我刚刚开始学习Xcode、SwiftUI等。通过创建一个学习应用程序，这也是有用的。我能够将数据导入为[UInt 16]并将其缩放为[UInt 8]，以显示为灰度图像。我创建了一个CGImage，它被分配给一个状态变量，但我得到了这个错误：
2023-06-13 10：03：04.497662-0700 DisplayFM 2 Image [6160：76497] [default] CGSWindowShmemCreateWithPort在端口0失败
我在CGImage创建后有一个断点;当我在调试会话中检查图像时，图像显示！看起来我正在做正确的事情，但是当我在调试中“继续”时，错误出现了。我一直无法弄清楚错误是在哪里产生的，但认为它是在显示/视图中。我将缩放后的[UInt 8]和图像元数据保存在类TheImage的示例theImage中。
我怀疑cgImage在函数“createCGImageFromUint 8“返回后没有保留指向图像数据的指针（或类似的），或者GeometryReader中的代码不正确。
其目的是允许用户拾取包含图像数据的文件，显示数据，并让用户在工具提示处检查未缩放的数据，然后使用另一个数据集重复。
(It具有讽刺意味的是，该应用程序的早期版本可以工作，但我没有使用最佳实践-加载和缩放图像的ContentView代码可能会在每次ContentView更新时调用。）

import SwiftUI
import CoreGraphics

// Calculates a Core Graphics image as ContentView's
// State variable "cgImage".
func createCGImageFromUint8( _ cgImage: inout CGImage?) {
    
    let width: Int = theImage.nCols
    let height: Int = theImage.nRows
    let numBytes = theImage.scaledArray.count
    let numComponents = numBytes / (height * width)
    let colorspace = CGColorSpaceCreateDeviceGray()
    let grayScaleData = CFDataCreate(nil, theImage.scaledArray, numBytes)
    let provider = CGDataProvider(data: grayScaleData!)!
    
    cgImage = CGImage(
        width: width,
        height: height,
        bitsPerComponent: 8,
        bitsPerPixel: 8 * numComponents,
        bytesPerRow: width * numComponents,
        space: colorspace,
        //bitmapInfo: CGBitmapInfo(rawValue: 0),
        bitmapInfo: CGBitmapInfo(rawValue: CGImageAlphaInfo.none.rawValue),
        provider: provider,
        decode: nil,
        shouldInterpolate: true,
        intent: CGColorRenderingIntent.defaultIntent)!
    
    // break point
     print("Return from createCGImageFromUint8")
    // Looking at cgImage in debug at this breakpoint
    // displays the image!
}

这是我的ContentView的开始：

import SwiftUI
import CoreGraphics

var theImage = TheImage() // Image vars, file

struct ContentView: View {
    
    @State var haveNewImage: Bool = false
    @State private var cgImage: CGImage? = nil
        
    // @State var imageDataView: (any View)? // what's this?
    
    var body: some View {
        VStack(alignment: .leading ) {
            
            FilePickerView(cgImage: $cgImage)
                .padding()  // at upper left corner WORKS
            
            // If a new file was picked: process and display it.
            if theImage.isNew { // displays image etc. GOAT
                Text("DEBUG New Image")
                CGImageView(cgImage: $cgImage)
            } else {
                HStack {
                    Spacer()
                    Text("Image not yet selected.")
                    Spacer()
                }
            }
        }    
    }

这是我的CGImageView。

import SwiftUI
import CoreGraphics
import AppKit

struct CGImageView: View {
    @Binding var cgImage: CGImage?

    @State private var opacity = 0.0
    @State private var minMax = theImage.minMax
    @State private var dnData: [UInt16] = theImage.backingArray
    
    var body: some View {
        var dnText = "" // to display tooltip
        Text(theImage.displayName)
            .padding(10)
        
        HStack {
            GeometryReader { geometry in
            //    Image(decorative: $cgImage as! CGImage , scale: 1.0)
                  Image(decorative: self.cgImage! , scale: 1.0)
                    .aspectRatio(contentMode: .fit)
                    .border(Color.red)
            }
            .frame(width: CGFloat(theImage.nCols), height: CGFloat(theImage.nRows))
            .opacity(opacity)
            .animation(.easeInOut(duration: 1.5), value: opacity)
            
            .onAppear {
                opacity = 1.0
            }
            
            .onDisappear {
                opacity = 0.0
            }
            
            .onTapGesture {
                print("TAPPED!") // do something
            }
            .onHover { (hover: Bool) in
                if hover {
                    //   let mouseLocation = NSEvent.mouseLocation
                    //   print("Mouse location: \(mouseLocation)")
                    NSCursor.crosshair.push()
                } else {
                    NSCursor.pop()
                }
            }
            
            .onContinuousHover { phase in
                switch phase {
                case .active(let location):  // col, row
                    let dn = theImage.getToolTipValue(mouse: location)
                    dnText = "raw DN \(dn)"
                    print("---> location x: \(location.x)")
                case .ended:
                    break
                }
            }
            .padding(10)

            Text("Mimimum \(minMax[0])\nMaximum \(minMax[1])\n\(dnText)")
                
        }
    }
}