iPhone編碼 - 如何添加旋轉到觸摸事件？

Question

何我可以添加一個旋轉的對象除了拖動？

我不需要多點觸摸。

code: 
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event { 
    UITouch *touch = [touches anyObject]; 
    currentTouch = [touch locationInView:self.view]; 
    CGFloat dx = currentTouch.x - carMove.position.x; 
    CGFloat dy = currentTouch.y - carMove.position.y; 
    CGFloat dist = sqrt(dx * dx + dy * dy); 
    if(dist <carMove.radius) { 
     carMove.velocity = CGPointMake(0.0, 0.0); 
     carMove.dragging = YES; 
    } 

    lastTouch = currentTouch; 
} 

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event { 
    UITouch *touch = [touches anyObject]; 
    currentTouch = [touch locationInView:self.view]; 
    if(carmove.dragging){ 
     carMove.position = currentTouch; 
     carMove.velocity = CGPointMake(currentTouch.x - lastTouch.x, currentTouch.y - lastTouch.y); 
    } 
    lastTouch = currentTouch; 
} 


- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event { 
    carMove.dragging = NO; 
} 

Answer 1

試着這麼做

for (int c=0; c < imagesArray.count; c++) { 

    MyCustomImageObject img = [imagesArray objectAtIndex:c]; 

    CGContextSaveGState(context); 

    CGContextTranslateCTM(context, 
    img.centreOfRotatedImageInBottomLeftPixelCoordsX, 
    img.centreOfRotatedImageInBottomLeftPixelCoordsY); 

    CGContextRotateCTM(context, img.floatingPointImageAngleInRadians); 

    CGContextDrawImage(context, 
    CGMakeRect(-img.width/2, -img.height/2, +img.width/2, +img.height/2), 
    image.CGImage); 

    CGContextRestoreGState(context); 
} 

或者，如果你想擁有每幅圖像視圖，使用代碼一樣，一旦在drawRect中環內：您的自定義圖像視圖的方法。

編輯

你需要的，如果你想在手機旋轉底座旋轉的加速度註冊事件。你需要應用低通濾波器，像蘋果建議的文檔，在接收事件的功能：

#define kFilteringFactor 0.1 
- (void)accelerometer:(UIAccelerometer *)accelerometer didAccelerate: 
    (UIAcceleration *)acceleration { 
    // Use a basic low-pass filter to keep only the gravity component of each axis. 
    accelX = (acceleration.x * kFilteringFactor) + (accelX * (1.0 - kFilteringFactor)); 
    accelY = (acceleration.y * kFilteringFactor) + (accelY * (1.0 - kFilteringFactor)); 
    accelZ = (acceleration.z * kFilteringFactor) + (accelZ * (1.0 - kFilteringFactor)); 
} 

然後，只需做一個ATAN（accelY，accelX），設置它的對象被移動並調用setNeedsDisplay。

如果性能不夠高，您可以嘗試測試發送到drawRect的CGRect並僅重繪在重繪矩形內的圖像;但要注意，如果矩形已移動，您還需要（擦除/擦除）它剛剛移動之前的矩形，因此請保留這些矩形的記錄，並根據舊矩形和新矩形中的最小和最大X值和Y值進行更大的重繪矩形。