Android编程实现在Bitmap上涂鸦效果

<?xml version="1.0" encoding="utf-8"?> 
<linearlayout xmlns:android="http://schemas.android.com/apk/res/android" 
 android:layout_width="fill_parent" 
 android:layout_height="fill_parent" 
 android:orientation="vertical" > 
 <linearlayout 
  android:id="@+id/handwriteview" 
  android:layout_width="wrap_content" 
  android:layout_height="wrap_content" /> 
 <linearlayout 
  android:layout_width="fill_parent" 
  android:layout_height="fill_parent" 
  android:orientation="horizontal" 
  android:gravity="center_horizontal" > 
  <button 
   android:id="@+id/clear" 
   android:layout_width="200dp" 
   android:layout_height="wrap_content" 
   android:text="清屏" /> 
 </linearlayout> 
</linearlayout> 

public class handwrite extends view 
{ 
 private paint paint = null; 
 private bitmap originalbitmap = null; 
 private bitmap new1bitmap = null; 
 private bitmap new2bitmap = null; 
 private float clickx = 0,clicky = 0; 
 private float startx = 0,starty = 0; 
 private boolean ismove = true; 
 private boolean isclear = false; 
 private int color = color.green; 
 private float strokewidth = 2.0f; 
 public handwrite(context context,bitmap b) 
 { 
  super(context); 
  originalbitmap = bitmap.createbitmap(b).copy(bitmap.config.argb_8888, true); 
  new1bitmap = bitmap.createbitmap(originalbitmap); 
 } 
 public void clear(){ 
  isclear = true; 
  new2bitmap = bitmap.createbitmap(originalbitmap); 
  invalidate(); 
 } 
 public void setstyle(float strokewidth){ 
  this.strokewidth = strokewidth; 
 } 
 @override 
 protected void ondraw(canvas canvas) 
 { 
  super.ondraw(canvas); 
  canvas.drawbitmap(handwriting(new1bitmap), 0, 0,null); 
 } 
 public bitmap handwriting(bitmap originalbitmap) 
 { 
  canvas canvas = null; 
  if(isclear){ 
   canvas = new canvas(new2bitmap); 
  } 
  else{ 
   canvas = new canvas(originalbitmap); 
  } 
  paint = new paint(); 
  paint.setstyle(style.stroke); 
  paint.setantialias(true); 
  paint.setcolor(color); 
  paint.setstrokewidth(strokewidth); 
  if(ismove){ 
   canvas.drawline(startx, starty, clickx, clicky, paint); 
  } 
  startx = clickx; 
  starty = clicky; 
  if(isclear){ 
   return new2bitmap; 
  } 
  return originalbitmap; 
 } 
 @override 
 public boolean ontouchevent(motionevent event) 
 { 
  clickx = event.getx(); 
  clicky = event.gety(); 
  if(event.getaction() == motionevent.action_down){ 
   ismove = false; 
   invalidate(); 
   return true; 
  } 
  else if(event.getaction() == motionevent.action_move){ 
   ismove = true; 
   invalidate(); 
   return true; 
  } 
  return super.ontouchevent(event); 
 } 
} 

public class handwritingactivity extends activity 
{ 
 /** called when the activity is first created. */ 
 private linearlayout handwrite = null; 
 private button clear = null; 
 int requestwidth=116;
 int requestheight=173;
 int insamplesize;
 @override 
 public void oncreate(bundle savedinstancestate) 
 { 
  super.oncreate(savedinstancestate); 
  setcontentview(r.layout.activity_hand_writing); 
  handwrite = (linearlayout)findviewbyid(r.id.handwriteview); 
  clear = (button)findviewbyid(r.id.clear); 
  clear.setonclicklistener(new clearlistener()); 
 } 
 private class clearlistener implements onclicklistener{ 
  public void onclick(view v) 
  { 
//   handwrite.clear(); 
   bitmapfactory.options opts = new options();
   opts.injustdecodebounds = true;// 让 bimapfactory假的解析这个位图,只获取位图的边框信息
   bitmapfactory.decoderesource(getresources(), r.drawable.cool, opts);
   if (opts.outheight > requestheight || opts.outwidth > requestwidth) {
    if (opts.outwidth > opts.outheight) {
     insamplesize = math.round((float) opts.outheight
       / (float) requestheight);
    } else {
     insamplesize = math.round((float) opts.outwidth
       / (float) requestwidth);
    }
   }
    system.out.println("宽度：" + opts.outwidth);
    system.out.println("高度：" + opts.outheight);
   opts.insamplesize = insamplesize;
   system.out.println(insamplesize);
   opts.injustdecodebounds = false;// 由于已经得到了缩放比例 ,让位图工厂真正的解析这个位图
   // 由于前面 我们已经解析了这个输入流, 需要重新初始化这个输入流
   bitmap b = bitmapfactory.decoderesource(getresources(), r.drawable.cool, opts);
   handwrite hw = new handwrite(handwritingactivity.this, b);
   system.out.println(b.getwidth());
   handwrite.addview(hw);
  } 
 } 
} 

/**
 * 使用方法：
 * 1. 创建tuyaview类实例
 * 2. 调用drawtuya方法
 * 3. 参数1：context
 * 4. 参数2：图像的byte[]字节数组
 * 5. imageview实例
 * 6. 画笔定义
 * **/
import com.ziipin.lhdc.utils.toastutil;
import android.content.context;
import android.graphics.bitmap;
import android.graphics.bitmapfactory;
import android.graphics.canvas;
import android.graphics.matrix;
import android.graphics.paint;
import android.graphics.bitmapfactory.options;
import android.view.motionevent;
import android.view.view;
import android.view.view.ontouchlistener;
import android.widget.imageview;
public class tuyaview {
 // 原始图片
 private bitmap morignbitmap;
 private bitmap meditbitmap;
 private int insamplesize;
 private int requestwidth = 500;
 private int requestheight = 700;
 /** 编辑图片的画布 */
 private canvas mcanvas;
 private imageview image;
 private paint mpaint;
 public bitmap drawtuya(context context, byte[] _data, imageview image,
   paint mpaint) {
  this.image = image;
  this.mpaint = mpaint;
  morignbitmap = bitmapfactory.decodebytearray(_data, 0, _data.length);
  return showeditbitmap(context, _data, image);
 }
 /**
  * 显示编辑的图片
  */
 private bitmap showeditbitmap(context context, byte[] _data, imageview image) {
  morignbitmap = getscalebitmap(_data, image);
  if (morignbitmap == null) {
   toastutil.show(context, "编辑出错");
  }
  meditbitmap = morignbitmap.copy(morignbitmap.getconfig(), true);
  mcanvas = new canvas(meditbitmap);
  mcanvas.drawbitmap(morignbitmap, new matrix(), new paint());
  image.setimagebitmap(meditbitmap);
  image.setontouchlistener(mtouchlistener);
  return meditbitmap;
 }
 /**
  * 获取结果缩放放后的图片
  * 
  * @return
  */
 private bitmap getscalebitmap(byte[] _data, imageview image) {
  bitmapfactory.options opts = new options();
  opts.injustdecodebounds = true;// 让 bimapfactory假的解析这个位图,只获取位图的边框信息
  bitmapfactory.decodebytearray(_data, 0, _data.length, opts);
  if (opts.outheight > requestheight || opts.outwidth > requestwidth) {
   if (opts.outwidth > opts.outheight) {
    insamplesize = math.round((float) opts.outheight
      / (float) requestheight);
   } else {
    insamplesize = math.round((float) opts.outwidth
      / (float) requestwidth);
   }
  }
  opts.insamplesize = insamplesize;
  opts.injustdecodebounds = false;// 由于已经得到了缩放比例 ,让位图工厂真正的解析这个位图
  // 由于前面 我们已经解析了这个输入流, 需要重新初始化这个输入流
  bitmap bmp = bitmapfactory
    .decodebytearray(_data, 0, _data.length, opts);
  return bmp;
 }
 // touch事件
 private ontouchlistener mtouchlistener = new ontouchlistener() {
  int startx = 0;
  int starty = 0;
  @override
  public boolean ontouch(view v, motionevent event) {
   switch (event.getaction()) {
   case motionevent.action_down:// 手指第一次触摸屏幕
    startx = (int) event.getx();
    starty = (int) event.gety();
    break;
   case motionevent.action_move: // 手指在imageview上中移动
    int x = (int) event.getx();
    int y = (int) event.gety();
    mcanvas.drawline(startx, starty, x, y, mpaint);
    startx = (int) event.getx();
    starty = (int) event.gety();
    image.invalidate();
    break;
   }
   return true;
  }
 };
}