我们专注攀枝花网站设计 攀枝花网站制作 攀枝花网站建设
成都网站建设公司服务热线：400-028-6601

网站建设知识

十年网站开发经验 + 多家企业客户 + 靠谱的建站团队

量身定制 + 运营维护+专业推广+无忧售后，网站问题一站解决

Android实现图片的裁剪(不调用系统功能)

接上一篇文章：Android实现图片区域裁剪功能

成都创新互联公司长期为近1000家客户提供的网站建设服务，团队从业经验10年，关注不同地域、不同群体，并针对不同对象提供差异化的产品和服务；打造开放共赢平台，与合作伙伴共同营造健康的互联网生态环境。为蓬莱企业提供专业的成都做网站、网站制作、成都外贸网站建设，蓬莱网站改版等技术服务。拥有十多年丰富建站经验和众多成功案例,为您定制开发。

上一篇文章提及了通过调用系统相册或拍照来实现图片的缩放\裁剪。不过这对于笔者项目的要求同样不适合,笔者需要的是通过对手机屏幕整个进行一个截图,并对这个截图进行裁剪操作。

依靠系统功能确实可以实现图片的裁剪，但是不够灵活。这里笔者提供一种较为灵活的做法。

但是这种做法的用户体验没有上篇文章的好，至于使用何种方法，读者应该自己衡量。

同样，我们先看实际效果图。

这里展示的是笔者项目的一小部分(阅读器):

Android实现图片的裁剪(不调用系统功能)

我们点击左下角的剪切按钮

Android实现图片的裁剪(不调用系统功能)

我们通过红色边框的四个角来控制裁剪的大小,移动红色框体来控制裁剪的位置区域。

接下来我们看看源码的实现：

首先点击剪切按钮的时候，我们应该生成一个Bitmap对象，传递给另一个Activty处理 

具体做法如下：

cutP.setOnClickListener(new View.OnClickListener() { 
 
   public void onClick(View v) { 
    //将一些按钮隐藏 
    cutP.setVisibility(View.INVISIBLE); 
    mTopBarSwitcher.setVisibility(View.INVISIBLE); 
    mPageSlider.setVisibility(View.INVISIBLE); 
    back.setVisibility(View.INVISIBLE); 
    mPageNumberView.setVisibility(View.INVISIBLE); 
    View view = MuPDFActivity.this.getWindow().getDecorView(); 
    if (false == view.isDrawingCacheEnabled()) { 
     view.setDrawingCacheEnabled(true); 
    } 
    Bitmap bitmap = view.getDrawingCache(); 
    ImageView imgv = new ImageView(MuPDFActivity.this); 
    imgv.setLayoutParams(new LayoutParams(LayoutParams.FILL_PARENT, 
      LayoutParams.FILL_PARENT-200)); 
    imgv.setImageBitmap(bitmap); 
    backBitmap = bitmap; 
    //传递给另一个Activity进行裁剪 
    Intent intent = new Intent(); 
    intent.setClass(MuPDFActivity.this, CutActivity.class); 
    startActivity(intent); 
 
   } 
    
  });

Tips：这里笔者是将这个截取的Bitmap对象传递给另一个Actvity做相关处理，这里如何在Activity之间进行Bitmap传递呢？这里我们简单的运用java语法特性来完成具体做法如下：

我们在ActvityA中有一个public static Bitmap bitmap对象，当ActivityA跳转到B时，我们直接通过ActivityA.bitmap来获取这个对象。

之后就是如何进行裁剪的操作了。操作在另一个Activity中进行。XML配置文件信息如下：  

<?xml version="1.0" encoding="utf-8"?>

通过配置文件可以看到我们自定义了一个View(ImageView)其实现如下：

package com.artifex.mupdf; 
 
import android.content.Context; 
import android.graphics.Bitmap; 
import android.graphics.Canvas; 
import android.graphics.Color; 
import android.graphics.Matrix; 
import android.graphics.Paint; 
import android.graphics.Rect; 
import android.graphics.RectF; 
import android.graphics.Bitmap.Config; 
import android.graphics.drawable.BitmapDrawable; 
import android.util.AttributeSet; 
import android.view.MotionEvent; 
import android.widget.ImageView; 
 
public class Crop_Canvas extends ImageView { 
 
 private final static int PRESS_LB = 0;//表示左下角矩形框 
 private final static int PRESS_LT = 1;//表示左上角矩形框 
 private final static int PRESS_RB = 2;//表示右下角矩形框 
 private final static int PRESS_RT = 3;//表示右上角矩形框 
 
 private Bitmap bitMap = null;    //原始图片 
 private RectF src = null;     //经过比例转换后的裁剪区域 
 private RectF dst = null;     //图片显示区域，也就是drawBitmap函数中的目标dst 
 private RectF ChooseArea = null;    //选择区域    
 private Paint mPaint = null;    //画笔 
 private Matrix matrix = null;    //矩阵 
  
 private int mx = 0;       //存储触笔移动时，之前�?��的触笔的x坐标 
 private int my = 0;       //存储触笔移动时，之前�?��的触笔的y坐标 
 private boolean touchFlag = false;   //触笔是否在屏幕之�? 
 private boolean cutFlag = false;   //是否点击了menu上的裁剪按钮 
 private int recFlag = -1;     //用来存储触笔点击了哪个小矩形框（改变选择区域大小的小矩形框） 
 private boolean firstFlag = false; 
  
 private RectF recLT = null;     //左上角的小矩形框 
 private RectF recRT = null;     //右上角的小矩形框 
 private RectF recLB = null;     //左下角的小矩形框 
 private RectF recRB = null;     //右下角的小矩形框 
 private static final int LEFT_AREA_ALPHA = 50 * 255 / 100; 
 private RectF leftRectL = null; 
 private RectF leftRectR = null; 
 private RectF leftRectT = null; 
 private RectF leftRectB = null; 
 private Paint leftAreaPaint = null; 
  
 public Crop_Canvas(Context context, AttributeSet attrs) { 
  super(context, attrs); 
  this.init(); 
 } 
  
 public Crop_Canvas(Context context) { 
  super(context); 
  this.init(); 
 } 
  
 public void init(){ 
  cutFlag = true; 
  recLT = new RectF(); 
  recLB = new RectF(); 
  recRT = new RectF(); 
  recRB = new RectF(); 
  dst = new RectF(); 
  mPaint = new Paint(); 
  mPaint.setColor(Color.RED); 
  mPaint.setStyle(Paint.Style.STROKE);  //将画笔的风格改为空心 
  ChooseArea = new RectF(); 
  this.setPressRecLoc(); 
  src = null; 
  firstFlag = true; 
   
  //选择框之外的灰色区域，分成四个矩形框 
   
  leftAreaPaint = new Paint(); 
  leftAreaPaint.setStyle(Paint.Style.FILL); 
  leftAreaPaint.setAlpha(Crop_Canvas.LEFT_AREA_ALPHA); 
 } 
  
 public void setBitmap(Bitmap bitmap){ 
  BitmapDrawable bd = new BitmapDrawable(bitmap); 
  src = new RectF(0,0,bd.getIntrinsicWidth(),bd.getIntrinsicHeight()); 
  this.bitMap = bitmap.copy(Config.ARGB_8888, true); 
   
  this.setImageBitmap(bitMap); 
  leftRectB = new RectF(); 
  leftRectL = new RectF(); 
  leftRectR = new RectF(); 
  leftRectT = new RectF(); 
 } 
  
 public void imageScale(){ 
  matrix = this.getImageMatrix(); 
  matrix.mapRect(dst, src); 
  int padding = this.getPaddingBottom(); 
  int width = bitMap.getWidth(); 
  int height = bitMap.getHeight(); 
  //dst.set(dst.left+padding,dst.top+padding,dst.right+padding,dst.bottom+padding); 
  dst.set(dst.left+20,dst.top+20,width-20,height - 40); 
  ChooseArea = new RectF(dst); 
  this.setPressRecLoc(); 
 } 
  
 public Bitmap getSubsetBitmap(){ 
  float ratioWidth = bitMap.getWidth()/(float)(dst.right-dst.left); 
  float ratioHeight = bitMap.getHeight()/(float)(dst.bottom - dst.top); 
  int left = (int)((ChooseArea.left - dst.left) * ratioWidth); 
  int right = (int)(left + (ChooseArea.right - ChooseArea.left) * ratioWidth); 
  int top = (int)((ChooseArea.top - dst.top) * ratioHeight); 
  int bottom = (int)(top + (ChooseArea.bottom - ChooseArea.top) * ratioHeight); 
  src = new RectF(left,top,right,bottom); 
  firstFlag = true; 
  set_LeftArea_Alpha(); 
  return Bitmap.createBitmap(bitMap, left, top, right-left, bottom-top); 
 } 
  
 //获得ChooseArea对象 
 public RectF getChooseArea(){ 
  return ChooseArea; 
 } 
  
 public void moveChooseArea(int move_x,int move_y){ 
  if(ChooseArea.left + move_x >= dst.left && ChooseArea.right + move_x <= dst.right 
  && ChooseArea.top + move_y >= dst.top && ChooseArea.bottom + move_y <= dst.bottom){ 
   ChooseArea.set(ChooseArea.left + move_x,ChooseArea.top+move_y 
     ,ChooseArea.right + move_x,ChooseArea.bottom+move_y); 
  }else{ 
   if(ChooseArea.left + move_x < dst.left){ 
    ChooseArea.set(dst.left,ChooseArea.top 
      ,ChooseArea.right+dst.left-ChooseArea.left,ChooseArea.bottom); 
   } 
   if(ChooseArea.right + move_x > dst.right){ 
    ChooseArea.set(ChooseArea.left+dst.right-ChooseArea.right,ChooseArea.top 
      ,dst.right,ChooseArea.bottom); 
   } 
    
   if(ChooseArea.top + move_y < dst.top){ 
    ChooseArea.set(ChooseArea.left,dst.top 
      ,ChooseArea.right,ChooseArea.bottom+dst.top-ChooseArea.top); 
   } 
    
   if(ChooseArea.bottom + move_y > dst.bottom){ 
    ChooseArea.set(ChooseArea.left,ChooseArea.top+dst.bottom-ChooseArea.bottom 
      ,ChooseArea.right,dst.bottom); 
   } 
  } 
  this.setPressRecLoc(); 
  mPaint.setColor(Color.GREEN); 
  this.invalidate(); 
 } 
  
 public boolean onTouchEvent(MotionEvent event){ 
  mPaint.setColor(Color.RED); 
   
   
  if(event.getAction() == MotionEvent.ACTION_DOWN && cutFlag){ 
   //System.out.println(event.getX() + "," + event.getY()); 
    
   mx = (int)event.getX(); 
   my = (int)event.getY(); 
   if(this.judgeLocation(mx,my)){ 
    touchFlag = true; 
    mPaint.setColor(Color.GREEN); 
    this.invalidate(); 
    return true; 
   }else{ 
    
    if(this.findPresseddst((int)event.getX(), (int)event.getY())){ 
     touchFlag = true; 
     mPaint.setColor(Color.RED); 
     return true; 
    } 
   } 
  } 
   
  if(event.getAction() == MotionEvent.ACTION_MOVE && touchFlag){ 
   //判断是否点击了哪个个小矩形框 
   if(this.isOutOfArea((int)event.getX(), (int)event.getY())){ 
    return true; 
   } 
    
   //如果选择区域大小跟图像大小一样时，就不能移动 
   if(ChooseArea.left == dst.left && ChooseArea.top == dst.top && 
    ChooseArea.right == dst.right && ChooseArea.bottom == dst.bottom){ 
   }else{ 
    this.moveChooseArea((int)event.getX() - mx, (int)event.getY() - my); 
    mx = (int)event.getX(); 
    my = (int)event.getY(); 
   } 
  } 
   
   
  if(event.getAction() == MotionEvent.ACTION_UP){ 
   recFlag = -1; 
   this.invalidate(); 
   touchFlag = false; 
  } 
   
  return super.onTouchEvent(event); 
 } 
  
  
  
  
 private boolean isOutOfArea(int x,int y){ 
  switch(recFlag){ 
  case Crop_Canvas.PRESS_LB: 
   this.pressLB(x - mx, y - my); 
   break; 
  case Crop_Canvas.PRESS_LT: 
   this.pressLT(x - mx, y - my); 
   break; 
  case Crop_Canvas.PRESS_RB: 
   this.pressRB(x - mx, y - my); 
   break; 
  case Crop_Canvas.PRESS_RT: 
   this.pressRT(x - mx, y - my); 
   break; 
  default:return false; 
  } 
  mx = x; 
  my = y; 
  this.invalidate(); 
  return true; 
 } 
  
 public boolean findPresseddst(int x,int y){ 
  boolean returnFlag = false; 
  if(this.isInRect(x, y, recLB)){ 
   recFlag = Crop_Canvas.PRESS_LB; 
   returnFlag = true; 
  }else if(this.isInRect(x, y, recLT)){ 
   recFlag = Crop_Canvas.PRESS_LT; 
   returnFlag = true; 
  }else if(this.isInRect(x, y, recRB)){ 
   recFlag = Crop_Canvas.PRESS_RB; 
   returnFlag = true; 
  }else if(this.isInRect(x, y, recRT)){ 
   recFlag = Crop_Canvas.PRESS_RT; 
   returnFlag = true; 
  } 
   
  return returnFlag; 
 } 
  
 public boolean isInRect(int x,int y,RectF rect){ 
  if(x >= rect.left -20 && x <= rect.right + 20 && y > rect.top - 20 && y < rect.bottom + 20){ 
   return true; 
  } 
  return false; 
 } 
  
 private void pressLB(int x,int y){ 
  float left = ChooseArea.left + x; 
  float right = ChooseArea.right; 
  float top = ChooseArea.top; 
  float bottom = ChooseArea.bottom + y; 
  if(left <= right - 30 && left >= dst.left && bottom <= dst.bottom && bottom >= top + 30){ 
    ChooseArea.set(left,top,right,bottom); 
  }else{ 
   if(left + x < dst.left){ 
    left = dst.left; 
   } 
    
   if(bottom + y > dst.bottom){ 
    bottom = dst.bottom; 
   } 
    
   if(ChooseArea.left + x > ChooseArea.right - 30){ 
    left = ChooseArea.right - 30; 
   } 
    
   if(ChooseArea.bottom + y < ChooseArea.top + 30){ 
    bottom = ChooseArea.top + 30; 
   } 
   ChooseArea.set(left,top,right,bottom); 
  } 
  this.setPressRecLoc(); 
 } 
  
  
 private void pressLT(int x,int y){ 
  float left = ChooseArea.left + x; 
  float right = ChooseArea.right; 
  float top = ChooseArea.top + y; 
  float bottom = ChooseArea.bottom; 
  if(left <= right - 30 && left >= dst.left && top <= bottom - 30 && top >= dst.top){ 
   ChooseArea.set(left,top,right,bottom); 
  }else{ 
   if(left < dst.left){ 
    left = dst.left; 
   } 
    
   if(top < dst.top){ 
    top = dst.top; 
   } 
    
   if(left > right - 30){ 
    left = right - 30; 
   } 
    
   if(top > bottom - 30){ 
    top = bottom - 30; 
   } 
   ChooseArea.set(left,top,right,bottom); 
  } 
  this.setPressRecLoc(); 
 } 
  
  
 private void pressRT(int x,int y){ 
  float left = ChooseArea.left; 
  float right = ChooseArea.right + x; 
  float top = ChooseArea.top + y; 
  float bottom = ChooseArea.bottom; 
   
  if(right <= dst.right && right >= left + 30 && top <= bottom - 30 && top >= dst.top){ 
   ChooseArea.set(left,top,right,bottom); 
  }else{ 
   if(right > dst.right){ 
    right = dst.right; 
   } 
    
   if(top < dst.top){ 
    top = dst.top; 
   } 
    
   if(right < left + 30){ 
    right = left + 30; 
   } 
    
   if(top > bottom - 30){ 
    top = bottom - 30; 
   } 
   ChooseArea.set(left,top,right,bottom); 
  } 
  this.setPressRecLoc(); 
 } 
  
  
 private void pressRB(int x,int y){ 
  float left = ChooseArea.left; 
  float right = ChooseArea.right + x; 
  float top = ChooseArea.top; 
  float bottom = ChooseArea.bottom + y; 
   
  if(right<= dst.right && right >= left + 30 && bottom <= dst.bottom && bottom >= top + 30){ 
   ChooseArea.set(left,top,right,bottom); 
  }else{ 
   if(right > dst.right){ 
    right = dst.right; 
   } 
    
   if(bottom > dst.bottom){ 
    bottom = dst.bottom; 
   } 
    
   if(right < left + 30){ 
    right = left + 30; 
   } 
    
   if(bottom < top + 30){ 
    bottom = top + 30; 
   } 
   ChooseArea.set(left,top,right,bottom); 
  } 
  this.setPressRecLoc(); 
 } 
  
 //每次改变选择区域矩形的大小或者移动，各角落上的小矩形也要改变它的Location 
 private void setPressRecLoc(){ 
  recLT.set(ChooseArea.left-5,ChooseArea.top-5 , ChooseArea.left+5, ChooseArea.top+5); 
  recLB.set(ChooseArea.left-5,ChooseArea.bottom-5 , ChooseArea.left+5, ChooseArea.bottom+5); 
  recRT.set(ChooseArea.right-5,ChooseArea.top-5 , ChooseArea.right+5, ChooseArea.top+5); 
  recRB.set(ChooseArea.right-5,ChooseArea.bottom-5 , ChooseArea.right+5, ChooseArea.bottom+5); 
 } 
  
 
 public boolean judgeLocation(float x,float y){ 
  float start_x = this.getChooseArea().left; 
  float start_y = this.getChooseArea().top; 
  float last_x = this.getChooseArea().right; 
  float last_y = this.getChooseArea().bottom; 
  //System.out.println("chubi:" + x + "," + y); 
  //System.out.println(start_y + "," + last_y); 
  if(x > start_x+10 && x < last_x-10 && y > start_y+10 && y < last_y-10){ 
   return true; 
  } 
  return false; 
 } 
  
 public void onDraw(Canvas canvas){ 
  super.onDraw(canvas); 
  if(firstFlag){ 
   this.imageScale(); 
   firstFlag = false; 
   mPaint.setColor(Color.RED); 
   System.out.println("Width: " + (dst.right - dst.left)); 
   System.out.println("Height: " + (dst.bottom - dst.top)); 
   System.out.println("Width: " + this.getDrawable().getIntrinsicWidth()); 
   System.out.println("Height: " + this.getDrawable().getIntrinsicHeight()); 
  }else{ 
   set_LeftArea_Alpha(); 
  } 
  canvas.drawRect(ChooseArea, mPaint); 
  mPaint.setColor(Color.BLUE); 
  canvas.drawRect(recLT, mPaint); 
  canvas.drawRect(recLB, mPaint); 
  canvas.drawRect(recRT, mPaint);  
  canvas.drawRect(recRB, mPaint); 
   
  canvas.drawRect(leftRectL, leftAreaPaint); 
  canvas.drawRect(leftRectR, leftAreaPaint); 
  canvas.drawRect(leftRectT, leftAreaPaint); 
  canvas.drawRect(leftRectB, leftAreaPaint); 
   
 } 
  
 public void set_LeftArea_Alpha(){ 
  leftRectL.set(dst.left, dst.top, ChooseArea.left, dst.bottom); 
  leftRectR.set(ChooseArea.right,dst.top,dst.right,dst.bottom); 
  leftRectT.set(ChooseArea.left, dst.top, ChooseArea.right, ChooseArea.top); 
  leftRectB.set(ChooseArea.left,ChooseArea.bottom,ChooseArea.right,dst.bottom); 
 } 
}

接下来直接看看Activity源码：

package com.artifex.mupdf.cut; 
 
 
import java.io.File; 
import java.io.FileNotFoundException; 
import java.io.FileOutputStream; 
import java.io.IOException; 
import java.util.ArrayList; 
 
import android.app.Activity; 
import android.graphics.Bitmap; 
import android.os.Bundle; 
import android.view.View; 
import android.view.View.OnClickListener; 
import android.view.Window; 
import android.widget.Button; 
 
import com.andorid.shu.love.R; 
import com.artifex.mupdf.Crop_Canvas; 
import com.artifex.mupdf.MuPDFActivity; 
 
public class CutActivity extends Activity { 
 private Crop_Canvas canvas = null; 
 private Bitmap backBitmap; 
 private Button cancel; 
 private Button ensure; 
 private Button toPDF; 
 
 @Override 
 protected void onCreate(Bundle savedInstanceState) { 
  super.onCreate(savedInstanceState); 
  requestWindowFeature(Window.FEATURE_NO_TITLE); 
  setContentView(R.layout.cut_image); 
  backBitmap = MuPDFActivity.backBitmap; 
  init(); 
  cancel = (Button) findViewById(R.id.cutCancel); 
  cancel.setOnClickListener(new OnClickListener() { 
 
   @Override 
   public void onClick(View v) { 
    CutActivity.this.finish(); 
   } 
  }); 
  ensure = (Button) findViewById(R.id.cutEnsure); 
  ensure.setOnClickListener(new OnClickListener() { 
   @Override 
   public void onClick(View v) { 
    //图片保存的路径，之后将之转换为PDF，并以附件的形似发送邮件 
    File tmp = new File("/sdcard/lovereader/pic"); 
    tmp.mkdirs(); 
    File f = new File("/sdcard/lovereader/pic/" + "testpic" + ".png"); 
    try { 
     f.createNewFile(); 
    } catch (IOException e1) { 
     // TODO Auto-generated catch block 
     e1.printStackTrace(); 
    } 
    FileOutputStream fOut = null; 
    try { 
      fOut = new FileOutputStream(f); 
    } catch (FileNotFoundException e) { 
      e.printStackTrace(); 
    } 
    canvas.getSubsetBitmap().compress(Bitmap.CompressFormat.PNG, 100, fOut); 
    try { 
      fOut.flush(); 
    } catch (IOException e) { 
      e.printStackTrace(); 
    } 
    try { 
      fOut.close(); 
    } catch (IOException e) { 
      e.printStackTrace(); 
    } 
   } 
  }); 
   
  toPDF = (Button)findViewById(R.id.toPDF); 
  toPDF.setOnClickListener(new OnClickListener() { 
    
   @Override 
   public void onClick(View v) { 
    // TODO Auto-generated method stub 
    ArrayList imageUrllist = new ArrayList(); 
    imageUrllist.add("/sdcard/lovereader/pic/" + "testpic" + ".png"); 
    String pdfUrl = "/sdcard/lovereader/tmp/Foreverlove.pdf"; 
    File tmp = new File("/sdcard/lovereader/tmp"); 
    tmp.mkdirs(); 
    File file = PdfManager.Pdf(imageUrllist, pdfUrl); 
    try { 
     file.createNewFile(); 
    } catch (IOException e) { 
     // TODO Auto-generated catch block 
     e.printStackTrace(); 
    } 
     
   } 
  }); 
 } 
 
 private void init() { 
  canvas = (Crop_Canvas) findViewById(R.id.myCanvas); 
  Bitmap bitmap = backBitmap; 
  canvas.setBitmap(bitmap); 
 } 
 
}

ok，不依靠系统的简单裁剪功能就实现了，这里笔者就不给出源代码下载了，上述代码读者只要自己改改就可以用了。

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持创新互联。


当前题目：Android实现图片的裁剪(不调用系统功能)
分享网址：http://mswzjz.cn/article/jpcsjs.html

其他资讯