The GtkPlot Widget Family
----------------------
Version 0.0.0, January 2011

GtkPlotLinear provides a widget for automated plotting of data on a linear-linear scale.
GtkPlotLogLinear, PlotLinearLog will provide similar functionality for plotting on a semilog scale.
GtkPlotLogLog will provide similar functionality for plotting on a log-log scale.
GtkPlotPolar provides similar functionality for a polar scale.
This program is my first attempt to write an object in a non-object-oriented language using object-oriented libraries and coded in as unobject-oriented a fashion as possible.
The program is coded preferentially to an in-line structure to maximise performance so my apologies to anyone that attempts to modify or understand it, but I like that my >10000 point graphs load fast.

Motivation; Technology; License
-------------------------------
GtkPlot builds upon GtkDrawingArea. It compiles & works under gtk+2. upgrading to gtk+3 is currently under work.
This code is released under the GNU LGPL version 2 (for the gtk+2 version; the LGPL version 3 for the gtk+3 version) or (at your option) any later versions, making it suitable for pretty much anything.

Usage
-----
Once the library is installed (see the INSTALL file) you can link to the shared library by:
1) In the source code link to the headers with, e.g.:
  #include <gtkplot-2.0/gtkplotlinear.h>
2) Compile your program by identifying gtkplot-2.0 with pkgconfig, e.g.:
  gcc -o testplotlinear testplotlinear.c `pkg-config --cflags --libs gtk+-2.0 gtk2plot-2.0`
A new plot can be made in gtk+2 using, e.g.:
  GtkWidget *plotname;
  plotname=gtk_plot_linear_new();
  gtk_widget_show(plotname);
Data can be sent to the plot using GArray structures as:
  GtkPlotLinear *plot;
  GArray *xarrayname, *yarrayname, *sizes, *indices;
  gint arraysize, n=0;
  ...
  xarrayname=g_array_sized_new(FALSE, FALSE, sizeof(gdouble), arraysize);
  yarrayname=g_array_sized_new(FALSE, FALSE, sizeof(gdouble), arraysize);
  ...
  sizes=g_array_sized_new(FALSE, FALSE, sizeof(gint), arraysize);
  g_array_append_val(sizes, arraysize);
  indices=g_array_sized_new(FALSE, FALSE, sizeof(gint), arraysize);
  g_array_append_val(indices, n);
  plot=GTK_PLOT_LINEAR(plotname);
  (plot->xdata)=xname;
  (plot->ydata)=yname;
  (plot->sizes)=sizes;
  (plot->ind)=indices;
(for polar plotting these xdata and ydata arrays are replaced by rdata and thdata with similar x,y -> r,th replacements throughout)
A new interface for doing this without memory leaks is under development.
Redrawing the axes can be done by:
  gdouble xmin, xmax, ymin, ymax;
  gtk_plot_linear_update_scale(plotname, xmin, xmax, ymin, ymax);
to get strict axis bounds or:
  gdouble xmin, xmax, ymin, ymax;
  gtk_plot_linear_update_scale_pretty(plotname, xmin, xmax, ymin, ymax);
to get the best fit of six or less major tick divisions at multiples of 1, 2 or 5 times a power of 10.
Properties can be changed or accessed using:
  g_object_set(G_OBJECT(plotname), "propertyname", value, ..., NULL);
  g_object_get(G_OBJECT(plotname), "propertyname", value, ..., NULL);
respectively, where the propertyname's are explained in the _class_init function (multiple propertyname-value pairs can be entered but there must always be a NULL at the end regardless).
Publically accessable variables described in the _PlotLinear struct in the plotlinear.h header file can be accessed with:
  GtkPlotLinear *plot;
  gchar *label;
  guint mode;
  ...
  mode=2;
  label="Frequency (Hz)";
  plot=GTK_PLOT_LINEAR(plotname);
  (plot->xlab)=g_strdup(label);
  (plot->flagd)=mode;
The widget also emits a signal "moved" when the mouse moves over it which is useful for getting the corresponding location in the graph as:
  void pltmv(GtkPlotLinear *plot, gpointer data)
    {
    gdouble x,y;
    
    x=(plot->xps);
    y=(plot->yps);
    }
  ...
  int main(int argc, char *argv[])
    GtkPlotLinear *plot;
    ...
    plot=GTK_PLOT_LINEAR(plotname);
    g_signal_connect(plot, "moved", G_CALLBACK(pltmv), NULL);
See the example file testplotlinear.c for an example of interacting with the GtkPlotLinear widget to its full extent.

Known Bugs/Issues
-----------------
GtkPlotPolar scales in an unhelpful manner and is generally very buggy (see TODO)

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