在PGU中自动向下滚动

Question

I am using PGU as a GUI for a game I am writing in python3 with pygame. This game is going to have multiplayer in it so I have been working on an in-game chat system. The chat system works and is displayed in a scroll area without problems however the scroll area does not scroll down automatically when new messages are received. This means every time there is a new message the user needs to scroll down manually to read the new messages. Does anyone know of a way to do this with PGU? Or does someone have recommendations for alternative way of doing this? Looking around on my own I found this example indicating it can be done however the code posted there doesn't seem to show the part I am looking for. Here is a dumbed down version of my own code. When a chat message is received then chatmessage is called automatically.

class ChatScreen:
    def __init__(self):
        self.desktop = gui.Desktop(theme=gui.Theme("data/themes/default/"))
        self.container = gui.Container(width=800,height=600)
        self.chatinput = gui.Input(size=65)
        self.chatdoc = gui.Document(width=1, height=10)
        self.chatscroll = gui.ScrollArea(self.chatdoc,width=600,height=100,hscrollbar=False)

        self.container.add(self.chatinput, 10, 550)
        self.container.add(self.chatscroll, 10, 440)
        self.desktop.init(self.container)

    def chatmessage(self, message):
        self.chatdoc.add(gui.Label(message))
        self.chatdoc.br(1)

Answer 1

I found my own solution to this problem. I'm posting the answer for anyone else that might have this issue in the future. Here is my updated example code with the fix:

class ChatScreen:
    def __init__(self):
        self.desktop = gui.Desktop(theme=gui.Theme("data/themes/default/"))
        self.container = gui.Container(width=800,height=600)
        self.chatinput = gui.Input(size=65)
        self.chatdoc = gui.Document(width=1, height=10)
        self.chatscroll = gui.ScrollArea(self.chatdoc,width=600,height=100,hscrollbar=False)

        self.container.add(self.chatinput, 10, 550)
        self.container.add(self.chatscroll, 10, 440)
        self.desktop.init(self.container)

    def chatmessage(self, message):
        self.chatdoc.add(gui.Label(message))
        self.chatdoc.br(1)
        self.desktop.loop()
        self.chatscroll.set_vertical_scroll(someint)

I found that set_vertical_scroll() forcibly sets where the scroll area is. By setting someint to a number greater then what the number of messages in the chat box it goes to the bottom. In a real working solution someint will need to be a variable that increases with the number of messages or there has to be a limit to the number of messages that are displayed (which is what I have done with my project).