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 /* For timeline datasets, the X and Y ranges need to be
332 * adjusted. The desired X range is the min/max of the X and Y
333 * ranges, and the desired Y range has a size of 1.0 (centered
334 * around the dataset's index) */
335 if (data->style == ACRE_STYLE_TIMELINE) {
336 if (data->min.y < data->min.x)
337 data->min.x = data->min.y;
338 if (data->max.y > data->max.x)
339 data->max.x = data->max.y;
341 data->min.y = acre->num_data -0.5;
342 data->max.y = acre->num_data + 0.5;
345 if (acre->num_data == 0) {
346 acre->x_axis.data_min = data->min.x;
347 acre->y_axis.data_min = data->min.y;
349 acre->x_axis.data_max = data->max.x;
350 acre->y_axis.data_max = data->max.y;
352 if (data->min.x < acre->x_axis.data_min)
353 acre->x_axis.data_min = data->min.x;
354 if (data->min.y < acre->y_axis.data_min)
355 acre->y_axis.data_min = data->min.y;
357 if (data->max.x > acre->x_axis.data_max)
358 acre->x_axis.data_max = data->max.x;
359 if (data->max.y > acre->y_axis.data_max)
360 acre->y_axis.data_max = data->max.y;
366 #define ACRE_FONT_FAMILY "sans"
367 #define ACRE_FONT_SIZE 12
368 #define ACRE_TITLE_FONT_SIZE 20
369 #define ACRE_PAD (ACRE_FONT_SIZE)
370 #define ACRE_TICK_MAJOR_SIZE 6
371 #define ACRE_TICK_MINOR_SIZE 3
372 #define ACRE_X_TICK_VALUE_PAD 2
373 #define ACRE_Y_TICK_VALUE_PAD 4
374 #define ACRE_LEGEND_PAD 4
375 #define ACRE_LEGEND_LINE_SIZE 10
378 _create_layout (acre_t *acre, const char *text)
385 cairo_save (acre->cr);
386 cairo_identity_matrix (acre->cr);
388 layout = pango_cairo_create_layout (acre->cr);
389 pango_layout_set_font_description (layout, acre->font);
390 pango_layout_set_text (layout, text, -1);
391 pango_layout_set_alignment (layout, PANGO_ALIGN_CENTER);
393 cairo_restore (acre->cr);
398 #define PRINTF_FORMAT(fmt_index, va_index) __attribute__ ((__format__(__printf__, fmt_index, va_index)))
401 _create_layout_vprintf (acre_t *acre, const char *fmt, va_list ap)
406 vasprintf (&text, fmt, ap);
408 layout = _create_layout (acre, text);
416 _create_layout_printf (acre_t *acre, const char *fmt, ...)
417 PRINTF_FORMAT (2, 3);
420 _create_layout_printf (acre_t *acre, const char *fmt, ...)
427 layout = _create_layout_vprintf (acre, fmt, ap);
435 _destroy_layout (PangoLayout *layout)
437 g_object_unref (layout);
441 _show_layout (cairo_t *cr, PangoLayout *layout)
443 pango_cairo_show_layout (cr, layout);
445 _destroy_layout (layout);
449 _draw_title_and_labels (acre_t *acre)
451 cairo_t *cr = acre->cr;
452 PangoFontDescription *title_font;
453 PangoLayout *title_layout, *x_axis_layout, *y_axis_layout;
454 PangoLayout *min_y, *max_y;
455 int min_y_width, max_y_width, y_axis_value_width;
456 int title_width, title_height;
457 int x_axis_width, x_axis_height;
458 int y_axis_width, y_axis_height;
459 PangoRectangle new_chart;
463 acre->font = pango_font_description_new ();
464 pango_font_description_set_family (acre->font, ACRE_FONT_FAMILY);
465 pango_font_description_set_absolute_size (acre->font,
466 ACRE_FONT_SIZE * PANGO_SCALE);
468 title_font = pango_font_description_new ();
469 pango_font_description_set_family (title_font, ACRE_FONT_FAMILY);
470 pango_font_description_set_absolute_size (title_font,
471 ACRE_TITLE_FONT_SIZE * PANGO_SCALE);
473 title_layout = _create_layout (acre, acre->title);
474 pango_layout_set_font_description (title_layout, title_font);
475 pango_font_description_free (title_font);
477 x_axis_layout = _create_layout (acre, acre->x_axis.label);
478 y_axis_layout = _create_layout (acre, acre->y_axis.label);
480 min_y = _create_layout_printf (acre, "%g",
481 round (acre->y_axis.view_min));
482 max_y = _create_layout_printf (acre, "%g",
483 round (acre->y_axis.view_max));
485 pango_layout_get_pixel_size (min_y, &min_y_width, NULL);
486 pango_layout_get_pixel_size (max_y, &max_y_width, NULL);
487 y_axis_value_width = MAX (min_y_width, max_y_width);
489 _destroy_layout (min_y);
490 _destroy_layout (max_y);
492 /* Iterate with the layout of the title and axis labels until they
493 * are stable, (this requires iteration since we don't know what
494 * to set their widths to in advance due to the wrapping of the
495 * other elements). */
497 pango_layout_set_width (title_layout, acre->chart.width * PANGO_SCALE);
498 pango_layout_set_width (x_axis_layout, acre->chart.width * PANGO_SCALE);
499 pango_layout_set_width (y_axis_layout, acre->chart.height * PANGO_SCALE);
501 pango_layout_get_pixel_size (title_layout, &title_width, &title_height);
502 pango_layout_get_pixel_size (x_axis_layout, &x_axis_width, &x_axis_height);
503 pango_layout_get_pixel_size (y_axis_layout, &y_axis_width, &y_axis_height);
505 new_chart.x = ACRE_PAD + y_axis_height +
506 ACRE_PAD + y_axis_value_width + ACRE_Y_TICK_VALUE_PAD;
507 new_chart.width = acre->width - acre->chart.x - ACRE_PAD;
509 new_chart.y = ACRE_PAD + title_height + ACRE_PAD;
510 new_chart.height = acre->height - acre->chart.y -
511 (ACRE_X_TICK_VALUE_PAD + ACRE_FONT_SIZE +
512 ACRE_PAD + x_axis_height + ACRE_PAD);
514 if (new_chart.x == acre->chart.x &&
515 new_chart.y == acre->chart.y &&
516 new_chart.width == acre->chart.width &&
517 new_chart.height == acre->chart.height)
522 acre->chart.x = new_chart.x;
523 acre->chart.y = new_chart.y;
524 acre->chart.width = new_chart.width;
525 acre->chart.height = new_chart.height;
528 cairo_set_source_rgb (cr, 0, 0, 0);
530 cairo_move_to (cr, acre->chart.x, ACRE_PAD);
531 _show_layout (cr, title_layout);
535 cairo_translate (cr, ACRE_PAD, acre->chart.y + acre->chart.height);
536 cairo_rotate (cr, - M_PI / 2.0);
537 cairo_move_to (cr, 0, 0);
538 _show_layout (cr, y_axis_layout);
542 cairo_move_to (cr, acre->chart.x,
543 acre->chart.y + acre->chart.height +
544 ACRE_FONT_SIZE + ACRE_PAD);
545 _show_layout (cr, x_axis_layout);
550 /* For a given axis range, compute a step size (in data space) to
551 * generate a suitable number of ticks (5 or so). */
553 _step_for_range (double range, int *minor_divisions)
555 double step, scale_factor;
557 /* We want roughly 5 major ticks for the chart. */
560 /* Normalize the step so we can easily snap it to a desirable
562 scale_factor = pow (10.0, floor (log10 (step)));
563 step /= scale_factor;
565 /* We want increments of 1, 2.5, 5, or 10 (times some power of
566 * 10). The threshold values between these are computed
567 * logarithmically. */
568 if (step < 3.535533905932738) {
569 if (step < 1.58113883008419) {
571 *minor_divisions = 4;
574 *minor_divisions = 5;
577 if (step < 7.071067811865475) {
579 *minor_divisions = 5;
582 *minor_divisions = 4;
586 /* Un-normalize and we now have the data value that we want to
588 return step * scale_factor;
591 /* Given an axis range, we can compute a desired data-space step
592 * amount for the major ticks (see _step_for_range). To get
593 * nice-looking pixel-snapped ticks we want to expand the range
596 _expand_range_for_width (double *axis_min, double *axis_max, int pixel_range)
598 double range, new_range, step, step_minor, pixel_step;
601 range = *axis_max - *axis_min;
603 step = _step_for_range (range, &minor_divisions);
604 step_minor = step / minor_divisions;
606 pixel_step = step_minor * (pixel_range / range);
608 /* We expand the range by the ratio of the pixel step to the floor
611 new_range = range * pixel_step / floor (pixel_step);
613 /* And spread the increase out on either side of the range. */
614 *axis_min -= (new_range - range) / 2.0;
615 *axis_max += (new_range - range) / 2.0;
618 /* Setup a transformation in acre->cr such that data values plotted
619 * will appear where they should within the chart.
622 _set_transform_to_data_space (acre_t *acre)
624 cairo_t *cr = acre->cr;
628 acre->chart.y + acre->chart.height);
630 acre->chart.width / (acre->x_axis.view_max - acre->x_axis.view_min),
631 - acre->chart.height /(acre->y_axis.view_max - acre->y_axis.view_min));
632 cairo_translate (cr, -acre->x_axis.view_min, -acre->y_axis.view_min);
636 _find_x_range_given_y_range (acre_t *acre,
637 double *x_min, double *x_max,
638 double y_min, double y_max)
646 for (d = 0; d < acre->num_data; d++) {
647 data = acre->data[d];
648 for (i = 0; i < data->num_points; i++) {
649 if (data->points[i].y >= y_min &&
650 data->points[i].y <= y_max)
653 *x_min = data->points[i].x;
654 *x_max = data->points[i].x;
657 if (data->points[i].x < *x_min)
658 *x_min = data->points[i].x;
659 if (data->points[i].x > *x_max)
660 *x_max = data->points[i].x;
666 /* If nothing is visible, punt to full X data range. */
668 *x_min = acre->x_axis.data_min;
669 *x_max = acre->x_axis.data_max;
674 _find_y_range_given_x_range (acre_t *acre,
675 double *y_min, double *y_max,
676 double x_min, double x_max)
684 for (d = 0; d < acre->num_data; d++) {
685 data = acre->data[d];
687 /* Never mess with the Y range for timeline data. */
688 if (data->style == ACRE_STYLE_TIMELINE)
691 for (i = 0; i < data->num_points; i++) {
692 if (data->points[i].x >= x_min &&
693 data->points[i].x <= x_max)
696 *y_min = data->points[i].y;
697 *y_max = data->points[i].y;
700 if (data->points[i].y < *y_min)
701 *y_min = data->points[i].y;
702 if (data->points[i].y > *y_max)
703 *y_max = data->points[i].y;
709 /* If nothing is visible, punt to full Y data range. */
711 *y_min = acre->y_axis.data_min;
712 *y_max = acre->y_axis.data_max;
717 _compute_axis_ranges (acre_t *acre)
719 double x_adjust, y_adjust;
720 cairo_t *cr = acre->cr;
722 /* If neither view range is set, set both to data ranges. */
723 if (! acre->x_axis.view_range_set && ! acre->y_axis.view_range_set)
725 acre->x_axis.view_min = acre->x_axis.data_min;
726 acre->x_axis.view_max = acre->x_axis.data_max;
728 acre->y_axis.view_min = acre->y_axis.data_min;
729 acre->y_axis.view_max = acre->y_axis.data_max;
731 /* Otherwise, auto-fit unset range based on data. */
732 if (acre->x_axis.view_range_set && ! acre->y_axis.view_range_set) {
733 _find_y_range_given_x_range (acre,
734 &acre->y_axis.view_min,
735 &acre->y_axis.view_max,
736 acre->x_axis.view_min,
737 acre->x_axis.view_max);
739 else if (acre->y_axis.view_range_set && ! acre->x_axis.view_range_set) {
740 _find_x_range_given_y_range (acre,
741 &acre->x_axis.view_min,
742 &acre->x_axis.view_max,
743 acre->y_axis.view_min,
744 acre->y_axis.view_max);
748 /* Then, increase the axis ranges just enough so that the step
749 * sizes for the ticks will be integers.
751 _expand_range_for_width (&acre->x_axis.view_min,
752 &acre->x_axis.view_max,
755 _expand_range_for_width (&acre->y_axis.view_min,
756 &acre->y_axis.view_max,
759 /* Finally, we also translate the axis ranges slightly so that the
760 * ticks land on half-integer device-pixel positions.
764 _set_transform_to_data_space (acre);
768 cairo_user_to_device (cr, &x_adjust, &y_adjust);
769 x_adjust = (round (x_adjust + 0.5) - 0.5) - x_adjust;
770 y_adjust = (round (y_adjust + 0.5) - 0.5) - y_adjust;
771 cairo_device_to_user_distance (cr, &x_adjust, &y_adjust);
773 acre->x_axis.view_min -= x_adjust;
774 acre->x_axis.view_max -= x_adjust;
776 acre->y_axis.view_min -= y_adjust;
777 acre->y_axis.view_max -= y_adjust;
783 _choose_colors (acre_t *acre)
785 cmsHPROFILE lab_profile, srgb_profile;
786 cmsHTRANSFORM lab_to_srgb;
788 double theta, radius, srgb[3];
791 lab_profile = cmsCreateLabProfile (NULL); /* D50 */
792 srgb_profile = cmsCreate_sRGBProfile ();
794 lab_to_srgb = cmsCreateTransform (lab_profile, TYPE_Lab_DBL,
795 srgb_profile, TYPE_RGB_DBL,
796 INTENT_PERCEPTUAL, 0);
798 acre->num_colors = acre->num_data;
800 if (acre->num_colors > acre->colors_size) {
801 acre->colors_size = acre->num_colors;
802 acre->colors = xrealloc (acre->colors,
803 acre->colors_size * sizeof (acre_color_t));
808 for (i = 0; i < acre->num_colors; i++) {
809 theta = 0.713 + 2 * M_PI * (double) i / acre->num_colors;
810 lab.a = radius * cos (theta);
811 lab.b = radius * sin (theta);
813 cmsDoTransform (lab_to_srgb, &lab, srgb, 1);
815 acre->colors[i].red = srgb[0];
816 acre->colors[i].green = srgb[1];
817 acre->colors[i].blue = srgb[2];
820 cmsDeleteTransform (lab_to_srgb);
821 cmsCloseProfile (lab_profile);
822 cmsCloseProfile (srgb_profile);
825 /* Draw the given dataset as a line. */
827 _draw_data_line (acre_t *acre, acre_data_t *data)
830 cairo_t *cr = acre->cr;
836 for (i = 0; i < data->num_points; i++) {
842 cairo_identity_matrix (cr);
843 cairo_set_line_width (cr, 1.0);
849 #define TIMELINE_BAR_HEIGHT 0.6
851 /* Draw the given dataset as a timeline. Each (X,Y) point (potentially
852 * with a name) specifies the (start,stop) of a single timeline bar.
854 * Each independent timeline dataset in the chart is given its own
855 * vertical position, as specified by 'y_position'.
858 _draw_data_timeline (acre_t *acre, acre_data_t *data, int y_position)
861 cairo_t *cr = acre->cr;
862 PangoLayout *timeline_label_layout;
863 double ignored, label_offset;
864 int labels_within_bar;
868 timeline_label_layout = _create_layout (acre, "Timeline");
869 pango_layout_set_font_description (timeline_label_layout, acre->font);
872 label_offset = ACRE_FONT_SIZE;
873 cairo_device_to_user_distance (cr, &ignored, &label_offset);
875 labels_within_bar = TIMELINE_BAR_HEIGHT / fabs (label_offset);
877 for (i = 0; i < data->num_points; i++) {
880 y_position - TIMELINE_BAR_HEIGHT / 2.0,
881 data->points[i].y - data->points[i].x,
882 TIMELINE_BAR_HEIGHT);
885 cairo_identity_matrix (cr);
886 cairo_set_line_width (cr, 1.0);
887 cairo_stroke_preserve (cr);
892 if (i <= data->num_names && data->names[i]) {
895 cairo_move_to (cr, data->points[i].x,
896 y_position + TIMELINE_BAR_HEIGHT / 2.0 +
897 (i % labels_within_bar) * label_offset);
898 pango_layout_set_text (timeline_label_layout, data->names[i], -1);
899 cairo_identity_matrix (cr);
900 pango_cairo_show_layout (cr, timeline_label_layout);
909 _destroy_layout (timeline_label_layout);
914 /* Draw all the datasets of the chart. */
916 _draw_data (acre_t *acre)
918 cairo_t *cr = acre->cr;
925 acre->chart.x, acre->chart.y,
926 acre->chart.width, acre->chart.height);
929 cairo_set_source_rgb (cr, 0, 0, 0);
931 _set_transform_to_data_space (acre);
933 for (i = 0; i < acre->num_data; i++) {
934 int color = i % acre->num_colors;
935 cairo_set_source_rgb (cr,
936 acre->colors[color].red,
937 acre->colors[color].green,
938 acre->colors[color].blue);
939 data = acre->data[i];
941 switch (data->style) {
942 case ACRE_STYLE_LINE:
943 _draw_data_line (acre, data);
945 case ACRE_STYLE_TIMELINE:
946 /* Position the timeline bars top-down */
947 _draw_data_timeline (acre, data, acre->num_data - 1 - i);
955 typedef enum _ticks { ACRE_TICKS_X, ACRE_TICKS_Y } acre_ticks_t;
958 _draw_ticks (acre_t *acre,
959 double axis_min, double axis_max,
962 cairo_t *cr = acre->cr;
963 double t, step, sub_step;
968 _set_transform_to_data_space (acre);
970 step = _step_for_range (axis_max - axis_min, &minor_divisions);
971 sub_step = step / minor_divisions;
973 for (t = (floor (axis_min / sub_step) + 1) * sub_step;
978 if (fabs((t / step) - round (t / step)) < 0.5 * (sub_step / step))
979 tick_size = ACRE_TICK_MAJOR_SIZE;
981 tick_size = ACRE_TICK_MINOR_SIZE;
986 if (ticks == ACRE_TICKS_X)
987 cairo_move_to (cr, t, acre->y_axis.view_min);
989 cairo_move_to (cr, acre->x_axis.view_min, t);
991 cairo_identity_matrix (cr);
993 if (ticks == ACRE_TICKS_X) {
994 cairo_rel_line_to (cr, 0, 0.5);
995 cairo_rel_line_to (cr, 0, -tick_size - 0.5);
997 cairo_rel_line_to (cr, -0.5, 0);
998 cairo_rel_line_to (cr, tick_size + 0.5, 0);
1001 cairo_set_line_width (cr, 1.0);
1007 if (tick_size == ACRE_TICK_MAJOR_SIZE)
1009 PangoLayout *layout;
1016 if (fabs (label_value) < (sub_step / 1000.))
1018 layout = _create_layout_printf (acre, "%g", label_value);
1020 if (ticks == ACRE_TICKS_X)
1021 cairo_move_to (cr, t, acre->y_axis.view_min);
1023 cairo_move_to (cr, acre->x_axis.view_min, t);
1025 cairo_identity_matrix (cr);
1026 pango_layout_get_pixel_size (layout, &width, &height);
1028 if (ticks == ACRE_TICKS_X)
1029 cairo_rel_move_to (cr, -width / 2, ACRE_X_TICK_VALUE_PAD);
1031 cairo_rel_move_to (cr, -width - ACRE_Y_TICK_VALUE_PAD,
1034 _show_layout (cr, layout);
1044 _draw_legend (acre_t *acre)
1046 PangoLayout *layout;
1047 int label_width, max_label_width = 0;
1050 cairo_t *cr = acre->cr;
1054 for (i = 0; i < acre->num_data; i++) {
1055 layout = _create_layout (acre, acre->data[i]->name);
1056 pango_layout_get_pixel_size (layout, &label_width, NULL);
1057 _destroy_layout (layout);
1058 if (label_width > max_label_width)
1059 max_label_width = label_width;
1062 width = ACRE_LEGEND_PAD + ACRE_LEGEND_LINE_SIZE + ACRE_LEGEND_PAD +
1063 max_label_width + ACRE_LEGEND_PAD;
1064 height = ACRE_LEGEND_PAD +
1065 acre->num_data * (ACRE_FONT_SIZE + ACRE_LEGEND_PAD);
1067 cairo_translate (cr, acre->chart.x, acre->chart.y);
1069 cairo_translate (cr,
1070 acre->chart.width - ACRE_LEGEND_PAD - width,
1073 cairo_rectangle (cr, -0.5, -0.5, width + 1.0, height + 1.0);
1074 cairo_set_source_rgb (cr, 0, 0, 0);
1075 cairo_set_line_width (cr, 1.0);
1078 cairo_translate (cr, ACRE_LEGEND_PAD, ACRE_LEGEND_PAD);
1080 for (i = 0; i < acre->num_data; i++) {
1081 cairo_rectangle (cr,
1082 0, ACRE_LEGEND_LINE_SIZE / 2,
1083 ACRE_LEGEND_LINE_SIZE, ACRE_LEGEND_LINE_SIZE / 2);
1084 cairo_set_source_rgb (cr,
1085 acre->colors[i % acre->num_colors].red,
1086 acre->colors[i % acre->num_colors].green,
1087 acre->colors[i % acre->num_colors].blue);
1090 layout = _create_layout (acre, acre->data[i]->name);
1091 cairo_move_to (cr, ACRE_LEGEND_LINE_SIZE + ACRE_LEGEND_PAD, 0);
1092 cairo_set_source_rgb (cr, 0, 0, 0);
1093 _show_layout (cr, layout);
1095 cairo_translate (cr, 0, ACRE_LEGEND_PAD + ACRE_FONT_SIZE);
1102 _draw_frame_and_ticks (acre_t *acre)
1104 cairo_t *cr = acre->cr;
1108 cairo_set_source_rgb (cr, 0, 0, 0); /* black */
1111 _draw_ticks (acre, acre->x_axis.view_min, acre->x_axis.view_max, ACRE_TICKS_X);
1112 _draw_ticks (acre, acre->y_axis.view_min, acre->y_axis.view_max, ACRE_TICKS_Y);
1115 cairo_rectangle (cr,
1116 acre->chart.x - 0.5, acre->chart.y - 0.5,
1117 acre->chart.width + 1.0, acre->chart.height + 1.0);
1118 cairo_set_line_width (cr, 1.0);
1124 /* Draw the plot to the given cairo context within a user-space
1125 * rectangle from (0, 0) to (width, height). This size includes all
1126 * space for extra-plot elements (such as the title, the axis labels,
1130 acre_draw (acre_t *acre, cairo_t *cr, int width, int height)
1134 acre->width = width;
1135 acre->height = height;
1137 acre->chart.width = width;
1138 acre->chart.height = height;
1142 cairo_set_source_rgb (cr, 1, 1, 1);
1144 _choose_colors (acre);
1146 /* We compute the axis ranges before doing label layout so that we
1147 * can account for the width of the y-axis value labels. */
1148 _compute_axis_ranges (acre);
1150 _draw_title_and_labels (acre);
1152 /* And we recompute the axis ranges now that the title and axis
1153 * label space is all measured and accounted for. */
1154 _compute_axis_ranges (acre);
1158 if (acre->num_data > 1)
1159 _draw_legend (acre);
1161 _draw_frame_and_ticks (acre);
1164 /* Create a new dataset---a collection of (x, y) datapoints. A single
1165 * plot can contain multiple datasets, (see acre_add_data). */
1167 acre_data_create (void)
1171 data = xmalloc (sizeof (acre_data_t));
1175 data->style = ACRE_STYLE_LINE;
1177 data->points = NULL;
1178 data->points_size = 0;
1179 data->num_points = 0;
1184 /* Destroy an acre dataset. Do not call this function if the dataset
1185 * has been added to an acre_t plot with acre_add_data. */
1187 acre_data_destroy (acre_data_t *data)
1191 for (i = 0; i < data->num_names; i++) {
1193 free (data->names[i]);
1199 free (data->points);
1205 acre_data_set_style (acre_data_t *data, acre_style_t style)
1207 data->style = style;
1210 /* Set the label for this dataset (to appear in the plot's key). */
1212 acre_data_set_name (acre_data_t *data, const char *name)
1216 data->name = strdup (name);
1219 /* Add a datapoint to the given dataset. */
1221 acre_data_add_point_2d (acre_data_t *data, double x, double y)
1223 if (data->num_points >= data->points_size) {
1224 data->points_size *= 2;
1225 if (data->points_size == 0)
1226 data->points_size = 16;
1227 data->points = xrealloc_ab (data->points,
1229 sizeof (acre_data_point_2d_t));
1232 data->points[data->num_points].x = x;
1233 data->points[data->num_points].y = y;
1235 if (data->num_points == 0) {
1242 if (x < data->min.x)
1244 if (y < data->min.y)
1247 if (x > data->max.x)
1249 if (y > data->max.y)
1256 /* Add a datapoint with a name to the given dataset. */
1258 acre_data_add_point_2d_named (acre_data_t *data, double x, double y, const char *name)
1262 acre_data_add_point_2d (data, x, y);
1264 if (data->names_size < data->points_size) {
1265 data->names_size = data->points_size;
1266 data->names = xrealloc_ab (data->names,
1271 /* Initialize any newly-created holes in the array to NULL. */
1272 for (i = data->num_names; i < data->num_points - 1; i++)
1273 data->names[i] = NULL;
1275 data->num_names = data->num_points;
1277 data->names[data->num_names - 1] = xstrdup (name);