donald-pinckney/DPGraphView

A reusable graphing view for iOS to easily plot continuous functions.

DPGraphView

A reusable graphing view for iOS to easily plot continuous functions.

Installation

Use CocoaPods!
Add pod 'DPGraphView' to your Podfile
Note that DPGraphView requires iOS 6.0 or later (not fully tested 😟)

Otherwise, feel free to copy-paste the source into your project.

How To Use

1. Set the dataSource property of a DPGraphView to be the data source for the plotting (probably self).
2. Implement the required methods in the DPGraphViewDataSource protocol: -(CGFloat)graphView:(DPGraphView *)graphView yValueForXValue:(CGFloat)x onPlotWithIndex:(NSUInteger)plotIndex and -(NSUInteger)numberOfPlotsInGraphView:(DPGraphView *)graphView
3. Optionally implement -(UIColor *)graphView:(DPGraphView *)graphView colorForPlotIndex:(NSUInteger)plotIndex to color specific plots. If you don't implement this, all plots will simply be black.
4. Optionally implement -(UIColor *)graphViewColorForGrid:(DPGraphView *)graphView to color the gridlines. If you don't implement this, the gridlines will simply be black.
5. Optionally implement -(UIColor *)graphViewColorFor[X][Y]Axis:(DPGraphView *)graphView to color the X and Y axes. If you don't implement this, the axes will simply be black.
6. Set minX, maxX, minY, and maxY properties of the DPGraphView.
7. Optionally set displayGridlines, dashGridlines, and displayAxes properties of the DPGraphView to enable and configure the display of gridline and axes. If you don't set these properties, no axes or gridlines will be rendered.
8. Add the DPGraphView, or do whatever you want with it.

Example Code

For this example code, I have my DPGraphView created in a Storyboard and connected to my Controller via an outlet. I simply override the setter to setup the properties of the DPGraphView, and then implement the methods in the protocol.

#import "ViewController.h"
#import "DPGraphView.h"

@interface ViewController () <DPGraphViewDataSource>
@property (nonatomic, weak) IBOutlet DPGraphView *graphView;
@end

@implementation ViewController

- (void) setGraphView:(DPGraphView *)graphView
{
    _graphView = graphView;
    
    _graphView.dataSource = self;
    _graphView.minX = -3;
    _graphView.maxX = 3;
    _graphView.minY = -4;
    _graphView.maxY = 4;
    _graphView.displayGridlines = YES;
    _graphView.displayAxes = YES;
    _graphView.dashGridlines = YES;
}


- (NSUInteger) numberOfPlotsInGraphView:(DPGraphView *)graphView
{
    return 3;
}

- (CGFloat) graphView:(DPGraphView *)graphView yValueForXValue:(CGFloat)x onPlotWithIndex:(NSUInteger)plotIndex
{
    switch (plotIndex) {
        case 0:
            return powf(x, 2);
            
        case 1:
            return expf(-x*x)*4;
            
        case 2:
            return powf(x, 3);
            
        default:
            return 0;
    }
}

- (UIColor *) graphView:(DPGraphView *)graphView colorForPlotIndex:(NSUInteger)plotIndex
{
    switch (plotIndex) {
        case 0:
            return [UIColor redColor];
            
        case 1:
            return [UIColor blueColor];
            
        case 2:
            return [UIColor yellowColor];
            
        default:
            return [UIColor blackColor];
    }
}

- (UIColor *) graphViewColorForGrid:(DPGraphView *)graphView
{
    return [UIColor colorWithRed:0.000 green:0.502 blue:0.251 alpha:1.000];
}

- (UIColor *) graphViewColorForXAxis:(DPGraphView *)graphView
{
    return [UIColor greenColor];
}

- (UIColor *) graphViewColorForYAxis:(DPGraphView *)graphView
{
    return [UIColor greenColor];
}

@end

And the result of the above code should look something like:

License

DPGraphView is available under the MIT license. See the LICENSE file for more info.