hexagram/src/fuel.c

#include <stdlib.h>
#include <math.h>

#include <hexagram/gauge.h>
#include <hexagram/fuel.h>

#define RAD (M_PI / 180.0)

#define LEVEL_MIN   0
#define LEVEL_WARN  2
#define LEVEL_MAX  15

#define ANGLE_MIN (144.0 * RAD)
#define ANGLE_MAX (216.0 * RAD)

#define FONT_FACE "Muli"

static int draw_bg(hexagram_gauge *gauge, cairo_t *cr) {
    hexagram_fuel *fuel = (hexagram_fuel *)gauge;
    int level;

    if (hexagram_dial_draw_bg(&fuel->dial, cr) < 0) {
        goto error_dial_draw_bg;
    }

    cairo_select_font_face(cr,
                           FONT_FACE,
                           CAIRO_FONT_SLANT_NORMAL,
                           CAIRO_FONT_WEIGHT_BOLD);

    cairo_set_font_size(cr, fuel->dial.radius * 0.1);

    cairo_set_source_rgb(cr, 1, 0, 0);
    hexagram_dial_draw_legend(&fuel->dial, cr, 0, "0");

    cairo_set_source_rgb(cr, 1, 1, 1);
    hexagram_dial_draw_legend(&fuel->dial, cr, fuel->dial.max_value, "1");

    cairo_set_line_width(cr, 6.0);

    for (level=0; level<=LEVEL_MAX; level++) {
        double min_radius;

        if (level < 2) {
            min_radius = 0.84;
            cairo_set_source_rgb(cr, 1, 0, 0);
        } else if (level < 4) {
            min_radius = 0.82;
            cairo_set_source_rgb(cr, 1, 0, 0);
        } else {
            min_radius = 0.82;
            cairo_set_source_rgb(cr, 1, 1, 1);
        }

        hexagram_dial_draw_mark(&fuel->dial, cr, min_radius, 0.87, level);
    }

    return 0;

error_dial_draw_bg:
    return -1;
}

int hexagram_fuel_init(hexagram_fuel *fuel,
                       double x,
                       double y,
                       double radius) {
    if (hexagram_dial_init(&fuel->dial,
                           HEXAGRAM_DIAL_BOTTOM,
                           x,
                           y,
                           radius,
                           ANGLE_MIN,
                           ANGLE_MAX,
                           LEVEL_MIN,
                           LEVEL_MAX) < 0) {
        goto error_dial_init;
    }

    fuel->dial.gauge.draw_bg = draw_bg;
    fuel->dial.value         = LEVEL_MIN;

    return 0;

error_dial_init:
    return -1;
}