CALayer 详解

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第一、综述

苹果官方文档:

Core Animation doesn‘t provide a means for actually displaying layers in a window, they must be hosted by a view. When paired with a view, the view must provide event-handling for the underlying layers, while the layers provide display of the content.

The view system in iOS is built directly on top of Core Animation layers. Every instance of UIView automatically creates an instance of a CALayer class and sets it as the value of the view’s layer property. You can add sublayers to the view’s layer as needed.

On Mac OS X you must configure an NSView instance in such a way that it can host a layer

第三、属性

1. 设置背景色，
2. 阴影的偏差值，
3. 阴影的半径，
4. 阴影的颜色，
5. 阴影的透明度，
6. 子层的frame值。
7. 把新的层add到view的层里。
8. 设置边缘宽度
9. 设置边缘颜色

CALayer *subLayer=[CALayerlayer];

    subLayer.frame=CGRectMake(80,140, 100, 100);

    subLayer.backgroundColor=[UIColorredColor].CGColor;

    subLayer.cornerRadius=15;

    subLayer.shadowColor=[UIColorblueColor].CGColor;

    subLayer.shadowOffset=CGSizeMake(0,2.0);

    subLayer.shadowOpacity=1.0;

    subLayer.borderColor=[UIColoryellowColor].CGColor;

    subLayer.borderWidth=3.0;

    [self.view.layeraddSublayer:subLayer];

截图：

第三、. masksToBounds : 很重要的属性，可以用此属性来防止子元素大小溢出父元素，如若防止溢出，设为 true

 CALayer *subLayer=[CALayerlayer];

    subLayer.frame=CGRectMake(80,140, 100, 100);

    subLayer.cornerRadius=15;

    subLayer.shadowColor=[UIColorblueColor].CGColor;

    subLayer.shadowOffset=CGSizeMake(0,2.0);

    subLayer.shadowOpacity=1.0;

    subLayer.borderColor=[UIColoryellowColor].CGColor;

    subLayer.borderWidth=3.0;

    subLayer.contents=(id)[UIImageimageNamed:@"sample.jpg"].CGImage;

    subLayer.masksToBounds=YES;

    [self.view.layeraddSublayer:subLayer];

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CALayer 详解

标签：style   blog   class   tar   ext   color   

原文地址：http://blog.csdn.net/richard_rufeng/article/details/25112431