[英]Real-time blur for UIImage by sliding on iOS
如何在liderValueChanged(_ :)上實現UIImage的實時模糊?
@IBOutlet weak var imageView: UIImageView!
@IBAction func sliderValueChanged(sender: UISlider) {
let blurRadius = sender.value
var img = imageView.image
// some image processing for img
//blurring for img
// some another image processing for img
imageView.image = img
}
由於存在其他圖像處理,我不適合UIImageView的模糊處理。
謝謝!
為了獲得最佳性能,應該將GLKView
與CIFilter
一起使用,而不是UIImageView
。
最簡單的實現之一就是這樣的代碼(Xcode6 / Swift1.2):
import UIKit
import GLKit
class BlurImageView: GLKView {
let clampFilter = CIFilter(name: "CIAffineClamp")!
let blurFilter = CIFilter(name: "CIGaussianBlur")!
let ciContext:CIContext
override init(frame: CGRect) {
let glContext = EAGLContext(API: .OpenGLES2)
ciContext = CIContext(
EAGLContext: glContext,
options: [
kCIContextWorkingColorSpace: NSNull()
]
)
super.init(frame: frame, context: glContext)
enableSetNeedsDisplay = true
}
required init(coder aDecoder: NSCoder) {
let glContext = EAGLContext(API: .OpenGLES2)
ciContext = CIContext(
EAGLContext: glContext,
options: [
kCIContextWorkingColorSpace: NSNull()
]
)
super.init(coder: aDecoder)
context = glContext
enableSetNeedsDisplay = true
}
@IBInspectable var inputImage: UIImage? {
didSet {
inputCIImage = inputImage.map { CIImage(image: $0)! }
}
}
@IBInspectable var blurRadius: Float = 0 {
didSet {
blurFilter.setValue(blurRadius, forKey: "inputRadius")
setNeedsDisplay()
}
}
var inputCIImage: CIImage? {
didSet { setNeedsDisplay() }
}
override func drawRect(rect: CGRect) {
if let inputCIImage = inputCIImage {
clampFilter.setValue(inputCIImage, forKey: kCIInputImageKey)
blurFilter.setValue(clampFilter.outputImage!, forKey: kCIInputImageKey)
let rect = CGRect(x: 0, y: 0, width: drawableWidth, height: drawableHeight)
ciContext.drawImage(blurFilter.outputImage!, inRect: rect, fromRect: inputCIImage.extent())
}
}
}
然后,您可以像這樣使用:
class ViewController: UIViewController {
@IBOutlet var imageView: BlurImageView!
override func viewDidLoad() {
super.viewDidLoad()
imageView.inputImage = UIImage(named:"testImage")!
}
@IBAction func sliderValueChanged(sender: UISlider) {
imageView.blurRadius = sender.value
}
}
有關更多說明和示例,請參見“ Core Image簡介-objc.io”及其示例代碼。
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