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/chart-geometry.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"
28 #include "gl/minmax.h"
31 #define _(msgid) gettext (msgid)
33 /* Write the legend of the chart */
35 histogram_write_legend (cairo_t *cr, const struct xrchart_geometry *geom,
36 double n, double mean, double stddev)
38 double y = geom->axis[SCALE_ORDINATE].data_min;
43 char *buf = xasprintf (_("N = %.2f"), n);
44 cairo_move_to (cr, geom->legend_left, y);
45 xrchart_label (cr, 'l', 'b', geom->font_size, buf);
46 y += geom->font_size * 1.5;
52 char *buf = xasprintf (_("Mean = %.1f"), mean);
53 cairo_move_to (cr,geom->legend_left, y);
54 xrchart_label (cr, 'l', 'b', geom->font_size, buf);
55 y += geom->font_size * 1.5;
61 char *buf = xasprintf (_("Std. Dev = %.2f"), stddev);
62 cairo_move_to (cr, geom->legend_left, y);
63 xrchart_label (cr, 'l', 'b', geom->font_size, buf);
71 hist_draw_bar (cairo_t *cr, const struct xrchart_geometry *geom,
72 const gsl_histogram *h, int bar, const char *tick_format_string,
73 const double tickscale, const bool tickoversize)
79 const size_t bins = gsl_histogram_bins (h);
82 (geom->axis[SCALE_ABSCISSA].data_max - geom->axis[SCALE_ABSCISSA].data_min) *
86 (geom->axis[SCALE_ABSCISSA].data_max - geom->axis[SCALE_ABSCISSA].data_min) / (double) bins ;
88 assert ( 0 == gsl_histogram_get_range (h, bar, &lower, &upper));
90 assert ( upper >= lower);
92 height = geom->axis[SCALE_ORDINATE].scale * gsl_histogram_get (h, bar);
95 geom->axis[SCALE_ABSCISSA].data_min + x_pos,
96 geom->axis[SCALE_ORDINATE].data_min,
99 cairo_set_source_rgb (cr,
100 geom->fill_colour.red / 255.0,
101 geom->fill_colour.green / 255.0,
102 geom->fill_colour.blue / 255.0);
103 cairo_fill_preserve (cr);
107 draw_tick (cr, geom, SCALE_ABSCISSA, tickoversize,
108 x_pos + width / 2.0, tick_format_string, (upper+lower)/2.0*tickscale);
113 xrchart_draw_histogram (const struct chart_item *chart_item, cairo_t *cr,
114 struct xrchart_geometry *geom)
116 struct histogram_chart *h = to_histogram_chart (chart_item);
119 char *tick_format_string;
121 double width, left_width, right_width, unused;
125 xrchart_write_title (cr, geom, _("HISTOGRAM"));
127 xrchart_write_ylabel (cr, geom, _("Frequency"));
128 xrchart_write_xlabel (cr, geom, chart_item_get_title (chart_item));
130 if (h->gsl_hist == NULL)
132 /* Probably all values are SYSMIS. */
136 xrchart_write_yscale (cr, geom, 0, gsl_histogram_max_val (h->gsl_hist));
138 /* Draw the ticks and compute if the rendered tick text is wider than the bin */
139 bins = gsl_histogram_bins (h->gsl_hist);
140 tick_format_string = chart_get_ticks_format (gsl_histogram_max (h->gsl_hist),
141 gsl_histogram_min (h->gsl_hist),
144 test_text = xasprintf(tick_format_string, gsl_histogram_max (h->gsl_hist)*tickscale);
145 xrchart_text_extents (cr, geom, test_text, &right_width, &unused);
147 test_text = xasprintf(tick_format_string, gsl_histogram_min (h->gsl_hist)*tickscale);
148 xrchart_text_extents (cr, geom, test_text, &left_width, &unused);
150 width = MAX(left_width, right_width);
151 tickoversize = width > 0.9 *
152 ((double)(geom->axis[SCALE_ABSCISSA].data_max - geom->axis[SCALE_ABSCISSA].data_min))/bins;
153 for (i = 0; i < bins; i++)
155 hist_draw_bar (cr, geom, h->gsl_hist, i, tick_format_string, tickscale, tickoversize);
157 free(tick_format_string);
159 histogram_write_legend (cr, geom, h->n, h->mean, h->stddev);
162 && h->n != SYSMIS && h->mean != SYSMIS && h->stddev != SYSMIS)
164 /* Draw the normal curve */
166 double x_min, x_max, not_used;
167 double abscissa_scale;
168 double ordinate_scale;
171 gsl_histogram_get_range (h->gsl_hist, 0, &x_min, ¬_used);
172 range = not_used - x_min;
173 gsl_histogram_get_range (h->gsl_hist, bins - 1, ¬_used, &x_max);
175 abscissa_scale = (geom->axis[SCALE_ABSCISSA].data_max - geom->axis[SCALE_ABSCISSA].data_min) / (x_max - x_min);
176 ordinate_scale = (geom->axis[SCALE_ORDINATE].data_max - geom->axis[SCALE_ORDINATE].data_min) /
177 gsl_histogram_max_val (h->gsl_hist);
179 cairo_move_to (cr, geom->axis[SCALE_ABSCISSA].data_min, geom->axis[SCALE_ORDINATE].data_min);
180 for (d = geom->axis[SCALE_ABSCISSA].data_min;
181 d <= geom->axis[SCALE_ABSCISSA].data_max;
182 d += (geom->axis[SCALE_ABSCISSA].data_max - geom->axis[SCALE_ABSCISSA].data_min) / 100.0)
184 const double x = (d - geom->axis[SCALE_ABSCISSA].data_min) / abscissa_scale + x_min;
185 const double y = h->n * range *
186 gsl_ran_gaussian_pdf (x - h->mean, h->stddev);
188 cairo_line_to (cr, d, geom->axis[SCALE_ORDINATE].data_min + y * ordinate_scale);