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176 lines
6.7 KiB
176 lines
6.7 KiB
/**************************************************************************** |
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* graphics/nxglib/nxglib_circletraps.c |
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* |
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* Copyright (C) 2011 Gregory Nutt. All rights reserved. |
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* Author: Gregory Nutt <spudmonkey@racsa.co.cr> |
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* |
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* Redistribution and use in source and binary forms, with or without |
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* modification, are permitted provided that the following conditions |
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* are met: |
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* |
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* 1. Redistributions of source code must retain the above copyright |
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* notice, this list of conditions and the following disclaimer. |
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* 2. Redistributions in binary form must reproduce the above copyright |
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* notice, this list of conditions and the following disclaimer in |
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* the documentation and/or other materials provided with the |
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* distribution. |
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* 3. Neither the name NuttX nor the names of its contributors may be |
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* used to endorse or promote products derived from this software |
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* without specific prior written permission. |
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* |
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS |
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE |
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, |
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, |
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS |
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED |
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN |
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
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* POSSIBILITY OF SUCH DAMAGE. |
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* |
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****************************************************************************/ |
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/**************************************************************************** |
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* Included Files |
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****************************************************************************/ |
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#include <nuttx/config.h> |
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#include <string.h> |
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#include <errno.h> |
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#include <fixedmath.h> |
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#include <nuttx/nx/nxglib.h> |
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/**************************************************************************** |
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* Pre-Processor Definitions |
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****************************************************************************/ |
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/* Trigonometry */ |
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#define SIN_0p0 0 /* sin(0) = 0 */ |
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#define COS_0p0 1 /* cos(0) = 1 */ |
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#define SIN_22p5 25080 /* sin(22.5) = 25080 / 65536 */ |
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#define COS_22p5 60547 /* cos(22.5) = 60547 / 65536 */ |
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#define SIN_45p0 46341 /* sin(45) = 46341 / 65536 */ |
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#define COS_45p0 SIN_45p0 /* cos(45) = sin(45) */ |
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/**************************************************************************** |
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* Private Types |
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****************************************************************************/ |
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/**************************************************************************** |
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* Private Data |
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****************************************************************************/ |
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/**************************************************************************** |
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* Public Data |
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****************************************************************************/ |
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/**************************************************************************** |
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* Private Functions |
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****************************************************************************/ |
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/**************************************************************************** |
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* Public Functions |
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****************************************************************************/ |
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/**************************************************************************** |
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* Name: nxgl_circletraps |
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* |
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* Description: |
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* Given a description of a a circle, return 8 trapezoids that can be |
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* used to fill the circle by nx_fillcircle() and other interfaces. |
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* |
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* Input parameters: |
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* center - A pointer to the point that is the center of the circle |
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* radius - The radius of the circle in pixels. |
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* circle - A pointer the first entry in an array of 8 trapezoids where |
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* the circle description will be returned. |
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* |
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* Returned value: |
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* None |
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* |
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****************************************************************************/ |
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void nxgl_circletraps(FAR const struct nxgl_point_s *center, nxgl_coord_t radius, |
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FAR struct nxgl_trapezoid_s *circle) |
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{ |
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nxgl_coord_t xoffs; |
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nxgl_coord_t yoffs; |
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circle[0].top.x1 = itob16(center->x); |
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circle[0].top.x2 = circle[0].top.x1; |
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circle[0].top.y = center->y - radius; |
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circle[7].bot.x1 = circle[0].top.x1; |
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circle[7].bot.x2 = circle[0].top.x1; |
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circle[7].bot.y = center->y + radius; |
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circle[3].bot.x1 = itob16(center->x - radius); |
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circle[3].bot.x2 = itob16(center->x + radius); |
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circle[3].bot.y = center->y; |
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circle[4].top.x1 = circle[3].bot.x1; |
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circle[4].top.x2 = circle[3].bot.x2; |
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circle[4].top.y = circle[3].bot.y; |
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/* Now 22.5, 67.5, 112.5, 157.5, 202.5, 247.5, 292.5, and 337.5 */ |
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xoffs = b16toi(b16muli(COS_22p5, radius) + b16HALF); |
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yoffs = b16toi(b16muli(SIN_22p5, radius) + b16HALF); |
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circle[2].bot.x1 = itob16(center->x - xoffs); |
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circle[2].bot.x2 = itob16(center->x + xoffs); |
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circle[2].bot.y = center->y - yoffs; |
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circle[3].top.x1 = circle[2].bot.x1; |
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circle[3].top.x2 = circle[2].bot.x2; |
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circle[3].top.y = circle[2].bot.y; |
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circle[4].bot.x1 = circle[2].bot.x1; |
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circle[4].bot.x2 = circle[2].bot.x2; |
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circle[4].bot.y = center->y + yoffs; |
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circle[5].top.x1 = circle[4].bot.x1; |
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circle[5].top.x2 = circle[4].bot.x2; |
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circle[5].top.y = circle[4].bot.y; |
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circle[0].bot.x1 = itob16(center->x - yoffs); |
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circle[0].bot.x2 = itob16(center->x + yoffs); |
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circle[0].bot.y = center->y - xoffs; |
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circle[1].top.x1 = circle[0].bot.x1; |
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circle[1].top.x2 = circle[0].bot.x2; |
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circle[1].top.y = circle[0].bot.y; |
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circle[6].bot.x1 = circle[1].top.x1; |
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circle[6].bot.x2 = circle[1].top.x2; |
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circle[6].bot.y = center->y + xoffs; |
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circle[7].top.x1 = circle[6].bot.x1; |
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circle[7].top.x2 = circle[6].bot.x2; |
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circle[7].top.y = circle[6].bot.y; |
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/* Finally, 45.0, 135.0, 225.0, 315.0 */ |
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xoffs = b16toi(b16muli(COS_45p0, radius) + b16HALF); |
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circle[1].bot.x1 = itob16(center->x - xoffs); |
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circle[1].bot.x2 = itob16(center->x + xoffs); |
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circle[1].bot.y = center->y - xoffs; |
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circle[2].top.x1 = circle[1].bot.x1; |
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circle[2].top.x2 = circle[1].bot.x2; |
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circle[2].top.y = circle[1].bot.y; |
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circle[5].bot.x1 = circle[1].bot.x1; |
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circle[5].bot.x2 = circle[1].bot.x2; |
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circle[5].bot.y = center->y + xoffs; |
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circle[6].top.x1 = circle[5].bot.x1; |
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circle[6].top.x2 = circle[5].bot.x2; |
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circle[6].top.y = circle[5].bot.y; |
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}
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