iOS - How to draw gradient along a path - ios

Question

This is the effect that I want to achieve:
This is the effect that I am having now:
Basically, I need to draw the gradient along the path of the arc, not linearly across the arc. I tried a lot of ways, some of them yield the same result, but some of them produced a result that is farther from expectation.
This is the code that I am having right now:
CGFloat lineSize = 12;
CGFloat radius = self.frame.size.width/2 - lineSize;
CGContextRef ctx = UIGraphicsGetCurrentContext();
//Define gradient
CGFloat colors [] =
{
0.9451f, 0.5804f, 0.2431f, 1.0f,
0.9922f, 0.9490f, 0.9020f, 1.0f,
1.0f, 1.0f, 1.0f, 1.0f,
0.8706f, 0.9020f, 0.9412f, 1.0f,
0.2941f, 0.6863f, 0.9176f, 1.0f
};
CGColorSpaceRef baseSpace = CGColorSpaceCreateDeviceRGB();
CGGradientRef gradient = CGGradientCreateWithColorComponents(baseSpace, colors, NULL, 5);
CGColorSpaceRelease(baseSpace), baseSpace = NULL;
//Define arc angle and points
CGFloat startAngle = 3.0f/4.0f * M_PI;
CGFloat endAngle = 1.0f/4.0f * M_PI;
CGFloat a = radius * cos(45);
CGFloat o = a * tan(45);
CGFloat y = CGRectGetMidY(rect) + o;
CGPoint startPoint = CGPointMake(0, y);
CGPoint endPoint = CGPointMake(self.frame.size.width, y);
CGMutablePathRef arc = CGPathCreateMutable();
CGPathAddArc(arc, NULL, CGRectGetMidX(rect), CGRectGetMidY(rect), radius,
startAngle, endAngle, NO);
CGPathRef strokedArc = CGPathCreateCopyByStrokingPath(arc, NULL, 10, kCGLineCapButt, kCGLineJoinMiter, 10);
CGContextAddPath(ctx, strokedArc);
CGContextClip(ctx);
CGContextDrawLinearGradient(ctx, gradient, startPoint, endPoint, 0);
CGGradientRelease(gradient);
I also tried changing this block of code:
CGMutablePathRef arc = CGPathCreateMutable();
CGPathAddArc(arc, NULL, CGRectGetMidX(rect), CGRectGetMidY(rect), radius,
startAngle, endAngle, NO);
CGPathRef strokedArc = CGPathCreateCopyByStrokingPath(arc, NULL, 10, kCGLineCapButt, kCGLineJoinMiter, 10);
CGContextAddPath(ctx, strokedArc);
CGContextClip(ctx);
CGContextDrawLinearGradient(ctx, gradient, startPoint, endPoint, 0);
CGGradientRelease(gradient);
to this block code:
CGContextAddArc(ctx, CGRectGetMidX(rect), CGRectGetMidY(rect), radius, startAngle, endAngle, NO);
CGContextSetLineWidth(ctx, lineSize);
CGContextSetLineCap(ctx, kCGLineCapRound);
CGContextReplacePathWithStrokedPath(ctx);
CGContextClip(ctx);
CGContextDrawLinearGradient(ctx, gradient, startPoint, endPoint, 0);
CGGradientRelease(gradient), gradient = NULL;
But still yields similar result as the one I am having now.

Answer 1

Try by changing the gradient values.
Change
//Define gradient
CGFloat colors [] =
{
0.9451f, 0.5804f, 0.2431f, 1.0f,
0.9922f, 0.9490f, 0.9020f, 1.0f,
1.0f, 1.0f, 1.0f, 1.0f,
0.8706f, 0.9020f, 0.9412f, 1.0f,
0.2941f, 0.6863f, 0.9176f, 1.0f
};
To something symmetric values. Like
CGFloat colors [] =
{
1.0f, 0.9176f, 0.6863f, 0.2941f,
1.0f, 0.9412f, 0.9020f, 0.8706f,
0.7432f, 1.0f, 1.0f, 0.7432f,
0.8706f, 0.9020f, 0.9412f, 1.0f,
0.2941f, 0.6863f, 0.9176f, 1.0f
};