text: /**
   * @file lv_btn.c
   *
   */
  
  /*********************
   *      INCLUDES
   *********************/
  
  #include "lv_btn.h"
  #if LV_USE_BTN != 0
  
  #include <string.h>
  #include "../lv_core/lv_group.h"
  #include "../lv_core/lv_debug.h"
  #include "../lv_draw/lv_draw.h"
  #include "../lv_themes/lv_theme.h"
  #include "../lv_misc/lv_area.h"
  #include "../lv_misc/lv_color.h"
  #include "../lv_misc/lv_math.h"
  
  /*********************
   *      DEFINES
   *********************/
  #define LV_OBJX_NAME "lv_btn"
  #define LV_BTN_INK_VALUE_MAX 256
  #define LV_BTN_INK_VALUE_MAX_SHIFT 8
  
  /**********************
   *      TYPEDEFS
   **********************/
  
  /**********************
   *  STATIC PROTOTYPES
   **********************/
  static lv_design_res_t lv_btn_design(lv_obj_t * btn, const lv_area_t * clip_area, lv_design_mode_t mode);
  static lv_res_t lv_btn_signal(lv_obj_t * btn, lv_signal_t sign, void * param);
  
  /**********************
   *  STATIC VARIABLES
   **********************/
  static lv_signal_cb_t ancestor_signal;
  static lv_design_cb_t ancestor_design;
  
  /**********************
   *      MACROS
   **********************/
  
  /**********************
   *   GLOBAL FUNCTIONS
   **********************/
  
  /**
   * Create a button object
   * @param par pointer to an object, it will be the parent of the new button
   * @param copy pointer to a button object, if not NULL then the new object will be copied from it
   * @return pointer to the created button
   */
  lv_obj_t * lv_btn_create(lv_obj_t * par, const lv_obj_t * copy)
  {
      LV_LOG_TRACE("button create started");
  
      lv_obj_t * btn;
  
      btn = lv_cont_create(par, copy);
      LV_ASSERT_MEM(btn);
      if(btn == NULL) return NULL;
  
      if(ancestor_signal == NULL) ancestor_signal = lv_obj_get_signal_cb(btn);
      if(ancestor_design == NULL) ancestor_design = lv_obj_get_design_cb(btn);
  
      /*Allocate the extended data*/
      lv_btn_ext_t * ext = lv_obj_allocate_ext_attr(btn, sizeof(lv_btn_ext_t));
      LV_ASSERT_MEM(ext);
      if(ext == NULL) {
          lv_obj_del(btn);
          return NULL;
      }
  
      ext->checkable = 0;
  
      lv_obj_set_signal_cb(btn, lv_btn_signal);
      lv_obj_set_design_cb(btn, lv_btn_design);
  
      /*If no copy do the basic initialization*/
      if(copy == NULL) {
          /*Set layout if the button is not a screen*/
          if(par) {
              lv_obj_set_size(btn, LV_DPI, LV_DPI / 3);
              lv_btn_set_layout(btn, LV_LAYOUT_CENTER);
          }
  
          lv_obj_set_click(btn, true); /*Be sure the button is clickable*/
  
          lv_theme_apply(btn, LV_THEME_BTN);
      }
      /*Copy 'copy'*/
      else {
          lv_btn_ext_t * copy_ext = lv_obj_get_ext_attr(copy);
          ext->checkable             = copy_ext->checkable;
  
          /*Refresh the style with new signal function*/
          lv_obj_refresh_style(btn, LV_STYLE_PROP_ALL);
      }
  
      LV_LOG_INFO("button created");
  
      return btn;
  }
  
  /*=====================
   * Setter functions
   *====================*/
  
  /**
   * Enable the toggled states
   * @param btn pointer to a button object
   * @param tgl true: enable toggled states, false: disable
   */
  void lv_btn_set_checkable(lv_obj_t * btn, bool tgl)
  {
      LV_ASSERT_OBJ(btn, LV_OBJX_NAME);
  
      lv_btn_ext_t * ext = lv_obj_get_ext_attr(btn);
  
      ext->checkable = tgl != false ? 1 : 0;
  }
  
  /**
   * Set the state of the button
   * @param btn pointer to a button object
   * @param state the new state of the button (from lv_btn_state_t enum)
   */
  void lv_btn_set_state(lv_obj_t * btn, lv_btn_state_t state)
  {
      LV_ASSERT_OBJ(btn, LV_OBJX_NAME);
  
      switch(state) {
          case LV_BTN_STATE_RELEASED:
              lv_obj_clear_state(btn, LV_STATE_PRESSED | LV_STATE_CHECKED | LV_STATE_DISABLED);
              break;
          case LV_BTN_STATE_PRESSED:
              lv_obj_clear_state(btn, LV_STATE_CHECKED | LV_STATE_DISABLED);
              lv_obj_add_state(btn, LV_STATE_PRESSED);
              break;
          case LV_BTN_STATE_CHECKED_RELEASED:
              lv_obj_add_state(btn, LV_STATE_CHECKED);
              lv_obj_clear_state(btn, LV_STATE_PRESSED | LV_STATE_DISABLED);
              break;
          case LV_BTN_STATE_CHECKED_PRESSED:
              lv_obj_add_state(btn, LV_STATE_PRESSED | LV_STATE_CHECKED);
              lv_obj_clear_state(btn, LV_STATE_DISABLED);
              break;
          case LV_BTN_STATE_DISABLED:
              lv_obj_clear_state(btn, LV_STATE_PRESSED | LV_STATE_CHECKED);
              lv_obj_add_state(btn, LV_STATE_DISABLED);
              break;
          case LV_BTN_STATE_CHECKED_DISABLED:
              lv_obj_clear_state(btn, LV_STATE_PRESSED);
              lv_obj_add_state(btn, LV_STATE_DISABLED | LV_STATE_CHECKED);
              break;
      }
  }
  
  /**
   * Toggle the state of the button (ON->OFF, OFF->ON)
   * @param btn pointer to a button object
   */
  void lv_btn_toggle(lv_obj_t * btn)
  {
      LV_ASSERT_OBJ(btn, LV_OBJX_NAME);
  
      if(lv_obj_get_state(btn, LV_BTN_PART_MAIN) & LV_STATE_CHECKED) {
          lv_obj_clear_state(btn, LV_STATE_CHECKED);
      }
      else {
          lv_obj_add_state(btn, LV_STATE_CHECKED);
      }
  }
  
  /*=====================
   * Getter functions
   *====================*/
  
  /**
   * Get the current state of the button
   * @param btn pointer to a button object
   * @return the state of the button (from lv_btn_state_t enum).
   * If the button is in disabled state `LV_BTN_STATE_DISABLED` will be ORed to the other button states.
   */
  lv_btn_state_t lv_btn_get_state(const lv_obj_t * btn)
  {
      LV_ASSERT_OBJ(btn, LV_OBJX_NAME);
  
      lv_state_t obj_state = lv_obj_get_state(btn, LV_BTN_PART_MAIN);
  
      if(obj_state & LV_STATE_DISABLED) {
          if(obj_state & LV_STATE_CHECKED) return LV_BTN_STATE_CHECKED_DISABLED;
          else return LV_BTN_STATE_DISABLED;
      }
  
      if(obj_state & LV_STATE_CHECKED) {
          if(obj_state & LV_STATE_PRESSED) return LV_BTN_STATE_CHECKED_PRESSED;
          else return LV_BTN_STATE_CHECKED_RELEASED;
      } else {
          if(obj_state & LV_STATE_PRESSED) return LV_BTN_STATE_PRESSED;
          else return LV_BTN_STATE_RELEASED;
      }
  }
  
  /**
   * Get the toggle enable attribute of the button
   * @param btn pointer to a button object
   * @return true: toggle enabled, false: disabled
   */
  bool lv_btn_get_checkable(const lv_obj_t * btn)
  {
      LV_ASSERT_OBJ(btn, LV_OBJX_NAME);
  
      lv_btn_ext_t * ext = lv_obj_get_ext_attr(btn);
  
      return ext->checkable != 0 ? true : false;
  }
  
  /**********************
   *   STATIC FUNCTIONS
   **********************/
  
  /**
   * Handle the drawing related tasks of the drop down lists
   * @param btn pointer to an object
   * @param mask the object will be drawn only in this area
   * @param mode LV_DESIGN_COVER_CHK: only check if the object fully covers the 'mask_p' area
   *                                  (return 'true' if yes)
   *             LV_DESIGN_DRAW: draw the object (always return 'true')
   *             LV_DESIGN_DRAW_POST: drawing after every children are drawn
   * @param return an element of `lv_design_res_t`
   */
  static lv_design_res_t lv_btn_design(lv_obj_t * btn, const lv_area_t * clip_area, lv_design_mode_t mode)
  {
      if(mode == LV_DESIGN_COVER_CHK) {
          return ancestor_design(btn, clip_area, mode);
      }
      else if(mode == LV_DESIGN_DRAW_MAIN) {
          ancestor_design(btn, clip_area, mode);
      }
      else if(mode == LV_DESIGN_DRAW_POST) {
          ancestor_design(btn, clip_area, mode);
      }
  
      return LV_DESIGN_RES_OK;
  }
  
  /**
   * Signal function of the button
   * @param btn pointer to a button object
   * @param sign a signal type from lv_signal_t enum
   * @param param pointer to a signal specific variable
   * @return LV_RES_OK: the object is not deleted in the function; LV_RES_INV: the object is deleted
   */
  static lv_res_t lv_btn_signal(lv_obj_t * btn, lv_signal_t sign, void * param)
  {
      lv_res_t res;
  
      /* Include the ancient signal function */
      res = ancestor_signal(btn, sign, param);
      if(res != LV_RES_OK) return res;
      if(sign == LV_SIGNAL_GET_TYPE) return lv_obj_handle_get_type_signal(param, LV_OBJX_NAME);
  
      bool tgl           = lv_btn_get_checkable(btn);
  
      if(sign == LV_SIGNAL_RELEASED) {
          /*If not dragged and it was not long press action then
           *change state and run the action*/
          if(lv_indev_is_dragging(param) == false && tgl) {
              uint32_t toggled = 0;
              if(lv_obj_get_state(btn, LV_BTN_PART_MAIN) & LV_STATE_CHECKED) {
                  lv_btn_set_state(btn, LV_BTN_STATE_RELEASED);
                  toggled = 0;
              }
              else {
                  lv_btn_set_state(btn, LV_BTN_STATE_CHECKED_RELEASED);
                  toggled = 1;
              }
  
              res = lv_event_send(btn, LV_EVENT_VALUE_CHANGED, &toggled);
              if(res != LV_RES_OK) return res;
          }
      }
      else if(sign == LV_SIGNAL_CONTROL) {
          char c = *((char *)param);
          if(c == LV_KEY_RIGHT || c == LV_KEY_UP) {
              if(lv_btn_get_checkable(btn)) {
                  lv_btn_set_state(btn, LV_BTN_STATE_CHECKED_RELEASED);
  
                  uint32_t state = 1;
                  res            = lv_event_send(btn, LV_EVENT_VALUE_CHANGED, &state);
                  if(res != LV_RES_OK) return res;
              }
  
          }
          else if(c == LV_KEY_LEFT || c == LV_KEY_DOWN) {
              if(lv_btn_get_checkable(btn)) {
                  lv_btn_set_state(btn, LV_BTN_STATE_RELEASED);
  
                  uint32_t state = 0;
                  res            = lv_event_send(btn, LV_EVENT_VALUE_CHANGED, &state);
                  if(res != LV_RES_OK) return res;
              }
          }
      }
  
      return res;
  }
  
  #endif
  