C interface to gnuplot. More...
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Data Structures | |
struct | _GNUPLOT_CTRL_ |
Typedefs | |
typedef struct _GNUPLOT_CTRL_ | gnuplot_ctrl |
gnuplot session handle (opaque type). | |
Functions | |
gnuplot_ctrl * | gnuplot_init (void) |
Opens up a gnuplot session, ready to receive commands. | |
void | gnuplot_close (gnuplot_ctrl *handle) |
Closes a gnuplot session previously opened by gnuplot_init() | |
void | gnuplot_cmd (gnuplot_ctrl *handle, char const *cmd,...) |
Sends a command to an active gnuplot session. | |
void | gnuplot_setstyle (gnuplot_ctrl *h, char *plot_style) |
Change the plotting style of a gnuplot session. | |
void | gnuplot_set_xlabel (gnuplot_ctrl *h, char *label) |
Sets the x label of a gnuplot session. | |
void | gnuplot_set_ylabel (gnuplot_ctrl *h, char *label) |
Sets the y label of a gnuplot session. | |
void | gnuplot_resetplot (gnuplot_ctrl *h) |
Resets a gnuplot session (next plot will erase previous ones). | |
void | gnuplot_plot_x (gnuplot_ctrl *handle, double *d, int n, char *title) |
Plots a 2d graph from a list of doubles. | |
void | gnuplot_plot_xy (gnuplot_ctrl *handle, double *x, double *y, int n, char *title) |
Plot a 2d graph from a list of points. | |
void | gnuplot_plot_once (char *title, char *style, char *label_x, char *label_y, double *x, double *y, int n) |
Open a new session, plot a signal, close the session. | |
void | gnuplot_plot_slope (gnuplot_ctrl *handle, double a, double b, char *title) |
Plot a slope on a gnuplot session. | |
void | gnuplot_plot_equation (gnuplot_ctrl *h, char *equation, char *title) |
Plot a curve of given equation y=f(x). | |
int | gnuplot_write_x_csv (char const *fileName, double const *d, int n, char const *title) |
int | gnuplot_write_xy_csv (char const *fileName, double const *x, double const *y, int n, char const *title) |
int | gnuplot_write_multi_csv (char const *fileName, double const **xListPtr, int n, int numColumns, char const *title) |
C interface to gnuplot.
gnuplot is a freely available, command-driven graphical display tool for Unix. It compiles and works quite well on a number of Unix flavours as well as other operating systems. The following module enables sending display requests to gnuplot through simple C calls.
Definition in file gnuplot_i.h.
gnuplot session handle (opaque type).
This structure holds all necessary information to talk to a gnuplot session. It is built and returned by gnuplot_init() and later used by all functions in this module to communicate with the session, then meant to be closed by gnuplot_close().
This structure is meant to remain opaque, you normally do not need to know what is contained in there.
void gnuplot_close | ( | gnuplot_ctrl * | handle | ) |
Closes a gnuplot session previously opened by gnuplot_init()
handle | Gnuplot session control handle. |
Kills the child PID and deletes all opened temporary files. It is mandatory to call this function to close the handle, otherwise temporary files are not cleaned and child process might survive.
Definition at line 137 of file gnuplot_i.c.
void gnuplot_cmd | ( | gnuplot_ctrl * | handle, |
char const * | cmd, | ||
... | |||
) |
Sends a command to an active gnuplot session.
handle | Gnuplot session control handle |
cmd | Command to send, same as a printf statement. |
This sends a string to an active gnuplot session, to be executed. There is strictly no way to know if the command has been successfully executed or not. The command syntax is the same as printf.
Examples:
gnuplot_cmd(g, "plot %d*x", 23.0); gnuplot_cmd(g, "plot %g * cos(%g * x)", 32.0, -3.0);
Since the communication to the gnuplot process is run through a standard Unix pipe, it is only unidirectional. This means that it is not possible for this interface to query an error status back from gnuplot.
handle | Gnuplot session control handle |
cmd | Command to send, same as a printf statement. |
This sends a string to an active gnuplot session, to be executed. There is strictly no way to know if the command has been successfully executed or not. The command syntax is the same as printf.
Examples:
gnuplot_cmd(g, "plot %d*x", 23.0); gnuplot_cmd(g, "plot %.18e * cos(%.18e * x)", 32.0, -3.0);
Since the communication to the gnuplot process is run through a standard Unix pipe, it is only unidirectional. This means that it is not possible for this interface to query an error status back from gnuplot.
Definition at line 183 of file gnuplot_i.c.
gnuplot_ctrl* gnuplot_init | ( | void | ) |
Opens up a gnuplot session, ready to receive commands.
This opens up a new gnuplot session, ready for input. The struct controlling a gnuplot session should remain opaque and only be accessed through the provided functions.
The session must be closed using gnuplot_close().
Definition at line 89 of file gnuplot_i.c.
void gnuplot_plot_equation | ( | gnuplot_ctrl * | h, |
char * | equation, | ||
char * | title | ||
) |
Plot a curve of given equation y=f(x).
h | Gnuplot session control handle. |
equation | Equation to plot. |
title | Title of the plot. |
Plots out a curve of given equation. The general form of the equation is y=f(x), you only provide the f(x) side of the equation.
Example:
gnuplot_ctrl *h ; char eq[80] ; h = gnuplot_init() ; strcpy(eq, "sin(x) * cos(2*x)") ; gnuplot_plot_equation(h, eq, "sine wave", normal) ; gnuplot_close(h) ;
Definition at line 512 of file gnuplot_i.c.
void gnuplot_plot_once | ( | char * | title, |
char * | style, | ||
char * | label_x, | ||
char * | label_y, | ||
double * | x, | ||
double * | y, | ||
int | n | ||
) |
Open a new session, plot a signal, close the session.
title | Plot title |
style | Plot style |
label_x | Label for X |
label_y | Label for Y |
x | Array of X coordinates |
y | Array of Y coordinates (can be NULL) |
n | Number of values in x and y. |
This function opens a new gnuplot session, plots the provided signal as an X or XY signal depending on a provided y, waits for a carriage return on stdin and closes the session.
It is Ok to provide an empty title, empty style, or empty labels for X and Y. Defaults are provided in this case.
Definition at line 453 of file gnuplot_i.c.
void gnuplot_plot_slope | ( | gnuplot_ctrl * | handle, |
double | a, | ||
double | b, | ||
char * | title | ||
) |
Plot a slope on a gnuplot session.
handle | Gnuplot session control handle. |
a | Slope. |
b | Intercept. |
title | Title of the plot. |
Plot a slope on a gnuplot session. The provided slope has an equation of the form y=ax+b
Example:
gnuplot_ctrl * h ; double a, b ; h = gnuplot_init() ; gnuplot_plot_slope(h, 1.0, 0.0, "unity slope") ; sleep(2) ; gnuplot_close(h) ;
Definition at line 494 of file gnuplot_i.c.
void gnuplot_plot_x | ( | gnuplot_ctrl * | handle, |
double * | d, | ||
int | n, | ||
char * | title | ||
) |
Plots a 2d graph from a list of doubles.
handle | Gnuplot session control handle. |
d | Array of doubles. |
n | Number of values in the passed array. |
title | Title of the plot. |
Plots out a 2d graph from a list of doubles. The x-coordinate is the index of the double in the list, the y coordinate is the double in the list.
Example:
gnuplot_ctrl *h ; double d[50] ; int i ; h = gnuplot_init() ; for (i=0 ; i<50 ; i++) { d[i] = (double)(i*i) ; } gnuplot_plot_x(h, d, 50, "parabola") ; sleep(2) ; gnuplot_close(h) ;
Definition at line 331 of file gnuplot_i.c.
void gnuplot_plot_xy | ( | gnuplot_ctrl * | handle, |
double * | x, | ||
double * | y, | ||
int | n, | ||
char * | title | ||
) |
Plot a 2d graph from a list of points.
handle | Gnuplot session control handle. |
x | Pointer to a list of x coordinates. |
y | Pointer to a list of y coordinates. |
n | Number of doubles in x (assumed the same as in y). |
title | Title of the plot. |
Plots out a 2d graph from a list of points. Provide points through a list of x and a list of y coordinates. Both provided arrays are assumed to contain the same number of values.
gnuplot_ctrl *h ; double x[50] ; double y[50] ; int i ; h = gnuplot_init() ; for (i=0 ; i<50 ; i++) { x[i] = (double)(i)/10.0 ; y[i] = x[i] * x[i] ; } gnuplot_plot_xy(h, x, y, 50, "parabola") ; sleep(2) ; gnuplot_close(h) ;
Definition at line 397 of file gnuplot_i.c.
void gnuplot_resetplot | ( | gnuplot_ctrl * | h | ) |
Resets a gnuplot session (next plot will erase previous ones).
h | Gnuplot session control handle. |
Resets a gnuplot session, i.e. the next plot will erase all previous ones.
Definition at line 284 of file gnuplot_i.c.
void gnuplot_set_xlabel | ( | gnuplot_ctrl * | h, |
char * | label | ||
) |
Sets the x label of a gnuplot session.
h | Gnuplot session control handle. |
label | Character string to use for X label. |
Sets the x label for a gnuplot session.
Definition at line 250 of file gnuplot_i.c.
void gnuplot_set_ylabel | ( | gnuplot_ctrl * | h, |
char * | label | ||
) |
Sets the y label of a gnuplot session.
h | Gnuplot session control handle. |
label | Character string to use for Y label. |
Sets the y label for a gnuplot session.
Definition at line 267 of file gnuplot_i.c.
void gnuplot_setstyle | ( | gnuplot_ctrl * | h, |
char * | plot_style | ||
) |
Change the plotting style of a gnuplot session.
h | Gnuplot session control handle |
plot_style | Plotting-style to use (character string) |
The provided plotting style is a character string. It must be one of the following:
Definition at line 219 of file gnuplot_i.c.
int gnuplot_write_multi_csv | ( | char const * | fileName, |
double const ** | xListPtr, | ||
int | n, | ||
int | numColumns, | ||
char const * | title | ||
) |
Writes a multi column CSV file for use with gnuplot commands later. Allows files to also be saved for post analysis with excel for example. Note that when used with gnuplot, since there may be more than one column the whole "1:3" or whatever should be used.
Uses title as gnuplot "comment" on the first line.
fileName | file name to write to. This should be the same name used in the gnuplot command |
xListPtr | A list of pointers to column buffers |
n | |
numColumns | Length of xListPtr list. Note that the CSV file will add an additional "index" column first. |
title | Title to write for the first line of the .csv file, will be preceeded by "#" |
Definition at line 605 of file gnuplot_i.c.
int gnuplot_write_x_csv | ( | char const * | fileName, |
double const * | d, | ||
int | n, | ||
char const * | title | ||
) |
Writes a CSV file for use with gnuplot commands later. Allows files to also be saved for post analysis with excel for example. Arguments are similar to gnuplot_plot_x()
Uses title as gnuplot "comment" on the first line.
fileName | file name to write to. This should be the same name used in the gnuplot command |
d | |
n | |
title |
Definition at line 528 of file gnuplot_i.c.
int gnuplot_write_xy_csv | ( | char const * | fileName, |
double const * | x, | ||
double const * | y, | ||
int | n, | ||
char const * | title | ||
) |
Writes a CSV file for use with gnuplot commands later. Allows files to also be saved for post analysis with excel for example. Arguments are similar to gnuplot_plot_xy()
Uses title as gnuplot "comment" on the first line.
fileName | file name to write to. This should be the same name used in the gnuplot command |
x | |
y | |
n | |
title |
Definition at line 566 of file gnuplot_i.c.