1 /* PSPP - a program for statistical analysis.
2 Copyright (C) 2004, 2009 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/>. */
20 #include <output/charts/piechart.h>
24 #include <gsl/gsl_math.h>
28 #include <data/value-labels.h>
29 #include <libpspp/str.h>
30 #include <output/charts/plot-chart.h>
31 #include <output/chart-provider.h>
43 static const struct chart_class piechart_class;
45 /* Draw a single slice of the pie */
47 draw_segment(plPlotter *,
48 double centre_x, double centre_y,
50 double start_angle, double segment_angle,
55 /* Creates and returns a chart that will render a piechart with
56 the given TITLE and the N_SLICES described in SLICES. */
58 piechart_create (const char *title, const struct slice *slices, int n_slices)
63 pie = xmalloc (sizeof *pie);
64 chart_init (&pie->chart, &piechart_class);
65 pie->title = xstrdup (title);
66 pie->slices = xnmalloc (n_slices, sizeof *pie->slices);
67 for (i = 0; i < n_slices; i++)
69 const struct slice *src = &slices[i];
70 struct slice *dst = &pie->slices[i];
72 ds_init_string (&dst->label, &src->label);
73 dst->magnitude = src->magnitude;
75 pie->n_slices = n_slices;
80 piechart_draw (const struct chart *chart, plPlotter *lp)
82 struct piechart *pie = (struct piechart *) chart;
83 struct chart_geometry geom;
84 double total_magnitude;
85 double left_label, right_label;
86 double centre_x, centre_y;
91 chart_geometry_init (lp, &geom);
93 left_label = geom.data_left + (geom.data_right - geom.data_left)/10.0;
94 right_label = geom.data_right - (geom.data_right - geom.data_left)/10.0;
96 centre_x = (geom.data_right + geom.data_left) / 2.0 ;
97 centre_y = (geom.data_top + geom.data_bottom) / 2.0 ;
99 radius = MIN (5.0 / 12.0 * (geom.data_top - geom.data_bottom),
100 1.0 / 4.0 * (geom.data_right - geom.data_left));
102 chart_write_title (lp, &geom, "%s", pie->title);
104 total_magnitude = 0.0;
105 for (i = 0; i < pie->n_slices; i++)
106 total_magnitude += pie->slices[i].magnitude;
109 for (i = 0; i < pie->n_slices ; ++i )
111 const double segment_angle =
112 pie->slices[i].magnitude / total_magnitude * 2 * M_PI ;
114 const double label_x = centre_x -
115 radius * sin(angle + segment_angle/2.0);
117 const double label_y = centre_y +
118 radius * cos(angle + segment_angle/2.0);
120 /* Fill the segment */
122 centre_x, centre_y, radius,
123 angle, segment_angle,
124 data_colour[i % N_CHART_COLOURS]);
126 /* Now add the labels */
127 if ( label_x < centre_x )
129 pl_line_r (lp, label_x, label_y, left_label, label_y );
130 pl_moverel_r (lp, 0, 5);
131 pl_alabel_r (lp, 0, 0, ds_cstr (&pie->slices[i].label));
135 pl_line_r (lp, label_x, label_y, right_label, label_y);
136 pl_moverel_r (lp, 0, 5);
137 pl_alabel_r (lp, 'r', 0, ds_cstr (&pie->slices[i].label));
140 angle += segment_angle;
143 /* Draw an outline to the pie */
144 pl_filltype_r (lp,0);
145 pl_fcircle_r (lp, centre_x, centre_y, radius);
147 chart_geometry_free (lp);
150 /* Fill a segment with the current fill colour */
152 fill_segment(plPlotter *lp,
153 double x0, double y0,
155 double start_angle, double segment_angle)
158 const double start_x = x0 - radius * sin(start_angle);
159 const double start_y = y0 + radius * cos(start_angle);
161 const double stop_x =
162 x0 - radius * sin(start_angle + segment_angle);
164 const double stop_y =
165 y0 + radius * cos(start_angle + segment_angle);
167 assert(segment_angle <= 2 * M_PI);
168 assert(segment_angle >= 0);
170 if ( segment_angle > M_PI )
172 /* Then we must draw it in two halves */
173 fill_segment(lp, x0, y0, radius, start_angle, segment_angle / 2.0 );
174 fill_segment(lp, x0, y0, radius, start_angle + segment_angle / 2.0,
175 segment_angle / 2.0 );
179 pl_move_r(lp, x0, y0);
181 pl_cont_r(lp, stop_x, stop_y);
182 pl_cont_r(lp, start_x, start_y);
194 /* Draw a single slice of the pie */
196 draw_segment(plPlotter *lp,
197 double x0, double y0,
199 double start_angle, double segment_angle,
202 const double start_x = x0 - radius * sin(start_angle);
203 const double start_y = y0 + radius * cos(start_angle);
208 pl_colorname_r(lp, colour);
213 fill_segment(lp, x0, y0, radius, start_angle, segment_angle);
214 pl_restorestate_r(lp);
216 /* Draw line dividing segments */
218 pl_fline_r(lp, x0, y0, start_x, start_y);
221 pl_restorestate_r(lp);
225 piechart_destroy (struct chart *chart)
227 struct piechart *pie = (struct piechart *) chart;
231 for (i = 0; i < pie->n_slices; i++)
233 struct slice *slice = &pie->slices[i];
234 ds_destroy (&slice->label);
240 static const struct chart_class piechart_class =