Question

I am using CorePlot to graph a set of data. Data for my x-axis consists of dates, while data for my y-axis consists of floats (which I then turn into NSNumber). I am getting data from a feed, and the feed returns numbers with a large number of decimals, eg: 0.46673718852844, 4.59392222219, 353.1293012045. I m using the following piece of code to properly format y-axis:

NSNumberFormatter *numberFormatter = [[[NSNumberFormatter alloc] init] autorelease];
[numberFormatter setNumberStyle:NSNumberFormatterDecimalStyle];
[numberFormatter setMaximumFractionDigits:3];
[numberFormatter setPositiveFormat:@"###0.000"];    
CPTXYAxis *y = axisSet.yAxis;
y.labelingPolicy = CPTAxisLabelingPolicyAutomatic;
y.minorTicksPerInterval = 1;
y.preferredNumberOfMajorTicks = 5;
y.labelFormatter = numberFormatter;

在大多数情况下,所有东西都行不通。然而,有时在轴线上的多个职位上表现出同样的价值。见以下图象:

“在座的影像描述”/。</p

The values are presented correctly, I would just like to avoid unnecessary (0.466) labels. I ve even tried to round the numbers to 3 decimals in numberForPlot method:

if(fieldEnum == CPTScatterPlotFieldY)
{ 
        float floatNum = r.value;
        floatNum *= 1000;
        int intValue = (int) floatNum;
        float decimal = floatNum - intValue;
        if (decimal > 0.5) {
            intValue++;
        }
        floatNum = intValue /1000.0;
        return [NSNumber numberWithFloat:floatNum];

}

但标签没有差别。

Answer 1

<代码>系指NumberOfMajorTicks 财产指标识法的使用量。如果你想三条标准,将其定为3条。您还可以增加数字格式的最大数字,以避免出现四舍五入的问题。

Answer 2

I believe that because you have said that you want 5 major ticks, that is what you are going to get, regardless of how close the y axis values are. If you sense that the values are too close together, you will probably have to adjust your preferredNumberOfMajorTicks property.

在我使用核心位置时,我放弃了自动轴心标签,我把自己的X和轴心标签放在一起。这是一项比以往更多的工作,但与自己做这项工作的灵活性一样。

Answer 3

What I did here was dynamically set my preferredNumberOfMajorTicks property while the graph is plotted. Since my formatter shows 3 decimal places, I used the following code to change the number of ticks depending on the Y axis range so that the formatter will show a unique value on the axis at each tick. Too many ticks means the decimal places get cut off and there are duplicate values on the Y axis.

            CPTXYAxis *y          = axisSet.yAxis;
            {
                y.preferredNumberOfMajorTicks = round([newYRange.length floatValue]/0.001);
            }

我希望这一帮助。

友情链接