MeshCore-Solo/examples/companion_radio/ui-lvgl/Theme.h

#pragma once
// Design tokens for ui-lvgl -- the one place colours, spacing and type live --
// and the rules every widget follows (install() below).
//
// The accent (amber by default; Settings > Display > Accent colour)
// on near-black, soft corners. The accent means one of three things:
//  - ACCENT fill, dark text: the primary action of a screen or popup
//    (Download, Install, Save, Go) -- stylePrimary() in UITask.cpp -- and
//    something selected / on (a tab, a chip, a segment, a mode that is
//    running, own bubbles) -- styleSelected();
//  - ACCENT text or icon: a name, a count, a background mode, a value.
// No accent mixed toward black for "selected": it came out brown.
// Everything else is BG / SURFACE / SURFACE_2 with TEXT or TEXT_MUTED.
#include <src/themes/lv_theme_private.h>   // lv_theme_t's fields, to layer a theme

namespace theme {
  // Colours (0xRRGGBB)
  static const uint32_t BG        = 0x0B0B0D;   // screen background
  static const uint32_t SURFACE   = 0x1A1A1F;   // cards, rows, bubbles (incoming)
  static const uint32_t SURFACE_2 = 0x27272E;   // pressed / raised
  static uint32_t ACCENT          = 0xFFB000;   // primary actions, names, badges, modes (setAccent)
  static const uint32_t TEXT      = 0xF2EEE6;
  static const uint32_t TEXT_MUTED= 0x9A958C;
  static const uint32_t OK        = 0x6FCF6F;   // delivered / relayed
  static const uint32_t FAIL      = 0xE5534B;   // not delivered

  // Spacing (px)
  static const int PAD     = 8;
  static const int GAP     = 6;
  static const int RADIUS  = 10;    // cards, rows, buttons (pills use LV_RADIUS_CIRCLE)
  static const int RADIUS_SM = 6;   // small cells inside those
  static const int STATUS_H = 22;   // top status bar
  static const int ROW_H   = 44;    // list row (touch target)

  // Type -- Noto Sans, generated by fonts/generate.sh (declared in lv_conf.h).
  // ui_font_40 holds digits / ':' / '-' / '.' only (clock, timer, stopwatch).
  #define THEME_FONT_SMALL  (&ui_font_12)
  #define THEME_FONT_BODY   (&ui_font_14)
  #define THEME_FONT_TITLE  (&ui_font_16)
  #define THEME_FONT_LARGE  (&ui_font_20)
  #define THEME_FONT_CLOCK  (&ui_font_40)
  // Status bar icons, refitted to one size (fonts/status_icons.py); any other
  // character falls back to ui_font_12.
  #define THEME_FONT_ICONS  (&ui_icons_14)

  // Extra FontAwesome glyphs baked into ui_font_12..20 beyond LVGL's LV_SYMBOL_*.
  #define UI_SYMBOL_STAR    "\xEF\x80\x85"   // U+F005, favourite
  #define UI_SYMBOL_MAP     "\xEF\x89\xB9"   // U+F279
  #define UI_SYMBOL_USERS   "\xEF\x83\x80"   // U+F0C0, Nearby
  #define UI_SYMBOL_COMPASS "\xEF\x85\x8E"   // U+F14E, Navigate
  #define UI_SYMBOL_FLAG    "\xEF\x80\xA4"   // U+F024, waypoint
  #define UI_SYMBOL_PIN     "\xEF\x8F\x85"   // U+F3C5, mark here (a place on the map)
  #define UI_SYMBOL_TACK    "\xEF\x82\x8D"   // U+F08D, thumbtack: pin to the Home dial
  #define UI_SYMBOL_CLOCK   "\xEF\x80\x97"   // U+F017, Clock tools
  #define UI_SYMBOL_STOPWATCH "\xEF\x8B\xB2" // U+F2F2
  #define UI_SYMBOL_RADIO   "\xEF\x94\x99"   // U+F519, broadcast tower
  #define UI_SYMBOL_CHART   "\xEF\x82\x80"   // U+F080, diagnostics
  #define UI_SYMBOL_KEY     "\xEF\x82\x84"   // U+F084, admin
  #define UI_SYMBOL_ROUTE   "\xEF\x93\x97"   // U+F4D7, trail
  #define UI_SYMBOL_MUTE    "\xEF\x9A\xA9"   // U+F6A9, muted (speaker with a cross)
  #define UI_SYMBOL_LOCK    "\xEF\x80\xA3"   // U+F023, quick panel: lock the screen
  #define UI_SYMBOL_SUN     "\xEF\x86\x85"   // U+F185, quick panel: brightness

  // Accent choices; the fill is the colour at 42% over the background.
  struct Accent { const char* name; uint32_t col; };
  static const Accent ACCENTS[] = {
    { "Amber", 0xFFB000 }, { "Orange", 0xFF7A2E }, { "Coral", 0xFF6B7A },
    { "Violet", 0xB18CFF }, { "Cyan", 0x3CC8E8 }, { "Lime", 0xB5E04A },
  };
  static const int ACCENT_COUNT = sizeof(ACCENTS) / sizeof(ACCENTS[0]);
  static int s_accent = 0;
  // `fg` at `pct` % over `bg`, worked out once: an opaque fill in the colour
  // a translucent one would blend to, without blending it every frame.
  static uint32_t mix(uint32_t fg, uint32_t bg, uint32_t pct) {
    uint32_t out = 0;
    for (int sh = 0; sh <= 16; sh += 8) {
      uint32_t c = (fg >> sh) & 0xFF, b = (bg >> sh) & 0xFF;
      out |= ((c * pct + b * (100 - pct)) / 100) << sh;
    }
    return out;
  }
  static void setAccent(int idx) {
    if (idx < 0 || idx >= ACCENT_COUNT) idx = 0;
    s_accent = idx;
    ACCENT = ACCENTS[idx].col;
  }

  // Over LVGL's default theme, for every widget: a checked button is
  // "selected" (the accent, dark text), buttons
  // have the card radius and give a little under the finger (the default
  // theme's transitions animate it both ways). Scrollbars are thin and hug
  // the edge, inside the padding every panel and list has, instead of the
  // default's 5 px bar 7 px in, which ran over right-aligned text.
  static lv_theme_t s_theme;
  static lv_style_t s_btn, s_press, s_checked, s_sbar;
  static void applyTheme(lv_theme_t* th, lv_obj_t* obj) {
    (void)th;
    lv_obj_add_style(obj, &s_sbar, LV_PART_SCROLLBAR);
    if (lv_obj_check_type(obj, &lv_button_class)) {
      lv_obj_add_style(obj, &s_btn, 0);
      lv_obj_add_style(obj, &s_press, LV_STATE_PRESSED);
      lv_obj_add_style(obj, &s_checked, LV_STATE_CHECKED);
    }
  }
  // (Re)builds the default theme in the current accent with this layer over it.
  static void install(lv_display_t* disp) {
    static bool styled = false;
    if (!styled) {
      styled = true;
      lv_style_init(&s_btn);
      lv_style_set_radius(&s_btn, RADIUS);
      lv_style_set_shadow_width(&s_btn, 0);
      lv_style_init(&s_press);
      lv_style_set_transform_width(&s_press, -2);
      lv_style_set_transform_height(&s_press, -2);
      lv_style_init(&s_checked);
      lv_style_set_text_color(&s_checked, lv_color_hex(BG));
      lv_style_init(&s_sbar);
      lv_style_set_width(&s_sbar, 3);
      lv_style_set_pad_right(&s_sbar, 2);    // vertical bar: 2 px off the edge
      lv_style_set_pad_bottom(&s_sbar, 2);   // horizontal bar likewise
      lv_style_set_pad_top(&s_sbar, RADIUS / 2);
      lv_style_set_pad_left(&s_sbar, RADIUS / 2);
    }
    lv_style_set_bg_color(&s_checked, lv_color_hex(ACCENT));
    lv_theme_t* base = lv_theme_default_init(disp, lv_color_hex(ACCENT), lv_color_hex(ACCENT), true, THEME_FONT_BODY);
    s_theme = *base;
    lv_theme_set_parent(&s_theme, base);
    lv_theme_set_apply_cb(&s_theme, applyTheme);
    lv_display_set_theme(disp, &s_theme);
    lv_obj_report_style_change(&s_checked);
  }
}