Interactive linecharts for the simplicity-loving iOS developer.

You just want some linecharts, and Core Plot makes you think

Search no more! ios-linechart is here!

Features

• Simple API. Lets you draw the first chart by the time you would need to find sample code for Core Plot.
• Interactivity. Lets users look at single datapoints.
• Support non-uniform steps on the x axis

Installation

Usage

Basic usage can be seen in the demo app contained in the repository.

First, import the main header:

    #import "LCLineChartView.h"

Alternatively, you can import the abbreviation header, which provides names without the LC prefix:

    #import "LineChart.h"

Each chart line is contained in a LCLineChartData object, which specifies a range of its data on the x axis (xMin / xMax), a color, a title (which is displayed in the legend) and an itemCount, the number of data points:

    LCLineChartData *d = [LCLineChartData new];
    d.xMin = 1;
    d.xMax = 31;
    d.title = @"The title for the legend";
    d.color = [UIColor redColor];
    d.itemCount = 10;

Additionally, each LCLineChartData object also has a getData property. This is simply a block that takes the number of a data point as its argument and returns LCLineChartDataItem objects, which wrap the individual data points:

    NSMutableArray *vals = [NSMutableArray new];
    for(NSUInteger i = 0; i < d.itemCount; ++i) {
        [vals addObject:@((rand() / (float)RAND_MAX) * (31 - 1) + 1)];
    }
    [vals sortUsingComparator:^NSComparisonResult(id obj1, id obj2) {
        return [obj1 compare:obj2];
    }];
    d.getData = ^(NSUInteger item) {
        float x = [vals[item] floatValue];
        float y = powf(2, x / 7);
        NSString *label1 = [NSString stringWithFormat:@"%d", item];
        NSString *label2 = [NSString stringWithFormat:@"%f", y];
        return [LCLineChartDataItem dataItemWithX:x y:y xLabel:label1 dataLabel:label2];
    };

The x and y properties of LCLineChartDataItem are, obviously, the x and y values of the data point. xLabel is the text displayed on the x axis when the data point is selected, dataLabel is usually just a textual representation of the y value, and is displayed in a bubble directly next to the data point when the user touches it.

Note that, to get a coherent chart, the x values for the items should be sorted. This will be the case anyway for most real-world data.

Finally, everything is packed up into a LCLineChartView:

    LCLineChartView *chartView = [[LCLineChartView alloc] initWithFrame:CGRectMake(20, 700, 500, 300)];
    chartView.yMin = 0;
    chartView.yMax = powf(2, 31 / 7) + 0.5;
    chartView.ySteps = @[@"0.0",
                         [NSString stringWithFormat:@"%.02f", chartView.yMax / 2],
                         [NSString stringWithFormat:@"%.02f", chartView.yMax]];
    chartView.data = @[d];

    [self.view addSubview:chartView];

The yMin and yMax properties should be self-evident. ySteps is an array of labels which are placed along the y axis. data is an array of all LineChartData objects to use. drawsDataPointOrnaments is a switch that determines whether circles are drawn around the actual data points.

Screenshots

FAQ

• The sample project doesn't compile

  The sample project, at the moment, needs CocoaPods. Install Cocoapods, then run pod install while you are in the ios-linechart directory.

• Will the project support bar charts, pie charts, ...?

  No.

Contact

Bug reports and pull requests are welcome! Contact me via e-mail or just by opening an issue on GitHub.