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/>. */
26 #include <output/charts/piechart.h>
27 #include <output/charts/plot-chart.h>
29 #include <output/chart.h>
30 #include <libpspp/str.h>
31 #include <data/value-labels.h>
36 /* Pie charts of course need to know Pi :) */
38 #define M_PI ( 22.0 / 7.0 )
43 /* Draw a single slice of the pie */
45 draw_segment(struct chart *ch,
46 double centre_x, double centre_y,
48 double start_angle, double segment_angle,
55 piechart_plot(const char *title, const struct slice *slices, int n_slices)
58 double total_magnetude=0;
74 left_label = ch->data_left + (ch->data_right - ch->data_left)/10.0;
75 right_label = ch->data_right - (ch->data_right - ch->data_left)/10.0;
76 centre_x = (ch->data_right + ch->data_left ) / 2.0;
77 centre_y = (ch->data_top + ch->data_bottom ) / 2.0;
78 radius = MIN (5.0 / 12.0 * (ch->data_top - ch->data_bottom),
79 1.0 / 4.0 * (ch->data_right - ch->data_left));
81 chart_write_title(ch, "%s", title);
83 for (i = 0 ; i < n_slices ; ++i )
84 total_magnetude += slices[i].magnetude;
86 for (i = 0 ; i < n_slices ; ++i )
88 static double angle=0.0;
90 const double segment_angle =
91 slices[i].magnetude / total_magnetude * 2 * M_PI ;
93 const double label_x = centre_x -
94 radius * sin(angle + segment_angle/2.0);
96 const double label_y = centre_y +
97 radius * cos(angle + segment_angle/2.0);
99 /* Fill the segment */
101 centre_x, centre_y, radius,
102 angle, segment_angle,
103 data_colour[i % N_CHART_COLOURS]);
105 /* Now add the labels */
106 if ( label_x < centre_x )
108 pl_line_r(ch->lp, label_x, label_y,
109 left_label, label_y );
110 pl_moverel_r(ch->lp,0,5);
111 pl_alabel_r (ch->lp, 0, 0, ds_cstr (&slices[i].label));
119 pl_moverel_r(ch->lp,0,5);
120 pl_alabel_r (ch->lp, 'r', 0, ds_cstr (&slices[i].label));
123 angle += segment_angle;
127 /* Draw an outline to the pie */
128 pl_filltype_r(ch->lp,0);
129 pl_fcircle_r (ch->lp, centre_x, centre_y, radius);
135 fill_segment(struct chart *ch,
136 double x0, double y0,
138 double start_angle, double segment_angle) ;
141 /* Fill a segment with the current fill colour */
143 fill_segment(struct chart *ch,
144 double x0, double y0,
146 double start_angle, double segment_angle)
149 const double start_x = x0 - radius * sin(start_angle);
150 const double start_y = y0 + radius * cos(start_angle);
152 const double stop_x =
153 x0 - radius * sin(start_angle + segment_angle);
155 const double stop_y =
156 y0 + radius * cos(start_angle + segment_angle);
158 assert(segment_angle <= 2 * M_PI);
159 assert(segment_angle >= 0);
161 if ( segment_angle > M_PI )
163 /* Then we must draw it in two halves */
164 fill_segment(ch, x0, y0, radius, start_angle, segment_angle / 2.0 );
165 fill_segment(ch, x0, y0, radius, start_angle + segment_angle / 2.0,
166 segment_angle / 2.0 );
170 pl_move_r(ch->lp, x0, y0);
172 pl_cont_r(ch->lp, stop_x, stop_y);
173 pl_cont_r(ch->lp, start_x, start_y);
181 pl_endpath_r(ch->lp);
187 /* Draw a single slice of the pie */
189 draw_segment(struct chart *ch,
190 double x0, double y0,
192 double start_angle, double segment_angle,
195 const double start_x = x0 - radius * sin(start_angle);
196 const double start_y = y0 + radius * cos(start_angle);
198 pl_savestate_r(ch->lp);
200 pl_savestate_r(ch->lp);
201 pl_colorname_r(ch->lp, colour);
203 pl_pentype_r(ch->lp,1);
204 pl_filltype_r(ch->lp,1);
206 fill_segment(ch, x0, y0, radius, start_angle, segment_angle);
207 pl_restorestate_r(ch->lp);
209 /* Draw line dividing segments */
210 pl_pentype_r(ch->lp, 1);
211 pl_fline_r(ch->lp, x0, y0, start_x, start_y);
214 pl_restorestate_r(ch->lp);