将颜色定义为 CGFloat

Question

我正在使用我在另一个 stackoverflow post 中找到的关于在 iOS 中绘制径向渐变的以下代码创建渐变

- (void)drawInContext:(CGContextRef)ctx
{ 
    if ([[[NSUserDefaults standardUserDefaults] objectForKey:@"theme"] isEqualToString:@"black"]) {

    }

    size_t gradLocationsNum = 2;
    CGFloat gradLocations[2] = {0.0f, 1.0f};
    CGFloat gradColors[8] = {156/255.0f, 97/255.0f, 249/255.0f,1.0f,41/255.0f,131/255.0f,242/255.0f,1.0f};
    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
    CGGradientRef gradient = CGGradientCreateWithColorComponents(colorSpace, gradColors, gradLocations, gradLocationsNum);
    CGColorSpaceRelease(colorSpace);

    CGPoint gradCenter= CGPointMake(self.bounds.size.width/2, self.bounds.size.height+100);
    float gradRadius = MAX(self.bounds.size.width , self.bounds.size.height) ;

    CGContextDrawRadialGradient(ctx, gradient, gradCenter, 0, gradCenter, gradRadius, kCGGradientDrawsAfterEndLocation);


    CGGradientRelease(gradient);
}

我不知道如何定义 CGFloat gradColors[8] = {156/255.0f, 97/255.0f, 249/255.0f,1.0f,41/255.0f,131/255.0f,242/255.0f,1.0f}; 以便我可以执行以下操作：

CGFloat gradColors[8];

if ...
    gradColors[8] = {156/255.0f, 97/255.0f, 249/255.0f,1.0f,41/255.0f,131/255.0f,242/255.0f,1.0f};
else if ...
    gradColors[8] = {156/255.0f, 97/255.0f, 249/255.0f,1.0f,41/255.0f,131/255.0f,242/255.0f,1.0f};

另外：有没有办法将UIColor 转换成这种格式？

Answer 1

您可以尝试使用CGGradientCreateWithColors()，它接受 CGColor 数组。

例如。

CGGradientRef gradient = CGGradientCreateWithColors(colorSpace, (__bridge CFArrayRef)@[(id)aUIColor1.CGColor, (id)aUIColor2.CGColor], gradientLocations);