143 lines
5.1 KiB
C
143 lines
5.1 KiB
C
/****************************************************************************
|
|
* libs/libnx/nxglib/nxglib_circlepts.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 <string.h>
|
|
#include <errno.h>
|
|
#include <fixedmath.h>
|
|
|
|
#include <nuttx/nx/nxglib.h>
|
|
|
|
/****************************************************************************
|
|
* Pre-Processor Definitions
|
|
****************************************************************************/
|
|
|
|
/* Trigonometry */
|
|
|
|
#define SIN_0p0 0 /* sin(0) = 0 */
|
|
#define COS_0p0 1 /* cos(0) = 1 */
|
|
#define SIN_22p5 25080 /* sin(22.5) = 25080 / 65536 */
|
|
#define COS_22p5 60547 /* cos(22.5) = 60547 / 65536 */
|
|
#define SIN_45p0 46341 /* sin(45) = 46341 / 65536 */
|
|
#define COS_45p0 SIN_45p0 /* cos(45) = sin(45) */
|
|
|
|
/* 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: nxgl_circlepts
|
|
*
|
|
* Description:
|
|
* Given a description of a circle, return a set of 16 points on the
|
|
* circumference of the circle. These points may then be used by
|
|
* nx_drawcircle() or related APIs to draw a circle outline.
|
|
*
|
|
* Input Parameters:
|
|
* center - A pointer to the point that is the center of the circle
|
|
* radius - The radius of the circle in pixels.
|
|
* circle - A pointer the first entry in an array of 16 points where the
|
|
* circle points will be returned.
|
|
*
|
|
* Returned Value:
|
|
* None
|
|
*
|
|
****************************************************************************/
|
|
|
|
void nxgl_circlepts(FAR const struct nxgl_point_s *center,
|
|
nxgl_coord_t radius,
|
|
FAR struct nxgl_point_s *circle)
|
|
{
|
|
nxgl_coord_t xoffs;
|
|
nxgl_coord_t yoffs;
|
|
|
|
/* 0, 90, 180, and 270 degrees are the easiest */
|
|
|
|
circle[POINT_0p0].x = center->x + radius;
|
|
circle[POINT_0p0].y = center->y;
|
|
circle[POINT_90p0].x = center->x;
|
|
circle[POINT_90p0].y = center->y + radius;
|
|
circle[POINT_180p0].x = center->x - radius;
|
|
circle[POINT_180p0].y = center->y;
|
|
circle[POINT_270p0].x = center->x;
|
|
circle[POINT_270p0].y = center->y - radius;
|
|
|
|
/* Now 22.5, 67.5, 112.5, 157.5, 202.5, 247.5, 292.5, and 337.5 */
|
|
|
|
xoffs = b16toi(b16muli(COS_22p5, radius) + b16HALF);
|
|
yoffs = b16toi(b16muli(SIN_22p5, radius) + b16HALF);
|
|
|
|
circle[POINT_22p5].x = center->x + xoffs;
|
|
circle[POINT_22p5].y = center->y + yoffs;
|
|
circle[POINT_157p5].x = center->x - xoffs;
|
|
circle[POINT_157p5].y = center->y + yoffs;
|
|
circle[POINT_202p5].x = center->x - xoffs;
|
|
circle[POINT_202p5].y = center->y - yoffs;
|
|
circle[POINT_337p5].x = center->x + xoffs;
|
|
circle[POINT_337p5].y = center->y - yoffs;
|
|
|
|
circle[POINT_67p5].x = center->x + yoffs;
|
|
circle[POINT_67p5].y = center->y + xoffs;
|
|
circle[POINT_112p5].x = center->x - yoffs;
|
|
circle[POINT_112p5].y = center->y + xoffs;
|
|
circle[POINT_247p5].x = center->x - yoffs;
|
|
circle[POINT_247p5].y = center->y - xoffs;
|
|
circle[POINT_292p5].x = center->x + yoffs;
|
|
circle[POINT_292p5].y = center->y - xoffs;
|
|
|
|
/* Finally, 45.0, 135.0, 225.0, 315.0 */
|
|
|
|
xoffs = b16toi(b16muli(COS_45p0, radius) + b16HALF);
|
|
|
|
circle[POINT_45p0].x = center->x + xoffs;
|
|
circle[POINT_45p0].y = center->y + xoffs;
|
|
circle[POINT_135p0].x = center->x - xoffs;
|
|
circle[POINT_135p0].y = center->y + xoffs;
|
|
circle[POINT_225p0].x = center->x - xoffs;
|
|
circle[POINT_225p0].y = center->y - xoffs;
|
|
circle[POINT_315p0].x = center->x + xoffs;
|
|
circle[POINT_315p0].y = center->y - xoffs;
|
|
}
|