Swing Hacks

Make Frames Resize Dynamically #100

Chapter 12, Miscellany

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501

HACK

A Word About Speed

When you have dynamic layout turned on, the window will repaint each

time the user moves the mouse. This will make the application feel respon-

sive because there is always information on the screen being updated. If your

frame contains an animated component, it will continue to play while the

user resizes the window.

The disadvantage of dynamic layout is that a resize will generate a whole lot

of repaint requests in a very short time. Even if the user moves the window

just one pixel, it will trigger a repaint on the entire frame (unlike scrolling,

which usually requires just repainting a strip at the bottom). If your paint-

ing code is slow (or you have a lot of components on screen), then the

dynamic layout could actually make your program feel slower. Be sure you

make your painting as fast as possible, perhaps skipping some of the more

complicated effects during the resize. You may also want to use dynamic lay-

out only in a program with a small streamlined window, such as a media

player or utility app.