plotSetXTicLabel

Purpose

Controls the formatting and angle of X-axis tick labels for 2-D graphs.

Format

plotSetXTicLabel(&myPlot, fmt[, angle])
Parameters:
  • &myPlot (struct pointer) – A plotControl structure pointer.
  • fmt (string) –

    the desired formatting for the X-axis tick labels.

    • Time series graphs use the same formatting type as function dttostr().
    • Other graph types use a sprintf() style formatting string. See Remarks below for more details.
  • angle (scalar) – Optional argument, the angle in degrees at which to display the X-axis tick labels.

Examples

Time series

// Declare and initialize plotControl structure
struct plotControl myPlot;
myPlot = plotGetDefaults("xy");

y = rndn(5, 1);

plotSetXTicLabel(&myPlot, "YYYY-MO");

// Start the series in January 1982
dtstart = 198201;

// Specify the data to be monthly
frequency = 12;

// Draw the time series plot
plotTS(myPlot, dtstart, frequency, y);

The code above produces a graph with X-tick labels like the image below:

_images/gauss15_psxtl_1.png

X-tick labels

Changing to format string to "MO/YYYY" will change the labels to appear like this:

01/1982

Changing to format string to "YYYY-QQ" will change the labels to appear like this:

1982-Q1

Other than time series

// Declare and initialize plotControl structure
struct plotControl myPlot;
myPlot = plotGetDefaults("xy");

x = seqa(0.015, 0.015, 10);
y = cos(x.^2);

plotSetXTicLabel(&myPlot, "%.3f");

// Draw the graph, using our format specifier
plotXY(myPlot, x, y);

The code above produces a graph with X-tick labels like the image below:

_images/gauss15_psxtl_1.png

XY formatted label

Remarks

Time series format specifier

  • The following format specifiers are supported for the second input to plotSetXTicLabel(), fmt when the plot will be drawn with plotTS():

    YYYY 4 digit year
    YR Last two digits of year
    QQ Quarter of the year. This is calculated from the month number.
    MO Number of month, 01-12
    DD Day of month, 01-31
    HH Hour of day, 00-23
    MI Minute of hour, 00-59
    SS Second of minute, 00-59
  • Extra text may be added to a time series X-tick label, by enclosing it in single-ticks. For example,

    plotSetXTicLabel(myPlot, "HH:MI 'PM'");
    

    would add the text PM to the end of the X-tick label, like this: 12:30 PM, or 02:15 PM. Note that the single-tick marks are not included as part of the label.

  • To learn more about DT scalar format, see Date and Time Formats, Section 1.0.1, or the functions dttostr() and strtodt()

Format specifier for other graph types

Graph types other than time series use a sprintf() style format string. The parameters of the format string are:

  • precision - a literal scalar numeral, the number of digits after the decimal point

  • format type - one of the following letters:

    d integer
    e scientific notation
    f floating point/decimal
    g either scientific or decimal, whichever is most compact

The format of the format string is:

"%.<precision><format type>"

Below are some examples of different format strings and how they would represent \(\pi\)

“%.2f” 3.14
“%.4f” 3.1415
“%.2e” 3.14e+00
“%.2g” 3.14
“%d” 3

This function sets an attribute in a plotControl structure. It does not affect an existing graph, or a new graph drawn using the default settings that are accessible from the Tools > Preferences > Graphics menu. See the GAUSS Graphics chapter for more information on the methods available for customizing your graphs.