canvas图片旋转

你用canvas，那就应该是2D绘图了，2D的话，地球自转使用matrix就行，我给你画布旋转的方法吧，比较简单:        Matrix m = new Matrix();
        m.postTranslate(x,y);//移动到地球中心点
        m.postRotate(degree);//旋转
        c.drawBitmap(bmp,m,paint);//画地球月球公转的话，使用下面函数来计算圆形上某点坐标：    protected float xn(float pointX,float pointY,float x,float y,double angle){
        double angleHude = Math.toRadians(angle);//角度转弧度
        double cosAngle = Math.cos(angleHude);
        double sinAngle = Math.sin(angleHude);
        return (float)((pointX-x)*cosAngle-(pointY-y)*sinAngle+x);
    }    protected float yn(float pointX,float pointY,float x,float y,double angle){
        double angleHude = Math.toRadians(angle);//角度转弧度
        double cosAngle = Math.cos(angleHude);
        double sinAngle = Math.sin(angleHude);
        return (float)((pointX-x)*sinAngle+(pointY-y)*cosAngle+y);
    }

大虾你好：
       我用你的代码画地球的时候，我想让地球图片在屏幕中间固定旋转；比如
              Matrix m = new Matrix();
m.postTranslate(width/2-bitmap_earth.getWidth()/2, height/2-bitmap_earth.getHeight()/2);
m.postRotate(10);
canvas.drawBitmap(bitmap_earth, m, paint1);
  开始旋转角度10度的时候，还在屏幕内，当我变成m.postRotate(70)的时候，图片旋转出屏幕外了。
     我想就在中间，一直旋转，旋转一周，请指点一下啊，很多不会。
  还有就是月球protected float xn(float pointX,float pointY,float x,float y,double angle)函数中的参数
  pointX，PointY ,x ,y分别表示啥意思。
能不能给一下完整的代码，呵呵，不好意思，很多不会。

那个是我没考虑周全
先给你地球自转的吧，公转的我看看下班之前能不能给你写出来：package org.yye.android.commons.rotate;import android.app.Activity;
import android.content.Context;
import android.graphics.*;
import android.os.Bundle;
import android.os.Handler;import android.util.DisplayMetrics;
import android.view.WindowManager;
import android.widget.ImageView;
import org.yye.android.commons.R;import java.util.HashMap;
import java.util.Map;/**
* User: ye.yang
* Date: 13-5-10
* Time: 上午10:57
*/
public class RotateActivity extends Activity {
    private float degree = 0f;
    private Canvas c;
    private Paint p;
    private Handler handler = new Handler();
    private ImageView iv;
    private int w,h;
    private Bitmap earthBmp;
    private int earthW,earthH;
    private Runnable task = new Runnable() {
        @Override
        public void run() {
            handler.postDelayed(this,(long)(0.01*1000));
            degree++;
            //Bitmap backgroundBmp = BitmapFactory.decodeResource(getResources(),R.drawable.grid);
            Bitmap backgroundBmp = Bitmap.createBitmap(w,h, Bitmap.Config.ARGB_8888);
            c = new Canvas(backgroundBmp);
            p = new Paint(Paint.ANTI_ALIAS_FLAG | Paint.DEV_KERN_TEXT_FLAG);            Rect r = new Rect(w/2-earthW/2,h/2-earthH/2,w/2+earthW/2,h/2+earthH/2);            c.save();
            c.rotate(degree, w / 2, h / 2);
            c.drawBitmap(earthBmp, null, r, p);
            c.restore();
            p.setStyle(Paint.Style.STROKE);
            c.drawRect(r,p);            iv.setImageBitmap(backgroundBmp);
        }
    };    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.rotate);
        w=getMetrics().get("width");
        h=getMetrics().get("height");
        earthBmp = BitmapFactory.decodeResource(getResources(),R.drawable.earth);
        earthW = earthBmp.getWidth();
        earthH = earthBmp.getHeight();
        iv = (ImageView)findViewById(R.id.rotate_iv);
        handler.post(task);
    }    private Map<String, Integer> getMetrics() {
        DisplayMetrics displayMetrics = new DisplayMetrics();
        WindowManager wm = getWindowManager();
        if(wm == null)
            wm = (WindowManager)getSystemService(Context.WINDOW_SERVICE);
        if (wm != null) {
            wm.getDefaultDisplay().getMetrics(displayMetrics);
        }
        int height = displayMetrics.heightPixels;
        int width = displayMetrics.widthPixels;
        Map<String, Integer> resultMap = new HashMap<String, Integer>();
        resultMap.put("width", width);
        resultMap.put("height", height);
        return resultMap;
    }    protected float xn(float pointX,float pointY,float x,float y,double angle){
        double angleHude = Math.toRadians(angle);//角度转弧度
        double cosAngle = Math.cos(angleHude);
        double sinAngle = Math.sin(angleHude);
        return (float)((pointX-x)*cosAngle-(pointY-y)*sinAngle+x);
    }    protected float yn(float pointX,float pointY,float x,float y,double angle){
        double angleHude = Math.toRadians(angle);//角度转弧度
        double cosAngle = Math.cos(angleHude);
        double sinAngle = Math.sin(angleHude);
        return (float)((pointX-x)*sinAngle+(pointY-y)*cosAngle+y);
    }
}

要下班了，先给你发一个吧，公转速度计算得有问题，中心点计算也有问题，你先看看吧。。:package org.yye.android.commons.rotate;import android.app.Activity;
import android.content.Context;
import android.graphics.*;
import android.os.Bundle;
import android.os.Handler;import android.util.DisplayMetrics;
import android.view.WindowManager;
import android.widget.ImageView;
import org.yye.android.commons.R;import java.util.HashMap;
import java.util.Map;/**
* User: ye.yang
* Date: 13-5-10
* Time: 上午10:57
*/
public class RotateActivity extends Activity {
    private float earthDegree = 0f;
    private float moonDegree = 0f;    private Canvas c;
    private Paint p;
    private Handler handler = new Handler();
    private ImageView iv;
    private int w,h;
    private Bitmap earthBmp,moonBmp;
    private int earthW,earthH;
    private float moonX,moonY;
    private Runnable task = new Runnable() {
        @Override
        public void run() {
            handler.postDelayed(this,(long)(0.01*1000));
            earthDegree++;
            Bitmap backgroundBmp = Bitmap.createBitmap(w,h, Bitmap.Config.ARGB_8888);
            c = new Canvas(backgroundBmp);
            p = new Paint(Paint.ANTI_ALIAS_FLAG | Paint.DEV_KERN_TEXT_FLAG);            Rect r = new Rect(w/2-earthW/2,h/2-earthH/2,w/2+earthW/2,h/2+earthH/2);            c.save();
            c.rotate(earthDegree, w / 2, h / 2);
            c.drawBitmap(earthBmp, null, r, p);
            c.restore();
            p.setStyle(Paint.Style.STROKE);
            c.drawRect(r,p);            moonDegree+=(1f/30);//自转一天的角度=公转30天的角度，都是360°，所以简单/30
            float tempX = moonX;
            moonX = xn(tempX,moonY,w/2,h/2, moonDegree);
            moonY = yn(tempX,moonY,w/2,h/2, moonDegree);
            c.drawBitmap(moonBmp,moonX,moonY,p);            iv.setImageBitmap(backgroundBmp);
        }
    };    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.rotate);
        w=getMetrics().get("width");
        h=getMetrics().get("height");
        earthBmp = BitmapFactory.decodeResource(getResources(), R.drawable.earth);
        moonBmp = BitmapFactory.decodeResource(getResources(), R.drawable.moon);
        earthW = earthBmp.getWidth();
        earthH = earthBmp.getHeight();
        moonX = w/2+100;
        moonY = h/2;
        iv = (ImageView)findViewById(R.id.rotate_iv);
        handler.post(task);
    }    private Map<String, Integer> getMetrics() {
        DisplayMetrics displayMetrics = new DisplayMetrics();
        WindowManager wm = getWindowManager();
        if(wm == null)
            wm = (WindowManager)getSystemService(Context.WINDOW_SERVICE);
        if (wm != null) {
            wm.getDefaultDisplay().getMetrics(displayMetrics);
        }
        int height = displayMetrics.heightPixels;
        int width = displayMetrics.widthPixels;
        Map<String, Integer> resultMap = new HashMap<String, Integer>();
        resultMap.put("width", width);
        resultMap.put("height", height);
        return resultMap;
    }    protected float xn(float pointX,float pointY,float x,float y,double angle){
        double angleHude = Math.toRadians(angle);//角度转弧度
        double cosAngle = Math.cos(angleHude);
        double sinAngle = Math.sin(angleHude);
        return (float)((pointX-x)*cosAngle-(pointY-y)*sinAngle+x);
    }    protected float yn(float pointX,float pointY,float x,float y,double angle){
        double angleHude = Math.toRadians(angle);//角度转弧度
        double cosAngle = Math.cos(angleHude);
        double sinAngle = Math.sin(angleHude);
        return (float)((pointX-x)*sinAngle+(pointY-y)*cosAngle+y);
    }
}

http://www.eoeandroid.com/thread-653-1-1.html 看一下这个

原来想太多了，其实公转也可以用同样的方法实现，这个应该是没问题了，在本机跑过了：
[code=java-android]
package org.yye.android.commons.rotate;import android.app.Activity;
import android.content.Context;
import android.graphics.*;
import android.os.Bundle;
import android.os.Handler;import android.util.DisplayMetrics;import android.view.WindowManager;
import android.widget.ImageView;
import org.yye.android.commons.R;import java.util.HashMap;
import java.util.Map;/**
* User: ye.yang
* Date: 13-5-10
* Time: 上午10:57
*/
public class RotateActivity extends Activity {
    private float earthDegree = 0f;
    private float moonDegree = 0f;    private Canvas c;
    private Paint p;
    private Handler handler = new Handler();
    private ImageView iv;
    private int w,h;
    private Bitmap earthBmp,moonBmp;
    private int earthW,earthH;
    private int moonW,moonH;
    private Runnable task = new Runnable() {
        @Override
        public void run() {
            handler.postDelayed(this,(long)(0.01*1000));
            earthDegree++;
            Bitmap backgroundBmp = Bitmap.createBitmap(w,h, Bitmap.Config.ARGB_8888);
            c = new Canvas(backgroundBmp);
            p = new Paint(Paint.ANTI_ALIAS_FLAG | Paint.DEV_KERN_TEXT_FLAG);            Rect r = new Rect(w/2-earthW/2,h/2-earthH/2,w/2+earthW/2,h/2+earthH/2);            c.save();
            c.rotate(earthDegree, w / 2, h / 2);
            c.drawBitmap(earthBmp, null, r, p);
            c.restore();
            p.setStyle(Paint.Style.STROKE);
            c.drawRect(r,p);            //自转一天的角度=公转30天的角度，都是360°，所以简单/30
            moonDegree-=(1f/10);//除与30太慢了，就/10了
            Rect rMoon = new Rect(w/2-moonW/2-50,h/2-moonH/2-50,w/2+moonW/2-50,h/2+moonH/2-50);
            c.save();
            c.rotate(moonDegree,w/2,h/2);
            c.drawBitmap(moonBmp,null,rMoon,p);
            c.restore();            iv.setImageBitmap(backgroundBmp);
        }
    };    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.rotate);
        w=getMetrics().get("width");
        h=getMetrics().get("height");
        earthBmp = BitmapFactory.decodeResource(getResources(), R.drawable.earth);
        moonBmp = BitmapFactory.decodeResource(getResources(), R.drawable.moon);
        earthW = earthBmp.getWidth();
        earthH = earthBmp.getHeight();
        moonW = moonBmp.getWidth();
        moonH = moonBmp.getHeight();
        iv = (ImageView)findViewById(R.id.rotate_iv);
        handler.post(task);
    }    private Map<String, Integer> getMetrics() {
        DisplayMetrics displayMetrics = new DisplayMetrics();
        WindowManager wm = getWindowManager();
        if(wm == null)
            wm = (WindowManager)getSystemService(Context.WINDOW_SERVICE);
        if (wm != null) {
            wm.getDefaultDisplay().getMetrics(displayMetrics);
        }
        int height = displayMetrics.heightPixels;
        int width = displayMetrics.widthPixels;
        Map<String, Integer> resultMap = new HashMap<String, Integer>();
        resultMap.put("width", width);
        resultMap.put("height", height);
        return resultMap;
    }
}
[/code]

调试易

canvas图片旋转

解决方案 »