Add GRAPH command initially with just scatterplots and histograms.

[pspp] / src / output / charts / scatterplot-cairo.c

diff --git a/src/output/charts/scatterplot-cairo.c b/src/output/charts/scatterplot-cairo.c
new file mode 100644 (file)
index 0000000..b555a12
--- /dev/null
+++ b/src/output/charts/scatterplot-cairo.c
@@ -0,0 +1,117 @@
+/* PSPP - a program for statistical analysis.
+   Copyright (C) 2014 Free Software Foundation, Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>. */
+
+#include <config.h>
+
+#include "output/charts/scatterplot.h"
+
+#include "data/case.h"
+#include "data/casereader.h"
+#include "data/variable.h"
+#include "output/cairo-chart.h"
+#include "libpspp/str.h"
+#include "libpspp/message.h"
+
+#include "gettext.h"
+#define _(msgid) gettext (msgid)
+
+
+void
+xrchart_draw_scatterplot (const struct chart_item *chart_item, cairo_t *cr,
+                         struct xrchart_geometry *geom)
+{
+  const struct scatterplot_chart *spc = to_scatterplot_chart (chart_item);
+  struct casereader *data;
+  struct ccase *c;
+  /* While reading the cases, a list with categories of the byvar is build */
+  /* All distinct values are stored in catvals                             */
+  /* Each category will later have a different plot colour                 */
+  const int MAX_PLOT_CATS = 20;
+  union value catvals[MAX_PLOT_CATS];
+  int n_catvals = 0;
+  int byvar_width = 0;
+  int i = 0;
+  const struct xrchart_colour *colour;
+  
+  if (spc->byvar)
+    byvar_width = var_get_width(spc->byvar);
+
+  xrchart_write_xscale (cr, geom,
+                      spc->x_min,
+                      spc->x_max, 5);
+  xrchart_write_yscale (cr, geom, spc->y_min, spc->y_max, 5);
+  xrchart_write_title (cr, geom, _("Scatterplot %s"), chart_item->title);
+  xrchart_write_xlabel (cr, geom, var_to_string(spc->xvar));
+  xrchart_write_ylabel (cr, geom, var_to_string(spc->yvar));
+
+  cairo_save (cr);
+  data = casereader_clone (spc->data);
+  for (; (c = casereader_read (data)) != NULL; case_unref (c))
+    {
+      if (spc->byvar)
+       {
+         const union value *val = case_data(c,spc->byvar);
+         for(i=0;i<n_catvals && !value_equal(&catvals[i],val,byvar_width);i++);
+         if (i == n_catvals) /* No entry found */
+           {
+             if (n_catvals < MAX_PLOT_CATS)
+               {
+                 struct string label;
+                 ds_init_empty(&label);
+                 if (var_is_value_missing(spc->byvar,val,MV_ANY))
+                   ds_put_cstr(&label,"missing");
+                 else
+                   var_append_value_name(spc->byvar,val,&label);
+                 value_clone(&catvals[n_catvals++],val,byvar_width);
+                 geom->n_datasets++;
+                 geom->dataset = xrealloc (geom->dataset,
+                                           geom->n_datasets * sizeof (*geom->dataset));
+
+                 geom->dataset[geom->n_datasets - 1] = strdup(ds_cstr(&label));
+                 ds_destroy(&label);
+               }
+             else /* Use the last plot category */
+               {
+                 *(spc->byvar_overflow) = true;
+                 i--;
+               }
+           }
+       }
+      colour = &data_colour [ i % XRCHART_N_COLOURS];
+      cairo_set_source_rgb (cr,
+                            colour->red / 255.0,
+                            colour->green / 255.0,
+                            colour->blue / 255.0);
+    
+      xrchart_datum (cr, geom, 0,
+                    case_data (c, spc->xvar)->f,
+                    case_data (c, spc->yvar)->f);
+    }
+  casereader_destroy (data);
+  cairo_restore(cr);
+
+  for(i=0;i<n_catvals;i++)
+    value_destroy(&catvals[i],byvar_width);
+
+  if (spc->byvar)
+    xrchart_write_legend(cr, geom);
+
+    
+
+  //  xrchart_line (cr, geom, npp->slope, npp->intercept,
+  //            npp->y_first, npp->y_last, XRCHART_DIM_Y);
+
+}