iphone ios CABasicAnimation animationWithKeyPath 一些规定的值

最新推荐文章于 2025-09-09 23:58:32 发布

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最新推荐文章于 2025-09-09 23:58:32 发布

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文章标签： iphone ios structure path

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本文详细介绍了如何使用CoreAnimation通过关键路径访问结构体字段，包括旋转、缩放、平移等，以及如何设置和获取这些结构体的值。

原文：

https://developer.apple.com/library/ios/#documentation/Cocoa/Conceptual/CoreAnimation_guide/Articles/KVCAdditions.html

Key Path Support for Structure Fields

CAAnimation provides support for accessing the fields of selected structures using key paths. This is useful for specifying these structure fields as the key paths for animations, as well as setting and getting values usingsetValue:forKeyPath: and valueForKeyPath:.

CATransform3D exposes the following fields:

Structure Field	Description
`rotation.x`	The rotation, in radians, in the x axis.
`rotation.y`	The rotation, in radians, in the y axis.
`rotation.z`	The rotation, in radians, in the z axis.
`rotation`	The rotation, in radians, in the z axis. This is identical to setting the `rotation.z` field.
`scale.x`	Scale factor for the x axis.
`scale.y`	Scale factor for the y axis.
`scale.z`	Scale factor for the z axis.
`scale`	Average of all three scale factors.
`translation.x`	Translate in the x axis.
`translation.y`	Translate in the y axis.
`translation.z`	Translate in the z axis.
`translation`	Translate in the x and y axis. Value is an NSSize or CGSize.

CGPoint exposes the following fields:

Structure Field	Description
`x`	The x component of the point.
`y`	The y component of the point.

CGSize exposes the following fields:

Structure Field	Description
`width`	The width component of the size.
`height`	The height component of the size.

CGRect exposes the following fields:

Structure Field	Description
`origin`	The origin of the rectangle as a `CGPoint`.
`origin.x`	The x component of the rectangle origin.
`origin.y`	The y component of the rectangle origin.
`size`	The size of the rectangle as a `CGSize`.
`size.width`	The width component of the rectangle size.
`size.height`	The height component of the rectangle size.

You can not specify a structure field key path using Objective-C 2.0 properties. This will not work:

    myLayer.transform.rotation.x=0;

Instead you must use setValue:forKeyPath: or valueForKeyPath: as shown below:

    [myLayer setValue:[NSNumber numberWithInt:0] forKeyPath:@"transform.rotation.x"];