To check for equality you can use, CGSizeEqualToSize function by Apple. CGSize firstSize = CGSizeMake(1.0,1.0); CGSize secondSize = CGSizeMake(5.0,3.0); if(CGSizeEqualToSize(firstSize, secondSize)) { //they are equal }else{ //they aren’t equal }
A subview will always be drawn on “top” of its superview. Depending on your specific requirements, you may need to have a plain UIView as the background/container view, with your existing subviews in there, and then your custom view as another subview added to the very top, so it has the highest Z-order. This would … Read more
This was an embarrassingly easy fix: apply a CAGradientLayer as my subview’s mask. CAGradientLayer *gradientLayer = [CAGradientLayer layer]; gradientLayer.frame = _fileTypeScrollView.bounds; gradientLayer.colors = [NSArray arrayWithObjects:(id)[UIColor whiteColor].CGColor, (id)[UIColor clearColor].CGColor, nil]; gradientLayer.startPoint = CGPointMake(0.8f, 1.0f); gradientLayer.endPoint = CGPointMake(1.0f, 1.0f); _fileTypeScrollView.layer.mask = gradientLayer; Thanks to Cocoanetics for pointing me in the right direction!
This took quite a while to figure out, mainly because I wanted to get it up and running in Swift using Core Image and CIColorCube. @Miguel’s explanation is spot on about the way you need to replace a “Hue angle range” with another “Hue angle range”. You can read his post above for details on … Read more
Thanks for the Q&A! Swift code as below: extension UIImage { class func circle(diameter: CGFloat, color: UIColor) -> UIImage { UIGraphicsBeginImageContextWithOptions(CGSizeMake(diameter, diameter), false, 0) let ctx = UIGraphicsGetCurrentContext() CGContextSaveGState(ctx) let rect = CGRectMake(0, 0, diameter, diameter) CGContextSetFillColorWithColor(ctx, color.CGColor) CGContextFillEllipseInRect(ctx, rect) CGContextRestoreGState(ctx) let img = UIGraphicsGetImageFromCurrentImageContext() UIGraphicsEndImageContext() return img } } Swift 3 version provided by … Read more
I would clip to the path you want to fill, and use CGContextDrawLinearGradient. Here is a simple implementation of drawRect: as an example: – (void) drawRect:(CGRect)rect { // Create a gradient from white to red CGFloat colors [] = { 1.0, 1.0, 1.0, 1.0, 1.0, 0.0, 0.0, 1.0 }; CGColorSpaceRef baseSpace = CGColorSpaceCreateDeviceRGB(); CGGradientRef gradient … Read more
Swift 4 @IBOutlet var dashedView: UIView! func drawDottedLine(start p0: CGPoint, end p1: CGPoint, view: UIView) { let shapeLayer = CAShapeLayer() shapeLayer.strokeColor = UIColor.lightGray.cgColor shapeLayer.lineWidth = 1 shapeLayer.lineDashPattern = [7, 3] // 7 is the length of dash, 3 is length of the gap. let path = CGMutablePath() path.addLines(between: [p0, p1]) shapeLayer.path = path view.layer.addSublayer(shapeLayer) } … Read more
UPDATE I’ve posted a Swift version of this answer separately. ORIGINAL This is a fun little problem. First of all, there are lots of ways to draw arrows, with curved or straight sides. Let’s pick a very simple way and label the measurements we’ll need: We want to write a function that takes the start … Read more
I’ll try to answer your question at a conceptual, 20,000ft level. I will try to disclaim my points where I’m over-generalizing, but I’ll attempt to hit the common case. Perhaps the easiest way to think about it is this: In the GPU’s memory you have textures which, for the purposes of this discussion, are bitmap … Read more
The documentation on the use of the bridge keyword can be found here. Specifically, I want to point out §3.2.4: (__bridge T) op casts the operand to the destination type T. If T is a retainable object pointer type, then op must have a non-retainable pointer type. If T is a non-retainable pointer type, then … Read more