Moving Images

[Andres Orellana]

How do I move a Image using the arrow keys on the keyboard?

[Elliott Slaughter]

You'll want to create an event loop similar to the one described in the user guide here:

http://code.google.com/p/lispbuilder/wiki/UsingLispbuilderSDL#The_Game_Loop

You can add a clause for :key-down-event and :key-up-event in the loop, and add some code that updates the position of the image. SDL will fire the :key-down-event when the key is pressed, and then the :key-up-event when the key is lifted again. In between, assuming you want the image to move at a constant rate, you can add code to the :idle event, which runs once each frame (default 30 fps), to move the image a little each frame.

See also:

http://lispbuilder.googlecode.com/svn/trunk/documentation/lispbuilder-sdl.html#frame-rate
http://lispbuilder.googlecode.com/svn/trunk/documentation/lispbuilder-sdl.html#enable-key-repeat

Hope that helps.

On Sun, Aug 18, 2013 at 10:52 PM, Andres Orellana <andyo...@gmail.com> wrote:

How do I move a Image using the arrow keys on the keyboard?

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Elliott Slaughter

"Don't worry about what anybody else is going to do. The best way to predict the future is to invent it." - Alan Kay

[Andres Orellana]

Thank you the links helped me out a lot