Skip to content

Instantly share code, notes, and snippets.

@bluwave

bluwave/CGDrawGradientCircleBorder

Created May 1, 2015 20:29
Show Gist options

  • Select an option

    Learn more about clone URLs
  • Save bluwave/c9e7d3175977dd70ca6e to your computer and use it in GitHub Desktop.

Select an option

Learn more about clone URLs
Save bluwave/c9e7d3175977dd70ca6e to your computer and use it in GitHub Desktop.
Download ZIP
Draw circle with a gradient color border, clear center
Raw
CGDrawGradientCircleBorder
// Draw circle
CGContextSaveGState(context);
CGFloat lineWidth = 2.0f;
CGPoint center = CGPointMake(rect.size.width / 2, rect.size.height / 2);
UIBezierPath *outerCirclePath = [UIBezierPath bezierPath];
[outerCirclePath addArcWithCenter:center radius:(rect.size.height / 2) - insetPad/2 startAngle:0 endAngle:2 * M_PI clockwise:YES];
UIBezierPath *innerCirclePath = [UIBezierPath bezierPath];
[innerCirclePath addArcWithCenter:center radius:((rect.size.height / 2) - lineWidth - (insetPad/2)) startAngle:0 endAngle:2 * M_PI clockwise:YES];
[outerCirclePath appendPath:innerCirclePath];
outerCirclePath.usesEvenOddFillRule = YES;
[outerCirclePath addClip];
// Circle gradient
CGContextAddPath(context, outerCirclePath.CGPath);
CGContextClip(context);
CGFloat locations[3] = {1.0, 0.70, 0.0};
UIColor *alphaColor = [self.borderColor colorWithAlphaComponent:0];
NSArray *colors = @[(id)alphaColor.CGColor, (id)alphaColor.CGColor, (id)self.borderColor.CGColor];
CGColorSpaceRef colorspace = CGColorSpaceCreateDeviceRGB();
CGGradientRef gradient = CGGradientCreateWithColors(colorspace, (CFArrayRef)colors, locations);
CGContextDrawLinearGradient(context, gradient, CGPointMake(rect.size.width, 0), CGPointMake(-1, 0), kCGGradientDrawsAfterEndLocation);
CGColorSpaceRelease(colorspace);
CGGradientRelease(gradient);
CGContextSetLineWidth(context, self.borderWidth);
CGContextStrokePath(context);
CGContextRestoreGState(context);
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment