Can we show gridlines at the base value or tip of each bars in a barchart using coreplot

Question

Can we show gridlines at the base value or tip of each bars in a barchart using coreplot(iOS).

If there is any approach to do this suggest me.

Answer 1

These are not grid lines since this is no grid, but what you can do is to add additional y axes for each vertical line you want to show. I use this principle to show an indicator line at the mouse position. Code is:

CPTXYAxis *y = axisSet.yAxis;
... some other setup

// The second y axis is used as the current location identifier.
indicatorLine = [[CPTXYAxis alloc] init];
indicatorLine.hidden = YES;
indicatorLine.coordinate = CPTCoordinateY;
indicatorLine.plotSpace = graph.defaultPlotSpace;
indicatorLine.labelingPolicy = CPTAxisLabelingPolicyNone;
indicatorLine.separateLayers = NO;
indicatorLine.preferredNumberOfMajorTicks = 0;
indicatorLine.minorTicksPerInterval = 0;

CPTMutableLineStyle *lineStyle = [CPTMutableLineStyle lineStyle];
lineStyle.lineWidth = 1;
lineStyle.lineColor = [CPTColor colorWithGenericGray: 64 / 255.0];
lineStyle.lineCap = kCGLineCapRound;
lineStyle.dashPattern = lineStyle.dashPattern = @[@10.0f, @5.0f];
indicatorLine.axisLineStyle = lineStyle;
indicatorLine.majorTickLineStyle = nil;

axisSet.axes = @[x, y, indicatorLine];

You can add as many as you want. Set their position (in data coordinate space, that is, your x data values) by

indicatorLine.orthogonalCoordinateDecimal = CPTDecimalFromFloat(index);

Index is here an x-data point, but can also include intermediate positions.