Question

Hi All
Can someone help me with this problem I have encountered

Can I plot a bargraph in coreplote with unequal bar width meaning Say my X-axis interval is 1 unit and I have set the bar graph width as same 1 unit. But there are certain points where x-axis value changes at 0.5units and i want the bar width to be equal to the width where change has occurred. And the data is dynamically changing. Is there any other solution that I can use and still looks like a bar graph. The only reason for using bar is I need to fill the plot space.

CPXYPlotSpace *plotSpace = (CPXYPlotSpace *)barChart.defaultPlotSpace;
        plotSpace.yRange = [CPPlotRange plotRangeWithLocation:CPDecimalFromInt(0) 
                                                       length:CPDecimalFromInt(rangeY)];
        plotSpace.xRange = [CPPlotRange plotRangeWithLocation:CPDecimalFromFloat(-0.5f) 
                                                       length:CPDecimalFromFloat(rangeX)];

        CPXYAxisSet *axisSet = (CPXYAxisSet *)barChart.axisSet;
        CPXYAxis *x = axisSet.xAxis;
        x.axisLineStyle = nil;
        x.majorTickLineStyle = nil;
        x.minorTickLineStyle = nil;
        x.majorIntervalLength = CPDecimalFromString(@"1");
        x.orthogonalCoordinateDecimal = CPDecimalFromString(@"0");

        x.title = [[[tempCol colName] componentsSeparatedByString:@"*@"] objectAtIndex:0];
        x.titleLocation = CPDecimalFromFloat((rangeX-1)/2);
        x.titleOffset = 25.0f;

        // Define some custom labels for the data elements
        x.labelRotation = 0;
        x.labelingPolicy = CPAxisLabelingPolicyNone;
        NSMutableArray *customTickLocations = [[NSMutableArray alloc] init];
        NSMutableArray *xAxisLabels = [[NSMutableArray alloc] init];
        for (int i = 0; i < [tempGraph.d2pArray count]; i++) {
            tempD2P = [tempGraph.d2pArray objectAtIndex:i];
            [customTickLocations addObject:[NSNumber numberWithInt:i]];
            [xAxisLabels addObject:[tempD2P d2pName]];
        }
        NSUInteger labelLocation = 0;
        NSMutableArray *customLabels = [NSMutableArray arrayWithCapacity:[xAxisLabels count]];
        for (NSNumber *tickLocation in customTickLocations) {
            CPAxisLabel *newLabel = [[CPAxisLabel alloc] 
                                     initWithText:[xAxisLabels objectAtIndex:labelLocation++] 
                                     textStyle:x.labelTextStyle];
            newLabel.tickLocation = [tickLocation decimalValue];
            newLabel.offset = 0;
            newLabel.rotation = 0;
            newLabel.alignment = CPAlignmentCenter;     
            [customLabels addObject:newLabel];
            [newLabel release];
            newLabel = nil;
        }
        [xAxisLabels release];
        xAxisLabels = nil;
        [customTickLocations release];
        customTickLocations = nil;
        x.axisLabels =  [NSSet setWithArray:customLabels];

        CPXYAxis *y = axisSet.yAxis;
        CPLineStyle *majorGridLineStyle = [CPLineStyle lineStyle];
        majorGridLineStyle.lineWidth = 0.75;
        majorGridLineStyle.lineColor = [CPColor colorWithCGColor:[[UIColor grayColor] CGColor]];
        y.axisLineStyle = nil;
        y.majorTickLineStyle = nil;
        y.majorGridLineStyle = majorGridLineStyle;
        y.minorTickLineStyle = nil;
        y.majorIntervalLength = CPDecimalFromInt(rangeY/8);
        y.orthogonalCoordinateDecimal = CPDecimalFromString(@"-0.5");
        y.title = [[[tempCol colName] componentsSeparatedByString:@"*@"] objectAtIndex:1];
        y.titleOffset = 30 + 5*log10(mult);
        y.titleLocation = CPDecimalFromInt(rangeY/2);
        NSNumberFormatter *formatter = [[NSNumberFormatter alloc] init];
        [formatter setMaximumFractionDigits:0];
        y.labelFormatter = formatter;
        [formatter release];
        formatter = nil;
        char firstChar = 'F';
        CPBarPlot *barPlot;
        // First bar plot
        for (int i = 0; i < noOfBarCharts; i++) {
            static CPTextStyle *whiteText = nil;
            if ( !whiteText ) {
                whiteText = [[CPTextStyle alloc] init];
                whiteText.color = [CPColor whiteColor];
                whiteText.fontSize = 14;
            }
            barPlot = [CPBarPlot tubularBarPlotWithColor:[CPColor colorWithComponentRed:[[[rgbArray objectAtIndex:0] objectAtIndex:i] floatValue]/255.0 
                                                                                  green:[[[rgbArray objectAtIndex:1] objectAtIndex:i] floatValue]/255.0 
                                                                                   blue:[[[rgbArray objectAtIndex:2] objectAtIndex:i] floatValue]/255.0 
                                                                                  alpha:1.0] 
                                          horizontalBars:NO];
            barPlot.baseValue = CPDecimalFromString(@"0");
            barPlot.dataSource = self;
            barPlot.barOffset = ([tempGraph.graType rangeOfString:@"GROUPED"].location != NSNotFound)?(i+0.5)-(noOfBarCharts/2):0;
            barPlot.labelOffset = 0;
            barPlot.barWidth = 20;
            barPlot.identifier = [NSString stringWithFormat:@"%d%c", [tempGraph.graID intValue], (firstChar - noOfBarCharts +1 + i)];
            barPlot.delegate = self;




            [barChart addPlot:barPlot 
                  toPlotSpace:plotSpace];

Answer 1

I figured it out myself instead of using a bar chart i used a scatter plot with step graph That did the trick :

Plot.interpolation = CPTScatterPlotInterpolationStepped;

and filled the plot with:

Plot.areaFill = [CPTFill fillWithColor:[CPTColor blueColor]];
Plot.areaBaseValue = CPTDecimalFromInteger(0);