您可以使用imageAsset.registerImage()
方法:
let scale1x = UITraitCollection(displayScale: 1.0)
let scale2x = UITraitCollection(displayScale: 2.0)
let scale3x = UITraitCollection(displayScale: 3.0)
let image = UIImage(named: "img.png")!
image.imageAsset.registerImage(UIImage(named: "img_2x.png")!, withTraitCollection: scale2x)
image.imageAsset.registerImage(UIImage(named: "img_3x.png")!, withTraitCollection: scale3x)
您可以为所有比例注册 2x 图像。
但是,我认为访问具有特定分辨率的图像并不是一个好主意。设置 1x、2x 和 3x 图像的想法是让系统决定应该加载哪个图像。如果你真的想要,你可以将 1x、2x 和 3x 图像的名称更改为 SmileyFace-Small、SmileyFace-regular、SmileyFace-large。
更新:
func imageWithTraitCollection(traitCollection: UITraitCollection) -> UIImage
可以参考具有特定比例的图像:
let image1 = image.imageAsset.imageWithTraitCollection(UITraitCollection(traitsFromCollections: [scale1x]))
let image2 = image.imageAsset.imageWithTraitCollection(UITraitCollection(traitsFromCollections: [scale2x]))
let image3 = image.imageAsset.imageWithTraitCollection(UITraitCollection(traitsFromCollections: [scale3x]))