以对数刻度 MS 图表(log-log)显示刻度标签

问题描述

我有一个在 Visual Studio 2015 (C#) 中使用 MS Charts 创建的图，带有对数刻度(两个轴)(见图).

I have a plot created with MS Charts in Visual Studio 2015 (C#) with logarithmic scales (both axes) (see figure).

我需要在 x 轴上添加更多的网格线和相应的标签.我想在 1 (2, 3, 4 ...) 和 10 之间以及 10 和 100 (20, 30, 40 ...) 之间标记每个小刻度，而且，我想在例如之间添加网格线10 和 20.

我在图表的轴属性中使用 1 的间隔作为标签，但它不起作用.

I used the Interval of 1 for the label in the axes properties of the chart but it didn't work.

推荐答案

After(!) 在非零 x 值处添加一个点 或 设置 chart.SuppressExceptions = true 您可以将这些属性用于 Chartarea ca:

After(!) adding a point at a non-zero x-value or setting chart.SuppressExceptions = true you can use these properties for a Chartarea ca:

ca.AxisX.IsLogarithmic = true;
ca.AxisX.LogarithmBase = 10;

// with 10 as the base it will go to 1, 10, 100, 1000..
ca.AxisX.Interval = 1;

// this adds 4 tickmarks into each interval:
ca.AxisX.MajorTickMark.Interval = 0.25;

// this add 8 gridlines into each interval:
ca.AxisX.MajorGrid.Interval = 0.125;

// this sets two i.e. adds one extra label per interval
ca.AxisX.LabelStyle.Interval = 0.5;
ca.AxisX.LabelStyle.Format = "#0.0";

更新:

由于您不想拥有自动标签(总是按值对齐)，您需要添加 CustomLabels.

Since you don't want to have automatic labels (which are always aligned by value) you need to add CustomLabels.

为此，您需要设置要显示标签的位置/值列表:

For this you need to set up a list of positions/values where you want a label to show:

    // pick a better name!
    List<double> xs = new List<double>() { 1, 2, 3, 4, 5, 10, 20, 50, 100, 200, 500, 1000};

接下来，我们需要为我们创建的每个 CustomLabel 分配一个 FromPosition 和一个 ToPosition.这总是有点棘手，但在这里甚至比平时更多..

Next we need to assign a FromPosition and a ToPosition to each CustomLabel we create. This is always a little tricky but here even more than usual..

这两个值需要间隔足够远以允许标签适合......所以我们选择了一个间隔因子:

The two values need to be spaced far enough to allow a label to fit in.. So we pick a spacer-factor:

    double spacer = 0.9d;

我们还关闭了自动拟合机制:

And we also turn off the auto-fitting mechanism:

    ca.AxisX.IsLabelAutoFit = false;

现在我们可以添加CustomLabels:

    for (int i = 0; i < xs.Count; i++)
    {
        CustomLabel cl = new CustomLabel();
        if (xs[i] == 1 || xs[i] <= 0)
        {
            cl.FromPosition = 0f;
            cl.ToPosition = 0.01f;
        }
        else
        {
            cl.FromPosition = Math.Log10(xs[i] * spacer);
            cl.ToPosition = Math.Log10(xs[i] / spacer);
        }

        cl.Text = xs[i] + "";
        ca.AxisX.CustomLabels.Add(cl);

    }

如您所见，我们需要使用应用于 Axis 的 Log10 函数来计算值，并且间距是通过乘以/除以间隔来实现的，而不是通过添加.间距值也必须经过Log10缩放并包含在函数中.

As you can see we need to calculate the values using the Log10 function that is applied to the Axis and the spacing is achieved by multiplying/dividing the spacer, not by adding. The spacing value must also be scaled by Log10 and is included in the function.

我们还需要处理1的值的情况，这相当于标签位置0；但这在乘/除它时不会产生任何间距.所以我们手动设置了一个合适的ToPosition.

We also need to take care of the case of a value of 1, which amounts to a label position of 0; but this won't result in any spacing when multiplying/dividing it. So we set a suitable ToPosition manually.

我希望我知道一种更简单的方法来做到这一点，但由于标签位置列表确实是您的选择，我怀疑是否存在捷径..

I wish I knew of an easier way to do this, but as the list of label positions is really your choice, I doubt there is a short-cut..

我在 40 和 50 处添加了点以显示一个标签如何匹配.另外请注意标签位置是如何混合的.随意使用你的！

I have added points at 40 and 50 to show how one label matches.. Also note how the label positions are somewhat mixed. Feel free to use yours!

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