LittleVGL 源码分析--srclv

    技术2022-07-11  84

    /** * @file math_base.h * */ #ifndef LV_MATH_H #define LV_MATH_H #ifdef __cplusplus extern "C" { #endif /********************* * INCLUDES *********************/ #include <stdint.h> /********************* * DEFINES *********************/ #define LV_MATH_MIN(a, b) ((a) < (b) ? (a) : (b)) #define LV_MATH_MAX(a, b) ((a) > (b) ? (a) : (b)) #define LV_MATH_ABS(x) ((x) > 0 ? (x) : (-(x))) #define LV_TRIGO_SIN_MAX 32767 #define LV_TRIGO_SHIFT 15 /**< >> LV_TRIGO_SHIFT to normalize*/ //规范化 #define LV_BEZIER_VAL_MAX 1024 /**< Max time in Bezier functions (not [0..1] to use integers) */ //贝塞尔函数中的最长时间(不是[0..1]使用整数) #define LV_BEZIER_VAL_SHIFT 10 /**< log2(LV_BEZIER_VAL_MAX): used to normalize up scaled values*/ //log2(LV_BEZIER_VAL_MAX):用于标准化按比例放大的值 /********************** * TYPEDEFS **********************/ /********************** * GLOBAL PROTOTYPES **********************/ /** * Return with sinus of an angle * @param angle 角度 * @return sinus of 'angle'. sin(-90) = -32767, sin(90) = 32767 */ int16_t lv_trigo_sin(int16_t angle); /** * Calculate a value of a Cubic Bezier function.计算一个三次贝塞尔函数的值。 * @param t time in range of [0..LV_BEZIER_VAL_MAX] 时间范围 * @param u0 start values in range of [0..LV_BEZIER_VAL_MAX]起始值范围 * @param u1 control value 1 values in range of [0..LV_BEZIER_VAL_MAX]控制值1范围 * @param u2 control value 2 in range of [0..LV_BEZIER_VAL_MAX]控制值2范围 * @param u3 end values in range of [0..LV_BEZIER_VAL_MAX]结束值范围 * @return the value calculated from the given parameters in range of [0..LV_BEZIER_VAL_MAX] 根据给定参数范围 */ int32_t lv_bezier3(uint32_t t, int32_t u0, int32_t u1, int32_t u2, int32_t u3); /********************** * MACROS **********************/ #ifdef __cplusplus } /* extern "C" */ #endif #endif /** * @file lv_math.c * */ /********************* * INCLUDES *********************/ #include "lv_math.h" #include <stdbool.h> #include <stdlib.h> /********************* * DEFINES *********************/ /********************** * TYPEDEFS **********************/ /********************** * STATIC PROTOTYPES **********************/ /********************** * STATIC VARIABLES **********************/ static int16_t sin0_90_table[] = { 0, 572, 1144, 1715, 2286, 2856, 3425, 3993, 4560, 5126, 5690, 6252, 6813, 7371, 7927, 8481, 9032, 9580, 10126, 10668, 11207, 11743, 12275, 12803, 13328, 13848, 14364, 14876, 15383, 15886, 16383, 16876, 17364, 17846, 18323, 18794, 19260, 19720, 20173, 20621, 21062, 21497, 21925, 22347, 22762, 23170, 23571, 23964, 24351, 24730, 25101, 25465, 25821, 26169, 26509, 26841, 27165, 27481, 27788, 28087, 28377, 28659, 28932, 29196, 29451, 29697, 29934, 30162, 30381, 30591, 30791, 30982, 31163, 31335, 31498, 31650, 31794, 31927, 32051, 32165, 32269, 32364, 32448, 32523, 32587, 32642, 32687, 32722, 32747, 32762, 32767}; /********************** * MACROS **********************/ /********************** * GLOBAL FUNCTIONS **********************/ /** * Return with sinus of an angle * @param angle * @return sinus of 'angle'. sin(-90) = -32767, sin(90) = 32767 */ int16_t lv_trigo_sin(int16_t angle) { int16_t ret = 0; angle = angle % 360; if(angle < 0) angle = 360 + angle; if(angle < 90) { ret = sin0_90_table[angle]; } else if(angle >= 90 && angle < 180) { angle = 180 - angle; ret = sin0_90_table[angle]; } else if(angle >= 180 && angle < 270) { angle = angle - 180; ret = -sin0_90_table[angle]; } else { /*angle >=270*/ angle = 360 - angle; ret = -sin0_90_table[angle]; } return ret; } /** * Calculate a value of a Cubic Bezier function. * @param t time in range of [0..LV_BEZIER_VAL_MAX] * @param u0 start values in range of [0..LV_BEZIER_VAL_MAX] * @param u1 control value 1 values in range of [0..LV_BEZIER_VAL_MAX] * @param u2 control value 2 in range of [0..LV_BEZIER_VAL_MAX] * @param u3 end values in range of [0..LV_BEZIER_VAL_MAX] * @return the value calculated from the given parameters in range of [0..LV_BEZIER_VAL_MAX] */ int32_t lv_bezier3(uint32_t t, int32_t u0, int32_t u1, int32_t u2, int32_t u3) { uint32_t t_rem = 1024 - t; uint32_t t_rem2 = (t_rem * t_rem) >> 10; uint32_t t_rem3 = (t_rem2 * t_rem) >> 10; uint32_t t2 = (t * t) >> 10; uint32_t t3 = (t2 * t) >> 10; uint32_t v1 = ((uint32_t)t_rem3 * u0) >> 10; uint32_t v2 = ((uint32_t)3 * t_rem2 * t * u1) >> 20; uint32_t v3 = ((uint32_t)3 * t_rem * t2 * u2) >> 20; uint32_t v4 = ((uint32_t)t3 * u3) >> 10; return v1 + v2 + v3 + v4; } /********************** * STATIC FUNCTIONS **********************/

    总结:一个sin角度函数 还没搞懂

       三次贝塞尔函数,还没搞懂:https://blog.csdn.net/qq_39328456/article/details/100895685

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