How i can rotate Drawable?

Minor · by **Minor** » Sat Feb 19, 2011 10:34 pm

Hello, i have 2 classes...

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public class Head extends GameObject{
 
    public Head(Drawable image) {
        super(image);
        mAngle = 270;
    }
 
    @Override
    protected void UpdatePoint() {
    }
 
    public void fire () {
 
    }
 
    public void rotate (int x, int y) {
        float a = (float) Math.sqrt(Math.abs(Math.pow((x-this.getCenterX()),2)+Math.pow((y-this.getCenterY()),2)));
        float b = (float) Math.sqrt(Math.abs(Math.pow((x - this.getCenterX()), 2)));
        float c = (float) Math.sqrt(Math.abs(Math.pow((y-this.getCenterY()),2)));
 
        float angle = (float) Math.acos((a*a+b*b+c*c)/2*a*b);
 
        if (x<this.getCenterX()) angle+= 90;
        if (y>this.getCenterY())
            if (x<this.getCenterX()) angle +=180;
                else angle += 270;
 
        // HOW ROTATE ?
    }
}
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public class GameView extends SurfaceView implements SurfaceHolder.Callback{
    private int mx, my;
 
    private GameThread mThread;
 
    private Head mHead;
 
    private static final String TAG = "ZZZZZuma";
    private int randomBall;
 
    public GameView(Context context, AttributeSet attrs) {
        super(context, attrs);
 
        getHolder().addCallback(this);
        mThread = new GameThread(getHolder(),this);
 
        Resources res = context.getResources();
        mHead = new Head(res.getDrawable(R.drawable.head));
        InitPositions(800,480);
    }
 
     @Override
    public boolean onTouchEvent(MotionEvent event) {
        mx = (int) event.getX();
        my = (int) event.getY();
 
        switch (event.getAction()){
            case MotionEvent.ACTION_DOWN: {
                mHead.fire();
            } break;
 
            case MotionEvent.ACTION_MOVE: {
               mHead.rotate(mx,my);
            } break;
 
            case MotionEvent.ACTION_UP: {
 
            } break;
        }
        return true;
    }
 
    public void InitPositions(int ScreenWidth, int ScreenHeight){
        mHead.setCoordinate((float) ScreenWidth / 2, (float) ScreenHeight / 2);
    }
 
    public void updateObjects(){
        //Log.v(TAG,"I'm update!");
        mHead.update();
    }
 
    @Override
    public void onDraw(Canvas canvas){
        //Log.v(TAG,"I'm draw!");
        canvas.drawColor(Color.BLACK);
 
        mHead.onDraw(canvas);
    }
 
}
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When i touch the screen, head turns in the direction of pressing. How do I rotate an image (Drawable) at a given angle? Sorry for my bad English.

cloudjubei · by **cloudjubei** » Wed Feb 23, 2011 6:34 pm

When you draw the object, so in your case mHead do this:

canvas.save();
canvas.rotate(calculateRotation(), (float)centreX, (float)centreY);
mHead.setBounds(topLeftX, topLeftY, topLeftX+width, topLeftY+height);
mHead.draw(canvas);
canvas.restore();

now in the place of calculateRotation() you can just put the angle which has to be in degrees if I remember correctly.
The canvas.save and restore, basically make sure that you don't rotate anything else.
Hope this helps!

How i can rotate Drawable?

How i can rotate Drawable?

Re: How i can rotate Drawable?

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