iphone - 使用CGAffineTransformMakeRotation时的抖动运动

Question

我在使用CGAffineTransformMakeRotation进行跳跃运动时遇到问题。在到达第1和第2象限的顶部之前，它似乎工作正常，下面是我正在使用的代码和youtube链接，其中显示了发生的情况。任何见解将不胜感激。

我的目标是旋转带有svg的UIWebView。由于我无法轻易地检测到单独的UIWebView触摸，因此将空白的UIImageView放在其上。这使我能够检测到触摸并防止弹出复制对话框。

http://www.youtube.com/watch?v=x_OmS0MPdEE&feature=youtu.be

    - (void)touchesMoved: (NSSet *)touches withEvent:(UIEvent *)event {
[super touchesBegan:touches withEvent:event];
NSArray *allTouches = [touches allObjects]; 
CGPoint location = [[allTouches objectAtIndex:0] locationInView:self.view];
if(selected == 1) {
    CGFloat rads = atan2f(location.y - (grid1.frame.size.height/2),location.x - (grid1.frame.size.width/2));
    grid1.transform = grid1Btn.transform = CGAffineTransformMakeRotation(rads);
}

    }

    - (void) touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event { 
[super touchesBegan:touches withEvent:event];
NSArray *allTouches = [touches allObjects]; 
CGPoint location = [[allTouches objectAtIndex:0] locationInView:self.view];

if(CGRectContainsPoint(grid1Btn.frame, location))
{
    selected = 1;
}
    }

    - (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
    {
        selected = -1;
    }

Answer 1

您在计算中使用了frame.size.*。请注意，这些值(与bounds.size.*不同)受transform影响。请改用grid1.center。这也更合乎逻辑(围绕中心旋转)。

接下来需要修复的是，触摸开始时不应跳到新位置:)