ios - UInt32 颜色的渐变效果？

Question

嘿，我是编程新手，我想知道是否可以创建 UInt32 类型的具有 2 种颜色(例如红色和蓝色)的渐变效果。 有什么建议么？谢谢

问题补充

这个想法是我只有像素信息:

        func fillRegion(pixelX: Int, pixelY: Int, withColor color: UIColor) {

    var red: CGFloat = 0, green: CGFloat = 0, blue: CGFloat = 0, alpha: CGFloat = 0
    color.getRed(&red, green: &green, blue: &blue, alpha: &alpha)

    let newColor = (UInt32)(alpha*255)<<24 | (UInt32)(red*255)<<16 | (UInt32)(green*255)<<8 | (UInt32)(blue*255)<<0

    let pixelColor = regionsData.advanced(by: (pixelY * imageHeight) + pixelX).pointee

    if pixelColor == blackColor { return }

    var pointerRegionsData: UnsafeMutablePointer<UInt32> = regionsData
    var pointerImageData: UnsafeMutablePointer<UInt32> = imageData

    var pixelsChanged = false

    for i in 0...(imageHeight * imageHeight - 1) {
        if pointerRegionsData.pointee == pixelColor {
            pointerImageData = imageData.advanced(by: i)
            if pointerImageData.pointee != newColor {
                pointerImageData.pointee = newColor
                pixelsChanged = true
            }
        }
        pointerRegionsData = pointerRegionsData.successor()
    }

    if pixelsChanged {
        self.image = UIImage(cgImage: imageContext.makeImage()!)
        DispatchQueue.main.async {
            CATransaction.setDisableActions(true)
            self.layer.contents = self.image.cgImage
            self.onImageDraw?(self.image)
        }
        self.playTapSound()
    }
}

现在它填充了简单的颜色，但我需要以某种方式设置渐变，我没有正确的形式，并且我无法设置 CAShapeLayer...因为我只有像素数信息和他的颜色，尽管我可以在这里更改颜色:

if pointerImageData.pointee != newColor {
                pointerImageData.pointee = newColor
                pixelsChanged = true
            }

但我不知道如何平滑地改变颜色，制作渐变效果，或者以某种方式识别周长并设置图层，不知道，任何想法都会像金子一样。

Answer 1

是的，可以使用CoreGraphics或CALayer。
为了简化，您可以覆盖返回 CAGradientLayer 的 View 的图层。
这是一个实现:

@implementation PGSGradientView

+ (Class)layerClass {
    return [CAGradientLayer class];
}

- (instancetype) initWithCoder:(NSCoder *)aDecoder {
    self = [super initWithCoder:aDecoder];
    if (self) {
        [self initializeGradient];
    }
    return self;
}

- (instancetype) initWithFrame:(CGRect)frame {
    self = [super initWithFrame:frame];
    if (self) {
        [self initializeGradient];
    }
    return self;
}

- (void) initializeGradient {
    [(CAGradientLayer*)self.layer setLocations:locations];
    [(CAGradientLayer*)self.layer setColors:colors];

}

@end

假设您有 2 个数组作为属性，一个是 locations，另一个是您要在渐变中添加的 colors。
locations 代表:

the starting location for each color. Also, and that’s important, those numbers should mandatorily range from 0.0 to 1.0. and is paired with the colors arrays.