text: /****************************************************************************
   * libs/libnx/nx/nx_drawcircle.c
   *
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements.  See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.  The
   * ASF licenses this file to you under the Apache License, Version 2.0 (the
   * "License"); you may not use this file except in compliance with the
   * License.  You may obtain a copy of the License at
   *
   *   http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
   * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
   * License for the specific language governing permissions and limitations
   * under the License.
   *
   ****************************************************************************/
  
  /****************************************************************************
   * Included Files
   ****************************************************************************/
  
  #include <nuttx/config.h>
  
  #include <sys/types.h>
  #include <debug.h>
  #include <errno.h>
  
  #include <nuttx/nx/nxglib.h>
  #include <nuttx/nx/nx.h>
  
  /****************************************************************************
   * Pre-Processor Definitions
   ****************************************************************************/
  
  /* Named indices into the 16 circle points generated by nxgl_circlepts */
  
  #define POINT_0p0      0
  #define POINT_22p5     1
  #define POINT_45p0     2
  #define POINT_67p5     3
  #define POINT_90p0     4
  #define POINT_112p5    5
  #define POINT_135p0    6
  #define POINT_157p5    7
  #define POINT_180p0    8
  #define POINT_202p5    9
  #define POINT_225p0    10
  #define POINT_247p5    11
  #define POINT_270p0    12
  #define POINT_292p5    13
  #define POINT_315p0    14
  #define POINT_337p5    15
  #define NCIRCLE_POINTS 16
  
  /****************************************************************************
   * Public Functions
   ****************************************************************************/
  
  /****************************************************************************
   * Name: nx_drawcircle
   *
   * Description:
   *  Draw a circular outline using the specified line thickness and color.
   *
   * Input Parameters:
   *   hwnd   - The window handle
   *   center - A pointer to the point that is the center of the circle
   *   radius - The radius of the circle in pixels.
   *   width  - The width of the line
   *   color  - The color to use to fill the line
   *
   * Returned Value:
   *   OK on success; ERROR on failure with errno set appropriately
   *
   ****************************************************************************/
  
  int nx_drawcircle(NXWINDOW hwnd, FAR const struct nxgl_point_s *center,
                    nxgl_coord_t radius, nxgl_coord_t width,
                    nxgl_mxpixel_t color[CONFIG_NX_NPLANES])
  {
    struct nxgl_point_s pts[NCIRCLE_POINTS];
    FAR struct nxgl_vector_s vector;
    int i;
    int ret;
  
    /* Convert the circle to a set of 16 points */
  
    nxgl_circlepts(center, radius, pts);
  
    /* Draw each pair of points as a vector */
  
    for (i = POINT_0p0; i < POINT_337p5; i++)
      {
        /* Draw one line segment */
  
        vector.pt1.x = pts[i].x;
        vector.pt1.y = pts[i].y;
        vector.pt2.x = pts[i + 1].x;
        vector.pt2.y = pts[i + 1].y;
  
        ret = nx_drawline(hwnd, &vector, width, color, NX_LINECAP_PT1);
        if (ret != OK)
          {
            return ret;
          }
      }
  
    /* The final, closing vector is a special case */
  
    vector.pt1.x = pts[POINT_337p5].x;
    vector.pt1.y = pts[POINT_337p5].y;
    vector.pt2.x = pts[POINT_0p0].x;
    vector.pt2.y = pts[POINT_0p0].y;
    return nx_drawline(hwnd, &vector, width, color, NX_LINECAP_PT1);
  }
  