从 UIImage (Swift) 获取 CIImage

Posted 2023-03-10

【中文标题】从 UIImage (Swift) 获取 CIImage

【英文标题】：Getting CIImage from UIImage (Swift)

【发布时间】：2014-11-23 03:17:28

【问题描述】：

试图从 UIImage 获取 CIImage 以便将其用于 CIFilter，但在最后一行得到以下异常：

Execution was interrupted, reason: EXC_BREAKPOINT (code=EXC_I386_BPT, subcode=0x0)

我做错了什么？

import UIKit

UIGraphicsBeginImageContextWithOptions(CGSizeMake(100,100), false, 0)
let con:CGContextRef = UIGraphicsGetCurrentContext()
CGContextAddEllipseInRect(con, CGRectMake(0,0,100,100))
CGContextSetFillColorWithColor(con, UIColor.blueColor().CGColor)
CGContextFillPath(con)
let im:UIImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()

let ciimage = CIImage(image: im) // <- Exception here

更新： 按照不要将 CIImage 实例化为变量的建议，我重新编写了初始代码 sn-p 以在操场上工作：

UIGraphicsBeginImageContextWithOptions(CGSizeMake(100,100), false, 0)
let con:CGContextRef = UIGraphicsGetCurrentContext()
CGContextAddEllipseInRect(con, CGRectMake(0,0,100,100))
CGContextSetFillColorWithColor(con, UIColor.blueColor().CGColor)
CGContextFillPath(con)
let im:UIImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()

//let ciimage = CIImage(image: im) // <- this was causing an exception

let filter = CIFilter(name: "CIGaussianBlur", withInputParameters: [kCIInputRadiusKey: 10, kCIInputImageKey: CIImage(image: im)]) // <- this does not cause an exception
let calayer = CALayer()
calayer.contents = CIContext(options:nil).createCGImage(filter.outputImage, fromRect: filter.outputImage.extent())
calayer.frame = CGRect(x: 0, y: 0, width: 270, height: 270)
var view = UIView()
view.frame = calayer.frame
view.layer.addSublayer(calayer)
XCPShowView("view", view)

【问题讨论】：

这在操场上失败，但对我来说在编译后的代码中工作 - 一定是操场环境的怪癖。

是的，在为我编译时也可以工作。

【参考方案1】：

如果您尝试使用过滤器，我解决了这个游乐场错误：

let pic = UIImage(named: "crumpled.jpg")
let filter = CIFilter(name: "CISepiaTone")
filter.setValue(CIImage(image: pic), forKey: kCIInputImageKey)
filter.setValue(0.8, forKey: kCIInputIntensityKey)
let ctx = CIContext(options:nil)
let cgImage = ctx.createCGImage(filter.outputImage, fromRect:filter.outputImage.extent())

【参考方案2】：

一行就可以了。

UIImage > CIImage

let ciimage = CIImage(image: image)

CIImage > UIImage

let image = UIImage(ciImage: ciimage)