Returns the amount to change the scrollbar's value by, given a block (usually "page") up/down request. A ScrollBarUI implementation typically calls this method when the user clicks above or below the scrollbar "knob" to change the value up or down by large amount. Subclasses my override this method to compute a value, e.g. the change required to scroll up or down one paragraph in a text document.
The JScrollPane component creates scrollbars (by default) that override this method and delegate to the viewports Scrollable view, if it has one. The Scrollable interface provides a more specialized version of this method.
Some look and feels implement custom scrolling behavior and ignore this property.
direction | is -1 or 1 for up/down respectively |
setBlockIncrement, setValue, Scrollable.getScrollableBlockIncrement
Diagram: Scrolling