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Vertical scrolling using Graphics2D help needed.

Has anyone had any experience in doing vertical scrolling using Graphics2D. Basically I need to create a vertical scrolling "widget" that I can use in Swing applets. I'd like just to be able to pass it a String and the widget will display the text, scrolling the previous text up if necessary.

I have created a component that will do this with a JList inside a JScrollPane. However, there is a large amount of data that currently is being received (via JMS) by my applet and I noticed that by scrolling using my current method (i.e. calling the method ensureIndexIsVisible() on the scrollpane) is processor intensive. Also, I have noticed that it is even more processor intensive if I turn on BACKINGSTORE_SCROLL_MODE in the viewport of the JScrollPane. Hence, I thought that Graphics2D may be a better approach.

I'd appreciate it if someone could either point me to a link that will give me an example of how to do this or respond with an example of their own.

Thanks in advance for your help.

heyhey_

if nobody else responds to your problem, I will post some code tomorrow (have to go now)

have a nice eveneing :)

mwalker

ASKER

Thanks heyhey. I will appreciate it.

Mick Barry

Just create an offscreen image of what you want to display and 'move' it up the screen.

heyhey_

do you want all the "old" info to be visible after scrolling ?

mwalker

ASKER

objects: I'm not experienced with drawing in Java. So, I'm not exactly sure what you mean by an offscreen image. I also don't know how to "move it up", which is why I posted this question.

heyhey: I do not need the either the "old" info to be visible or accessible after scrolling.

heyhey_

so you need custom component that displays several rows of text and when new text is appened the old one scroll up (and possible disappear) ?

mwalker

ASKER

You are exactly correct. If you can show me a simple subclass of JPanel that uses Graphics2D for displaying the text and scrolls up (and possibly disappears), I can add more stuff as I need it (e.g. rendering lines in different colors based on the data sent to it).

Thanks.

heyhey_

sorry, I was very busy these last few days, I will try to post some sample code during the weekend.

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heyhey_

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heyhey_

any news ?

mwalker

ASKER

heyhey: This is exactly what I needed. Thanks so much.