hexagram/src/thermo.c

#include <math.h>

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

#define RAD (M_PI / 180.0)

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

#define LEVEL_MIN   48
#define LEVEL_WARN 116
#define LEVEL_MAX  127

#define FONT_FACE "Muli"

static int draw_bg(hexagram_gauge *gauge, cairo_t *cr) {
    hexagram_thermo *thermo = (hexagram_thermo *)gauge;
    double incr;
    int i;

    if (hexagram_dial_draw_bg(&thermo->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, thermo->dial.radius * 0.1);

    cairo_set_source_rgb(cr, 1, 1, 1);
    hexagram_dial_draw_legend(&thermo->dial, cr, 0.725, thermo->dial.min_value, "C");

    cairo_set_source_rgb(cr, 1, 0, 0);
    hexagram_dial_draw_legend(&thermo->dial, cr, 0.725, thermo->dial.max_value, "H");

    cairo_set_line_width(cr, 6.0);

    incr = (thermo->dial.max_value - thermo->dial.min_value) / 8.0;

    for (i=0; i<9; i++) {
        double level = thermo->dial.min_value + i * incr;

        if (level >= LEVEL_WARN) {
            cairo_set_source_rgb(cr, 0.8, 0, 0);
        } else {
            cairo_set_source_rgb(cr, 1, 1, 1);
        }

        hexagram_dial_draw_mark(&thermo->dial, cr, 0.83, 0.87, level);

        level += incr;
    }

    return 0;

error_dial_draw_bg:
    return -1;
}

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

    thermo->dial.gauge.draw_bg = draw_bg;
    thermo->dial.value         = LEVEL_MIN;
    thermo->level_warn         = LEVEL_WARN;

    return 0;

error_dial_init:
    return -1;
}