How do I use RGBA in pygame.draw

Question

fluids_ 0 Newbie Poster

8 Months Ago

I am trying to make a drawing board in pygame but I want to be able to change the opacity using RGBA but it doesn't seem to be working, my code below:

import pygame as pg
import sys, os
from pygame.locals import *
pg.init()
draw = 0
color = 0
thick = 30
sav = 0
c = 0
r = 0
g = 0
b = 0
a = 255
l = 0
n = 0
z = 0
i9 = 1
circle = []
long = 0
drawing_name = ''
load_name = ''
th = False
fill = r,g,b,a
WHITE = 255,255,255
file = 0
surf = pg.image.load('dot.png') 
surf.fill((r,g,b))   
color_ = pg.cursors.Cursor((20,20), surf)
pg.mouse.set_cursor(color_)
screen = pg.display.set_mode((1440,900),pg.FULLSCREEN)
pg.display.set_caption('Drawing board')
screen.fill(WHITE)
#pg.mouse.set_visible(False)
font1 = pg.font.SysFont('Chalkduster', 50)
font2 = pg.font.SysFont('Chalkduster', 25)
text1 = font1.render('What do you want to name your artwork:', True, (0, 0, 0))
textRect1 = text1.get_rect()
textRect1.center = (700, 500)
text2 = font1.render(drawing_name, True, (0, 0, 0))
textRect2 = text2.get_rect()
textRect2.center = (700, 500)
text3 = font1.render('Too Long!', True, (0, 0, 0))
textRect3 = text3.get_rect()
textRect3.center = (700, 700)
text4 = font1.render('What do artwork do you want to load:', True, (0, 0, 0))
textRect4 = text4.get_rect()
textRect4.center = (700, 500)
text5 = font1.render(load_name, True, (0, 0, 0))
textRect5 = text5.get_rect()
textRect5.center = (700, 600)
text6 = font2.render('Not a drawing!', True, (0, 0, 0))
textRect6 = text6.get_rect()
textRect6.center = (700, 700)
line_pos_lst = []
def save():
    global sav
    sav += 1
    screen.blit(text1, textRect1)
while True:
    print(a)
    fill = r,g,b,[a]
    surf = pg.Surface((thick+20, thick+20))
    surf.fill((r,g,b))
    color_ = pg.cursors.Cursor((20,20), surf)
    pg.mouse.set_cursor(color_)
    for event in pg.event.get():
        if event.type == pg.QUIT:
            running = False
            pg.quit()
            sys.exit()
        if event.type == pg.KEYDOWN:
            if event.key == pg.K_SPACE:
                if sav % 2 == 0:
                    screen.fill(WHITE)
            if event.key == pg.K_TAB:
                if sav % 2 == 0:
                    draw += 1
                    pg.mouse.set_visible(True)
            if event.key == pg.K_p:
                if sav % 2 == 0:
                    r = 255
                    g = 255
                    b = 255
                    a = 255
                    color += 1
            if event.key == pg.K_0:
                if sav % 2 == 0:
                    thick = 5
            if event.key == pg.K_1:
                if sav % 2 == 0:
                    thick = 10
            if event.key == pg.K_2:
                if sav % 2 == 0:
                    thick = 20
            if event.key == pg.K_3:
                if sav % 2 == 0:
                    thick = 30
            if event.key == pg.K_4:
                if sav % 2 == 0:
                    thick = 40
            if event.key == pg.K_5:
                if sav % 2 == 0:
                    thick = 50
            if event.key == pg.K_q:
                if sav % 2 == 0:
                    color1 = [r,g,b,a]
            if event.key == pg.K_w:
                if sav % 2 == 0:
                    color2 = [r,g,b,a]
            if event.key == pg.K_e:
                if sav % 2 == 0:
                    color3 = [r,g,b,a]
            if event.key == pg.K_a:
                if sav % 2 == 0:
                    r = color1[0]
                    g = color1[1]
                    b = color1[2]
                    a = color1[3]
            if event.key == pg.K_s:
                if sav % 2 == 0:
                    r = color2[0]
                    g = color2[1]
                    b = color2[2]
                    a = color2[3]
            if event.key == pg.K_d:
                if sav % 2 == 0:
                    r = color3[0]
                    g = color3[1]
                    b = color3[2]
                    a = color3[3]
            if event.key == pg.K_m:
                if sav % 2 == 0:
                    screen.fill(fill)
            if event.key == pg.K_c:
                if sav % 2 == 0:
                    r = 0
                    g = 0
                    b = 0
                    a = 255
            if event.key == pg.K_r:
                if sav % 2 == 0:
                    r += 10
            if event.key == pg.K_g:
                if sav % 2 == 0:
                    g += 10
            if event.key == pg.K_b:
                if sav % 2 == 0:
                    b += 10
            if event.key == pg.K_PLUS:
                if sav % 2 == 0:
                    a += 10
            if event.key == pg.K_MINUS:
                if sav % 2 == 0:
                    a -= 10
            if event.key == pg.K_F4:
                pg.image.save(screen, 'temp' + str(i9) + '.png')
                save()
                a += 1
                std = True
                while std:
                    pg.draw.rect(screen, (255,255,255), Rect(100, 400, 1240, 400))
                    text2 = font1.render(drawing_name, True, (0, 0, 0))
                    textRect2 = text2.get_rect()
                    textRect2.topleft = (300,600)
                    screen.blit(text2, textRect2)
                    save()
                    if len(drawing_name) == 30:
                        screen.blit(text3, textRect3)
                        long = 1
                    else:
                        long = 0
                    for event in pg.event.get():
                        if event.type == KEYDOWN:
                            if event.key == pg.K_BACKSPACE:
                                drawing_name = drawing_name[:-1]
                            elif event.key == pg.K_RETURN:
                                a9 = pg.image.load('temp' + str(i9) + '.png')
                                screen.blit(a9,(0,0))
                                pg.image.save(screen, 'drawing_' + drawing_name + ".png")
                                drawing_name = ''
                                std = False
                            else:
                                if long == 0:
                                    if event.unicode == ' ':
                                        drawing_name += '_'
                                    else:
                                        drawing_name += event.unicode
                    pg.display.update()
                sav += 1
                screen.fill((255,255,255))
                continue
            if event.key == pg.K_F6:
                screen.blit(text4, textRect4)
                sav += 1
                th = True
                while th:
                    pg.draw.rect(screen, (255,255,255), Rect(100, 400, 1240, 400))
                    screen.blit(text4, textRect4)
                    screen.blit(text5, textRect5)
                    text5 = font1.render(load_name, True, (0, 0, 0))
                    textRect5 = text5.get_rect()
                    textRect5.center = (700, 600)
                    if len(load_name) == 30:
                        screen.blit(text3, textRect3)
                        long = 1
                    else:
                        long = 0
                    if file == 1:
                        screen.blit(text6, textRect6)
                    if os.path.isfile('drawing_' + load_name + '.png') == True:
                        file = 0
                    for event in pg.event.get():
                        if event.type == KEYDOWN:
                            if event.key == pg.K_BACKSPACE:
                                load_name = load_name[:-1]
                            elif event.key == pg.K_RETURN:
                                if os.path.isfile('drawing_' + load_name + '.png') == True:
                                    z0 = pg.image.load('drawing_' + load_name + '.png')
                                    screen.blit(z0,(0,0))
                                    load_name = ''
                                    th = False
                                else:
                                    file = 1 
                            else:
                                if long == 0:
                                    if event.unicode == ' ':
                                        load_name += '_'
                                    else:
                                        load_name += event.unicode
                    pg.display.update()
                continue
            if event.key == pg.K_F9:
                if sav % 2 == 0:
                    pg.mouse.set_visible(True)
                    c += 1
                    circle.append(pg.mouse.get_pos())
                    if len(circle) == 2:
                        x1,y1 = circle[0]
                        x2,y2 = circle[1]
                        radius = ((x1 - x2)**2 + (y1 - y2)**2)**0.5
                        pg.draw.circle(screen, (r,g,b,a),[x1, y1], radius, thick+20)
                        circle.clear()
            if event.key == pg.K_l:
                if sav % 2 == 0:
                    pg.mouse.set_cursor(pg.SYSTEM_CURSOR_CROSSHAIR)
                    pg.mouse.set_visible(True)
                    c += 1
                    l += 1
            if event.key == pg.K_ESCAPE:
                pg.quit()
                sys.exit()
        if event.type == pg.MOUSEBUTTONDOWN:
            if sav % 2 == 0:
                line_pos_lst.append(pg.mouse.get_pos())
                n += 1
                l += 1
                if len(line_pos_lst) == 2:
                    pg.draw.line(screen, (r,g,b,a), line_pos_lst[0], line_pos_lst[1], width=thick+20 )
                    print(line_pos_lst[0],line_pos_lst[1])
                    n += 1
                    line_pos_lst.clear()
    if draw % 2 == 0:
        if c % 2 == 0:
            if color % 2 != 1:
                pg.mouse.set_visible(False)
                r %= 255
                g %= 255
                b %= 255
                a %= 255
            x,y = pg.mouse.get_pos()
            pg.draw.circle(screen, (r,g,b,a),[x, y], thick, 0)
    pg.display.update()

Can you help me?

python

3 Contributors
2 Replies
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15 Hours Discussion Span
Latest Post 8 Months Ago Latest Post by Reverend Jim

All 2 Replies

Reverend Jim 4,780 Hi, I'm Jim, one of DaniWeb's moderators.

8 Months Ago

First of all, please, please, please learn to

add whitespace
add comments
break up monolithic code into logical segments
pick meaningful variable names (or at least document them)

Rather than debugging your code I'll give you an example of blitting a semi-transparent circle

import pygame

pygame.init()

width, height = 800, 600
screen = pygame.display.set_mode((width, height))
pygame.display.set_caption('Semi-transparent Circle')

circle = pygame.Surface((100, 100), pygame.SRCALPHA)
colour = (0, 0, 0, 128)
centre = (50, 50)
radius = 40

pygame.draw.circle(circle, colour, centre, radius)

running = True

while running:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            running = False

    screen.fill((255, 255, 255))
    screen.blit(circle, (width // 2 - 50, height // 2 - 50))
    pygame.display.update()

pygame.quit()

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rproffitt 2,580 "Nothing to see here." Moderator · Answer 1 · 2023-08-03T15:43:44+00:00

I think that's a basic flaw in your approach. That is, to draw RGBA you'll have an new image set as RGBA. Such as:
img = Image.new('RGBA', (100, 100), (255, 255, 255))

But I don't see that so your draws will be RGB.

PS. See example at https://stackoverflow.com/questions/69857786/how-to-lower-transparency-to-line-in-pillow

How do I use RGBA in pygame.draw

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