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/cartesian.h>
22 #include <cairo/cairo.h>
26 #include <output/chart.h>
27 #include <output/chart-provider.h>
28 #include <output/charts/plot-chart.h>
29 #include <libpspp/compiler.h>
40 static const struct dataset dataset[DATASETS] =
47 /* Plot a data point */
49 chart_datum (cairo_t *cr, const struct chart_geometry *geom,
50 int dataset UNUSED, double x, double y)
52 double x_pos = (x - geom->x_min) * geom->abscissa_scale + geom->data_left;
53 double y_pos = (y - geom->y_min) * geom->ordinate_scale + geom->data_bottom;
55 chart_draw_marker (cr, x_pos, y_pos, MARKER_SQUARE, 15);
58 /* Draw a line with slope SLOPE and intercept INTERCEPT.
59 between the points limit1 and limit2.
60 If lim_dim is CHART_DIM_Y then the limit{1,2} are on the
61 y axis otherwise the x axis
64 chart_line(cairo_t *cr, const struct chart_geometry *geom,
65 double slope, double intercept,
66 double limit1, double limit2, enum CHART_DIM lim_dim)
71 if ( lim_dim == CHART_DIM_Y )
73 x1 = ( limit1 - intercept ) / slope;
74 x2 = ( limit2 - intercept ) / slope;
82 y1 = slope * x1 + intercept;
83 y2 = slope * x2 + intercept;
86 y1 = (y1 - geom->y_min) * geom->ordinate_scale + geom->data_bottom;
87 y2 = (y2 - geom->y_min) * geom->ordinate_scale + geom->data_bottom;
88 x1 = (x1 - geom->x_min) * geom->abscissa_scale + geom->data_left;
89 x2 = (x2 - geom->x_min) * geom->abscissa_scale + geom->data_left;
91 cairo_move_to (cr, x1, y1);
92 cairo_line_to (cr, x2, y2);