Android旋轉位圖並繪製畫布

我想旋轉使用矩陣的位圖。然後我試圖在畫布上繪製它。但它只是失望！Android旋轉位圖並繪製畫布

這裏是我下面的代碼：

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); 

}

}

我已刪除了規模帆布和事件偵聽器等功能。使代碼小巧易讀。

我週期性地調用了setDirection方法，但之後它被稱爲「userImage」drawable就消失了。任何人都可以請提出來是怎麼回事錯在這裏..

感謝

來源

2013-11-04 vinzzz

那麼，什麼是你的要求是什麼呢？你想旋轉userImage並在畫布上繪製它？ –

是的，這是真的..我想旋轉圖像，並繪製圖像「可繪製」，而不是BitMapdrawable ...因爲我在後面處理一些事件，這是必要的... ... – vinzzz

於是我發現了什麼是錯誤的。該旋轉位圖被罰款運行，但由於我不設界限上繪製了「userImage 「drawable在位置0,0被繪製，高度和寬度爲0,0，因此它是DISAPPEARING。我固定，通過改變興田旋轉功能的位圖如下圖所示：

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); 

}

需要落實的userImage.Setbounds ...

來源

2013-11-04 17:04:20 vinzzz

Android旋轉位圖並繪製畫布

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