X-Git-Url: https://git.cworth.org/git?a=blobdiff_plain;f=acre.c;h=12be71d249952421f0fb17caa956e3cd74377a0f;hb=af6a6a5cafbbbbb1d5e1cffcab4c5903853d9758;hp=6d1262abe0af95f72864255d0781c688d3bf65fd;hpb=bdcec99e706ccb2af0600bce67b7ade6e0abf348;p=acre diff --git a/acre.c b/acre.c index 6d1262a..12be71d 100644 --- a/acre.c +++ b/acre.c @@ -19,11 +19,13 @@ #define _ISOC99_SOURCE /* for round() */ #define _XOPEN_SOURCE 500 +#define _GNU_SOURCE /* for asprintf() */ #include "acre.h" #include "xmalloc.h" #include +#include #include typedef struct _acre_data_point_2d { @@ -56,6 +58,7 @@ struct _acre { /* Data for drawing. */ cairo_t *cr; + PangoFontDescription *font; /* Total size including labels. */ int width; @@ -87,6 +90,11 @@ acre_create (void) acre->data_size = 0; acre->num_data = 0; + acre->chart.x = 0; + acre->chart.y = 0; + acre->chart.width = 0; + acre->chart.height = 0; + return acre; } @@ -152,16 +160,84 @@ acre_add_data (acre_t *acre, acre_data_t *data) #define ACRE_FONT_FAMILY "sans" #define ACRE_FONT_SIZE 12 -#define ACRE_TITLE_FONT_SIZE 32 +#define ACRE_TITLE_FONT_SIZE 20 #define ACRE_PAD (ACRE_FONT_SIZE) -#define ACRE_TICK_SIZE 6 +#define ACRE_TICK_MAJOR_SIZE 6 +#define ACRE_TICK_MINOR_SIZE 3 +#define ACRE_X_TICK_VALUE_PAD 2 +#define ACRE_Y_TICK_VALUE_PAD 4 + +static PangoLayout * +_create_layout (acre_t *acre, const char *text) +{ + PangoLayout *layout; + + layout = pango_cairo_create_layout (acre->cr); + pango_layout_set_font_description (layout, acre->font); + pango_layout_set_text (layout, text, -1); + pango_layout_set_alignment (layout, PANGO_ALIGN_CENTER); + + return layout; +} + +#define PRINTF_FORMAT(fmt_index, va_index) __attribute__ ((__format__(__printf__, fmt_index, va_index))) + +static PangoLayout * +_create_layout_vprintf (acre_t *acre, const char *fmt, va_list ap) +{ + PangoLayout *layout; + char *text; + + vasprintf (&text, fmt, ap); + + layout = _create_layout (acre, text); + + free (text); + + return layout; +} + +static PangoLayout * +_create_layout_printf (acre_t *acre, const char *fmt, ...) + PRINTF_FORMAT (2, 3); + +static PangoLayout * +_create_layout_printf (acre_t *acre, const char *fmt, ...) +{ + va_list ap; + PangoLayout *layout; + + va_start (ap, fmt); + + layout = _create_layout_vprintf (acre, fmt, ap); + + va_end (ap); + + return layout; +} + +static void +_destroy_layout (PangoLayout *layout) +{ + g_object_unref (layout); +} + +static void +_show_layout (cairo_t *cr, PangoLayout *layout) +{ + pango_cairo_show_layout (cr, layout); + + _destroy_layout (layout); +} static void _draw_title_and_labels (acre_t *acre) { cairo_t *cr = acre->cr; - PangoFontDescription *acre_font, *title_font; + PangoFontDescription *title_font; PangoLayout *title_layout, *x_axis_layout, *y_axis_layout; + PangoLayout *min_y, *max_y; + int min_y_width, max_y_width, y_axis_value_width; int title_width, title_height; int x_axis_width, x_axis_height; int y_axis_width, y_axis_height; @@ -169,9 +245,9 @@ _draw_title_and_labels (acre_t *acre) cairo_save (cr); - acre_font = pango_font_description_new (); - pango_font_description_set_family (acre_font, ACRE_FONT_FAMILY); - pango_font_description_set_absolute_size (acre_font, + acre->font = pango_font_description_new (); + pango_font_description_set_family (acre->font, ACRE_FONT_FAMILY); + pango_font_description_set_absolute_size (acre->font, ACRE_FONT_SIZE * PANGO_SCALE); title_font = pango_font_description_new (); @@ -179,29 +255,28 @@ _draw_title_and_labels (acre_t *acre) pango_font_description_set_absolute_size (title_font, ACRE_TITLE_FONT_SIZE * PANGO_SCALE); - title_layout = pango_cairo_create_layout (cr); + title_layout = _create_layout (acre, acre->title); pango_layout_set_font_description (title_layout, title_font); - pango_layout_set_text (title_layout, acre->title, -1); - pango_layout_set_alignment (title_layout, PANGO_ALIGN_CENTER); - x_axis_layout = pango_cairo_create_layout (cr); - pango_layout_set_font_description (x_axis_layout, acre_font); - pango_layout_set_text (x_axis_layout, acre->x_axis.label, -1); - pango_layout_set_alignment (x_axis_layout, PANGO_ALIGN_CENTER); + x_axis_layout = _create_layout (acre, acre->x_axis.label); + y_axis_layout = _create_layout (acre, acre->y_axis.label); + + min_y = _create_layout_printf (acre, "%g", + round (acre->y_axis.min)); + max_y = _create_layout_printf (acre, "%g", + round (acre->y_axis.max)); - y_axis_layout = pango_cairo_create_layout (cr); - pango_layout_set_font_description (y_axis_layout, acre_font); - pango_layout_set_text (y_axis_layout, acre->y_axis.label, -1); - pango_layout_set_alignment (y_axis_layout, PANGO_ALIGN_CENTER); + pango_layout_get_pixel_size (min_y, &min_y_width, NULL); + pango_layout_get_pixel_size (max_y, &max_y_width, NULL); + y_axis_value_width = MAX (min_y_width, max_y_width); + + _destroy_layout (min_y); + _destroy_layout (max_y); /* Iterate with the layout of the title and axis labels until they * are stable, (this requires iteration since we don't know what * to set their widths to in advance due to the wrapping of the * other elements). */ - acre->chart.x = 0; - acre->chart.y = 0; - acre->chart.width = acre->width; - acre->chart.height = acre->height; while (1) { pango_layout_set_width (title_layout, acre->chart.width * PANGO_SCALE); pango_layout_set_width (x_axis_layout, acre->chart.width * PANGO_SCALE); @@ -212,11 +287,13 @@ _draw_title_and_labels (acre_t *acre) pango_layout_get_pixel_size (y_axis_layout, &y_axis_width, &y_axis_height); new_chart.x = ACRE_PAD + y_axis_height + - ACRE_PAD + ACRE_FONT_SIZE; + ACRE_PAD + y_axis_value_width + ACRE_Y_TICK_VALUE_PAD; new_chart.width = acre->width - acre->chart.x - ACRE_PAD; new_chart.y = ACRE_PAD + title_height + ACRE_PAD; - new_chart.height = acre->height - acre->chart.y - (ACRE_FONT_SIZE + ACRE_PAD + x_axis_height + ACRE_PAD); + new_chart.height = acre->height - acre->chart.y - + (ACRE_X_TICK_VALUE_PAD + ACRE_FONT_SIZE + + ACRE_PAD + x_axis_height + ACRE_PAD); if (new_chart.x == acre->chart.x && new_chart.y == acre->chart.y && @@ -235,21 +312,21 @@ _draw_title_and_labels (acre_t *acre) cairo_set_source_rgb (cr, 0, 0, 0); cairo_move_to (cr, acre->chart.x, ACRE_PAD); - pango_cairo_show_layout (cr, title_layout); + _show_layout (cr, title_layout); cairo_save (cr); { cairo_translate (cr, ACRE_PAD, acre->chart.y + acre->chart.height); cairo_rotate (cr, - M_PI / 2.0); cairo_move_to (cr, 0, 0); - pango_cairo_show_layout (cr, y_axis_layout); + _show_layout (cr, y_axis_layout); } cairo_restore (cr); cairo_move_to (cr, acre->chart.x, acre->chart.y + acre->chart.height + ACRE_FONT_SIZE + ACRE_PAD); - pango_cairo_show_layout (cr, x_axis_layout); + _show_layout (cr, x_axis_layout); cairo_restore (cr); } @@ -257,7 +334,7 @@ _draw_title_and_labels (acre_t *acre) /* For a given axis range, compute a step size (in data space) to * generate a suitable number of ticks (5 or so). */ static double -_step_for_range (double range) +_step_for_range (double range, int *minor_divisions) { double step, scale_factor; @@ -273,15 +350,21 @@ _step_for_range (double range) * 10). The threshold values between these are computed * logarithmically. */ if (step < 3.535533905932738) { - if (step < 1.58113883008419) + if (step < 1.58113883008419) { step = 1.0; - else + *minor_divisions = 4; + } else { step = 2.5; + *minor_divisions = 5; + } } else { - if (step < 7.071067811865475) + if (step < 7.071067811865475) { step = 5.0; - else + *minor_divisions = 5; + } else { step = 10.0; + *minor_divisions = 4; + } } /* Un-normalize and we now have the data value that we want to @@ -293,18 +376,27 @@ _step_for_range (double range) * amount for the major ticks (see _step_for_range). To get * nice-looking pixel-snapped ticks we want to expand the range * slightly. */ -static double -_expand_range (double data_range, int pixel_size) +static void +_expand_range_for_width (double *axis_min, double *axis_max, int pixel_range) { - double step, pixel_step; + double range, new_range, step, step_minor, pixel_step; + int minor_divisions; + + range = *axis_max - *axis_min; - step = _step_for_range (data_range); - pixel_step = step * pixel_size / data_range; + step = _step_for_range (range, &minor_divisions); + step_minor = step / minor_divisions; + + pixel_step = step_minor * (pixel_range / range); /* We expand the range by the ratio of the pixel step to the floor * of the pixel_step. */ - return data_range * pixel_step / floor (pixel_step); + new_range = range * pixel_step / floor (pixel_step); + + /* And spread the increase out on either side of the range. */ + *axis_min -= (new_range - range) / 2.0; + *axis_max += (new_range - range) / 2.0; } /* Setup a transformation in acre->cr such that data values plotted @@ -329,10 +421,14 @@ _compute_axis_ranges (acre_t *acre) { unsigned int d, i; acre_data_t *data; - double x_range, new_x_range, x_adjust; - double y_range, new_y_range, y_adjust; + double x_adjust, y_adjust; cairo_t *cr = acre->cr; + acre->x_axis.min = acre->data[0]->points[0].x; + acre->x_axis.max = acre->data[0]->points[0].x; + acre->y_axis.min = acre->data[0]->points[0].y; + acre->y_axis.min = acre->data[0]->points[0].y; + /* First, simply find the extrema of the data. */ for (d = 0; d < acre->num_data; d++) { data = acre->data[d]; @@ -349,21 +445,33 @@ _compute_axis_ranges (acre_t *acre) } } - /* Next, increase the axis ranges just enough so that the step - * sizes for the ticks will be integers. - */ - x_range = acre->x_axis.max - acre->x_axis.min; - new_x_range = _expand_range (x_range, acre->chart.width); + /* Next, we want to ensure that the data never collides with the + * ticks. So we expand each axis on its minimum side as needed. */ + cairo_save (cr); + { + double x, y; + + _set_transform_to_data_space (acre); - y_range = acre->y_axis.max - acre->y_axis.min; - new_y_range = _expand_range (y_range, acre->chart.height); + x = ACRE_TICK_MAJOR_SIZE + 2.0; + y = ACRE_TICK_MAJOR_SIZE + 2.0; + cairo_device_to_user_distance (cr, &x, &y); - /* And spread the increase out on either side of the range. */ - acre->x_axis.min -= (new_x_range - x_range) / 2.0; - acre->x_axis.max += (new_x_range - x_range) / 2.0; + acre->x_axis.min -= x; + acre->y_axis.min += y; + } + cairo_restore (cr); + + /* Then, increase the axis ranges just enough so that the step + * sizes for the ticks will be integers. + */ + _expand_range_for_width (&acre->x_axis.min, + &acre->x_axis.max, + acre->chart.width); - acre->y_axis.min -= (new_y_range - y_range) / 2.0; - acre->y_axis.max += (new_y_range - y_range) / 2.0; + _expand_range_for_width (&acre->y_axis.min, + &acre->y_axis.max, + acre->chart.height); /* Finally, we also translate the axis ranges slightly so that the * ticks land on half-integer device-pixel positions. @@ -394,6 +502,16 @@ _draw_data (acre_t *acre) cairo_t *cr = acre->cr; unsigned int d, i; acre_data_t *data; +#define NUM_COLORS 3 + struct { + double r; + double g; + double b; + } colors [NUM_COLORS] = { + {1, 0, 0}, + {0, 1, 0}, + {0, 0, 1} + }; cairo_save (cr); @@ -402,6 +520,11 @@ _draw_data (acre_t *acre) _set_transform_to_data_space (acre); for (d = 0; d < acre->num_data; d++) { + int color = d % NUM_COLORS; + cairo_set_source_rgb (cr, + colors[color].r, + colors[color].g, + colors[color].b); data = acre->data[d]; cairo_new_path (cr); for (i = 0; i < data->num_points; i++) { @@ -421,56 +544,104 @@ _draw_data (acre_t *acre) cairo_restore (cr); } +typedef enum _ticks { ACRE_TICKS_X, ACRE_TICKS_Y } acre_ticks_t; + static void -_draw_frame_and_ticks (acre_t *acre) +_draw_ticks (acre_t *acre, + double axis_min, double axis_max, + acre_ticks_t ticks) { cairo_t *cr = acre->cr; - double step, x, y; + double t, step, sub_step; + int minor_divisions; cairo_save (cr); - cairo_set_source_rgb (cr, 0, 0, 0); /* black */ + _set_transform_to_data_space (acre); - /* First the ticks within data space. */ - cairo_save (cr); + step = _step_for_range (axis_max - axis_min, &minor_divisions); + sub_step = step / minor_divisions; + + for (t = (floor (axis_min / sub_step) + 1) * sub_step; + t <= axis_max; + t += sub_step) { - _set_transform_to_data_space (acre); + int tick_size; + if (fabs((t / step) - round (t / step)) < 0.5 * (sub_step / step)) + tick_size = ACRE_TICK_MAJOR_SIZE; + else + tick_size = ACRE_TICK_MINOR_SIZE; - step = _step_for_range (acre->x_axis.max -acre->x_axis.min); - x = (floor (acre->x_axis.min / step) + 1) * step; - while (x <= acre->x_axis.max) { - cairo_move_to (cr, x, acre->y_axis.min); - cairo_save (cr); - { - cairo_identity_matrix (cr); + /* tick */ + cairo_save (cr); + { + if (ticks == ACRE_TICKS_X) + cairo_move_to (cr, t, acre->y_axis.min); + else + cairo_move_to (cr, acre->x_axis.min, t); + + cairo_identity_matrix (cr); + + if (ticks == ACRE_TICKS_X) { cairo_rel_line_to (cr, 0, 0.5); - cairo_rel_line_to (cr, 0, -ACRE_TICK_SIZE-0.5); - cairo_set_line_width (cr, 1.0); - cairo_stroke (cr); + cairo_rel_line_to (cr, 0, -tick_size - 0.5); + } else { + cairo_rel_line_to (cr, -0.5, 0); + cairo_rel_line_to (cr, tick_size + 0.5, 0); } - cairo_restore (cr); - x += step; + + cairo_set_line_width (cr, 1.0); + cairo_stroke (cr); } + cairo_restore (cr); + + /* label */ + if (tick_size == ACRE_TICK_MAJOR_SIZE) + { + PangoLayout *layout; + int width, height; - step = _step_for_range (acre->y_axis.max -acre->y_axis.min); - y = (floor (acre->y_axis.min / step) + 1) * step; - while (y <= acre->y_axis.max) { - cairo_move_to (cr, acre->x_axis.min, y); cairo_save (cr); - { - cairo_identity_matrix (cr); - cairo_rel_line_to (cr, -0.5, 0); - cairo_rel_line_to (cr, ACRE_TICK_SIZE+0.5, 0); - cairo_set_line_width (cr, 1.0); - cairo_stroke (cr); - } + + layout = _create_layout_printf (acre, "%g", t); + + if (ticks == ACRE_TICKS_X) + cairo_move_to (cr, t, acre->y_axis.min); + else + cairo_move_to (cr, acre->x_axis.min, t); + + cairo_identity_matrix (cr); + pango_layout_get_pixel_size (layout, &width, &height); + + if (ticks == ACRE_TICKS_X) + cairo_rel_move_to (cr, -width / 2, ACRE_X_TICK_VALUE_PAD); + else + cairo_rel_move_to (cr, -width - ACRE_Y_TICK_VALUE_PAD, + -height/2); + + _show_layout (cr, layout); + cairo_restore (cr); - y += step; } } + cairo_restore (cr); +} - /* Then the frame drawn in pixel space. */ +static void +_draw_frame_and_ticks (acre_t *acre) +{ + cairo_t *cr = acre->cr; + + cairo_save (cr); + + cairo_set_source_rgb (cr, 0, 0, 0); /* black */ + + /* ticks */ + _draw_ticks (acre, acre->x_axis.min, acre->x_axis.max, ACRE_TICKS_X); + _draw_ticks (acre, acre->y_axis.min, acre->y_axis.max, ACRE_TICKS_Y); + + /* frame */ cairo_rectangle (cr, acre->chart.x - 0.5, acre->chart.y - 0.5, acre->chart.width + 1.0, acre->chart.height + 1.0); @@ -489,17 +660,25 @@ void acre_draw (acre_t *acre, cairo_t *cr, int width, int height) { acre->cr = cr; + acre->width = width; acre->height = height; + acre->chart.width = width; + acre->chart.height = height; + cairo_save (cr); cairo_set_source_rgb (cr, 1, 1, 1); - cairo_paint (cr); + /* We compute the axis ranges before doing label layout so that we + * can account for the width of the y-axis value labels. */ + _compute_axis_ranges (acre); _draw_title_and_labels (acre); + /* And we recompute the axis ranges now that the title and axis + * label space is all measured and accounted for. */ _compute_axis_ranges (acre); _draw_data (acre);