ios - 从 UIImage 获取 CIImage (Swift)

Question

尝试从 UIImage 获取 CIImage 以便将其用于 CIFilter，但在最后一行出现以下异常:

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，我重新编写了我的初始代码片段以在 Playground 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)

Answer 1

如果您尝试使用过滤器，我解决了这个 playground 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())