General Plot Options

Scale Tab

This tab can be used in order to customize the data range and the type of scale displayed by the axes of a 2D plot layer.

Figure 5-149. General plot options dialog: The Scale Tab.

In this tab, one can also set the number of ticks used for each axis. This can be done in two ways: 1) Set the number of labels to use for the entire scale. Whatever number you enter, QtiPlot may adjust the value so as to produce a prettier plot (for example, if you enter 7 ticks for a 0..100 scale, QtiPlot will use 10 major ticks spaced evenly from 10 to 100). 2) Set the Step increment and QtiPlot will generate as many ticks as needed to fill the scale range using the indicated increment. This produces tick spacings and labels which are more like those that are typically done on hand drawn graphs.

When the Type of the scale is logarithmic (e.g. Log10 or Log2), setting the value of the step to N results in an actual increment of xN for the values displayed by the tick labels, where x equals 10 for Log10 scales and 2 for Log2 scales.

Please note that the number of major ticks cannot exceed the Max Number value defined in the 2D Plots -> Ticks tab of the Preferences dialog. In case you need to display more tick labels (or equivalently use a smaller step size) than allowed by this default limit, you must modify it first.

Grid Tab

The grid tab is used to draw grid lines on the plot. The frequency of the lines are related to the number of labels and major ticks set with the Scale tab.

Figure 5-150. General plot options dialog: The Grid Tab.

Axis Tab

The third tab is used to modify the setting of the different axes. You must select the axis to be customized in the right window. The label of that axis can then be modified in the title window - see the text options dialog section for more details.

Figure 5-151. General plot options dialog: The Axis Tab.

Special Ticks Tab

The Special Ticks tab is used to customize the major tick labels for the different axes. You must select the axis to be customized from the list on the right side of the dialog window. The positions of the ticks are displayed in the first column of the table. These positions cannot be modified, editing being disabled for all cells in this column.

It is possible to customize the default labels displayed in the second column of the table as <auto>. In order to finish editing a tick label you need to press the Return or Enter keys or the Apply button. Editing is also considered finished and the modifications are applied when you change the active cell of the table, either with the mouse or by pressing the Tab key. Empty tick labels are not accepted and are automatically replaced with the default value.

You can define custom colors for each tick label by pressing the corresponding push button in the third column of the table. This will pop-up a color selection dialog.

The tick labels can be shown or hidden by checking or unchecking the corresponding box from the last column. Hidden tick labels cannot be edited. The visibility of the first and last axis tick labels can also be controlled via the Hide Ticks list box in the Axis tab. If these labels were already hidden by the user - this option was set to At Axis Begin, At Axis End or At Axis Begin & End - the check boxes corresponding to these labels in the ticks table are disabled and the text Automatic is displayed next to them.

Figure 5-152. General plot options dialog: The Special Ticks Tab.

General Tab

The General settings tab is used to customize global aspects of the plot. The canvas is the drawing area of the 2D plot layer that is bounded by the four side axes. It is possible to draw a frame around the canvas and define its color and thickness using the controls in the Canvas frame box.

The visibility of the backbone line for all side axes can be controled with a single click with the help of the Draw backbones check box. Please beware that having both the Canvas frame and the Draw backbones options enabled simultaneously results in a frame width larger than the value specified by the Thickness spin box.

The controls in the Axes group box allow to modify the lengths of the major and minor ticks for all layer axes. You can also define a maximum number of major ticks using the Max Number spin box. The value of this parameter becomes the maximum limit for the Major Ticks value in the Scale tab of this dialog

Figure 5-153. General plot options dialog: General Settings.

The Display list box can be used in order to quickly customize the layout of the axes. There are four predefined axes layouts available:


It is the classical layout, the axes are displayed alongside the canvas drawing area.

Crossing Axes Layout

Two crossing axes, one vertical and one horizontal, are drawn inside the layer canvas. Their positions can be customized using the Horizontal and Vertical input boxes as percentages of the canvas size.

Bottom + Vertical

Two axes are displayed: the bottom axis and a vertical axis inside the layer canvas. The position of the vertical axis can be customized using the Vertical input box as a percentage of the length of the bottom axis.

Left + Horizontal

Two axes are displayed: the left axis and a horizontal axis inside the layer canvas. The position of the horizontal axis can be customized using the Horizontal input box as a percentage of the length of the left axis.