1 /* PSPP - a program for statistical analysis.
2 Copyright (C) 2009, 2011, 2014 Free Software Foundation, Inc.
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.
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.
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/>. */
18 #include "math/decimal.h"
19 #include "output/charts/plot-hist.h"
22 #include <gsl/gsl_randist.h>
24 #include "data/val-type.h"
25 #include "output/cairo-chart.h"
27 #include "gl/xvasprintf.h"
30 #define _(msgid) gettext (msgid)
32 /* Write the legend of the chart */
34 histogram_write_legend (cairo_t *cr, const struct xrchart_geometry *geom,
35 double n, double mean, double stddev)
37 double y = geom->axis[SCALE_ORDINATE].data_min;
42 char *buf = xasprintf (_("N = %.2f"), n);
43 cairo_move_to (cr, geom->legend_left, y);
44 xrchart_label (cr, 'l', 'b', geom->font_size, buf);
45 y += geom->font_size * 1.5;
51 char *buf = xasprintf (_("Mean = %.1f"), mean);
52 cairo_move_to (cr,geom->legend_left, y);
53 xrchart_label (cr, 'l', 'b', geom->font_size, buf);
54 y += geom->font_size * 1.5;
60 char *buf = xasprintf (_("Std. Dev = %.2f"), stddev);
61 cairo_move_to (cr, geom->legend_left, y);
62 xrchart_label (cr, 'l', 'b', geom->font_size, buf);
70 hist_draw_bar (cairo_t *cr, const struct xrchart_geometry *geom,
71 const gsl_histogram *h, int bar, bool label)
77 const size_t bins = gsl_histogram_bins (h);
80 (geom->axis[SCALE_ABSCISSA].data_max - geom->axis[SCALE_ABSCISSA].data_min) *
84 (geom->axis[SCALE_ABSCISSA].data_max - geom->axis[SCALE_ABSCISSA].data_min) / (double) bins ;
86 assert ( 0 == gsl_histogram_get_range (h, bar, &lower, &upper));
88 assert ( upper >= lower);
90 height = geom->axis[SCALE_ORDINATE].scale * gsl_histogram_get (h, bar);
93 geom->axis[SCALE_ABSCISSA].data_min + x_pos,
94 geom->axis[SCALE_ORDINATE].data_min,
97 cairo_set_source_rgb (cr,
98 geom->fill_colour.red / 255.0,
99 geom->fill_colour.green / 255.0,
100 geom->fill_colour.blue / 255.0);
101 cairo_fill_preserve (cr);
107 struct decimal decupper;
108 struct decimal declower;
109 struct decimal middle;
110 decimal_from_double (&declower, lower);
111 decimal_from_double (&decupper, upper);
113 decimal_add (&middle, &decupper);
114 decimal_int_divide (&middle, 2);
115 char *str = decimal_to_string (&middle);
116 draw_tick (cr, geom, SCALE_ABSCISSA, bins > 10,
117 x_pos + width / 2.0, "%s", str);
123 xrchart_draw_histogram (const struct chart_item *chart_item, cairo_t *cr,
124 struct xrchart_geometry *geom)
126 struct histogram_chart *h = to_histogram_chart (chart_item);
130 xrchart_write_title (cr, geom, _("HISTOGRAM"));
132 xrchart_write_ylabel (cr, geom, _("Frequency"));
133 xrchart_write_xlabel (cr, geom, chart_item_get_title (chart_item));
135 if (h->gsl_hist == NULL)
137 /* Probably all values are SYSMIS. */
141 bins = gsl_histogram_bins (h->gsl_hist);
143 xrchart_write_yscale (cr, geom, 0, gsl_histogram_max_val (h->gsl_hist));
145 for (i = 0; i < bins; i++)
147 hist_draw_bar (cr, geom, h->gsl_hist, i, true);
150 histogram_write_legend (cr, geom, h->n, h->mean, h->stddev);
153 && h->n != SYSMIS && h->mean != SYSMIS && h->stddev != SYSMIS)
155 /* Draw the normal curve */
157 double x_min, x_max, not_used;
158 double abscissa_scale;
159 double ordinate_scale;
162 gsl_histogram_get_range (h->gsl_hist, 0, &x_min, ¬_used);
163 range = not_used - x_min;
164 gsl_histogram_get_range (h->gsl_hist, bins - 1, ¬_used, &x_max);
166 abscissa_scale = (geom->axis[SCALE_ABSCISSA].data_max - geom->axis[SCALE_ABSCISSA].data_min) / (x_max - x_min);
167 ordinate_scale = (geom->axis[SCALE_ORDINATE].data_max - geom->axis[SCALE_ORDINATE].data_min) /
168 gsl_histogram_max_val (h->gsl_hist);
170 cairo_move_to (cr, geom->axis[SCALE_ABSCISSA].data_min, geom->axis[SCALE_ORDINATE].data_min);
171 for (d = geom->axis[SCALE_ABSCISSA].data_min;
172 d <= geom->axis[SCALE_ABSCISSA].data_max;
173 d += (geom->axis[SCALE_ABSCISSA].data_max - geom->axis[SCALE_ABSCISSA].data_min) / 100.0)
175 const double x = (d - geom->axis[SCALE_ABSCISSA].data_min) / abscissa_scale + x_min;
176 const double y = h->n * range *
177 gsl_ran_gaussian_pdf (x - h->mean, h->stddev);
179 cairo_line_to (cr, d, geom->axis[SCALE_ORDINATE].data_min + y * ordinate_scale);