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;
40 /* The name of this data set. */
43 /* The style for rendering (line, bar, etc.) */
46 /* Minimum and mximum extents of data. */
47 acre_data_point_2d_t min;
48 acre_data_point_2d_t max;
50 /* The data itself. */
51 acre_data_point_2d_t *points;
52 unsigned int points_size;
53 unsigned int num_points;
55 /* The names of data points (if any).
57 * This array is indexed with the same index as the 'points' array
58 * to provide names for points. It is legal for this array to be
59 * NULL or smaller than 'points', (in which case, the
60 * corresponding points simply have no names).
63 unsigned int names_size;
64 unsigned int num_names;
67 typedef struct _acre_axis {
74 /* Range of data to be viewed. */
78 /* Has the view range been set? */
82 typedef struct _acre_color {
94 unsigned int data_size;
95 unsigned int num_data;
97 /* Data for drawing. */
99 PangoFontDescription *font;
100 acre_color_t *colors;
104 /* Total size including labels. */
108 /* Position and size of chart alone. */
109 PangoRectangle chart;
113 _find_x_range_given_y_range (acre_t *acre,
114 double *x_min, double *x_max,
115 double y_min, double y_max);
118 _find_y_range_given_x_range (acre_t *acre,
119 double *y_min, double *y_max,
120 double x_min, double x_max);
122 /* Create a new, empty plot. */
128 acre = xmalloc (sizeof (acre_t));
132 acre->x_axis.label = NULL;
133 acre->x_axis.data_min = 0.0;
134 acre->x_axis.data_max = 0.0;
135 acre->x_axis.view_min = 0.0;
136 acre->x_axis.view_max = 0.0;
137 acre->x_axis.view_range_set = false;
139 acre->y_axis.label = NULL;
140 acre->y_axis.data_min = 0.0;
141 acre->y_axis.data_max = 0.0;
142 acre->y_axis.view_min = 0.0;
143 acre->y_axis.view_max = 0.0;
144 acre->y_axis.view_range_set = false;
153 acre->num_colors = 0;
154 acre->colors_size = 0;
161 acre->chart.width = 0;
162 acre->chart.height = 0;
167 /* Destroy a plot. */
169 acre_destroy (acre_t *acre)
174 free (acre->x_axis.label);
175 free (acre->y_axis.label);
177 for (i = 0; i < acre->num_data; i++)
178 acre_data_destroy (acre->data[i]);
188 acre_set_title (acre_t *acre, const char *title)
192 acre->title = strdup (title);
196 acre_set_x_axis_label (acre_t *acre, const char *label)
198 free (acre->x_axis.label);
200 acre->x_axis.label = strdup (label);
204 acre_set_y_axis_label (acre_t *acre, const char *label)
206 free (acre->y_axis.label);
208 acre->y_axis.label = strdup (label);
212 acre_get_x_axis_data_range (acre_t *acre, double *x_min, double *x_max)
215 *x_min = acre->x_axis.data_min;
218 *x_max = acre->x_axis.data_max;
222 acre_get_x_axis_range (acre_t *acre, double *x_min, double *x_max)
224 /* If an X range has been set, return that. */
225 if (acre->x_axis.view_range_set) {
227 *x_min = acre->x_axis.view_min;
230 *x_max = acre->x_axis.view_max;
235 /* Otherwise, if a Y range has been set, use that to compute X. */
236 if (acre->y_axis.view_range_set) {
237 _find_x_range_given_y_range (acre, x_min, x_max,
238 acre->y_axis.view_min,
239 acre->y_axis.view_max);
244 /* Neither view range set. Return full, data-based X range. */
245 acre_get_x_axis_data_range (acre, x_min, x_max);
249 acre_set_x_axis_range (acre_t *acre, double x_min, double x_max)
251 acre->x_axis.view_min = x_min;
252 acre->x_axis.view_max = x_max;
254 acre->x_axis.view_range_set = true;
258 acre_set_x_axis_range_auto (acre_t *acre)
260 acre->x_axis.view_range_set = false;
264 acre_get_y_axis_data_range (acre_t *acre, double *y_min, double *y_max)
267 *y_min = acre->y_axis.data_min;
270 *y_max = acre->y_axis.data_max;
274 acre_get_y_axis_range (acre_t *acre, double *y_min, double *y_max)
276 /* If a Y range has been set, return that. */
277 if (acre->y_axis.view_range_set) {
279 *y_min = acre->y_axis.view_min;
282 *y_max = acre->y_axis.view_max;
287 /* Otherwise, if an X range has been set, use that to compute Y. */
288 if (acre->x_axis.view_range_set) {
289 _find_y_range_given_x_range (acre, y_min, y_max,
290 acre->x_axis.view_min,
291 acre->x_axis.view_max);
296 /* Neither view range set. Return full data-based Y range. */
297 acre_get_y_axis_data_range (acre, y_min, y_max);
301 acre_set_y_axis_range (acre_t *acre, double y_min, double y_max)
303 acre->y_axis.view_min = y_min;
304 acre->y_axis.view_max = y_max;
306 acre->y_axis.view_range_set = true;
310 acre_set_y_axis_range_auto (acre_t *acre)
312 acre->y_axis.view_range_set = false;
315 /* Add a dataset to the plot. The plot assumes ownership of the
316 * dataset so it is not necessary to call acre_data_destroy on it. */
318 acre_add_data (acre_t *acre, acre_data_t *data)
320 if (acre->num_data >= acre->data_size) {
321 acre->data_size *= 2;
322 if (acre->data_size == 0)
324 acre->data = xrealloc_ab (acre->data,
326 sizeof (acre_data_t *));
329 acre->data[acre->num_data] = data;
331 if (acre->num_data == 0) {
332 acre->x_axis.data_min = data->min.x;
333 acre->y_axis.data_min = data->min.y;
335 acre->x_axis.data_max = data->max.x;
336 acre->y_axis.data_max = data->max.y;
338 if (data->min.x < acre->x_axis.data_min)
339 acre->x_axis.data_min = data->min.x;
340 if (data->min.y < acre->y_axis.data_min)
341 acre->y_axis.data_min = data->min.y;
343 if (data->max.x > acre->x_axis.data_max)
344 acre->x_axis.data_max = data->max.x;
345 if (data->max.y > acre->y_axis.data_max)
346 acre->y_axis.data_max = data->max.y;
352 #define ACRE_FONT_FAMILY "sans"
353 #define ACRE_FONT_SIZE 12
354 #define ACRE_TITLE_FONT_SIZE 20
355 #define ACRE_PAD (ACRE_FONT_SIZE)
356 #define ACRE_TICK_MAJOR_SIZE 6
357 #define ACRE_TICK_MINOR_SIZE 3
358 #define ACRE_X_TICK_VALUE_PAD 2
359 #define ACRE_Y_TICK_VALUE_PAD 4
360 #define ACRE_LEGEND_PAD 4
361 #define ACRE_LEGEND_LINE_SIZE 10
364 _create_layout (acre_t *acre, const char *text)
371 cairo_save (acre->cr);
372 cairo_identity_matrix (acre->cr);
374 layout = pango_cairo_create_layout (acre->cr);
375 pango_layout_set_font_description (layout, acre->font);
376 pango_layout_set_text (layout, text, -1);
377 pango_layout_set_alignment (layout, PANGO_ALIGN_CENTER);
379 cairo_restore (acre->cr);
384 #define PRINTF_FORMAT(fmt_index, va_index) __attribute__ ((__format__(__printf__, fmt_index, va_index)))
387 _create_layout_vprintf (acre_t *acre, const char *fmt, va_list ap)
392 vasprintf (&text, fmt, ap);
394 layout = _create_layout (acre, text);
402 _create_layout_printf (acre_t *acre, const char *fmt, ...)
403 PRINTF_FORMAT (2, 3);
406 _create_layout_printf (acre_t *acre, const char *fmt, ...)
413 layout = _create_layout_vprintf (acre, fmt, ap);
421 _destroy_layout (PangoLayout *layout)
423 g_object_unref (layout);
427 _show_layout (cairo_t *cr, PangoLayout *layout)
429 pango_cairo_show_layout (cr, layout);
431 _destroy_layout (layout);
435 _draw_title_and_labels (acre_t *acre)
437 cairo_t *cr = acre->cr;
438 PangoFontDescription *title_font;
439 PangoLayout *title_layout, *x_axis_layout, *y_axis_layout;
440 PangoLayout *min_y, *max_y;
441 int min_y_width, max_y_width, y_axis_value_width;
442 int title_width, title_height;
443 int x_axis_width, x_axis_height;
444 int y_axis_width, y_axis_height;
445 PangoRectangle new_chart;
449 acre->font = pango_font_description_new ();
450 pango_font_description_set_family (acre->font, ACRE_FONT_FAMILY);
451 pango_font_description_set_absolute_size (acre->font,
452 ACRE_FONT_SIZE * PANGO_SCALE);
454 title_font = pango_font_description_new ();
455 pango_font_description_set_family (title_font, ACRE_FONT_FAMILY);
456 pango_font_description_set_absolute_size (title_font,
457 ACRE_TITLE_FONT_SIZE * PANGO_SCALE);
459 title_layout = _create_layout (acre, acre->title);
460 pango_layout_set_font_description (title_layout, title_font);
461 pango_font_description_free (title_font);
463 x_axis_layout = _create_layout (acre, acre->x_axis.label);
464 y_axis_layout = _create_layout (acre, acre->y_axis.label);
466 min_y = _create_layout_printf (acre, "%g",
467 round (acre->y_axis.view_min));
468 max_y = _create_layout_printf (acre, "%g",
469 round (acre->y_axis.view_max));
471 pango_layout_get_pixel_size (min_y, &min_y_width, NULL);
472 pango_layout_get_pixel_size (max_y, &max_y_width, NULL);
473 y_axis_value_width = MAX (min_y_width, max_y_width);
475 _destroy_layout (min_y);
476 _destroy_layout (max_y);
478 /* Iterate with the layout of the title and axis labels until they
479 * are stable, (this requires iteration since we don't know what
480 * to set their widths to in advance due to the wrapping of the
481 * other elements). */
483 pango_layout_set_width (title_layout, acre->chart.width * PANGO_SCALE);
484 pango_layout_set_width (x_axis_layout, acre->chart.width * PANGO_SCALE);
485 pango_layout_set_width (y_axis_layout, acre->chart.height * PANGO_SCALE);
487 pango_layout_get_pixel_size (title_layout, &title_width, &title_height);
488 pango_layout_get_pixel_size (x_axis_layout, &x_axis_width, &x_axis_height);
489 pango_layout_get_pixel_size (y_axis_layout, &y_axis_width, &y_axis_height);
491 new_chart.x = ACRE_PAD + y_axis_height +
492 ACRE_PAD + y_axis_value_width + ACRE_Y_TICK_VALUE_PAD;
493 new_chart.width = acre->width - acre->chart.x - ACRE_PAD;
495 new_chart.y = ACRE_PAD + title_height + ACRE_PAD;
496 new_chart.height = acre->height - acre->chart.y -
497 (ACRE_X_TICK_VALUE_PAD + ACRE_FONT_SIZE +
498 ACRE_PAD + x_axis_height + ACRE_PAD);
500 if (new_chart.x == acre->chart.x &&
501 new_chart.y == acre->chart.y &&
502 new_chart.width == acre->chart.width &&
503 new_chart.height == acre->chart.height)
508 acre->chart.x = new_chart.x;
509 acre->chart.y = new_chart.y;
510 acre->chart.width = new_chart.width;
511 acre->chart.height = new_chart.height;
514 cairo_set_source_rgb (cr, 0, 0, 0);
516 cairo_move_to (cr, acre->chart.x, ACRE_PAD);
517 _show_layout (cr, title_layout);
521 cairo_translate (cr, ACRE_PAD, acre->chart.y + acre->chart.height);
522 cairo_rotate (cr, - M_PI / 2.0);
523 cairo_move_to (cr, 0, 0);
524 _show_layout (cr, y_axis_layout);
528 cairo_move_to (cr, acre->chart.x,
529 acre->chart.y + acre->chart.height +
530 ACRE_FONT_SIZE + ACRE_PAD);
531 _show_layout (cr, x_axis_layout);
536 /* For a given axis range, compute a step size (in data space) to
537 * generate a suitable number of ticks (5 or so). */
539 _step_for_range (double range, int *minor_divisions)
541 double step, scale_factor;
543 /* We want roughly 5 major ticks for the chart. */
546 /* Normalize the step so we can easily snap it to a desirable
548 scale_factor = pow (10.0, floor (log10 (step)));
549 step /= scale_factor;
551 /* We want increments of 1, 2.5, 5, or 10 (times some power of
552 * 10). The threshold values between these are computed
553 * logarithmically. */
554 if (step < 3.535533905932738) {
555 if (step < 1.58113883008419) {
557 *minor_divisions = 4;
560 *minor_divisions = 5;
563 if (step < 7.071067811865475) {
565 *minor_divisions = 5;
568 *minor_divisions = 4;
572 /* Un-normalize and we now have the data value that we want to
574 return step * scale_factor;
577 /* Given an axis range, we can compute a desired data-space step
578 * amount for the major ticks (see _step_for_range). To get
579 * nice-looking pixel-snapped ticks we want to expand the range
582 _expand_range_for_width (double *axis_min, double *axis_max, int pixel_range)
584 double range, new_range, step, step_minor, pixel_step;
587 range = *axis_max - *axis_min;
589 step = _step_for_range (range, &minor_divisions);
590 step_minor = step / minor_divisions;
592 pixel_step = step_minor * (pixel_range / range);
594 /* We expand the range by the ratio of the pixel step to the floor
597 new_range = range * pixel_step / floor (pixel_step);
599 /* And spread the increase out on either side of the range. */
600 *axis_min -= (new_range - range) / 2.0;
601 *axis_max += (new_range - range) / 2.0;
604 /* Setup a transformation in acre->cr such that data values plotted
605 * will appear where they should within the chart.
608 _set_transform_to_data_space (acre_t *acre)
610 cairo_t *cr = acre->cr;
614 acre->chart.y + acre->chart.height);
616 acre->chart.width / (acre->x_axis.view_max - acre->x_axis.view_min),
617 - acre->chart.height /(acre->y_axis.view_max - acre->y_axis.view_min));
618 cairo_translate (cr, -acre->x_axis.view_min, -acre->y_axis.view_min);
622 _find_x_range_given_y_range (acre_t *acre,
623 double *x_min, double *x_max,
624 double y_min, double y_max)
632 for (d = 0; d < acre->num_data; d++) {
633 data = acre->data[d];
634 for (i = 0; i < data->num_points; i++) {
635 if (data->points[i].y >= y_min &&
636 data->points[i].y <= y_max)
639 *x_min = data->points[i].x;
640 *x_max = data->points[i].x;
643 if (data->points[i].x < *x_min)
644 *x_min = data->points[i].x;
645 if (data->points[i].x > *x_max)
646 *x_max = data->points[i].x;
652 /* If nothing is visible, punt to full X data range. */
654 *x_min = acre->x_axis.data_min;
655 *x_max = acre->x_axis.data_max;
660 _find_y_range_given_x_range (acre_t *acre,
661 double *y_min, double *y_max,
662 double x_min, double x_max)
670 for (d = 0; d < acre->num_data; d++) {
671 data = acre->data[d];
672 for (i = 0; i < data->num_points; i++) {
673 if (data->points[i].x >= x_min &&
674 data->points[i].x <= x_max)
677 *y_min = data->points[i].y;
678 *y_max = data->points[i].y;
681 if (data->points[i].y < *y_min)
682 *y_min = data->points[i].y;
683 if (data->points[i].y > *y_max)
684 *y_max = data->points[i].y;
690 /* If nothing is visible, punt to full Y data range. */
692 *y_min = acre->y_axis.data_min;
693 *y_max = acre->y_axis.data_max;
698 _compute_axis_ranges (acre_t *acre)
700 double x_adjust, y_adjust;
701 cairo_t *cr = acre->cr;
703 /* If neither view range is set, set both to data ranges. */
704 if (! acre->x_axis.view_range_set && ! acre->y_axis.view_range_set)
706 acre->x_axis.view_min = acre->x_axis.data_min;
707 acre->x_axis.view_max = acre->x_axis.data_max;
709 acre->y_axis.view_min = acre->y_axis.data_min;
710 acre->y_axis.view_max = acre->y_axis.data_max;
712 /* Otherwise, auto-fit unset range based on data. */
713 if (acre->x_axis.view_range_set && ! acre->y_axis.view_range_set) {
714 _find_y_range_given_x_range (acre,
715 &acre->y_axis.view_min,
716 &acre->y_axis.view_max,
717 acre->x_axis.view_min,
718 acre->x_axis.view_max);
720 else if (acre->y_axis.view_range_set && ! acre->x_axis.view_range_set) {
721 _find_x_range_given_y_range (acre,
722 &acre->x_axis.view_min,
723 &acre->x_axis.view_max,
724 acre->y_axis.view_min,
725 acre->y_axis.view_max);
729 /* Then, increase the axis ranges just enough so that the step
730 * sizes for the ticks will be integers.
732 _expand_range_for_width (&acre->x_axis.view_min,
733 &acre->x_axis.view_max,
736 _expand_range_for_width (&acre->y_axis.view_min,
737 &acre->y_axis.view_max,
740 /* Finally, we also translate the axis ranges slightly so that the
741 * ticks land on half-integer device-pixel positions.
745 _set_transform_to_data_space (acre);
749 cairo_user_to_device (cr, &x_adjust, &y_adjust);
750 x_adjust = (round (x_adjust + 0.5) - 0.5) - x_adjust;
751 y_adjust = (round (y_adjust + 0.5) - 0.5) - y_adjust;
752 cairo_device_to_user_distance (cr, &x_adjust, &y_adjust);
754 acre->x_axis.view_min -= x_adjust;
755 acre->x_axis.view_max -= x_adjust;
757 acre->y_axis.view_min -= y_adjust;
758 acre->y_axis.view_max -= y_adjust;
764 _choose_colors (acre_t *acre)
766 cmsHPROFILE lab_profile, srgb_profile;
767 cmsHTRANSFORM lab_to_srgb;
769 double theta, radius, srgb[3];
772 lab_profile = cmsCreateLabProfile (NULL); /* D50 */
773 srgb_profile = cmsCreate_sRGBProfile ();
775 lab_to_srgb = cmsCreateTransform (lab_profile, TYPE_Lab_DBL,
776 srgb_profile, TYPE_RGB_DBL,
777 INTENT_PERCEPTUAL, 0);
779 acre->num_colors = acre->num_data;
781 if (acre->num_colors > acre->colors_size) {
782 acre->colors_size = acre->num_colors;
783 acre->colors = xrealloc (acre->colors,
784 acre->colors_size * sizeof (acre_color_t));
789 for (i = 0; i < acre->num_colors; i++) {
790 theta = 0.713 + 2 * M_PI * (double) i / acre->num_colors;
791 lab.a = radius * cos (theta);
792 lab.b = radius * sin (theta);
794 cmsDoTransform (lab_to_srgb, &lab, srgb, 1);
796 acre->colors[i].red = srgb[0];
797 acre->colors[i].green = srgb[1];
798 acre->colors[i].blue = srgb[2];
801 cmsDeleteTransform (lab_to_srgb);
802 cmsCloseProfile (lab_profile);
803 cmsCloseProfile (srgb_profile);
806 /* Draw the given dataset as a line. */
808 _draw_data_line (acre_t *acre, acre_data_t *data)
811 cairo_t *cr = acre->cr;
817 for (i = 0; i < data->num_points; i++) {
823 cairo_identity_matrix (cr);
824 cairo_set_line_width (cr, 1.0);
830 /* Draw all the datasets of the chart. */
832 _draw_data (acre_t *acre)
834 cairo_t *cr = acre->cr;
841 acre->chart.x, acre->chart.y,
842 acre->chart.width, acre->chart.height);
845 cairo_set_source_rgb (cr, 0, 0, 0);
847 _set_transform_to_data_space (acre);
849 for (i = 0; i < acre->num_data; i++) {
850 int color = i % acre->num_colors;
851 cairo_set_source_rgb (cr,
852 acre->colors[color].red,
853 acre->colors[color].green,
854 acre->colors[color].blue);
855 data = acre->data[i];
857 switch (data->style) {
858 case ACRE_STYLE_LINE:
859 _draw_data_line (acre, data);
867 typedef enum _ticks { ACRE_TICKS_X, ACRE_TICKS_Y } acre_ticks_t;
870 _draw_ticks (acre_t *acre,
871 double axis_min, double axis_max,
874 cairo_t *cr = acre->cr;
875 double t, step, sub_step;
880 _set_transform_to_data_space (acre);
882 step = _step_for_range (axis_max - axis_min, &minor_divisions);
883 sub_step = step / minor_divisions;
885 for (t = (floor (axis_min / sub_step) + 1) * sub_step;
890 if (fabs((t / step) - round (t / step)) < 0.5 * (sub_step / step))
891 tick_size = ACRE_TICK_MAJOR_SIZE;
893 tick_size = ACRE_TICK_MINOR_SIZE;
898 if (ticks == ACRE_TICKS_X)
899 cairo_move_to (cr, t, acre->y_axis.view_min);
901 cairo_move_to (cr, acre->x_axis.view_min, t);
903 cairo_identity_matrix (cr);
905 if (ticks == ACRE_TICKS_X) {
906 cairo_rel_line_to (cr, 0, 0.5);
907 cairo_rel_line_to (cr, 0, -tick_size - 0.5);
909 cairo_rel_line_to (cr, -0.5, 0);
910 cairo_rel_line_to (cr, tick_size + 0.5, 0);
913 cairo_set_line_width (cr, 1.0);
919 if (tick_size == ACRE_TICK_MAJOR_SIZE)
928 if (fabs (label_value) < (sub_step / 1000.))
930 layout = _create_layout_printf (acre, "%g", label_value);
932 if (ticks == ACRE_TICKS_X)
933 cairo_move_to (cr, t, acre->y_axis.view_min);
935 cairo_move_to (cr, acre->x_axis.view_min, t);
937 cairo_identity_matrix (cr);
938 pango_layout_get_pixel_size (layout, &width, &height);
940 if (ticks == ACRE_TICKS_X)
941 cairo_rel_move_to (cr, -width / 2, ACRE_X_TICK_VALUE_PAD);
943 cairo_rel_move_to (cr, -width - ACRE_Y_TICK_VALUE_PAD,
946 _show_layout (cr, layout);
956 _draw_legend (acre_t *acre)
959 int label_width, max_label_width = 0;
962 cairo_t *cr = acre->cr;
966 for (i = 0; i < acre->num_data; i++) {
967 layout = _create_layout (acre, acre->data[i]->name);
968 pango_layout_get_pixel_size (layout, &label_width, NULL);
969 _destroy_layout (layout);
970 if (label_width > max_label_width)
971 max_label_width = label_width;
974 width = ACRE_LEGEND_PAD + ACRE_LEGEND_LINE_SIZE + ACRE_LEGEND_PAD +
975 max_label_width + ACRE_LEGEND_PAD;
976 height = ACRE_LEGEND_PAD +
977 acre->num_data * (ACRE_FONT_SIZE + ACRE_LEGEND_PAD);
979 cairo_translate (cr, acre->chart.x, acre->chart.y);
982 acre->chart.width - ACRE_LEGEND_PAD - width,
985 cairo_rectangle (cr, -0.5, -0.5, width + 1.0, height + 1.0);
986 cairo_set_source_rgb (cr, 0, 0, 0);
987 cairo_set_line_width (cr, 1.0);
990 cairo_translate (cr, ACRE_LEGEND_PAD, ACRE_LEGEND_PAD);
992 for (i = 0; i < acre->num_data; i++) {
994 0, ACRE_LEGEND_LINE_SIZE / 2,
995 ACRE_LEGEND_LINE_SIZE, ACRE_LEGEND_LINE_SIZE / 2);
996 cairo_set_source_rgb (cr,
997 acre->colors[i % acre->num_colors].red,
998 acre->colors[i % acre->num_colors].green,
999 acre->colors[i % acre->num_colors].blue);
1002 layout = _create_layout (acre, acre->data[i]->name);
1003 cairo_move_to (cr, ACRE_LEGEND_LINE_SIZE + ACRE_LEGEND_PAD, 0);
1004 cairo_set_source_rgb (cr, 0, 0, 0);
1005 _show_layout (cr, layout);
1007 cairo_translate (cr, 0, ACRE_LEGEND_PAD + ACRE_FONT_SIZE);
1014 _draw_frame_and_ticks (acre_t *acre)
1016 cairo_t *cr = acre->cr;
1020 cairo_set_source_rgb (cr, 0, 0, 0); /* black */
1023 _draw_ticks (acre, acre->x_axis.view_min, acre->x_axis.view_max, ACRE_TICKS_X);
1024 _draw_ticks (acre, acre->y_axis.view_min, acre->y_axis.view_max, ACRE_TICKS_Y);
1027 cairo_rectangle (cr,
1028 acre->chart.x - 0.5, acre->chart.y - 0.5,
1029 acre->chart.width + 1.0, acre->chart.height + 1.0);
1030 cairo_set_line_width (cr, 1.0);
1036 /* Draw the plot to the given cairo context within a user-space
1037 * rectangle from (0, 0) to (width, height). This size includes all
1038 * space for extra-plot elements (such as the title, the axis labels,
1042 acre_draw (acre_t *acre, cairo_t *cr, int width, int height)
1046 acre->width = width;
1047 acre->height = height;
1049 acre->chart.width = width;
1050 acre->chart.height = height;
1054 cairo_set_source_rgb (cr, 1, 1, 1);
1056 _choose_colors (acre);
1058 /* We compute the axis ranges before doing label layout so that we
1059 * can account for the width of the y-axis value labels. */
1060 _compute_axis_ranges (acre);
1062 _draw_title_and_labels (acre);
1064 /* And we recompute the axis ranges now that the title and axis
1065 * label space is all measured and accounted for. */
1066 _compute_axis_ranges (acre);
1070 if (acre->num_data > 1)
1071 _draw_legend (acre);
1073 _draw_frame_and_ticks (acre);
1076 /* Create a new dataset---a collection of (x, y) datapoints. A single
1077 * plot can contain multiple datasets, (see acre_add_data). */
1079 acre_data_create (void)
1083 data = xmalloc (sizeof (acre_data_t));
1087 data->style = ACRE_STYLE_LINE;
1089 data->points = NULL;
1090 data->points_size = 0;
1091 data->num_points = 0;
1096 /* Destroy an acre dataset. Do not call this function if the dataset
1097 * has been added to an acre_t plot with acre_add_data. */
1099 acre_data_destroy (acre_data_t *data)
1103 for (i = 0; i < data->num_names; i++) {
1105 free (data->names[i]);
1111 free (data->points);
1116 /* Set the label for this dataset (to appear in the plot's key). */
1118 acre_data_set_name (acre_data_t *data, const char *name)
1122 data->name = strdup (name);
1125 /* Add a datapoint to the given dataset. */
1127 acre_data_add_point_2d (acre_data_t *data, double x, double y)
1129 if (data->num_points >= data->points_size) {
1130 data->points_size *= 2;
1131 if (data->points_size == 0)
1132 data->points_size = 16;
1133 data->points = xrealloc_ab (data->points,
1135 sizeof (acre_data_point_2d_t));
1138 data->points[data->num_points].x = x;
1139 data->points[data->num_points].y = y;
1141 if (data->num_points == 0) {
1148 if (x < data->min.x)
1150 if (y < data->min.y)
1153 if (x > data->max.x)
1155 if (y > data->max.y)
1162 /* Add a datapoint with a name to the given dataset. */
1164 acre_data_add_point_2d_named (acre_data_t *data, double x, double y, const char *name)
1168 acre_data_add_point_2d (data, x, y);
1170 if (data->names_size < data->points_size) {
1171 data->names_size = data->points_size;
1172 data->names = xrealloc_ab (data->names,
1177 /* Initialize any newly-created holes in the array to NULL. */
1178 for (i = data->num_names; i < data->num_points - 1; i++)
1179 data->names[i] = NULL;
1181 data->num_names = data->num_points;
1183 data->names[data->num_names - 1] = xstrdup (name);