public CurrentPageChanger(
JScrollPane scrollpane,
AbstractDocumentView documentView,
List<AbstractPageViewComponent> pageComponents,
boolean addWheelMouseListener) {
this.pageComponents = pageComponents;
this.scrollpane = scrollpane;
this.documentView = documentView;
documentViewModel = documentView.getViewModel();
// listen for scroll bar manaipulators
this.documentView.addMouseListener(this);
this.scrollpane.getHorizontalScrollBar().addAdjustmentListener(this);
this.scrollpane.getHorizontalScrollBar().addMouseListener(this);
this.scrollpane.getVerticalScrollBar().addAdjustmentListener(this);
this.scrollpane.getVerticalScrollBar().addMouseListener(this);
// addMouseListenerToAnyButtonsIn(scrollpane.getHorizontalScrollBar());
// addMouseListenerToAnyButtonsIn(scrollpane.getVerticalScrollBar());
// load wheel mouse listener
mouseWheelCurrentPageListener = MouseWheelCurrentPageListener.install(scrollpane, this);
}
public void calculateCurrentPage() {
if (pageComponents != null) {
Rectangle viewport = scrollpane.getViewport().getViewRect();
// find visible pages
ArrayList<PageViewComponent> visiblePages = new ArrayList<PageViewComponent>(10);
Rectangle pageBounds;
int pageCount = 0;
for (AbstractPageViewComponent pageComponent : pageComponents) {
if (pageComponent != null) {
pageBounds = documentViewModel.getPageBounds(pageCount);
if (pageBounds != null && pageComponent.isShowing()) {
visiblePages.add(pageComponent);
}
}
pageCount++;
}
// find center point of view port
int x = viewport.x + (viewport.width / 2);
int y = viewport.y + (viewport.height / 2);
Point centerView = new Point(x, y);
// find out which page center is closest to center and thus the new current page
double minLength = Double.MAX_VALUE;
int minPage = -1;
double tmpDistance;
for (PageViewComponent pageComponent : visiblePages) {
if (pageComponent != null) {
pageBounds = documentViewModel.getPageBounds(pageComponent.getPageIndex());
x = pageBounds.x + (pageBounds.width / 2);
y = pageBounds.y + (pageBounds.height / 2);
// find minimum page.
tmpDistance = centerView.distance(x, y);
if (tmpDistance < minLength) {
minLength = tmpDistance;
minPage = pageComponent.getPageIndex();
}
}
}
// clean up
visiblePages.clear();
visiblePages.trimToSize();
// finally send out event to update page number
int oldCurrentPage = documentViewModel.getViewCurrentPageIndex();
documentViewModel.setViewCurrentPageIndex(minPage);
DocumentViewControllerImpl documentViewController =
(DocumentViewControllerImpl) documentView.getParentViewController();
documentViewController.firePropertyChange(
PropertyConstants.DOCUMENT_CURRENT_PAGE, oldCurrentPage, minPage);
}
}
public void dispose() {
// remove standard mouse listeners
documentView.removeMouseListener(this);
scrollpane.getHorizontalScrollBar().removeAdjustmentListener(this);
scrollpane.getHorizontalScrollBar().removeMouseListener(this);
scrollpane.getVerticalScrollBar().removeAdjustmentListener(this);
scrollpane.getVerticalScrollBar().removeMouseListener(this);
// Remove wheel mouse listener
MouseWheelCurrentPageListener.uninstall(scrollpane, mouseWheelCurrentPageListener);
}