lvgl/src/lv_draw/lv_draw_arc.c

/**
 * @file lv_draw_arc.c
 *
 */

/*********************
 *      INCLUDES
 *********************/
#include "lv_draw_arc.h"
#include "lv_draw_mask.h"
#include "../lv_misc/lv_math.h"  // LV_TRIGO_SHIFT

/*********************
 *      DEFINES
 *********************/

/**********************
 *      TYPEDEFS
 **********************/

/**********************
 *  STATIC PROTOTYPES
 **********************/

/**********************
 *  STATIC VARIABLES
 **********************/

/**********************
 *      MACROS
 **********************/

/**********************
 *   GLOBAL FUNCTIONS
 **********************/

/**
 * Draw an arc. (Can draw pie too with great thickness.)
 * @param center_x the x coordinate of the center of the arc
 * @param center_y the y coordinate of the center of the arc
 * @param radius the radius of the arc
 * @param mask the arc will be drawn only in this mask
 * @param start_angle the start angle of the arc (0 deg on the bottom, 90 deg on the right)
 * @param end_angle the end angle of the arc
 * @param style style of the arc (`body.thickness`, `body.main_color`, `body.opa` is used)
 * @param opa_scale scale down all opacities by the factor
 */
void lv_draw_arc(lv_coord_t center_x, lv_coord_t center_y, uint16_t radius, const lv_area_t * clip_area,
                 uint16_t start_angle, uint16_t end_angle, const lv_style_t * style, lv_opa_t opa_scale)
{
    lv_style_t circle_style;
    lv_style_copy(&circle_style, style);
    circle_style.body.radius = LV_RADIUS_CIRCLE;
    circle_style.body.opa = LV_OPA_TRANSP;
    circle_style.body.border.width = style->line.width;
    circle_style.body.border.color = style->line.color;

    lv_draw_mask_angle_param_t mask_angle_param;
    lv_draw_mask_angle_init(&mask_angle_param, center_x, center_y, start_angle, end_angle);

    int16_t mask_angle_id = lv_draw_mask_add(&mask_angle_param, NULL);

    lv_area_t area;
    area.x1 = center_x - radius;
    area.y1 = center_y - radius;
    area.x2 = center_x + radius;
    area.y2 = center_y + radius;

    lv_draw_rect(&area, clip_area, &circle_style, LV_OPA_COVER);

    lv_draw_mask_remove_id(mask_angle_id);

    if(style->line.rounded) {
      circle_style.body.main_color = style->line.color;
      circle_style.body.grad_color = style->line.color;
      circle_style.body.opa        = LV_OPA_COVER;
      circle_style.body.border.width = 0;

      lv_coord_t thick_half = style->line.width / 2;
      lv_coord_t cir_x      = ((radius - thick_half + 1) * lv_trigo_sin(90 - start_angle) >> LV_TRIGO_SHIFT);
      lv_coord_t cir_y      = ((radius - thick_half + 1) * lv_trigo_sin(start_angle) >> LV_TRIGO_SHIFT);
  
      lv_area_t round_area;
        round_area.x1 = cir_x + center_x - thick_half + 1;
        round_area.y1 = cir_y + center_y - thick_half + 1;
        round_area.x2 = cir_x + center_x + thick_half;
        round_area.y2 = cir_y + center_y + thick_half;
      
      lv_draw_rect(&round_area, clip_area, &circle_style, LV_OPA_COVER);
 
      cir_x      = ((radius - thick_half + 1) * lv_trigo_sin(90 - end_angle) >> LV_TRIGO_SHIFT);
      cir_y      = ((radius - thick_half + 1) * lv_trigo_sin(end_angle) >> LV_TRIGO_SHIFT);
  
        round_area.x1 = cir_x + center_x - thick_half + 1;
        round_area.y1 = cir_y + center_y - thick_half + 1;
        round_area.x2 = cir_x + center_x + thick_half;
        round_area.y2 = cir_y + center_y + thick_half;
  
      lv_draw_rect(&round_area, clip_area, &circle_style, LV_OPA_COVER);
    }
}


/**********************
 *   STATIC FUNCTIONS
 **********************/