Android笔记三十.图形特效处理

<span style="font-family:Times New Roman;font-size:18px;">package com.example.matrix;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Matrix;
import android.graphics.drawable.BitmapDrawable;
import android.util.AttributeSet;
import android.view.KeyEvent;
import android.view.View;
public class MyView extends View {
 private Bitmap bitmap; // 初始化图片资源
 private int width, height; // 位图高、宽
 private Matrix matrix = new Matrix(); // Matrix实例
 private float sx = 0.0f; // 设置倾斜度
 private float scale = 1.0f; // 设置缩放比例
 private boolean isScale = false;	//判断是缩放还是旋转
 /*
  * 1.构造方法 功能：获得当前位图资源并且使得当前视图获得焦点
  */
 public MyView(Context context, AttributeSet attrs) {
  super(context, attrs);
  bitmap = ((BitmapDrawable) context.getResources().getDrawable(R.drawable.a)).getBitmap();
            // 获得当前位图资源
  width = bitmap.getWidth(); // 返回位图的宽度
  height = bitmap.getHeight(); // 返回位图的高度
  this.setFocusable(true); // 使当前视图获得焦点
 }
 /*
  * 2.onDraw方法 功能：选择Matrix控制功能，创建新位图并绘制到View视图
  */
 @Override
 protected void onDraw(Canvas canvas) {
  super.onDraw(canvas);
  // a.设置Matrix，选择Matrix控制功能
  matrix.reset(); // 重置Matrix
  if (!isScale) // 设置Matrix为旋转或者缩放位图
  {
   matrix.setSkew(sx, 0); // 控制Matrix进行旋转
  } else {
   matrix.setScale(scale, scale);// 控制Matrix进行缩放
  }
  // b.根据原始位图和Matrix创建新图片
  Bitmap bitmap2 = Bitmap.createBitmap(bitmap, 0, 0, width, height, matrix, true);
  // c.View的canvas绘制新位图
  canvas.drawBitmap(bitmap2, matrix, null);
 }
 /* 3.触屏事件 */
 @Override
 public boolean onKeyDown(int keyCode, KeyEvent event) {
  switch (keyCode) {
  //向左倾斜
  case KeyEvent.KEYCODE_A:
   isScale = false;
   sx +=0.1;
   postInvalidate();	 //重绘View,即调用onDraw方法
   break;
  //向右倾斜
  case KeyEvent.KEYCODE_D:
   isScale = false;
   sx -=0.1;
   postInvalidate();	 //重绘View,即调用onDraw方法
   break;
  //放大
  case KeyEvent.KEYCODE_W:
   isScale = true;
   if(scale<2.0)
       scale +=0.1;
   postInvalidate();	 //重绘View,即调用onDraw方法
   break;
  //缩小
  case KeyEvent.KEYCODE_S:
   isScale = true;
   if(scale>0.5)
    scale -=0.1;
   postInvalidate();	 //重绘View,即调用onDraw方法
   break;
  }
  return super.onKeyDown(keyCode, event);
 }
}</span>

<span style="font-family:Times New Roman;font-size:18px;">package com.example.drawbitmapmesh;
import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.os.Bundle;
import android.view.MotionEvent;
import android.view.View;
public class WrapTest extends Activity {  
    private Bitmap bitmap;  
    @Override  
    public void onCreate(Bundle savedInstanceState) {  
        super.onCreate(savedInstanceState);  
        setContentView(new MyView(this,R.drawable.photo));  
     }   
     private class MyView extends View  
       {  
             //定义两个常量,这两个常量指定该图片横向,纵向上都被划分为20格  
             private final int WIDTH = 20;  
             private final int HEIGHT = 20;  
             //记录该图片上包含441个顶点  
             private final int COUNT = (WIDTH + 1) * (HEIGHT + 1);   
             //定义一个数组,记录Bitmap上的21*21个点的坐标  
             private final float[] verts = new float[COUNT * 2];  
             //定义一个数组,记录Bitmap上的21*21个点经过扭曲后的坐标  
             //对图片扭曲的关键就是修改该数组里元素的值  
             private final float[] orig = new float[COUNT * 2];  
             /*1.构造方法*/
          public MyView(Context context, int drawableId) 
   {
    super(context);
    setFocusable(true);	 //使当前位图获取焦点
    bitmap = BitmapFactory.decodeResource(getResources(), drawableId);	//根据指定资源加载图片
    float bitmapWidth = bitmap.getWidth();	 //获取位图的宽度
    float bitmapHeight = bitmap.getHeight();	 //获取位图的高度
    int index = 0;
    for(int y = 0; y <= HEIGHT; y++)  
             {  
                 float fy = bitmapHeight * y / HEIGHT;  
                 for(int x = 0 ; x <= WIDTH; x++)  
                 {  
                     float fx = bitmapWidth * x / WIDTH;  
                     //初始化orig,verts数组  
                     //初始化,orig,verts两个数组均匀地保存了21 * 21个点的x,y坐标　  
                     orig[index * 2 + 0] = verts[index * 2 + 0] = fx;  
                     orig[index * 2 + 1] = verts[index * 2 + 1] = fy;  
                     index += 1;  
                 }  
             }  
    setBackgroundColor(Color.WHITE);	//设置背景颜色
  }
  /*2.绘图方法
   * 功能：绘制图形。对bitmap按verts数组进行扭曲
   * 从第一个点(由第5个参数0控制)开始扭曲*/
  @Override
  protected void onDraw(Canvas canvas) {
    canvas.drawBitmapMesh(bitmap, WIDTH, HEIGHT, verts, 0, null, 0, null);
  }

  /*3.工具方法
   * 功能：用于根据触摸事件的位置计算verts数组里各元素的值*/
  private void warp(float cx,float cy)
  {
   for(int i=0;i<COUNT*2;i+=2)
   {
    float dx = cx - orig[i+0];
    float dy = cy - orig[i+1];
    float dd = dx*dx+dy*dy;
    //计算每个坐标点与当前(cx,cy)之间的距离
    float d = (float)Math.sqrt(dd);
    //计算扭曲度，距离当前点(cx,cy)越远，扭曲度越小
    float pull = 80000 / ((float)(dd*d));
    //对verts数组(保存bitmap上21*21个点经过扭曲后的坐标)重新赋值
    if(pull>=1)
    {
     verts[i+0]=cx;
     verts[i+1]=cy;
    }
    else
    {
     //控制各顶点向触摸事件发生点偏移
     verts[i+0] = orig[i+0]+dx*pull;
     verts[i+1] = orig[i+1]+dy*pull;
    }
    invalidate();	//通知View组件重绘
   }
  }
  
  /*4.触摸屏监听器
   * 功能：触碰事件响应-调用warp方法根据触摸屏事件的坐标来扭曲verts数组*/
  @Override
  public boolean onTouchEvent(MotionEvent event) 
  {
   warp(event.getX(),event.getY());
   return true;
  }
    }
  }</span>

<span style="font-family:Times New Roman;font-size:18px;">package com.example.shader;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.view.View;
public class MyView extends View {
 Paint paint= new Paint() ;
 public MyView(Context context, AttributeSet attrs)
 {
  super(context, attrs);
  paint= new Paint();
  paint.setAntiAlias(true); // 去锯齿
  paint.setStyle(Paint.Style.FILL); // 设置画笔的填充风格
 }
 @Override
 protected void onDraw(Canvas canvas) {
  canvas.drawRect(30, 30, 200,200, paint);
 }
}</span>

<span style="font-family:Times New Roman;font-size:18px;">package com.example.shader;

import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.BitmapShader;
import android.graphics.Color;
import android.graphics.ComposeShader;
import android.graphics.LinearGradient;
import android.graphics.PorterDuff;
import android.graphics.RadialGradient;
import android.graphics.Shader;
import android.graphics.Shader.TileMode;
import android.graphics.SweepGradient;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;


public class ShaderTest extends Activity implements OnClickListener
{
 private Shader[] shaders  = new Shader[5];	 //声明位图渲染对象
 private int[] colors;	//声明颜色数组
 MyView myView;	 //自定义视图类
 /*1.初始化*/
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        myView = (MyView)findViewById(R.id.my_view);
        Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.water);	//获取Bitmap实例
        colors = new int[] {Color.RED,Color.GREEN,Color.BLUE};	     //设置渐变的颜色组
        shaders[0] = new BitmapShader(bitmap, TileMode.REPEAT, TileMode.MIRROR);//实例话BitmapShader，x坐标方法重复图形，y坐标方向镜像图形
        shaders[1] =new LinearGradient(0, 0, 100, 100, colors, null, TileMode.REPEAT); //实例化LinearGradient
        shaders[2]=new RadialGradient(100, 100, 80, colors, null, TileMode.REPEAT);	 //实例化RadialGradient
        shaders[3]=new SweepGradient(160, 160, colors, null);	 //实例化SweepGradient
        shaders[4]=new ComposeShader(shaders[1], shaders[2], PorterDuff.Mode.DARKEN);//实例化ComposeShader
        //获取界面按钮并为其注册事件监听器
        Button btn1 = (Button)findViewById(R.id.bn1);
        Button btn2 = (Button)findViewById(R.id.bn2);
        Button btn3 = (Button)findViewById(R.id.bn3);
        Button btn4 = (Button)findViewById(R.id.bn4);
        Button btn5 = (Button)findViewById(R.id.bn5);
        btn1.setOnClickListener(this);
        btn2.setOnClickListener(this);
        btn3.setOnClickListener(this);
        btn4.setOnClickListener(this);
        btn5.setOnClickListener(this);   
    }

 @Override
 public void onClick(View source)
 {
   switch(source.getId())
   {
   case R.id.bn1:
    myView.paint.setShader(shaders[0]);
    break;
   case R.id.bn2:
    myView.paint.setShader(shaders[1]);
    break;
   case R.id.bn3:
    myView.paint.setShader(shaders[2]);
    break;
   case R.id.bn4:
    myView.paint.setShader(shaders[3]);
    break;
   case R.id.bn5:
    myView.paint.setShader(shaders[4]);
    break;
   }
   //重绘界面
   myView.invalidate();
 }
}</span>

<span style="font-family:Times New Roman;font-size:18px;"><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
     android:orientation="vertical"
     android:layout_width="match_parent"
     android:layout_height="match_parent">
  <!-- 5个Button按钮(略) -->
    <!-- 位图 -->
    <com.example.shader.MyView
        android:id="@+id/my_view"
        android:layout_width="match_parent"
        android:layout_height="251dp" />
</LinearLayout></span>