Android旋转位图并绘制画布

我想旋转使用矩阵的位图。然后我试图在画布上绘制它。但它只是失望！Android旋转位图并绘制画布

这里是我下面的代码：

public class MultitouchView extends View { 

private static final int INVALID_POINTER_ID = -1; 
private static final String TAG = "MultitouchView"; 
private Drawable image; 
private Drawable userImage; 

Bitmap userOriginal; 
Bitmap userResult; 

private float scaleFactor = 1.0f; 
private ScaleGestureDetector scaleGestureDetector; 

private float mPosX; 
private float mPosY; 

private float mLastTouchX; 
private float mLastTouchY; 
private int mActivePointerId = INVALID_POINTER_ID; 

private int direction = 0; 

Context context; 

public MultitouchView(Context context) { 
    super(context); 
    image = context.getResources().getDrawable(
      R.drawable.plain_black_wallpaper); 
    image.setBounds(0, 0, image.getIntrinsicWidth(), 
      image.getIntrinsicHeight()); 

    userOriginal = BitmapFactory.decodeResource(this.getResources(), R.drawable.navigation); 

    userImage = context.getResources().getDrawable(R.drawable.navigation); 
    userImage.setBounds(500, 500, 550, 550); 

    setFocusable(true); 

    scaleGestureDetector = new ScaleGestureDetector(context, 
      new ScaleListener()); 
} 

@Override 
protected void onDraw(Canvas canvas) { 
    super.onDraw(canvas); 
    // Set the image bounderies 
    canvas.save(); 
    //scale canvas 
    canvas.scale(scaleFactor, scaleFactor); 
    image.draw(canvas); 
    canvas.translate(mPosX, mPosY); 

    //rotate user drawable 

    userImage.draw(canvas); 

    canvas.restore(); 
} 

public void setDirection(int direction) { 
     this.direction = direction; 
     rotateBitmap(); 
     invalidate(); 
     } 

private void rotateBitmap() { 
    Matrix matrix = new Matrix(); 
    matrix.postRotate(this.direction); 
    userResult = Bitmap.createBitmap(userOriginal,0,0, userOriginal.getWidth(), userOriginal.getHeight(), matrix,true); 
    userImage=new BitmapDrawable(this.getResources(),userResult); 

}

}

我已删除了规模帆布和事件侦听器等功能。使代码小巧易读。

我周期性地调用了setDirection方法，但之后它被称为“userImage”drawable就消失了。任何人都可以请提出来是怎么回事错在这里..

感谢

来源

2013-11-04 vinzzz

那么，什么是你的要求是什么呢？你想旋转userImage并在画布上绘制它？ –

是的，这是真的..我想旋转图像，并绘制图像“可绘制”，而不是BitMapdrawable ...因为我在后面处理一些事件，这是必要的... ... – vinzzz

于是我发现了什么是错误的。该旋转位图被罚款运行，但由于我不设界限上绘制了“userImage “drawable在位置0,0被绘制，高度和宽度为0,0，因此它是DISAPPEARING。我固定，通过改变兴田旋转功能的位图如下图所示：

private void rotateBitmap() { 
    Matrix matrix = new Matrix(); 
    matrix.postRotate(this.direction); 
    userResult = Bitmap.createBitmap(userOriginal,0,0, userOriginal.getWidth(), userOriginal.getHeight(), matrix,true); 
    userImage=new BitmapDrawable(this.getResources(),userResult); 
    userImage.setBounds(500, 500, 550, 550); 

}

需要落实的userImage.Setbounds ...

来源

2013-11-04 17:04:20 vinzzz

Android旋转位图并绘制画布

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