diff options
Diffstat (limited to 'nuttx/graphics/nxglib/nxglib_circlepts.c')
| -rw-r--r-- | nuttx/graphics/nxglib/nxglib_circlepts.c | 171 |
1 files changed, 171 insertions, 0 deletions
diff --git a/nuttx/graphics/nxglib/nxglib_circlepts.c b/nuttx/graphics/nxglib/nxglib_circlepts.c new file mode 100644 index 000000000..a6d59280d --- /dev/null +++ b/nuttx/graphics/nxglib/nxglib_circlepts.c @@ -0,0 +1,171 @@ +/**************************************************************************** + * graphics/nxglib/nxglib_circlepts.c + * + * Copyright (C) 2011 Gregory Nutt. All rights reserved. + * Author: Gregory Nutt <spudmonkey@racsa.co.cr> + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in + * the documentation and/or other materials provided with the + * distribution. + * 3. Neither the name NuttX nor the names of its contributors may be + * used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS + * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE + * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, + * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS + * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED + * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN + * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + * + ****************************************************************************/ + +/**************************************************************************** + * 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 + +/**************************************************************************** + * Private Types + ****************************************************************************/ + +/**************************************************************************** + * Private Data + ****************************************************************************/ + +/**************************************************************************** + * Public Data + ****************************************************************************/ + +/**************************************************************************** + * Private Functions + ****************************************************************************/ + +/**************************************************************************** + * 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; +} |