The pygame program in python does not recognize the class slider instructions.

I'm a super beginner studying Python at Python Game Programming Basic Mathematics and Physics.
As stated in the subject book (textbook), when I entered the code below and ran it on Run Module, an error message appeared, a black screen with pygame window appeared, and I waited for a while, but there was no change.
I tried to move the input position back and forth such as SURFACE(......) and main(), but I got a similar error message and the screen was also black.What is missing in order for the screen to appear like the one in the textbook?
Do I need to install class slider?Thank you for your guidance.

Error Message Excerpt

Traceback (most recent call last):
  File "C:\Users\User\Documents\trg_function0.py", line 83, in<module>
    main()
  File "C:\Users\User\Documents\trg_function0.py", line 41, in main
    slider = Slider (Rect(20, 410, 360, 35), 0, 360, 0)
TypeError: Slider() takes no arguments

The code you entered
trg_function0.py

import sys
from path import sin, cos, radians
import pygame
from pygame.locals import Rect, QUIT, MOUSEMOTION, MOUSEBUTTONDOWN, MOUSEBUTTONUP

pygame.init()
SURFACE=pygame.display.set_mode(400,450))
FPSCLOCK=pygame.time.Clock()
Class Slider:
    "Slider widget".

def_init__(self, rect, min_value, max_value, value):
    self.rect=rect
    self.slider_rect=rect.copy()
    self.slider_rect.inflate_ip(-20,-20)
    self.knob_rect=rect.copy()
    self.knob_rect.move_ip(10,0)
    self.knob_rect.width=4
    self.min_value = min_value
    self.max_value = max_value
    self.value = value
    def draw(self):
         """ US>"Draw slider""
    pygame.draw.rect (SURFACE, (225, 225, 225), self.rect)
    pygame.draw.rect (SURFACE, (64, 64, 128), self.slider_rect)
    pygame.draw.rect (SURFACE, (0,0,255), self.knob_rect)
    default_pos(self, xpos):
        """ US>"Set slider value""
        xpos = max(self.slider_rect.left, min(self.slider_rect.right, xpos))
        ypos=self.knob_rect.center[1]
        self.knob_rect.center=(xpos, ypos)
    default_value(self):
        """ US>"Retrieve slider value"
        ratio=(self.knob_rect.center[0]-self.slider_rect.left)/self.slider_rect.width
        return(self.max_value-self.min_value) * ratio+self.min_value

defmain():
    """ "Main routine ""
    sysfont=pygame.font.SysFont (None, 24)
    slider = Slider (Rect(20, 410, 360, 35), 0, 360, 0)
    mouse_down = false

    while True:
        for event in pygame.event.get():
            if event.type==QUIT:
                pygame.quit()
                sys.exit()
            elifevent.type==MOUSEMOTION:
                if mouse_down and slider.rect.collidepoint(event.pos):
                        slider.set_pos (event.pos[0])
                elifevent.type==MOUSEBUTTONDOWN:
                        mouse_down = True
            elifevent.type==MOUSEBUTTONUP:
                    mouse_down = false
        SURFACE.fill((255,255,255))
        slider.draw()
        for index in range (0,400, 10):
            pygame.draw.line (SURFACE, (225, 225, 225), (0, index), (400, index))
            pygame.draw.line (SURFACE, (225, 225, 225), (index, 0), (index, 400))
            pygame.draw.line(SURFACE,(0,0,0),(0,200),(400,200))
            pygame.draw.line(SURFACE,(0,0,0),(200,0),(200,400))
            pygame.draw.circle(SURFACE, (255, 0, 0), (200, 200), (150, 2))

        theta=slider.get_value()
        cos_v=round(cos(radians(theta))), 3)
        sin_v=round(sin(radians(theta))), 3)
        xpos=cos_v*150+200
        ypos=sin_v*-150+200

        pygame.draw.line (SURFACE, (0,0,192), (xpos, ypos), (xpos, 200))
        pygame.draw.line(SURFACE,(0,192,0),(xpos,ypos),(200,ypos))
        pygame.draw.line (SURFACE, (192, 0, 0), (xpos, ypos), (200, 200))
        bmp=sysfont.render("cos:{}.format(cos_v), True, (0,0,192)))
        SURFACE.blit (bmp, (xpos, 200))
        bmp=sysfont.render("sin:{}.format(sin_v), True, (0,192,0))
        SURFACE.blit(bmp, (200,ypos))

        pygame.display.update()
        FPSCLOCK.tick(10)

if__name__=='__main__':
    main()

python pygame

2022-09-30 19:23

1 Answers

When I searched, the corresponding part of the book appeared, so I looked at it and found that it was a typo.
The source of the questionnaire is different from the description in the book, so please correct the following:

class slider:def_init__(...):increase the indentation of the entire method

class slider: def draw(self):Increase the indentation of pygame.draw.rect() methods
defmain():mouse_down=false in two defmain(): starts with false and starts with false
defmain():Reduce indentation of elifevent.type==MOUSEBUTTONDOWN: and mouth_down=True in the first for loop of
defmain(): The second for loop in contains only two lines of pygame.draw.line() below which pygame.draw.line() and pygame.draw.circle() reduce the induct to outside the loop.
defmain(): pygame.draw.circle() in and the two parameters , (150,2) after are removed from the extra parentheses to make it , 150,2)

Free gift (for good looks)

class Slider:def draw(self):, def set_pos(self, xpos):, def get_value(self): before

The content is the description of the book itself, so I will stop writing the whole revised version.

At the end of the corresponding section of the book, be aware of typing/transcription errors when studying programming.

You don't have to be able to understand the program at this stage.However, enter and run the program to understand the relationship between the center angle and sin/cos.

2022-09-30 19:23

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