使用CoreImage生成条纹纹理 - 没有锐利的边缘

Question

我正在使用CoreImage框架生成带有条纹的图像，但是输出结果的边缘不正确，如下图所示。我使用的代码如下。

fileprivate func generateImage(_ width: CGFloat, _ height: CGFloat, withColor1: CIColor, withColor2: CIColor) -> CGImage? {

   let context = CIContext()

   if #available(iOS 10.0, *) {
   let stripes = CIFilter(name: "CIStripesGenerator", withInputParameters: [
                "inputColor0" : withColor2,
                "inputColor1" : withColor1,
                "inputWidth" : NSNumber(value: 10),
                "inputSharpness" : NSNumber(value: 0.7)

                ])!.outputImage!

    let rotate = CIFilter(name: "CIAffineTransform", withInputParameters: [ "inputImage" : stripes,"inputTransform" : NSValue(cgAffineTransform: CGAffineTransform(rotationAngle: -75.0))])!.outputImage!

    return context.createCGImage(rotate, from: CGRect(x: 0, y: 0, width: width, height: 50.0))!

        } else {
            // Fallback on earlier versions
        }

        return nil

    }

高清晰度

低清晰度(0.7)

我需要的是下面这个

- Saranjith

Answer 1

将弧度值.pi / -4赋给CGAffineTransform的rotationAngle属性，而不是角度值。请注意保留HTML标记。

import UIKit
import CoreImage

fileprivate func
generateImage(_ width: CGFloat, _ height: CGFloat, withColor1: CIColor, withColor2: CIColor) -> CGImage? {

    let context = CIContext()

    let stripes = CIFilter(
        name: "CIStripesGenerator"
    ,   parameters: [
            "inputColor0"   : withColor2
        ,   "inputColor1"   : withColor1
        ,   "inputWidth"    : NSNumber( value: 10 )
        ,   "inputSharpness": NSNumber( value: 1 )
        ]
    )!.outputImage!

    let rotate = CIFilter(
        name: "CIAffineTransform"
    ,   parameters: [
            "inputImage"    : stripes
        ,   "inputTransform": NSValue( cgAffineTransform: CGAffineTransform( rotationAngle: .pi / -4 ) )
        ]
    )!.outputImage!

    return context.createCGImage( rotate, from: CGRect( x: 0, y: 0, width: width, height: height ) )!
}


class ViewController: UIViewController {
    @IBOutlet   weak    var oIV:    UIImageView!
    override func viewDidLoad() {
        super.viewDidLoad()
        oIV.image = UIImage(
            cgImage: generateImage(
                oIV.bounds.width
            ,   oIV.bounds.height
            ,   withColor1: CIColor( red:0, green:0, blue:0, alpha:1 )
            ,   withColor2: CIColor( red:1, green:1, blue:1, alpha:1 )
            )!
        )
    }
}

结果：

这是一个关于IT技术方面的结果。

- Satachito

Answer 2

你可以尝试类似这样的方法，但我还没有进行充分的测试：

let generatedImage = generateImage(...)

let scaleX = yourView.frame.size.width / generatedImage.extent.size.width
let scaleY = yourView.frame.size.height / generatedImage.extent.size.height

let transformedImage = generatedImage.transformed(by: CGAffineTransform(scaleX: scaleX, y: scaleY))

- fulvio

---

我会检查一下。这里需要使用什么锐度级别？ - Saranjith

对我没用。该图像旨在作为填充显示在Swift图表数据集中。 - Saranjith