srcWidth, int srcHeight, int dstWidth, int dstHeight, ScaleType scalingLogic) {
          if (scalingLogic == ScaleType.FIT_XY) {
            final float srcAspect = (float)srcWidth / (float)srcHeight;
            final float dstAspect = (float)dstWidth / (float)dstHeight;
            if (srcAspect > dstAspect) {
              return new Rect(00, dstWidth, (int)(dstWidth / srcAspect));
            else {
              return new Rect(00, (int)(dstHeight * srcAspect), dstHeight);
            }
          else {
            return new Rect(00, dstWidth, dstHeight);
          }
        }
        /**
         *
         * @param unscaledBitmap the bitmap of source
         * @param scale the scale you want
         * @param scalingLogic it is ScaleType
         * @return the scaled bitmap
         */
        //根据放大倍数获得截取图安scale放大的图
        public static Bitmap createBMScaleBitmap(Bitmap unscaledBitmap, Double scale, ScaleType scalingLogic){
        int dstWidth = (int)(unscaledBitmap.getWidth()* scale);
        int dstHeight = (int)(unscaledBitmap.getHeight()*scale);
        return createScaledBitmap(unscaledBitmap, dstWidth, dstHeight, scalingLogic);
    }
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  
}



移动截图起点规则

          每缩放一次,就以图的中心为截获图的中心(Ox,Oy),起点为(Ox-needwidth/2,Oy - needhight/2)。

          在缩放时,把放大后的图在逻辑上的坐标划分为m份,(1单位为屏幕的宽或高),同时每移动一次,就移动1/4份(即每次移动1/4屏幕)。 (单次移动的宽或高像素为                (bitmapWidth/m*n或bitmapHight/m*n,其中n是缩放的倍数,m为计算缩放后的图片高宽跟屏幕对应的宽高的比例,以此得到的值作为x或y的坐标最大值,坐标单位为一个屏幕,每滑次移动半个屏幕或1/3屏幕

         结合安卓的滑动或移动的灵敏度,能完美的模拟出效果图(亲测,如果移动规则用跟踪手的移动位移来移动图片是行不通的,不知道市面上能作出这样的效果是什么样的一个算法,还有待探究)
核心实现代码及注释如下

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package com.imageopen;
import android.app.Activity;
import android.graphics.Bitmap;
import android.os.Bundle;
import android.util.DisplayMetrics;
import android.util.Log;
import android.view.Menu;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.View.OnTouchListener;
import android.view.Window;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.ImageView.ScaleType;
public class BigzoonImage extends Activity {
    ImageView myImageView;
    Button bigButton;//放大按钮
    Button smallButton;//缩小按钮
    View myButtons;
    private Bitmap myBitmap;
    private double bigSize = 1.25;//每次放大的比列
    private double smallSize = 0.8;//每次缩小的比例
    double size = 1;//当前放大的倍数
    double pixel = 30.00;//限制图片缩小时的最小像素
    int bmpWidth;//图片宽度
    int bmpHight;//图片高度
    int bmpSizeWidth;//放大后的图片宽度bmpwidth*size
    int bmpSizeHight;
    int x ;//
    int y ;//
    int screenWidth;      // 屏幕宽(像素,如:480px)
    int screenHeight;     // 屏幕高(像素,如:800px)
    int dstHeight;
    int dstWidth;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        super.onCreate(savedInstanceState);
        setContentView(R.layout.bigzoonimage_main);
        init();
    }
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            
    private void init(){//初始化各参数的值
        myImageView = (ImageView)findViewById(R.id.bitmap_image);
        bigButton = (Button)findViewById(R.id.button_big);
        smallButton = (Button)findViewById(R.id.button_small);
        myButtons = (View)findViewById(R.id.bitmap_button);
        MyBitmapFactory myBitmapFactory = new MyBitmapFactory(this);
        myBitmap = myBitmapFactory.getDrawBmp(R.drawable.bitmap_test);//事先加载一张图片
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
        myImageView.setImageBitmap(myBitmap);
        myImageView.setOnTouchListener(ImageOpenListener);
        bigButton.setOnClickListener(sizeButton);//添加按钮触发事件
        smallButton.setOnClickListener(sizeButton);//同上
        DisplayMetrics dm = new DisplayMetrics();  //声明一个屏幕像素的类屏幕像素
        dm = getResources().getDisplayMetrics();  //得到屏幕像素
        screenWidth  = dm.widthPixels;      // 屏幕宽(像素,如:480px)
        screenHeight = dm.heightPixels;     // 屏幕高(像素,如:800px)
    }
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            
    private void big(){//放大时图片的变化
        size = bigSize * size;
        Bitmap newBitmap = myBitmap;
        newBitmap = bigCal(myBitmap);
        newBitmap = MyBitMap.createScaledBitmap(newBitmap, dstWidth, dstHeight, ScaleType.FIT_XY);
        myImageView.setImageBitmap(newBitmap);
    }
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            
    private void small(){//缩小时图片的变化
        size = smallSize * size;
        Bitmap newBitmap = myBitmap;//得到原图的截取图
        newBitmap = bigCal(newBitmap);
        newBitmap = MyBitMap.createScaledBitmap(newBitmap, dstWidth, dstHeight, ScaleType.FIT_XY);
        myImageView.setImageBitmap(newBitmap);
    }
    private OnClickListener sizeButton = new OnClickListener() {//放大缩小的事件
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
            if(v == bigButton){
                big();
                }
            else small();
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    
        }
    };
    //每缩放一次,就以图的中心为截获图的中心(Ox,Oy),起点为(Ox-needwidth/2,Oy - needhight/2),宽高为屏幕宽高的图。
    public Bitmap bigCal(Bitmap bitmap){//缩放得到原图的截取图
        bmpWidth = bitmap.getWidth();
        bmpHight = bitmap.getHeight();
        //放大的size最小值,16是指限制的截取的图片最小像素,要是缩小的很小,那么一丁点没有意义,这里的16看个人意思
        int sizeMax = Math.min(myBitmap.getWidth()/16, myBitmap.getHeight()/16);//限定放大的最大倍数
        double sizeMin = Math.max(pixel/myBitmap.getWidth(), pixel/myBitmap.getHeight());//限制缩小的size最小倍数
        if(size > sizeMax){
            size = sizeMax;
        }
        if(size < sizeMin){
            size = sizeMin;
        }
        bmpSizeWidth = (int)(bmpWidth*size);
        bmpSizeHight = (int)(bmpHight*size);
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
        if(screenWidth > bmpSizeWidth){
            x = 0;
            dstWidth = bmpSizeWidth;
        }else{
            x = (int)((bmpSizeWidth - screenWidth)/(2*size));
            bmpWidth = (int)(screenWidth / size);
            dstWidth = screenWidth;
        }
        if(screenHeight > bmpSizeHight){
            y = 0;
            dstHeight = bmpSizeHight;
        }else{
            y = (int)((bmpSizeHight - screenHeight)/(2*size));//放大时计算以中心的为截取中心的所要截图的左上点坐标(x,y)
            bmpHight = (int)(screenHeight / size);
            dstHeight = screenHeight;
        }
        bitmap = Bitmap.createBitmap(bitmap, x, y, bmpWidth, bmpHight);
        return bitmap;
        }
    //计算缩放的倍数跟屏幕的比例,以得到的值作为x或y的坐标最大值,坐标单位为一个屏幕,每滑动次移动半个屏幕或1/3屏幕
    public double rowOrCowNum(int sizeBitmapWH, int screenWH){
        double num = (sizeBitmapWH * size)/screenWH;
        return num;
    }
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            
    public Bitmap movCal(Bitmap bitmap, int dx, int dy){//计算移动后的要截取的图
        double coordinateX = rowOrCowNum(myBitmap.getWidth() , screenWidth);//缩放后x坐标,
        double coordinateY = rowOrCowNum(myBitmap.getHeight(), screenHeight);//缩放后y的坐标
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
        if(coordinateX > 1){
            if(dx > 0){
            x -= (myBitmap.getWidth()/(coordinateX * 4));
            if(x < 0){
                x = 0;
            }
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    
            }
            if(dx < 0){
                x += (myBitmap.getWidth()/(coordinateX *4));
                if(x > (myBitmap.getWidth() - bmpWidth)){
                    x = myBitmap.getWidth() - bmpWidth;
                }
            }
        }
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    
            if(coordinateY > 1){
                if(dy > 0){
                y -= (myBitmap.getHeight()/(coordinateY * 4));
                if(y < 0){
                    y = 0;
                }
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        
                }
                if(dy < 0){
                    y += (myBitmap.getHeight()/(coordinateY *4));
                    if(y > (myBitmap.getHeight() - bmpHight)){
                        y = myBitmap.getHeight() - bmpHight;
                    }
                }
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    
        }
        bitmap = Bitmap.createBitmap(bitmap, x, y, bmpWidth, bmpHight);
        bitmap = MyBitMap.createScaledBitmap(bitmap, dstWidth, dstHeight, ScaleType.FIT_XY);
        return bitmap;
    }
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            
    private OnTouchListener ImageOpenListener = new OnTouchListener() {//移动监听
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
        int lastX;
        int lastY;
        int left;//图片的左边界的坐标
        int right;//图片右边界坐标
        int top;//图片上边界的坐标
        int bottom;//图片下边界的坐标
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
        @Override
        public boolean onTouch(View v, MotionEvent event) {
            // TODO Auto-generated method stub
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    
            switch(event.getAction()){
            case MotionEvent.ACTION_DOWN:
                lastX = (int)event.getRawX();
                lastY = (int)event.getRawY();
                break;
            case MotionEvent.ACTION_MOVE:
                int dx = (int)event.getRawX() - lastX;//dx为在屏幕的x轴上移动的距离
                int dy = (int)event.getRawY() - lastY;//dy为在屏幕的y轴上移动的距离
                Bitmap newBitmap;
                //计算缩放的图片是否找出屏幕范围,如果是
                if(bmpSizeWidth > screenWidth||bmpSizeHight > screenHeight){
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            
                    if(bmpSizeWidth > screenWidth){
                        left = 0;
                        right = screenWidth;
                    }else{
                        left = v.getLeft() + dx;
                        right = v.getRight() + dx;
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
                    }
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            
                    if(bmpSizeHight > screenHeight){
                        top = 0;
                        bottom = screenHeight;
                    }else {
                        top = v.getTop() + dy;
                        bottom = v.getBottom() + dy;
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            
                    }
                    if((dx > 3 || dx < -3) && (dy > 3 ||dy  < -3)){//设置灵敏度,一定要设置
                    newBitmap = movCal(myBitmap, dx, dy);
                    myImageView.setImageBitmap(newBitmap);
                    }
                }
                else{//如果没有超出则移动ImageView
                    left = v.getLeft() + dx;
                    top = v.getTop() + dy;
                    bottom = v.getBottom() + dy;
                    right = v.getRight() + dx;
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        
                }
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        
                v.layout(left, top, right, bottom);
                lastX = (int)event.getRawX();
                lastY = (int)event.getRawY();
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        
                break;
            }
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    
            return true;
        }
    };
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            
    @Override
    protected void onPause() {
        // TODO Auto-generated method stub
        System.exit(0);
        super.onPause();
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
    }
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            
    @Override
    protected void onStop() {
        // TODO Auto-generated method stub
        System.exit(0);
        super.onStop();
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
    }
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.activity_main, menu);
        return true;
    }
}


 另外有一个辅助类,就是获取各类渠道图片的封装类

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import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Bitmap.CompressFormat;
import android.graphics.Bitmap.Config;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.LinearGradient;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.PorterDuff.Mode;
import android.graphics.PorterDuffXfermode;
import android.graphics.Shader.TileMode;
import android.util.Base64;
/**
 * 功能:得到原始的bitmap,就是unscaledbitmap;将得到bitmap字节流
 * @author ZhangJianLin
 *
 */
public class MyBitmapFactory {
    Context context;
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       
    public MyBitmapFactory(Context context) {
    // TODO Auto-generated constructor stub
        this.context = context;
}
    public Bitmap getFileBmp(String path){//通过路径获得图片
        Bitmap bm = BitmapFactory.decodeFile(path);
        return bm;
    }
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       
    public Bitmap getDrawBmp(int id){//通过本项目id获得图片
        Bitmap bm = BitmapFactory.decodeResource(context.getResources(), id);
        return bm;
    }
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       
    public Bitmap getStringBmp(InputStream inputstring){//从流中获取图片
        Bitmap bm = BitmapFactory.decodeStream(inputstring);
        return bm;
    }
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       
    public Bitmap getArrayBmp(byte[] data, int offset, int length){//从字节转化成图片
        Bitmap bm = BitmapFactory.decodeByteArray(data, offset, length);
        return bm;
    }
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       
    //获得带倒影的图片方法
    public static Bitmap createReflectionImageWithOrigin(Bitmap bitmap){
    final int reflectionGap = 4;
    int width = bitmap.getWidth();
    int height = bitmap.getHeight();
    Matrix matrix = new Matrix();
    matrix.preScale(1, -1);
    Bitmap reflectionImage = Bitmap.createBitmap(bitmap,
    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(bitmap, 00null);
    Paint deafalutPaint = new Paint();
    canvas.drawRect(0, height,width,height + reflectionGap,
    deafalutPaint);
    canvas.drawBitmap(reflectionImage, 0, height + reflectionGap, null);
    Paint paint = new Paint();
    LinearGradient shader = new LinearGradient(0,
    bitmap.getHeight(), 0, bitmapWithReflection.getHeight()
    + reflectionGap, 0x70ffffff0x00ffffff, TileMode.CLAMP);
    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;
    }
    public Bitmap stringtoBitmap(String string){//从string到bitmap
        //将字符串转换成Bitmap类型
        Bitmap bitmap=null;
        try {
        byte[]bitmapArray;
        bitmapArray=Base64.decode(string, Base64.DEFAULT);
    bitmap=BitmapFactory.decodeByteArray(bitmapArray, 0, bitmapArray.length);
    catch (Exception e) {
    e.printStackTrace();
    }
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          
        return bitmap;
        }
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            
        public String bitmaptoString(Bitmap bitmap){
    //将Bitmap转换成字符串
        String string=null;
        ByteArrayOutputStream bStream=new ByteArrayOutputStream();
        bitmap.compress(CompressFormat.PNG,100,bStream);
        byte[]bytes=bStream.toByteArray();
        string=Base64.encodeToString(bytes,Base64.DEFAULT);
        return string;
        }
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           
        public Bitmap returnBitMap(String url) {//从网络中获得图片
            URL myFileUrl = null;
            Bitmap bitmap = null;
            try {
                    myFileUrl = new URL(url);
            catch (MalformedURLException e) {
                    e.printStackTrace();
            }
            try {
                    HttpURLConnection conn = (HttpURLConnection) myFileUrl
                                    .openConnection();
                    conn.setDoInput(true);
                    conn.connect();
                    InputStream is = conn.getInputStream();
                    bitmap = BitmapFactory.decodeStream(is);
                    is.close();
            catch (IOException e) {
                    e.printStackTrace();
            }
            return bitmap;
    }
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           
}


本实验中所用到的布局如下

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<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity" >
    <ImageView
        android:id="@+id/bitmap_image"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_centerVertical="true"
        android:src="@drawable/ic_launcher" />
    <LinearLayout
        android:id="@+id/bitmap_button"
        android:layout_width="80dp"
        android:layout_height="40dp"
        android:layout_alignParentBottom="true"
        android:layout_alignParentLeft="true"
        android:layout_marginBottom="16dp"
        android:layout_marginLeft="14dp"
        android:orientation="horizontal" >
        <Button
            android:id="@+id/button_small"
            android:layout_width="40dp"
            android:layout_height="40dp"
            android:background="@drawable/bitmap_small" />
        <Button
            android:id="@+id/button_big"
            android:layout_width="40dp"
            android:layout_height="40dp"
            android:background="@drawable/bitmap_big" />
    </LinearLayout>
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              
</RelativeLayout>


效果如下图

原图:


214337724.jpg


放大后

214337371.jpg



本实验有如下缺陷:(很容易改进)

       1、移动时给用户的体验还不错。有一点点缺陷

       2、放大时image边上有空白,这是因为计算截图时的误差

改进思路:

对于一、改进移动时的x,y及每次移动的算法规则;每次移动的距离为屏幕的1/m,提高m值,或用算法动态改变m值

       对于二、当放大后的图像的宽高都大于屏幕的宽高,截获放大后的图设为全屏背景




本文转自lilin9105 51CTO博客,原文链接:http://blog.51cto.com/7071976/1208469,如需转载请自行联系原作者

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