johnyorke / jygraphview

Simple line graph view for iOS.

Hello there

iOS developer since 2013, currently working on my sleep app in my spare time.

I sometimes write at johnyorke.me and you can also find me on Twitter.

Having a good time...all the time.

jygraphview's Issues

Having trouble using it on the watch

I'm trying to use the graphing on the watch but when I copy the four files you mention I'll need it runs into compile error saying that it can't find UIView. From what I read UIView is not available on the WatchKit. I'm trying to compare with your demo app but can't see where/how I can make the changes so that JYGraphView and JYGraphPoint files don't give me errors. Your help is much appreciated.

The mechanism about drawing curving lines

Great work. I have been reading the code and quite interested in

drawCurvedLineBetweenPoints

What is the theory behind the following code? I understand it is drawing curving lines. But I am wondering why the following code draws smooth curving lines. Maths! ;)

    for (int index = 1; index < points.count - 2 ; index++) {

        CGPoint point0 = [self pointAtIndex:index - 1 ofArray:points];
        CGPoint point1 = [self pointAtIndex:index ofArray:points];
        CGPoint point2 = [self pointAtIndex:index + 1 ofArray:points];
        CGPoint point3 = [self pointAtIndex:index + 2 ofArray:points];

        for (int i = 1; i < granularity ; i++) {
            float t = (float) i * (1.0f / (float) granularity);
            float tt = t * t;
            float ttt = tt * t;

            CGPoint pi;
            pi.x = 0.5 * (2*point1.x+(point2.x-point0.x)*t +
                          (2*point0.x-5*point1.x+4*point2.x-point3.x)*tt +
                          (3*point1.x-point0.x-3*point2.x+point3.x)*ttt)
            ;
            pi.y = 0.5 * (2*point1.y+(point2.y-point0.y)*t +
                          (2*point0.y-5*point1.y+4*point2.y-point3.y)*tt +
                          (3*point1.y-point0.y-3*point2.y+point3.y)*ttt);

            if (pi.y > self.graphView.frame.size.height) {
                pi.y = self.graphView.frame.size.height;
            }
            else if (pi.y < 0){
                pi.y = 0;
            }

            if (pi.x > point0.x) {
                [path addLineToPoint:pi];
            }
        }

        [path addLineToPoint:point2];
    }

Overlay more than one dataset?

Is it possible to add overlaying more than one dataset? Say, temperature and humidity on the same graph?

Thx.

Append/dynamic values?

Hi. I was wondering if this is set up to handle dynamically adding data. I would like to add real time capabilities to it and wanted to check first if that's something included

Thanks!

Clear View before plot a second time

I have noticed that if you call plotGraphData more than one time, the view maintains the previous drawing plus the new one.
How can avoid this?
I would like use this for a real time graph.
Thank you!

how to set width between points

I am a new user of Xcode. I don't know how to change the width between points.
please tell me. thank you.

Removing Previously Drawn Graph Lines Without Reallocated (Programmatic Allocation)

Hey guys! I have to first say, this is a GREAT and easy-to-use custom class. A job well done!

One issue I had with it though. When programmatically defining a JYGraphView, and throwing it into a ViewDidLoad, I didn't want to reallocate my instance every time to remove the previously drawn lines with the updated Graph Data. So I created this method inside of JYGraphView. I was going to make a pull request, but I found out this was a private repo. So, here's the code. Figured anyone else that ran into the same problem could use it too:

// Used to clear previously drawn sublayers, or lines, and replots graph
// Be sure to update your JYGraphView's graphData and graphDataLabels before calling this

• (void)redrawGraphAfterUpdatingGraphData
  {
  [[self layer] setSublayers: nil];
  [self plotGraphData];
  }

Feel free to add this to your repo for JYGraphView!

Cocoapod?

It would be great if this library was published as a Cocoapod.