Swift - port bar graph code from obj-c - objective-c

Question

SOLUTION: Here is the GitHub link for the class I eventually created / will expand on https://github.com/ckalas/SimpleSwiftBarGraph
I'm trying to (in playground) draw a bar graph using Core Graphics. I'm basing it off this code in Obj-C:
- (void)drawRect:(CGRect)rect {
CGFloat height = self.bounds.size.height;
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextClearRect(context, rect);
CGContextSetFillColorWithColor(context, [UIColor grayColor].CGColor);
CGFloat barWidth = 30;
int count = 0;
for (NSNumber *num in values) {
CGFloat x = count * (barWidth + 10);
CGRect barRect = CGRectMake(x, height - ([num floatValue] * height), barWidth, [num floatValue] * height);
CGContextAddRect(context, barRect);
count++;
}
CGContextFillPath(context);
}
I'm trying to convert this, but at the second line, Xcode doesn't know about UIGraphicsGetCurrentContext(). Can anyone offer help?
EDIT: Here is my current code...issues now are in the for loop where I commented, no matter what combination of stuff I try I cannot get that line to work. Just errors can't convert type to type, I've tried declaring the array as an [NSNumber], no luck.
class CustomView: UIView {
init(frame: CGRect) {
super.init(frame: frame)
}
override func drawRect(rect: GCRect) {
let values: [UInt8] = [1,2,3]
let height = self.bounds.size.height
let context = UIGraphicsGetCurrentContext()
CGContextClearRect(context, self.frame)
CGContextSetFillColorWithColor(context, UIColor.grayColor().CGColor!);
let barWidth = 30.0 as CGFloat
var count = 0 as CGFloat
for number in values {
let x = count * (barWidth + 10) as CGFloat
let barRect = CGRectMake(x, (height - number*height), barWidth, number*height) // issues here can't convert one type to another
CGContextAddRect(context, barRect)
count++
}
CGContextFillPath(context)
}

Answer 1

Declare your values array to be of type [CGFloat]. I made a few other stylistic changes (removed semicolons, CGColor is already implicitly unwrapped so ! is not needed, and prefer type declaration to cast).
class CustomView: UIView {
init(frame: CGRect) {
super.init(frame: frame)
}
override func drawRect(rect: CGRect) {
let values: [CGFloat] = [0.3, 0.6, 0.9]
let height = self.bounds.size.height
let context = UIGraphicsGetCurrentContext()
CGContextClearRect(context, self.frame)
CGContextSetFillColorWithColor(context, UIColor.grayColor().CGColor)
let barWidth:CGFloat = 30.0
var count:CGFloat = 0
for number in values {
let x = count * (barWidth + 10)
let barRect = CGRectMake(x, (height - number*height), barWidth, number*height)
CGContextAddRect(context, barRect)
count++
}
CGContextFillPath(context)
}
}
The values in the values array should range from 0.0 for no bar height to 1.0 for full bar height.