UIImageView在触摸方向旋转动画 [英] UIImageView rotation animation in the touched direction

问题描述

我有一个UIImageView有一个箭头的图像。当用户点击UIView，这个箭头应该指向水龙头的方向，它应该只是改变变换的位置。我实现了以下代码。但它不能按预期工作。我添加了一个屏幕截图。在这个截图中，当我触摸点左上角的箭头方向应该如图所示。但它不会发生。

I have one UIImageView having an image of an arrow. When user taps on the UIView this arrow should point to the direction of the tap maintaing its position it should just change the transform. I have implemented following code. But it not working as expected. I have added a screenshot. In this screenshot when i touch the point upper left the arrow direction should be as shown.But it is not happening so.

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{

 UITouch *touch=[[event allTouches]anyObject];
 touchedPoint= [touch locationInView:touch.view];
 imageViews.transform = CGAffineTransformMakeRotation(DEGREES_TO_RADIANS(rangle11));
 previousTouchedPoint = touchedPoint ;
}

- (CGFloat) pointPairToBearingDegrees:(CGPoint)startingPoint secondPoint:(CGPoint) endingPoint
{

 CGPoint originPoint = CGPointMake(endingPoint.x - startingPoint.x, endingPoint.y - startingPoint.y); // get origin point to origin by subtracting end from start
   float bearingRadians = atan2f(originPoint.y, originPoint.x); // get bearing in radians
float bearingDegrees = bearingRadians * (180.0 / M_PI); // convert to degrees
bearingDegrees = (bearingDegrees > 0.0 ? bearingDegrees : (360.0 + bearingDegrees)); // correct discontinuity
return bearingDegrees;
}

推荐答案

我假设你想要一个箭头图像指向你碰到，我试过，这是我可以想出的。我把一个带有向上箭头的图像视图（没有尝试从任何其他位置开始，日志给出正确的角度）和在不同的位置触摸，它旋转和指向触摸的位置。希望它帮助（尝试一些旧的数学:-)）

I assume you wanted an arrow image to point to where ever you touch, I tried and this is what i could come up with. I put an image view with an arrow pointing upwards (haven't tried starting from any other position, log gives correct angles) and on touching on different locations it rotates and points to touched location. Hope it helps ( tried some old math :-) )

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{

    UITouch *touch=[[event allTouches]anyObject];
    touchedPoint= [touch locationInView:touch.view];
    CGFloat angle = [self getAngle:touchedPoint];
    imageView.transform = CGAffineTransformMakeRotation(angle);

}

-(CGFloat) getAngle: (CGPoint) touchedPoints
{
    CGFloat x1 = imageView.center.x;
    CGFloat y1 = imageView.center.y;

    CGFloat x2 = touchedPoints.x;
    CGFloat y2 = touchedPoints.y;

    CGFloat x3 = x1;
    CGFloat y3 = y2;

    CGFloat oppSide = sqrtf(((x2-x3)*(x2-x3)) + ((y2-y3)*(y2-y3)));
    CGFloat adjSide = sqrtf(((x1-x3)*(x1-x3)) + ((y1-y3)*(y1-y3)));

    CGFloat angle = atanf(oppSide/adjSide);
    // Quadrant Identifiaction
    if(x2 < imageView.center.x)
    {
        angle = 0-angle;
    }


    if(y2 > imageView.center.y)
    {
        angle = M_PI/2 + (M_PI/2 -angle);
    }
     NSLog(@"Angle is %2f",angle*180/M_PI);
    return angle;

}

-anoop4real

-anoop4real

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