Controlling labeled ticks

Labeled ticks visualize the numeric limits of axes. They are represented by the ILTickCollection class, wich can get accessed via the LabeledTicks member of each axis:

panel.Axes[0].LabeledTicks

Each tick is composed of

• four small tick lines and
• a corresponding label (number),

Tick lines start at a main axis line and run perpendicular to that line over a certain length. That length is dynamically adjusted by multiplying the actual display length of the viewing cube by the ILTickCollection.TickFraction member.

One may also determine, if the tick line run into or out of the cube (Direction) and which ticks are displayed: near or far ticks (Display). The term 'near' means the side, where the axis chooses to display the tick labels on. 'Far' is the opposite side (no tick labels shown). The color of tick lines can be set for 'far' ticks and for 'near' ticks independently.

Tick labels are drawn next to one tick line for each position. The axis automatically determines, where and how to draw the label, so it will always be readable by the user - no matter, how the cube is rotated. One can set font, color and padding for the labels. The ILTickCollection.Precision member specifies, how many digits the true numbers are rounded to at most.

In the following example the efect of Padding is demonstrated. The example contains a form with an ILPanel and a scroll bar. Use the scroll bar to set the padding in realtime. Increasing the padding will increase the space between labels and the axis lines, which in turn will cause the whole viewing cube to shrink.

int labPadding = hScrollBar1.Value / 3;
m_panel.Axes[1].LabeledTicks.Padding = labPadding;
// invalidating the panel, causes redraw
m_panel.Invalidate(); 

Example demonstrating the effect of Padding

Download the complete example as VS2005 solution here.

Positioning of 'nice labels'

Its a nontrivial task to find nice looking labels between the axis limits. ILTickCollection manages this automatically on default (Mode member). The user may give a hint, which numbers to prefer. The RenderingHint can be set to one of the following values:

We provide another example, demonstrating the effect of the RenderingHint property. Use the combo box at runtime to choose between available settings. The effect is displayed on the Y axis immediately.

private void comboBox1_SelectedValueChanged(object sender, EventArgs e) {
    try {
        TickLabelRenderingHint hint 
            = (TickLabelRenderingHint)Enum.Parse(
                    typeof(TickLabelRenderingHint),comboBox1.Text);
        // suggest the rendering method to axis
        m_panel.Axes.YAxis.LabeledTicks.RenderingHint = hint; 
        m_panel.Axes.YAxis.LabeledTicks.LabelColor = Color.Red; 
        // cause the immediate redraw of the ILPanel 
        m_panel.Invalidate(); 
    } catch (Exception) {
    }
}

Download the complete example as VS2005 solution here.

ILTickCollection summary

The following table lists all important properties for the ILTickCollection class.