'Check the keys that are evaluated on every main loop iteration.
I.e., they aren\'t just evaluated when first pressed down'

def CheckKeys(self):

    pygame.event.pump()
    self.keys = keys = pygame.key.get_pressed()
    if keys[pygame.K_LEFT]:
        self.viewCenter -= (0.5, 0)
    elif keys[pygame.K_RIGHT]:
        self.viewCenter += (0.5, 0)
    if keys[pygame.K_UP]:
        self.viewCenter += (0, 0.5)
    elif keys[pygame.K_DOWN]:
        self.viewCenter -= (0, 0.5)
    if keys[pygame.K_HOME]:
        self.viewZoom = 1.0
        self.viewCenter = (0.0, 20.0)
