objective-c - 在 ImageView 中将数组绘制为图形

Question

如何将数组绘制为 ImageView ？

我一直在 Playground 中测试它并且它有效，但如何在实际项目中将其绘制为 ImageView ？

let sineArraySize = 64

let frequency1 = 4.0
let phase1 = 0.0
let amplitude1 = 2.0
let sineWave = (0..<sineArraySize).map {
    amplitude1 * sin(2.0 * M_PI / Double(sineArraySize) * Double($0) * frequency1 + phase1)
}


func plotArrayInPlayground<T>(arrayToPlot:Array<T>, title:String) {
    for currentValue in arrayToPlot {
        XCPCaptureValue(title, currentValue)
    }
}


plotArrayInPlayground(sineWave, "Sine wave 1")

Answer 1

您可以这样做的一种方法:

// this function creates a plot of an array of doubles where it scales to the provided width and the x-axis is on half height
func plotArray(arr: [Double], width: Double, height: Double) -> NSImage {
    if arr.isEmpty { return NSImage() }
    let xAxisHeight = height / 2
    let increment = width / Double(arr.count)
    let image = NSImage(size: NSSize(width: width, height: height))

    image.lockFocus()
    // set background color
    NSColor.whiteColor().set()

    NSRectFill(NSRect(x: 0, y: 0, width: width, height: height))

    let path = NSBezierPath()
    // line width of plot
    path.lineWidth = 5
    path.moveToPoint(NSPoint(x: 0, y: arr[0] * increment + xAxisHeight))

    var i = increment
    for value in dropFirst(sineWave) {
        path.lineToPoint(NSPoint(x: i, y: value * increment + xAxisHeight))
        i += increment
    }

    // set plot color
    NSColor.blueColor().set()
    path.stroke()

    image.unlockFocus()
    return image
}

var imageView = NSImageView()
imageView.image = plotArray(sineWave, 500, 200)
// have fun