How to use

visibleAmountProperty

method

in

javafx.scene.control.ScrollBar

private static void setupUnitIncrement(ScrollBar bar) {
  bar.unitIncrementProperty().bind(new DoubleBinding() {
    { bind(bar.maxProperty(), bar.visibleAmountProperty()); }
    @Override
    protected double computeValue() {
      double max = bar.getMax();
      double visible = bar.getVisibleAmount();
      return max > visible
          ? 16 / (max - visible) * max
          : 0;
    }
  });
}

public void bind(ScrollBar bar) {
  bar.minProperty().bind(this.min);
  bar.maxProperty().bind(this.max);
  bar.visibleAmountProperty().bind(this.contentAreaHeight.divide(this.contentHeight.divide(this.max)));
  bar.valueProperty().bindBidirectional(this.offset);
  recomputeAll();
}

vScrollBar.minProperty().bind(scrollPane.vminProperty());
vScrollBar.maxProperty().bind(scrollPane.vmaxProperty());
vScrollBar.visibleAmountProperty().bind(scrollPane.heightProperty().divide(pane.heightProperty()));
scrollPane.vvalueProperty().bindBidirectional(vScrollBar.valueProperty());
hScrollBar.minProperty().bind(scrollPane.hminProperty());
hScrollBar.maxProperty().bind(scrollPane.hmaxProperty());
hScrollBar.visibleAmountProperty().bind(scrollPane.widthProperty().divide(pane.heightProperty()));
scrollPane.hvalueProperty().bindBidirectional(hScrollBar.valueProperty());

public void bindHorizontalScrollbar(ScrollBar bar) {
  bar.setMin(0);
  DoubleBinding max = this.contentBody.widthProperty().subtract(widthProperty());
  DoubleBinding factor = this.contentBody.widthProperty().divide(max);
  bar.maxProperty().bind(this.contentBody.widthProperty().divide(factor));
  bar.visibleAmountProperty().bind(widthProperty().divide(factor));
  this.offsetX.bind(bar.valueProperty());
}

hbar.blockIncrementProperty().bind(hbar.visibleAmountProperty());
vbar.blockIncrementProperty().bind(vbar.visibleAmountProperty());