Android练习之Bitmap.createBitmap

code

通过matrix.postScale对图片变形：放大缩小、左右旋转

package com.example.flexd14;

import android.os.Bundle;
import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Matrix;
import android.graphics.drawable.BitmapDrawable;
import android.util.DisplayMetrics;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.AbsoluteLayout;
import android.widget.Button;
import android.widget.ImageView;

/**
 * 通过矩阵变化得到新的bitmap
 *
 */
public class MainActivity extends Activity {
    
    private ImageView iv;
    
    //zoom
    private Button bt1;
    private Button bt2;
    private AbsoluteLayout layout1;
    private Bitmap bm;
    private int id = 0;//缩放标记
    private int displayWidth;//屏幕宽度
    private int displayHeight;
    private float scaleWidth = 1;//修改比例后的宽度
    private float scaleHeight = 1;
    
    //rotate
    private Button bt3;
    private Button bt4;
    private int scaleTimes;//
    private int scaleAngle;//角度
    

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        //取屏幕分辨率
        DisplayMetrics dm = new DisplayMetrics();
        getWindowManager().getDefaultDisplay().getMetrics(dm);
        displayWidth = dm.widthPixels;
        displayHeight = dm.heightPixels-80;//减去button的高度
        Log.i("displayWidth", String.valueOf(displayWidth));
        Log.i("displayHeight", String.valueOf(displayHeight));

        //Widgets
        BitmapFactory.Options opts = new BitmapFactory.Options();//采样值 解决java.lang.OutOfMemoryError
        opts.inSampleSize = 3;
        bm = BitmapFactory.decodeResource(getResources(), R.drawable.ic_launcher, opts);//
        
        iv = (ImageView) findViewById(R.id.iv1);
        layout1 = (AbsoluteLayout) findViewById(R.id.layout1);
        bt1 = (Button) findViewById(R.id.bt1);
        bt2 = (Button) findViewById(R.id.bt2);
        bt3 = (Button) findViewById(R.id.bt3);
        bt4 = (Button) findViewById(R.id.bt4);
        
        //
        scaleTimes = 1;
        scaleAngle = 10;
        iv.setImageBitmap(bm);
        
        //
        bt1.setOnClickListener(new OnClickListener() {
            
            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                zoomIn();
            }
        });
        bt2.setOnClickListener(new OnClickListener() {
            
            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                zoomOut();
            }
        });
        bt3.setOnClickListener(new OnClickListener() {
            
            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                rotateACW();
            }
        });
        bt4.setOnClickListener(new OnClickListener() {
            
            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                rotateCW();
            }
        });

    }

    /**
     * Zoom In ++
     */
    public void zoomIn(){
        //计算当前宽高 按照比例缩放后的宽高
        //当前宽高
        int bmWidth = bm.getWidth();
        int bmHeight = bm.getHeight();
        //设定缩放比例
        double scale=1.1;
        //缩放后
        scaleWidth = (float)scale*bmWidth;
        scaleHeight = (float)scale*bmHeight;
        //矩阵运算
        Matrix matrix = new Matrix();
        matrix.postScale(scaleWidth, scaleHeight);
        //新控件
        Log.i("bmWidth", String.valueOf(bmWidth));
        Log.i("bmHeight", String.valueOf(bmHeight));
        Bitmap scaleBm = Bitmap.createBitmap(bm,0,0,bmWidth,bmHeight,matrix,true);
        
        //imageView
        if(0==id){
            //第一次按则移除最初的imageView
            layout1.removeView(iv);
        }else{
            //否则移除上次产生的imageView
            layout1.removeView((ImageView)findViewById(id));
        }
        id++;
        
        //new ImageView
        ImageView iv2 = new ImageView(this);
        iv2.setId(id);
        iv2.setImageBitmap(scaleBm);
        layout1.addView(iv2);
        setContentView(layout1);
        
        // 如果下次放大后超过屏幕大小了则把button禁止
        if (scaleWidth * scale > displayWidth || scaleHeight * scale > displayHeight) {
            Log.i("<>", "Button disabled");
            bt1.setEnabled(false);
        }
        
    }
    
    /**
     * Zoom Out --
     */
    public void zoomOut(){
        int bmWidth2 = bm.getWidth();
        int bmHeight2 = bm.getHeight();
        float scale2 = (float) 0.8;
        
        scaleWidth = scale2*bmWidth2;
        scaleHeight = scale2*bmHeight2;
        
        Matrix matrix2 = new Matrix();
        matrix2.postScale(scaleWidth, scaleHeight);
        Bitmap scaleBm2 = Bitmap.createBitmap(bm,0,0,bmWidth2,bmHeight2,matrix2,true);
        //(Bitmap source, int x, int y, int width, int height, Matrix m, boolean filter)
        
        if(0==id){
            layout1.removeView(iv);
        }else{
            layout1.removeView((ImageView)findViewById(id));
        }
        id++;
        
        ImageView iv3 = new ImageView(this);
        iv3.setId(id);
        iv3.setImageBitmap(scaleBm2);
        layout1.addView(iv3);
        setContentView(layout1);
        
        bt1.setEnabled(true);
    }
    
    /**
     * 向左逆时针旋转
     */
    public void rotateACW(){
        //最大角度
        scaleAngle--;
        if(scaleAngle<-5)
        {
          scaleAngle = -5;
        }
        
        //宽高比
        int bmWidth = bm.getWidth();
        int bmHeight = bm.getHeight();
        int newWidth = bmWidth * scaleTimes;
        int newHeight = bmHeight * scaleTimes;
        
        float scaleWidth = ((float) newWidth) / bmWidth;
        float scaleHeight = ((float) newHeight) / bmHeight;
        
        //矩阵变形
        Matrix matrix = new Matrix();
        //大小
        matrix.postScale(scaleWidth, scaleHeight);
        //旋转
        //matrix.postRotate(5*ScaleAngle);
        matrix.setRotate(5*scaleAngle);
        
        //从bp变得新的bitmap
        Bitmap rotateBm = Bitmap.createBitmap(bm, 0, 0, bmWidth, bmHeight, matrix, true);
        BitmapDrawable bd = new BitmapDrawable(rotateBm);
        iv.setImageDrawable(bd);
    }
    
    /**
     * 向右顺时针旋转
     */
    public void rotateCW(){
        scaleAngle++;
        if(scaleAngle>5)
        {
          scaleAngle = 5;
        }

        //scaleTimes = 2;
        int bmWidth = bm.getWidth();
        int bmHeight = bm.getHeight();
        int newWidth = bmWidth * scaleTimes;
        int newHeight = bmHeight * scaleTimes;

        float scaleWidth = ((float) newWidth) / bmWidth; 
        float scaleHeight = ((float) newHeight) / bmHeight; 
        
        Matrix matrix = new Matrix(); 
        matrix.postScale(scaleWidth, scaleHeight);
        
        matrix.postRotate(5*scaleAngle);
        //matrix.setRotate(5*scaleAngle);

        Bitmap resizedBitmap = Bitmap.createBitmap(bm, 0, 0, bmWidth, bmHeight, matrix, true);
        BitmapDrawable bd = new BitmapDrawable(resizedBitmap);
        iv.setImageDrawable(bd);
    }
    
    @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;
    }

}