text: /**
   * @file lv_lmeter.c
   *
   */
  
  /*********************
   *      INCLUDES
   *********************/
  #include "lv_lmeter.h"
  #if LV_USE_LMETER != 0
  
  #include "../lv_core/lv_debug.h"
  #include "../lv_draw/lv_draw.h"
  #include "../lv_themes/lv_theme.h"
  #include "../lv_core/lv_group.h"
  #include "../lv_misc/lv_math.h"
  
  /*********************
   *      DEFINES
   *********************/
  #define LV_OBJX_NAME "lv_lmeter"
  
  #define LV_LMETER_LINE_UPSCALE 5 /*2^x upscale of line to make rounding*/
  #define LV_LMETER_LINE_UPSCALE_MASK ((1 << LV_LMETER_LINE_UPSCALE) - 1)
  
  /**********************
   *      TYPEDEFS
   **********************/
  
  /**********************
   *  STATIC PROTOTYPES
   **********************/
  static bool lv_lmeter_design(lv_obj_t * lmeter, const lv_area_t * mask, lv_design_mode_t mode);
  static lv_res_t lv_lmeter_signal(lv_obj_t * lmeter, lv_signal_t sign, void * param);
  static lv_coord_t lv_lmeter_coord_round(int32_t x);
  
  /**********************
   *  STATIC VARIABLES
   **********************/
  static lv_signal_cb_t ancestor_signal;
  
  /**********************
   *      MACROS
   **********************/
  
  /**********************
   *   GLOBAL FUNCTIONS
   **********************/
  
  /**
   * Create a line meter objects
   * @param par pointer to an object, it will be the parent of the new line meter
   * @param copy pointer to a line meter object, if not NULL then the new object will be copied from
   * it
   * @return pointer to the created line meter
   */
  lv_obj_t * lv_lmeter_create(lv_obj_t * par, const lv_obj_t * copy)
  {
      LV_LOG_TRACE("line meter create started");
  
      /*Create the ancestor of line meter*/
      lv_obj_t * new_lmeter = lv_obj_create(par, copy);
      LV_ASSERT_MEM(new_lmeter);
      if(new_lmeter == NULL) return NULL;
  
      if(ancestor_signal == NULL) ancestor_signal = lv_obj_get_signal_cb(new_lmeter);
  
      /*Allocate the line meter type specific extended data*/
      lv_lmeter_ext_t * ext = lv_obj_allocate_ext_attr(new_lmeter, sizeof(lv_lmeter_ext_t));
      LV_ASSERT_MEM(ext);
      if(ext == NULL) return NULL;
  
      /*Initialize the allocated 'ext' */
      ext->min_value   = 0;
      ext->max_value   = 100;
      ext->cur_value   = 0;
      ext->line_cnt    = 21;  /*Odd scale number looks better*/
      ext->scale_angle = 240; /*(scale_num - 1) * N looks better */
      ext->angle_ofs = 0;
  
      /*The signal and design functions are not copied so set them here*/
      lv_obj_set_signal_cb(new_lmeter, lv_lmeter_signal);
      lv_obj_set_design_cb(new_lmeter, lv_lmeter_design);
  
      /*Init the new line meter line meter*/
      if(copy == NULL) {
          lv_obj_set_size(new_lmeter, LV_DPI, LV_DPI);
  
          /*Set the default styles*/
          lv_theme_t * th = lv_theme_get_current();
          if(th) {
              lv_lmeter_set_style(new_lmeter, LV_LMETER_STYLE_MAIN, th->style.lmeter);
          } else {
              lv_lmeter_set_style(new_lmeter, LV_LMETER_STYLE_MAIN, &lv_style_pretty_color);
          }
      }
      /*Copy an existing line meter*/
      else {
          lv_lmeter_ext_t * copy_ext = lv_obj_get_ext_attr(copy);
          ext->scale_angle           = copy_ext->scale_angle;
          ext->line_cnt              = copy_ext->line_cnt;
          ext->min_value             = copy_ext->min_value;
          ext->max_value             = copy_ext->max_value;
          ext->cur_value             = copy_ext->cur_value;
  
          /*Refresh the style with new signal function*/
          lv_obj_refresh_style(new_lmeter);
      }
  
      LV_LOG_INFO("line meter created");
  
      return new_lmeter;
  }
  
  /*=====================
   * Setter functions
   *====================*/
  
  /**
   * Set a new value on the line meter
   * @param lmeter pointer to a line meter object
   * @param value new value
   */
  void lv_lmeter_set_value(lv_obj_t * lmeter, int16_t value)
  {
      LV_ASSERT_OBJ(lmeter, LV_OBJX_NAME);
  
      lv_lmeter_ext_t * ext = lv_obj_get_ext_attr(lmeter);
      if(ext->cur_value == value) return;
  
      ext->cur_value = value > ext->max_value ? ext->max_value : value;
      ext->cur_value = ext->cur_value < ext->min_value ? ext->min_value : ext->cur_value;
      lv_obj_invalidate(lmeter);
  }
  
  /**
   * Set minimum and the maximum values of a line meter
   * @param lmeter pointer to he line meter object
   * @param min minimum value
   * @param max maximum value
   */
  void lv_lmeter_set_range(lv_obj_t * lmeter, int16_t min, int16_t max)
  {
      LV_ASSERT_OBJ(lmeter, LV_OBJX_NAME);
  
      lv_lmeter_ext_t * ext = lv_obj_get_ext_attr(lmeter);
      if(ext->min_value == min && ext->max_value == max) return;
  
      ext->max_value = max;
      ext->min_value = min;
      if(ext->cur_value > max) {
          ext->cur_value = max;
          lv_lmeter_set_value(lmeter, ext->cur_value);
      }
      if(ext->cur_value < min) {
          ext->cur_value = min;
          lv_lmeter_set_value(lmeter, ext->cur_value);
      }
      lv_obj_invalidate(lmeter);
  }
  
  /**
   * Set the scale settings of a line meter
   * @param lmeter pointer to a line meter object
   * @param angle angle of the scale (0..360)
   * @param line_cnt number of lines
   */
  void lv_lmeter_set_scale(lv_obj_t * lmeter, uint16_t angle, uint16_t line_cnt)
  {
      LV_ASSERT_OBJ(lmeter, LV_OBJX_NAME);
  
      lv_lmeter_ext_t * ext = lv_obj_get_ext_attr(lmeter);
      if(ext->scale_angle == angle && ext->line_cnt == line_cnt) return;
  
      ext->scale_angle = angle;
      ext->line_cnt    = line_cnt;
  
      lv_obj_invalidate(lmeter);
  }
  
  /**
   * Set the set an offset for the line meter's angles to rotate it.
   * @param lmeter pointer to a line meter object
   * @param angle angle where the meter will be facing (with its center)
   */
  void lv_lmeter_set_angle_offset(lv_obj_t * lmeter, uint16_t angle)
  {
      lv_lmeter_ext_t * ext = lv_obj_get_ext_attr(lmeter);
      if(ext->angle_ofs == angle) return;
  
      ext->angle_ofs = angle;
  
      lv_obj_invalidate(lmeter);
  }
  
  /*=====================
   * Getter functions
   *====================*/
  
  /**
   * Get the value of a line meter
   * @param lmeter pointer to a line meter object
   * @return the value of the line meter
   */
  int16_t lv_lmeter_get_value(const lv_obj_t * lmeter)
  {
      LV_ASSERT_OBJ(lmeter, LV_OBJX_NAME);
  
      lv_lmeter_ext_t * ext = lv_obj_get_ext_attr(lmeter);
      return ext->cur_value;
  }
  
  /**
   * Get the minimum value of a line meter
   * @param lmeter pointer to a line meter object
   * @return the minimum value of the line meter
   */
  int16_t lv_lmeter_get_min_value(const lv_obj_t * lmeter)
  {
      LV_ASSERT_OBJ(lmeter, LV_OBJX_NAME);
  
      lv_lmeter_ext_t * ext = lv_obj_get_ext_attr(lmeter);
      return ext->min_value;
  }
  
  /**
   * Get the maximum value of a line meter
   * @param lmeter pointer to a line meter object
   * @return the maximum value of the line meter
   */
  int16_t lv_lmeter_get_max_value(const lv_obj_t * lmeter)
  {
      LV_ASSERT_OBJ(lmeter, LV_OBJX_NAME);
  
      lv_lmeter_ext_t * ext = lv_obj_get_ext_attr(lmeter);
      return ext->max_value;
  }
  
  /**
   * Get the scale number of a line meter
   * @param lmeter pointer to a line meter object
   * @return number of the scale units
   */
  uint16_t lv_lmeter_get_line_count(const lv_obj_t * lmeter)
  {
      LV_ASSERT_OBJ(lmeter, LV_OBJX_NAME);
  
      lv_lmeter_ext_t * ext = lv_obj_get_ext_attr(lmeter);
      return ext->line_cnt;
  }
  
  /**
   * Get the scale angle of a line meter
   * @param lmeter pointer to a line meter object
   * @return angle_ofs of the scale
   */
  uint16_t lv_lmeter_get_scale_angle(const lv_obj_t * lmeter)
  {
      LV_ASSERT_OBJ(lmeter, LV_OBJX_NAME);
  
      lv_lmeter_ext_t * ext = lv_obj_get_ext_attr(lmeter);
      return ext->scale_angle;
  }
  
  /**
   * get the set an offset for the line meter.
   * @param lmeter pointer to a line meter object
   * @return angle offset (0..360)
   */
  uint16_t lv_lmeter_get_angle_offset(lv_obj_t * lmeter)
  {
      lv_lmeter_ext_t * ext = lv_obj_get_ext_attr(lmeter);
  
      return ext->angle_ofs;
  }
  /**********************
   *   STATIC FUNCTIONS
   **********************/
  
  /**
   * Handle the drawing related tasks of the line meters
   * @param lmeter 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 true/false, depends on 'mode'
   */
  static bool lv_lmeter_design(lv_obj_t * lmeter, const lv_area_t * mask, lv_design_mode_t mode)
  {
      /*Return false if the object is not covers the mask_p area*/
      if(mode == LV_DESIGN_COVER_CHK) {
          return false;
      }
      /*Draw the object*/
      else if(mode == LV_DESIGN_DRAW_MAIN) {
          lv_lmeter_ext_t * ext    = lv_obj_get_ext_attr(lmeter);
          const lv_style_t * style = lv_obj_get_style(lmeter);
          lv_opa_t opa_scale       = lv_obj_get_opa_scale(lmeter);
          lv_style_t style_tmp;
          lv_style_copy(&style_tmp, style);
  
  #if LV_USE_GROUP
          lv_group_t * g = lv_obj_get_group(lmeter);
          if(lv_group_get_focused(g) == lmeter) {
              style_tmp.line.width += 1;
          }
  #endif
  
          lv_coord_t r_out = lv_obj_get_width(lmeter) / 2;
          lv_coord_t r_in  = r_out - style->body.padding.left;
          if(r_in < 1) r_in = 1;
  
          lv_coord_t x_ofs  = lv_obj_get_width(lmeter) / 2 + lmeter->coords.x1;
          lv_coord_t y_ofs  = lv_obj_get_height(lmeter) / 2 + lmeter->coords.y1;
          int16_t angle_ofs = ext->angle_ofs + 90 + (360 - ext->scale_angle) / 2;
          int16_t level =
              (int32_t)((int32_t)(ext->cur_value - ext->min_value) * ext->line_cnt) / (ext->max_value - ext->min_value);
          uint8_t i;
  
          style_tmp.line.color = style->body.main_color;
  
          /*Calculate every coordinate in a bigger size to make rounding later*/
          r_out = r_out << LV_LMETER_LINE_UPSCALE;
          r_in  = r_in << LV_LMETER_LINE_UPSCALE;
  
          for(i = 0; i < ext->line_cnt; i++) {
              /*Calculate the position a scale label*/
              int16_t angle = (i * ext->scale_angle) / (ext->line_cnt - 1) + angle_ofs;
  
              lv_coord_t y_out = (int32_t)((int32_t)lv_trigo_sin(angle) * r_out) >> LV_TRIGO_SHIFT;
              lv_coord_t x_out = (int32_t)((int32_t)lv_trigo_sin(angle + 90) * r_out) >> LV_TRIGO_SHIFT;
              lv_coord_t y_in  = (int32_t)((int32_t)lv_trigo_sin(angle) * r_in) >> LV_TRIGO_SHIFT;
              lv_coord_t x_in  = (int32_t)((int32_t)lv_trigo_sin(angle + 90) * r_in) >> LV_TRIGO_SHIFT;
  
              /*Rounding*/
              x_out = lv_lmeter_coord_round(x_out);
              x_in  = lv_lmeter_coord_round(x_in);
              y_out = lv_lmeter_coord_round(y_out);
              y_in  = lv_lmeter_coord_round(y_in);
  
              lv_point_t p1;
              lv_point_t p2;
  
              p2.x = x_in + x_ofs;
              p2.y = y_in + y_ofs;
  
              p1.x = x_out + x_ofs;
              p1.y = y_out + y_ofs;
  
              if(i >= level)
                  style_tmp.line.color = style->line.color;
              else {
                  style_tmp.line.color =
                      lv_color_mix(style->body.grad_color, style->body.main_color, (255 * i) / ext->line_cnt);
              }
  
              lv_draw_line(&p1, &p2, mask, &style_tmp, opa_scale);
          }
  
      }
      /*Post draw when the children are drawn*/
      else if(mode == LV_DESIGN_DRAW_POST) {
      }
  
      return true;
  }
  
  /**
   * Signal function of the line meter
   * @param lmeter pointer to a line meter 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_lmeter_signal(lv_obj_t * lmeter, lv_signal_t sign, void * param)
  {
      lv_res_t res;
  
      /* Include the ancient signal function */
      res = ancestor_signal(lmeter, 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);
  
      if(sign == LV_SIGNAL_CLEANUP) {
          /*Nothing to cleanup. (No dynamically allocated memory in 'ext')*/
      } else if(sign == LV_SIGNAL_STYLE_CHG) {
          lv_obj_refresh_ext_draw_pad(lmeter);
      } else if(sign == LV_SIGNAL_REFR_EXT_DRAW_PAD) {
          const lv_style_t * style = lv_lmeter_get_style(lmeter, LV_LMETER_STYLE_MAIN);
          lmeter->ext_draw_pad     = LV_MATH_MAX(lmeter->ext_draw_pad, style->line.width);
      }
  
      return res;
  }
  
  /**
   * Round a coordinate which is upscaled  (>=x.5 -> x + 1;   <x.5 -> x)
   * @param x a coordinate which is greater then it should be
   * @return the downscaled and rounded coordinate  (+-1)
   */
  static lv_coord_t lv_lmeter_coord_round(int32_t x)
  {
  #if LV_LMETER_LINE_UPSCALE > 0
      bool was_negative = false;
      if(x < 0) {
          was_negative = true;
          x            = -x;
      }
  
      x = (x >> LV_LMETER_LINE_UPSCALE) + ((x & LV_LMETER_LINE_UPSCALE_MASK) >> (LV_LMETER_LINE_UPSCALE - 1));
  
      if(was_negative) x = -x;
  
      return x;
  #else
      return x;
  #endif
  }
  
  #endif
  