Android实现图片的裁剪(不调用系统功能)

概述接上一篇文章：Android实现图片区域裁剪功能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

接上一篇文章：Android实现图片区域裁剪功能

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 *** 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):

我们点击左下角的剪切按钮

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 *** 作了。 *** 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"?> <relativeLayout xmlns:androID="http://schemas.androID.com/apk/res/androID"  androID:layout_wIDth="match_parent"  androID:layout_height="match_parent"  >  <com.artifex.mupdf.Crop_Canvas   androID:ID="@+ID/myCanvas"   androID:layout_wIDth="fill_parent"   androID:layout_height="fill_parent"   androID:background="#313131"   />  <button   androID:ID="@+ID/cutCancel"   androID:layout_height="wrap_content"   androID:layout_wIDth="wrap_content"   androID:text="取消"   androID:layout_alignParentBottom="true"   androID:layout_alignParentleft="true"/>  <button   androID:ID="@+ID/cutEnsure"   androID:layout_height="wrap_content"   androID:layout_wIDth="wrap_content"   androID:text="确定"   androID:layout_alignParentBottom="true"   androID:layout_centerInParent="true"/>  <button   androID:ID="@+ID/topdf"   androID:layout_wIDth="wrap_content"   androID:layout_height="wrap_content"   androID:text="Topdf"   androID:layout_alignParentBottom="true"   androID:layout_alignParentRight="true"/> </relativeLayout> 

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,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,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,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,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,recLT)){    recFlag = Crop_Canvas.PRESS_LT;    returnFlag = true;   }else if(this.isInRect(x,recRB)){    recFlag = Crop_Canvas.PRESS_RB;    returnFlag = true;   }else if(this.isInRect(x,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,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,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,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,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,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,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,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,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.bottom+5);   recRT.set(ChooseArea.right-5,ChooseArea.right+5,ChooseArea.top+5);   recRB.set(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,ChooseArea.left,dst.bottom);   leftRectR.set(ChooseArea.right,dst.bottom);   leftRectT.set(ChooseArea.left,ChooseArea.top);   leftRectB.set(ChooseArea.left,ChooseArea.bottom,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<String> imageUrlList = new ArrayList<String>();     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编程小技巧。

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