1 /* acre - A cairo-based library for creating plots and charts.
3 * Copyright © 2009 Carl Worth <cworth@cworth.org>
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License as
7 * published by the Free Software Foundation; either version 2 of the
8 * License, or (at your option) any later version.
10 * This program is distributed in the hope that it will be useful, but
11 * WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * General Public License for more details.
15 * You should have received a copy of the GNU General Public License along
16 * with this program; if not, write to the Free Software Foundation, Inc.,
17 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
20 #define _ISOC99_SOURCE /* for round() */
21 #define _XOPEN_SOURCE 500
22 #define _GNU_SOURCE /* for asprintf() */
34 typedef struct _acre_data_point_2d {
37 } acre_data_point_2d_t;
42 acre_data_point_2d_t min;
43 acre_data_point_2d_t max;
45 acre_data_point_2d_t *points;
46 unsigned int points_size;
47 unsigned int num_points;
50 typedef struct _acre_axis {
57 /* Range of data to be viewed. */
61 /* Has the view range been set? */
65 typedef struct _acre_color {
77 unsigned int data_size;
78 unsigned int num_data;
80 /* Data for drawing. */
82 PangoFontDescription *font;
87 /* Total size including labels. */
91 /* Position and size of chart alone. */
96 _find_x_range_given_y_range (acre_t *acre,
97 double *x_min, double *x_max,
98 double y_min, double y_max);
101 _find_y_range_given_x_range (acre_t *acre,
102 double *y_min, double *y_max,
103 double x_min, double x_max);
105 /* Create a new, empty plot. */
111 acre = xmalloc (sizeof (acre_t));
115 acre->x_axis.label = NULL;
116 acre->x_axis.data_min = 0.0;
117 acre->x_axis.data_max = 0.0;
118 acre->x_axis.view_min = 0.0;
119 acre->x_axis.view_max = 0.0;
120 acre->x_axis.view_range_set = false;
122 acre->y_axis.label = NULL;
123 acre->y_axis.data_min = 0.0;
124 acre->y_axis.data_max = 0.0;
125 acre->y_axis.view_min = 0.0;
126 acre->y_axis.view_max = 0.0;
127 acre->y_axis.view_range_set = false;
136 acre->num_colors = 0;
143 acre->chart.width = 0;
144 acre->chart.height = 0;
149 /* Destroy a plot. */
151 acre_destroy (acre_t *acre)
156 free (acre->x_axis.label);
157 free (acre->y_axis.label);
159 for (i = 0; i < acre->num_data; i++)
160 acre_data_destroy (acre->data[i]);
170 acre_set_title (acre_t *acre, const char *title)
174 acre->title = strdup (title);
178 acre_set_x_axis_label (acre_t *acre, const char *label)
180 free (acre->x_axis.label);
182 acre->x_axis.label = strdup (label);
186 acre_set_y_axis_label (acre_t *acre, const char *label)
188 free (acre->y_axis.label);
190 acre->y_axis.label = strdup (label);
194 acre_get_x_axis_data_range (acre_t *acre, double *x_min, double *x_max)
197 *x_min = acre->x_axis.data_min;
200 *x_max = acre->x_axis.data_max;
204 acre_get_x_axis_range (acre_t *acre, double *x_min, double *x_max)
206 /* If an X range has been set, return that. */
207 if (acre->x_axis.view_range_set) {
209 *x_min = acre->x_axis.view_min;
212 *x_max = acre->x_axis.view_max;
217 /* Otherwise, if a Y range has been set, use that to compute X. */
218 if (acre->y_axis.view_range_set) {
219 _find_x_range_given_y_range (acre, x_min, x_max,
220 acre->y_axis.view_min,
221 acre->y_axis.view_max);
226 /* Neither view range set. Return full, data-based X range. */
227 acre_get_x_axis_data_range (acre, x_min, x_max);
231 acre_set_x_axis_range (acre_t *acre, double x_min, double x_max)
233 acre->x_axis.view_min = x_min;
234 acre->x_axis.view_max = x_max;
236 acre->x_axis.view_range_set = true;
240 acre_set_x_axis_range_auto (acre_t *acre)
242 acre->x_axis.view_range_set = false;
246 acre_get_y_axis_data_range (acre_t *acre, double *y_min, double *y_max)
249 *y_min = acre->y_axis.data_min;
252 *y_max = acre->y_axis.data_max;
256 acre_get_y_axis_range (acre_t *acre, double *y_min, double *y_max)
258 /* If a Y range has been set, return that. */
259 if (acre->y_axis.view_range_set) {
261 *y_min = acre->y_axis.view_min;
264 *y_max = acre->y_axis.view_max;
269 /* Otherwise, if an X range has been set, use that to compute Y. */
270 if (acre->x_axis.view_range_set) {
271 _find_y_range_given_x_range (acre, y_min, y_max,
272 acre->x_axis.view_min,
273 acre->x_axis.view_max);
278 /* Neither view range set. Return full data-based Y range. */
279 acre_get_y_axis_data_range (acre, y_min, y_max);
283 acre_set_y_axis_range (acre_t *acre, double y_min, double y_max)
285 acre->y_axis.view_min = y_min;
286 acre->y_axis.view_max = y_max;
288 acre->y_axis.view_range_set = true;
292 acre_set_y_axis_range_auto (acre_t *acre)
294 acre->y_axis.view_range_set = false;
297 /* Add a dataset to the plot. The plot assumes ownership of the
298 * dataset so it is not necessary to call acre_data_destroy on it. */
300 acre_add_data (acre_t *acre, acre_data_t *data)
302 if (acre->num_data >= acre->data_size) {
303 acre->data_size *= 2;
304 if (acre->data_size == 0)
306 acre->data = xrealloc_ab (acre->data,
308 sizeof (acre_data_t *));
311 acre->data[acre->num_data] = data;
313 if (acre->num_data == 0) {
314 acre->x_axis.data_min = data->min.x;
315 acre->y_axis.data_min = data->min.y;
317 acre->x_axis.data_max = data->max.x;
318 acre->y_axis.data_max = data->max.y;
320 if (data->min.x < acre->x_axis.data_min)
321 acre->x_axis.data_min = data->min.x;
322 if (data->min.y < acre->y_axis.data_min)
323 acre->y_axis.data_min = data->min.y;
325 if (data->max.x > acre->x_axis.data_max)
326 acre->x_axis.data_max = data->max.x;
327 if (data->max.y > acre->y_axis.data_max)
328 acre->y_axis.data_max = data->max.y;
334 #define ACRE_FONT_FAMILY "sans"
335 #define ACRE_FONT_SIZE 12
336 #define ACRE_TITLE_FONT_SIZE 20
337 #define ACRE_PAD (ACRE_FONT_SIZE)
338 #define ACRE_TICK_MAJOR_SIZE 6
339 #define ACRE_TICK_MINOR_SIZE 3
340 #define ACRE_X_TICK_VALUE_PAD 2
341 #define ACRE_Y_TICK_VALUE_PAD 4
342 #define ACRE_LEGEND_PAD 4
343 #define ACRE_LEGEND_LINE_SIZE 10
346 _create_layout (acre_t *acre, const char *text)
350 layout = pango_cairo_create_layout (acre->cr);
351 pango_layout_set_font_description (layout, acre->font);
352 pango_layout_set_text (layout, text, -1);
353 pango_layout_set_alignment (layout, PANGO_ALIGN_CENTER);
358 #define PRINTF_FORMAT(fmt_index, va_index) __attribute__ ((__format__(__printf__, fmt_index, va_index)))
361 _create_layout_vprintf (acre_t *acre, const char *fmt, va_list ap)
366 vasprintf (&text, fmt, ap);
368 layout = _create_layout (acre, text);
376 _create_layout_printf (acre_t *acre, const char *fmt, ...)
377 PRINTF_FORMAT (2, 3);
380 _create_layout_printf (acre_t *acre, const char *fmt, ...)
387 layout = _create_layout_vprintf (acre, fmt, ap);
395 _destroy_layout (PangoLayout *layout)
397 g_object_unref (layout);
401 _show_layout (cairo_t *cr, PangoLayout *layout)
403 pango_cairo_show_layout (cr, layout);
405 _destroy_layout (layout);
409 _draw_title_and_labels (acre_t *acre)
411 cairo_t *cr = acre->cr;
412 PangoFontDescription *title_font;
413 PangoLayout *title_layout, *x_axis_layout, *y_axis_layout;
414 PangoLayout *min_y, *max_y;
415 int min_y_width, max_y_width, y_axis_value_width;
416 int title_width, title_height;
417 int x_axis_width, x_axis_height;
418 int y_axis_width, y_axis_height;
419 PangoRectangle new_chart;
423 acre->font = pango_font_description_new ();
424 pango_font_description_set_family (acre->font, ACRE_FONT_FAMILY);
425 pango_font_description_set_absolute_size (acre->font,
426 ACRE_FONT_SIZE * PANGO_SCALE);
428 title_font = pango_font_description_new ();
429 pango_font_description_set_family (title_font, ACRE_FONT_FAMILY);
430 pango_font_description_set_absolute_size (title_font,
431 ACRE_TITLE_FONT_SIZE * PANGO_SCALE);
433 title_layout = _create_layout (acre, acre->title);
434 pango_layout_set_font_description (title_layout, title_font);
436 x_axis_layout = _create_layout (acre, acre->x_axis.label);
437 y_axis_layout = _create_layout (acre, acre->y_axis.label);
439 min_y = _create_layout_printf (acre, "%g",
440 round (acre->y_axis.view_min));
441 max_y = _create_layout_printf (acre, "%g",
442 round (acre->y_axis.view_max));
444 pango_layout_get_pixel_size (min_y, &min_y_width, NULL);
445 pango_layout_get_pixel_size (max_y, &max_y_width, NULL);
446 y_axis_value_width = MAX (min_y_width, max_y_width);
448 _destroy_layout (min_y);
449 _destroy_layout (max_y);
451 /* Iterate with the layout of the title and axis labels until they
452 * are stable, (this requires iteration since we don't know what
453 * to set their widths to in advance due to the wrapping of the
454 * other elements). */
456 pango_layout_set_width (title_layout, acre->chart.width * PANGO_SCALE);
457 pango_layout_set_width (x_axis_layout, acre->chart.width * PANGO_SCALE);
458 pango_layout_set_width (y_axis_layout, acre->chart.height * PANGO_SCALE);
460 pango_layout_get_pixel_size (title_layout, &title_width, &title_height);
461 pango_layout_get_pixel_size (x_axis_layout, &x_axis_width, &x_axis_height);
462 pango_layout_get_pixel_size (y_axis_layout, &y_axis_width, &y_axis_height);
464 new_chart.x = ACRE_PAD + y_axis_height +
465 ACRE_PAD + y_axis_value_width + ACRE_Y_TICK_VALUE_PAD;
466 new_chart.width = acre->width - acre->chart.x - ACRE_PAD;
468 new_chart.y = ACRE_PAD + title_height + ACRE_PAD;
469 new_chart.height = acre->height - acre->chart.y -
470 (ACRE_X_TICK_VALUE_PAD + ACRE_FONT_SIZE +
471 ACRE_PAD + x_axis_height + ACRE_PAD);
473 if (new_chart.x == acre->chart.x &&
474 new_chart.y == acre->chart.y &&
475 new_chart.width == acre->chart.width &&
476 new_chart.height == acre->chart.height)
481 acre->chart.x = new_chart.x;
482 acre->chart.y = new_chart.y;
483 acre->chart.width = new_chart.width;
484 acre->chart.height = new_chart.height;
487 cairo_set_source_rgb (cr, 0, 0, 0);
489 cairo_move_to (cr, acre->chart.x, ACRE_PAD);
490 _show_layout (cr, title_layout);
494 cairo_translate (cr, ACRE_PAD, acre->chart.y + acre->chart.height);
495 cairo_rotate (cr, - M_PI / 2.0);
496 cairo_move_to (cr, 0, 0);
497 _show_layout (cr, y_axis_layout);
501 cairo_move_to (cr, acre->chart.x,
502 acre->chart.y + acre->chart.height +
503 ACRE_FONT_SIZE + ACRE_PAD);
504 _show_layout (cr, x_axis_layout);
509 /* For a given axis range, compute a step size (in data space) to
510 * generate a suitable number of ticks (5 or so). */
512 _step_for_range (double range, int *minor_divisions)
514 double step, scale_factor;
516 /* We want roughly 5 major ticks for the chart. */
519 /* Normalize the step so we can easily snap it to a desirable
521 scale_factor = pow (10.0, floor (log10 (step)));
522 step /= scale_factor;
524 /* We want increments of 1, 2.5, 5, or 10 (times some power of
525 * 10). The threshold values between these are computed
526 * logarithmically. */
527 if (step < 3.535533905932738) {
528 if (step < 1.58113883008419) {
530 *minor_divisions = 4;
533 *minor_divisions = 5;
536 if (step < 7.071067811865475) {
538 *minor_divisions = 5;
541 *minor_divisions = 4;
545 /* Un-normalize and we now have the data value that we want to
547 return step * scale_factor;
550 /* Given an axis range, we can compute a desired data-space step
551 * amount for the major ticks (see _step_for_range). To get
552 * nice-looking pixel-snapped ticks we want to expand the range
555 _expand_range_for_width (double *axis_min, double *axis_max, int pixel_range)
557 double range, new_range, step, step_minor, pixel_step;
560 range = *axis_max - *axis_min;
562 step = _step_for_range (range, &minor_divisions);
563 step_minor = step / minor_divisions;
565 pixel_step = step_minor * (pixel_range / range);
567 /* We expand the range by the ratio of the pixel step to the floor
570 new_range = range * pixel_step / floor (pixel_step);
572 /* And spread the increase out on either side of the range. */
573 *axis_min -= (new_range - range) / 2.0;
574 *axis_max += (new_range - range) / 2.0;
577 /* Setup a transformation in acre->cr such that data values plotted
578 * will appear where they should within the chart.
581 _set_transform_to_data_space (acre_t *acre)
583 cairo_t *cr = acre->cr;
587 acre->chart.y + acre->chart.height);
589 acre->chart.width / (acre->x_axis.view_max - acre->x_axis.view_min),
590 - acre->chart.height /(acre->y_axis.view_max - acre->y_axis.view_min));
591 cairo_translate (cr, -acre->x_axis.view_min, -acre->y_axis.view_min);
595 _find_x_range_given_y_range (acre_t *acre,
596 double *x_min, double *x_max,
597 double y_min, double y_max)
605 for (d = 0; d < acre->num_data; d++) {
606 data = acre->data[d];
607 for (i = 0; i < data->num_points; i++) {
608 if (data->points[i].y >= y_min &&
609 data->points[i].y <= y_max)
612 *x_min = data->points[i].x;
613 *x_max = data->points[i].x;
616 if (data->points[i].x < *x_min)
617 *x_min = data->points[i].x;
618 if (data->points[i].x > *x_max)
619 *x_max = data->points[i].x;
625 /* If nothing is visible, punt to full X data range. */
627 *x_min = acre->x_axis.data_min;
628 *x_max = acre->x_axis.data_max;
633 _find_y_range_given_x_range (acre_t *acre,
634 double *y_min, double *y_max,
635 double x_min, double x_max)
643 for (d = 0; d < acre->num_data; d++) {
644 data = acre->data[d];
645 for (i = 0; i < data->num_points; i++) {
646 if (data->points[i].x >= x_min &&
647 data->points[i].x <= x_max)
650 *y_min = data->points[i].y;
651 *y_max = data->points[i].y;
654 if (data->points[i].y < *y_min)
655 *y_min = data->points[i].y;
656 if (data->points[i].y > *y_max)
657 *y_max = data->points[i].y;
663 /* If nothing is visible, punt to full Y data range. */
665 *y_min = acre->y_axis.data_min;
666 *y_max = acre->y_axis.data_max;
671 _compute_axis_ranges (acre_t *acre)
673 double x_adjust, y_adjust;
674 cairo_t *cr = acre->cr;
676 /* If neither view range is set, set both to data ranges. */
677 if (! acre->x_axis.view_range_set && ! acre->y_axis.view_range_set)
679 acre->x_axis.view_min = acre->x_axis.data_min;
680 acre->x_axis.view_max = acre->x_axis.data_max;
682 acre->y_axis.view_min = acre->y_axis.data_min;
683 acre->y_axis.view_max = acre->y_axis.data_max;
685 /* Otherwise, auto-fit unset range based on data. */
686 if (acre->x_axis.view_range_set && ! acre->y_axis.view_range_set) {
687 _find_y_range_given_x_range (acre,
688 &acre->y_axis.view_min,
689 &acre->y_axis.view_max,
690 acre->x_axis.view_min,
691 acre->x_axis.view_max);
693 else if (acre->y_axis.view_range_set && ! acre->x_axis.view_range_set) {
694 _find_x_range_given_y_range (acre,
695 &acre->x_axis.view_min,
696 &acre->x_axis.view_max,
697 acre->y_axis.view_min,
698 acre->y_axis.view_max);
702 /* Then, increase the axis ranges just enough so that the step
703 * sizes for the ticks will be integers.
705 _expand_range_for_width (&acre->x_axis.view_min,
706 &acre->x_axis.view_max,
709 _expand_range_for_width (&acre->y_axis.view_min,
710 &acre->y_axis.view_max,
713 /* Finally, we also translate the axis ranges slightly so that the
714 * ticks land on half-integer device-pixel positions.
718 _set_transform_to_data_space (acre);
722 cairo_user_to_device (cr, &x_adjust, &y_adjust);
723 x_adjust = (round (x_adjust + 0.5) - 0.5) - x_adjust;
724 y_adjust = (round (y_adjust + 0.5) - 0.5) - y_adjust;
725 cairo_device_to_user_distance (cr, &x_adjust, &y_adjust);
727 acre->x_axis.view_min -= x_adjust;
728 acre->x_axis.view_max -= x_adjust;
730 acre->y_axis.view_min -= y_adjust;
731 acre->y_axis.view_max -= y_adjust;
737 _choose_colors (acre_t *acre)
739 cmsHPROFILE lab_profile, srgb_profile;
740 cmsHTRANSFORM lab_to_srgb;
742 double theta, radius, srgb[3];
745 lab_profile = cmsCreateLabProfile (NULL); /* D50 */
746 srgb_profile = cmsCreate_sRGBProfile ();
748 lab_to_srgb = cmsCreateTransform (lab_profile, TYPE_Lab_DBL,
749 srgb_profile, TYPE_RGB_DBL,
750 INTENT_PERCEPTUAL, 0);
752 acre->num_colors = acre->num_data;
754 if (acre->num_colors > acre->colors_size) {
755 acre->colors_size = acre->num_colors;
756 acre->colors = xrealloc (acre->colors,
757 acre->colors_size * sizeof (acre_color_t));
762 for (i = 0; i < acre->num_colors; i++) {
763 theta = 0.713 + 2 * M_PI * (double) i / acre->num_colors;
764 lab.a = radius * cos (theta);
765 lab.b = radius * sin (theta);
767 cmsDoTransform (lab_to_srgb, &lab, srgb, 1);
769 acre->colors[i].red = srgb[0];
770 acre->colors[i].green = srgb[1];
771 acre->colors[i].blue = srgb[2];
774 cmsDeleteTransform (lab_to_srgb);
775 cmsCloseProfile (lab_profile);
776 cmsCloseProfile (srgb_profile);
780 _draw_data (acre_t *acre)
782 cairo_t *cr = acre->cr;
789 acre->chart.x, acre->chart.y,
790 acre->chart.width, acre->chart.height);
793 cairo_set_source_rgb (cr, 0, 0, 0);
795 _set_transform_to_data_space (acre);
797 for (d = 0; d < acre->num_data; d++) {
798 int color = d % acre->num_colors;
799 cairo_set_source_rgb (cr,
800 acre->colors[color].red,
801 acre->colors[color].green,
802 acre->colors[color].blue);
803 data = acre->data[d];
807 for (i = 0; i < data->num_points; i++) {
814 cairo_identity_matrix (cr);
815 cairo_set_line_width (cr, 1.0);
824 typedef enum _ticks { ACRE_TICKS_X, ACRE_TICKS_Y } acre_ticks_t;
827 _draw_ticks (acre_t *acre,
828 double axis_min, double axis_max,
831 cairo_t *cr = acre->cr;
832 double t, step, sub_step;
837 _set_transform_to_data_space (acre);
839 step = _step_for_range (axis_max - axis_min, &minor_divisions);
840 sub_step = step / minor_divisions;
842 for (t = (floor (axis_min / sub_step) + 1) * sub_step;
847 if (fabs((t / step) - round (t / step)) < 0.5 * (sub_step / step))
848 tick_size = ACRE_TICK_MAJOR_SIZE;
850 tick_size = ACRE_TICK_MINOR_SIZE;
855 if (ticks == ACRE_TICKS_X)
856 cairo_move_to (cr, t, acre->y_axis.view_min);
858 cairo_move_to (cr, acre->x_axis.view_min, t);
860 cairo_identity_matrix (cr);
862 if (ticks == ACRE_TICKS_X) {
863 cairo_rel_line_to (cr, 0, 0.5);
864 cairo_rel_line_to (cr, 0, -tick_size - 0.5);
866 cairo_rel_line_to (cr, -0.5, 0);
867 cairo_rel_line_to (cr, tick_size + 0.5, 0);
870 cairo_set_line_width (cr, 1.0);
876 if (tick_size == ACRE_TICK_MAJOR_SIZE)
883 layout = _create_layout_printf (acre, "%g", t);
885 if (ticks == ACRE_TICKS_X)
886 cairo_move_to (cr, t, acre->y_axis.view_min);
888 cairo_move_to (cr, acre->x_axis.view_min, t);
890 cairo_identity_matrix (cr);
891 pango_layout_get_pixel_size (layout, &width, &height);
893 if (ticks == ACRE_TICKS_X)
894 cairo_rel_move_to (cr, -width / 2, ACRE_X_TICK_VALUE_PAD);
896 cairo_rel_move_to (cr, -width - ACRE_Y_TICK_VALUE_PAD,
899 _show_layout (cr, layout);
909 _draw_legend (acre_t *acre)
912 int label_width, max_label_width = 0;
915 cairo_t *cr = acre->cr;
919 for (i = 0; i < acre->num_data; i++) {
920 layout = _create_layout (acre, acre->data[i]->name);
921 pango_layout_get_pixel_size (layout, &label_width, NULL);
922 _destroy_layout (layout);
923 if (label_width > max_label_width)
924 max_label_width = label_width;
927 width = ACRE_LEGEND_PAD + ACRE_LEGEND_LINE_SIZE + ACRE_LEGEND_PAD +
928 max_label_width + ACRE_LEGEND_PAD;
929 height = ACRE_LEGEND_PAD +
930 acre->num_data * (ACRE_FONT_SIZE + ACRE_LEGEND_PAD);
932 cairo_translate (cr, acre->chart.x, acre->chart.y);
935 acre->chart.width - ACRE_LEGEND_PAD - width,
938 cairo_rectangle (cr, -0.5, -0.5, width + 1.0, height + 1.0);
939 cairo_set_source_rgb (cr, 0, 0, 0);
940 cairo_set_line_width (cr, 1.0);
943 cairo_translate (cr, ACRE_LEGEND_PAD, ACRE_LEGEND_PAD);
945 for (i = 0; i < acre->num_data; i++) {
947 0, ACRE_LEGEND_LINE_SIZE / 2,
948 ACRE_LEGEND_LINE_SIZE, ACRE_LEGEND_LINE_SIZE / 2);
949 cairo_set_source_rgb (cr,
950 acre->colors[i % acre->num_colors].red,
951 acre->colors[i % acre->num_colors].green,
952 acre->colors[i % acre->num_colors].blue);
955 layout = _create_layout (acre, acre->data[i]->name);
956 cairo_move_to (cr, ACRE_LEGEND_LINE_SIZE + ACRE_LEGEND_PAD, 0);
957 cairo_set_source_rgb (cr, 0, 0, 0);
958 _show_layout (cr, layout);
960 cairo_translate (cr, 0, ACRE_LEGEND_PAD + ACRE_FONT_SIZE);
967 _draw_frame_and_ticks (acre_t *acre)
969 cairo_t *cr = acre->cr;
973 cairo_set_source_rgb (cr, 0, 0, 0); /* black */
976 _draw_ticks (acre, acre->x_axis.view_min, acre->x_axis.view_max, ACRE_TICKS_X);
977 _draw_ticks (acre, acre->y_axis.view_min, acre->y_axis.view_max, ACRE_TICKS_Y);
981 acre->chart.x - 0.5, acre->chart.y - 0.5,
982 acre->chart.width + 1.0, acre->chart.height + 1.0);
983 cairo_set_line_width (cr, 1.0);
989 /* Draw the plot to the given cairo context within a user-space
990 * rectangle from (0, 0) to (width, height). This size includes all
991 * space for extra-plot elements (such as the title, the axis labels,
995 acre_draw (acre_t *acre, cairo_t *cr, int width, int height)
1000 acre->height = height;
1002 acre->chart.width = width;
1003 acre->chart.height = height;
1007 cairo_set_source_rgb (cr, 1, 1, 1);
1009 _choose_colors (acre);
1011 /* We compute the axis ranges before doing label layout so that we
1012 * can account for the width of the y-axis value labels. */
1013 _compute_axis_ranges (acre);
1015 _draw_title_and_labels (acre);
1017 /* And we recompute the axis ranges now that the title and axis
1018 * label space is all measured and accounted for. */
1019 _compute_axis_ranges (acre);
1023 if (acre->num_data > 1)
1024 _draw_legend (acre);
1026 _draw_frame_and_ticks (acre);
1029 /* Create a new dataset---a collection of (x, y) datapoints. A single
1030 * plot can contain multiple datasets, (see acre_add_data). */
1032 acre_data_create (void)
1036 data = xmalloc (sizeof (acre_data_t));
1040 data->points = NULL;
1041 data->points_size = 0;
1042 data->num_points = 0;
1047 /* Destroy an acre dataset. Do not call this function if the dataset
1048 * has been added to an acre_t plot with acre_add_data. */
1050 acre_data_destroy (acre_data_t *data)
1052 free (data->points);
1057 /* Set the label for this dataset (to appear in the plot's key). */
1059 acre_data_set_name (acre_data_t *data, const char *name)
1063 data->name = strdup (name);
1066 /* Add a datapoint to the given dataset. */
1068 acre_data_add_point_2d (acre_data_t *data, double x, double y)
1070 if (data->num_points >= data->points_size) {
1071 data->points_size *= 2;
1072 if (data->points_size == 0)
1073 data->points_size = 16;
1074 data->points = xrealloc_ab (data->points,
1076 sizeof (acre_data_point_2d_t));
1079 data->points[data->num_points].x = x;
1080 data->points[data->num_points].y = y;
1082 if (data->num_points == 0) {
1089 if (x < data->min.x)
1091 if (y < data->min.y)
1094 if (x > data->max.x)
1096 if (y > data->max.y)