1 /* PSPP - a program for statistical analysis.
2 Copyright (C) 2014, 2015 Free Software Foundation, Inc.
3
4 This program is free software: you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation, either version 3 of the License, or
7 (at your option) any later version.
8
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
13
14 You should have received a copy of the GNU General Public License
15 along with this program. If not, see <http://www.gnu.org/licenses/>. */
16
17 #include <config.h>
18
19 #include "output/charts/scatterplot.h"
20
21 #include "data/case.h"
22 #include "data/casereader.h"
23 #include "data/variable.h"
24 #include "output/cairo-chart.h"
25 #include "libpspp/str.h"
26 #include "libpspp/message.h"
27
28 #include "gettext.h"
29 #define _(msgid) gettext (msgid)
30
31 static const struct xrchart_colour black = {0,0,0};
32
33 void
xrchart_draw_scatterplot(const struct chart_item * chart_item,cairo_t * cr,struct xrchart_geometry * geom)34 xrchart_draw_scatterplot (const struct chart_item *chart_item, cairo_t *cr,
35 struct xrchart_geometry *geom)
36 {
37 const struct scatterplot_chart *spc = to_scatterplot_chart (chart_item);
38 struct casereader *data;
39 struct ccase *c;
40 /* While reading the cases, a list with categories of the byvar is build */
41 /* All distinct values are stored in catvals */
42 /* Each category will later have a different plot colour */
43 const int MAX_PLOT_CATS = 20;
44 union value catvals[MAX_PLOT_CATS];
45 int n_catvals = 0;
46 int byvar_width = 0;
47 int i = 0;
48 const struct xrchart_colour *colour;
49
50 if (spc->byvar)
51 byvar_width = var_get_width (spc->byvar);
52
53 if (! xrchart_write_xscale (cr, geom, spc->x_min, spc->x_max))
54 return;
55 if (! xrchart_write_yscale (cr, geom, spc->y_min, spc->y_max))
56 return;
57 xrchart_write_title (cr, geom, _("Scatterplot %s"), chart_item->title);
58 xrchart_write_xlabel (cr, geom, spc->xlabel);
59 xrchart_write_ylabel (cr, geom, spc->ylabel);
60
61 cairo_save (cr);
62 data = casereader_clone (spc->data);
63 for (; (c = casereader_read (data)) != NULL; case_unref (c))
64 {
65 if (spc->byvar)
66 {
67 const union value *val = case_data_idx (c,SP_IDX_BY);
68 for(i=0;i<n_catvals && !value_equal (&catvals[i],val,byvar_width);i++);
69 if (i == n_catvals) /* No entry found */
70 {
71 if (n_catvals < MAX_PLOT_CATS)
72 {
73 struct string label;
74 ds_init_empty (&label);
75 if (var_is_value_missing (spc->byvar,val,MV_ANY))
76 ds_put_cstr (&label,"missing");
77 else
78 var_append_value_name (spc->byvar,val,&label);
79 value_clone (&catvals[n_catvals++],val,byvar_width);
80 geom->n_datasets++;
81 geom->dataset = xrealloc (geom->dataset,
82 geom->n_datasets * sizeof (*geom->dataset));
83
84 geom->dataset[geom->n_datasets - 1] = strdup (ds_cstr(&label));
85 ds_destroy (&label);
86 }
87 else /* Use the last plot category */
88 {
89 *(spc->byvar_overflow) = true;
90 i--;
91 }
92 }
93 colour = &data_colour[i % XRCHART_N_COLOURS];
94 }
95 else
96 colour = &black;
97
98 cairo_set_source_rgb (cr,
99 colour->red / 255.0,
100 colour->green / 255.0,
101 colour->blue / 255.0);
102
103 xrchart_datum (cr, geom, 0,
104 case_data_idx (c, SP_IDX_X)->f,
105 case_data_idx (c, SP_IDX_Y)->f);
106 }
107 casereader_destroy (data);
108 cairo_restore (cr);
109
110 for(i=0;i<n_catvals;i++)
111 value_destroy (&catvals[i],byvar_width);
112
113 if (spc->byvar)
114 xrchart_write_legend (cr, geom);
115
116 }
117