我的Chart.Axes的Nicer AxisArrowStyle箭头 [英] Nicer AxisArrowStyle arrows for my Chart.Axes

问题描述

我回答了一个

那么我们如何解决呢？

解决方案

图表的 axis.AxisArrowStyle 枚举不允许我们选择一个较小的箭头，只有一个较小的箭头。

所以我们需要自己绘制：

下面是一个简单但有效的代码段：

  private void chart1_PrePaint （object sender，ChartPaintEventArgs e）
 {
 if（e.ChartElement.ToString（）。StartsWith（ChartArea-））
 {
 //获取轴的端点：$ b​​ $ b ChartArea CA = chart1.ChartAreas [0]; 
 float xx =（float）CA.AxisX.ValueToPixelPosition（CA.AxisX.Maximum）; 
 float xy =（float）CA.AxisY.ValueToPixelPosition（CA.AxisY.Crossing）; 
 float yx =（float）CA.AxisX.ValueToPixelPosition（CA.AxisX.Crossing）; 
 float yy =（float）CA.AxisY.ValueToPixelPosition（CA.AxisY.Maximum）; 
 
 //一个简单的箭头几何形状：
 int arrowSize = 18; // size in pixels 
 Point [] arrowPoints = new Point [3] {new Point（-arrowSize，-arrowSize / 2），
 new Point（-arrowSize，arrowSize / 2），Point.Empty }; 
 
 //通过移动和/或旋转图形对象来绘制两个箭头：
 e.ChartGraphics.Graphics.TranslateTransform（xx + arrowSize，xy）; 
 e.ChartGraphics.Graphics.FillPolygon（Brushes.Black，arrowPoints）; 
 e.ChartGraphics.Graphics.TranslateTransform（yx -xx -arrowSize，yy -xy -arrowSize）; 
 e.ChartGraphics.Graphics.RotateTransform（-90）; 
 e.ChartGraphics.Graphics.FillPolygon（Brushes.Black，arrowPoints）; 
 e.ChartGraphics.Graphics.ResetTransform（）; 
} 
} 
  

I answered a question on how to set up a Chart to look like a regular mathematical graph, i.e. with the axes centered and with nice arrows to the top and to the right..

However I found the built-in AxisArrowStyle.Triangle to be rather big and found no way to make it smaller.

Lines - A line-shaped arrow is used for the relevant axis.

None - No arrow is used for the relevant axis.

SharpTriangle - A sharp triangular arrow is used for the relevant axis.

Triangle - A triangular arrow is used for the relevant axis.

Here is the original look of it:

So how can we fix this?

解决方案

The Chart's axis.AxisArrowStyle enumeration doesn't let us pick a smaller arrow, only a slimmer one.

So we need to draw it ourselves:

Here is a simple but effective piece of code that achieves just that:

private void chart1_PrePaint(object sender, ChartPaintEventArgs e)
{
    if (e.ChartElement.ToString().StartsWith("ChartArea-") )
    {
        // get the positions of the axes' ends:
        ChartArea CA = chart1.ChartAreas[0];
        float xx = (float)CA.AxisX.ValueToPixelPosition(CA.AxisX.Maximum);
        float xy = (float)CA.AxisY.ValueToPixelPosition(CA.AxisY.Crossing);
        float yx = (float)CA.AxisX.ValueToPixelPosition(CA.AxisX.Crossing);
        float yy = (float)CA.AxisY.ValueToPixelPosition(CA.AxisY.Maximum);

        // a simple arrowhead geometry:
        int arrowSize = 18;   // size in pixels
        Point[] arrowPoints = new Point[3]   { new Point(-arrowSize, -arrowSize / 2), 
             new Point(-arrowSize, arrowSize / 2), Point.Empty };

        // draw the two arrows by moving and/or rotating the graphics object:
        e.ChartGraphics.Graphics.TranslateTransform(xx + arrowSize, xy);
        e.ChartGraphics.Graphics.FillPolygon(Brushes.Black, arrowPoints);
        e.ChartGraphics.Graphics.TranslateTransform(yx -xx -arrowSize, yy -xy -arrowSize);
        e.ChartGraphics.Graphics.RotateTransform(-90);
        e.ChartGraphics.Graphics.FillPolygon(Brushes.Black, arrowPoints);
        e.ChartGraphics.Graphics.ResetTransform();
    }
}

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