Question

I m 试图在其次表中从物体中生成的电离层电离层。例如,我可能有一个包含广场和一个圈子的子座。我想能够在括号中产生一个lip子,把这两个形状的结合起来。谁能解释如何做到这一点? 至今为止,我能看到的是:

1 - the superview s drawRect: method is called before its subviews drawRects are, and
2 - the ContextRef that s accessible in all three instances is the same.

Other than that I m stumped. Thanks,
Howard

Answer 1

简言之,你们必须通过所有次表加以调整,使每个人都能改变目前的背景道路,然后将这条道路作为一条lipp路。你们可以要求从每一种观点出发,或者把背景传递给每一种观点。

CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSaveGState( context );
CGContextBeginPath( context );

for ( view in subviews ) {
  if ( [view respondsToSelector:@selector(pathTranslatedForView:)] ) {
    CGContextAddPath( context , [(MyCustomViewPath *)view pathTranslatedForView:self] );
  }
}

CGContextClip( context );
// do stuff with clipping path
CGContextRestoreGState( context );

Edit:

在提出分观点时,您不妨调整背景,以便0,0,即所谓的观点,而不是表面观点:

CGRect frame = [view frame];
CGContextTranslateCTM( context , -frame.origin.x , -frame.origin.y );
CGContextAddPath( context , [(MyCustomViewPath *)view path]; 
CGContextTranslateCTM( context , frame.origin.x , frame.origin.y );

Answer 2

也许会试图确定背景的科罗·托查尔:调查意见——新陈词将消失,而只是走路。

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