Iphone iOS RGB颜色不正确？

我用RGB（135213,0）画一条线，RGB（135213,0）应该是。但是iOS显示黄线！！为什么？

将每个值除以255即RGB（135/255213/255,0）

您需要使值在[0,1]范围内。因此，需要将每个值除以255

 UIGraphicsBeginImageContext(self.view.frame.size);
    [drawImage.image drawInRect:CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height)];
    CGContextSetLineCap(UIGraphicsGetCurrentContext(), kCGLineCapRound);
    CGContextSetLineWidth(UIGraphicsGetCurrentContext(), 8.0);
    CGContextSetRGBStrokeColor(UIGraphicsGetCurrentContext(), 135.0,213.0,0.0,1.0);
    CGContextBeginPath(UIGraphicsGetCurrentContext());
    CGContextMoveToPoint(UIGraphicsGetCurrentContext(),currentPoint.x, currentPoint.y);
    CGContextAddLineToPoint(UIGraphicsGetCurrentContext(), currentPoint.x, currentPoint.y);
    CGContextStrokePath(UIGraphicsGetCurrentContext());
    drawImage.image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

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最大值为1.0，将每个参数除以255.0

CGContextSetRGBStrokeColor(UIGraphicsGetCurrentContext(), 135.0/255.0,213.0/255.0,0.0,1.0);