旋转CAShapeLayer

Question

我在试着旋转一个CAShapeLayer

             UIBezierPath *aPath = [UIBezierPath bezierPath];
             CGFloat originx = (97.5+250);
             CGFloat originy = (205+250);
             [aPath moveToPoint:CGPointMake(originx,originy)];
             [aPath addArcWithCenter:CGPointMake(originx+15, originy-30) radius:15 startAngle:DEGREES_TO_RADIANS(180) endAngle:DEGREES_TO_RADIANS(360) clockwise:YES];
             [aPath addLineToPoint:CGPointMake(originx+30,originy)];
             CAShapeLayer *shapeLayer = [CAShapeLayer layer];
             shapeLayer.anchorPoint = CGPointMake(originx, originy);
             shapeLayer.path = [aPath CGPath];
             shapeLayer.strokeColor = [[UIColor blueColor] CGColor];
             shapeLayer.lineWidth = 3.0;
             shapeLayer.fillColor = [[UIColor blueColor] CGColor];
             [aPath closePath];
             shapeLayer.transform = CATransform3DMakeRotation(310 * M_PI/180, 0.0, 0.0, 1.0);
             [self.view.layer addSublayer:shapeLayer];

我想在形状本身内围绕一个轴旋转形状(上面的代码使我的小形状在离实际中心几百像素的轴线上旋转。

我觉得应该用这样的锚点来控制：

shapeLayer.anchorPoint = CGPointMake(originx, originy); 

但在代码中它似乎什么也做不了。有什么想法吗？

Answer 1

anchorPoint相对于层的边界。你不能使用锚点放置你的层。相反，您可以将您的形状相对于零点，旋转它，并将其移动到所需的点。旋转和平移是通过变换完成的。