summer update

bug_standalone.py

@@ -0,0 +1,27 @@
+import pygame
+w,h=800,200
+fps=60
+pygame.init()
+screen = pygame.display.set_mode([w, h])
+color=pygame.Color("white")
+clock=pygame.time.Clock()
+radius=40
+x,y=800,100
+def get_bbox(x,y):
+    left = x - radius
+    top = y - radius
+    width = radius * 2
+    height = radius * 2
+    return pygame.Rect((left, top), (width, height))
+
+while True:
+    pygame.event.pump()
+    old_x=x
+    x-=5
+    screen.fill(pygame.Color("black"),get_bbox(old_x,y))
+    pygame.draw.circle(screen, color, (x, y), radius, 1)
+    pygame.display.update([get_bbox(x,y),get_bbox(old_x,y)])
+##    pygame.display.flip()
+    clock.tick(fps)
+##    time_passed=clock.get_time()
+##    print(time_passed)