如果您的渐变比 2 色渐变更复杂，您可以考虑将 CGGradientRef 绘制到临时 CGImageRef 中并直接从图像缓冲区读取 RGBA 值。
这是我与 5 个渐变色标和颜色有关的事情：
CGFloat tmpImagewidth = 1000.0f; // Make this bigger or smaller if you need more or less resolution (number of different colors).
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
// create a gradient
CGFloat locations[] = { 0.0,
0.35,
0.55,
0.8,
1.0 };
NSArray *colors = @[(__bridge id) [UIColor redColor].CGColor,
(__bridge id) [UIColor greenColor].CGColor,
(__bridge id) [UIColor blueColor].CGColor,
(__bridge id) [UIColor yellowColor].CGColor,
(__bridge id) [UIColor redColor].CGColor,
];
CGGradientRef gradient = CGGradientCreateWithColors(colorSpace, (__bridge CFArrayRef) colors, locations);
CGPoint startPoint = CGPointMake(0, 0);
CGPoint endPoint = CGPointMake(tmpImagewidth, 0);
// create a bitmap context to draw the gradient to, 1 pixel high.
CGContextRef context = CGBitmapContextCreate(NULL, tmpImagewidth, 1, 8, 0, colorSpace, kCGImageAlphaPremultipliedLast);
// draw the gradient into it
CGContextAddRect(context, CGRectMake(0, 0, tmpImagewidth, 1));
CGContextClip(context);
CGContextDrawLinearGradient(context, gradient, startPoint, endPoint, 0);
// Get our RGB bytes into a buffer with a couple of intermediate steps...
// CGImageRef -> CFDataRef -> byte array
CGImageRef cgImage = CGBitmapContextCreateImage(context);
CGDataProviderRef provider = CGImageGetDataProvider(cgImage);
CFDataRef pixelData = CGDataProviderCopyData(provider);
// cleanup:
CGGradientRelease(gradient);
CGColorSpaceRelease(colorSpace);
CGImageRelease(cgImage);
CGContextRelease(context);
const UInt8* data = CFDataGetBytePtr(pixelData);
// we got all the data we need.
// bytes in the data buffer are a succession of R G B A bytes
// For instance, the color of the point 27% in our gradient is:
CGFloat x = tmpImagewidth * .27;
int pixelIndex = (int)x * 4; // 4 bytes per color
UIColor *color = [UIColor colorWithRed:data[pixelIndex + 0]/255.0f
green:data[pixelIndex + 1]/255.0f
blue:data[pixelIndex + 2]/255.0f
alpha:data[pixelIndex + 3]/255.0f];
// done fetching color data, finally release the buffer
CGDataProviderRelease(provider);
我并不是说这比上面答案中的“数学方式”更好，当然，生成临时图像会产生内存和 CPU 税。然而，这样做的好处是，无论您需要多少渐变停止，代码复杂性都保持不变......
