Python的正弦和余弦给出不正确的值 [英] Python sin and cosine giving incorrect values

问题描述

我有从2点画一条线的代码；一个位于屏幕中间底部，另一个指向鼠标指针.我试图通过不超过我设置的 length 参数来约束该点.这是代码:

I have code that draws a line from 2 points; One on the middle bottom of the screen, and the other to the mouse pointer. I am trying to constrain the point by not exceeding a length parameter that I set. Heres the code:

import pygame
import Resources as r
import math as m

pygame.init()

class Segment():



    def __init__(self, _screen, _id, _start_pos, _length):
        self.screen = _screen
        self.id = _id
        self.start_pos = _start_pos
        self.length = _length

    def update(self):
        if self.id == 1:
            mouse_pos = pygame.mouse.get_pos()


            self.angle = m.atan2(mouse_pos[1]-self.start_pos[1],mouse_pos[0]-self.start_pos[0])
            self.a = self.start_pos
            self.b = (m.cos(self.angle)*self.length, m.sin(self.angle)*self.length)


            self.draw_line(self.a, self.b, r.black, 4)




    def draw_line(self, start, end, color, width):
        if self.id == 1:
            pygame.draw.line(self.screen, color, start, end, width)

    def get_data(self):
        return (self.start_pos, self.end_)

运行该程序时，我看到的结果与预期的非常不同，它与鼠标不对齐，并且通常在移动鼠标时来回摆动.

I am seeing very different results when I run this that I would expect, it doesnt line up with my mouse and often just oscillates back and forth when the mouse is moved.

推荐答案

self.b是根据原点0、0而不是self.start_pos计算的.

self.b is calculated based on origin 0, 0, not self.start_pos.

将self.a中的坐标添加到self.b.

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