图像无法在UIImageView中呈现

Question

此图像由以下函数生成，拒绝显示在UIImageView

中

https://www.dropbox.com/s/7f65yxsqxzqqies/soundwave.png?dl=0

生成图片时这是iOS问题还是错误？

谢谢

private func plotLogGraph(_ samples: [CGFloat], maximumValue max: CGFloat, zeroValue min: CGFloat, imageHeight: CGFloat,color:UIColor) -> UIImage? {
    let imageSize = CGSize(width: CGFloat(samples.count), height: imageHeight)
    UIGraphicsBeginImageContext(imageSize)
    guard let context = UIGraphicsGetCurrentContext() else {
        return nil
    }

    context.setAlpha(1.0)
    context.setLineWidth(1.0)
    context.setStrokeColor(color.cgColor)

    let sampleDrawingScale: CGFloat
    if max == min {
        sampleDrawingScale = 0
    } else {
        sampleDrawingScale = imageHeight / 2 / (max - min)
    }
    let verticalMiddle = imageHeight / 2
    for (x, sample) in samples.enumerated() {
        let height = (sample - min) * sampleDrawingScale
        context.move(to: CGPoint(x: CGFloat(x), y: verticalMiddle - height))
        context.addLine(to: CGPoint(x: CGFloat(x), y: verticalMiddle + height))
        context.strokePath();
    }
    guard let image = UIGraphicsGetImageFromCurrentImageContext() else {
        return nil;
    }

    UIGraphicsEndImageContext()
    return image;
}

渲染示例只是显示图像的全屏ImageView，请参阅 https://github.com/jonathanort/ImageTest