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/*******************************************************************************
* Copyright (c) 2000, 2004 IBM Corporation and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Common Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/cpl-v10.html
*
* Contributors:
* IBM Corporation - initial API and implementation
*******************************************************************************/
package org.eclipse.swt.dnd;
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.widgets.*;
import org.eclipse.swt.SWT;
import org.eclipse.swt.internal.win32.OS;
import org.eclipse.swt.internal.win32.TVITEM;
class TreeDragUnderEffect extends DragUnderEffect {
private Tree tree;
private int currentEffect = DND.FEEDBACK_NONE;
private TreeItem[] selection = new TreeItem[0];
private TreeItem scrollItem;
private long scrollBeginTime;
private static final int SCROLL_HYSTERESIS = 600; // milli seconds
private TreeItem expandItem;
private long expandBeginTime;
private static final int EXPAND_HYSTERESIS = 1000; // milli seconds
TreeDragUnderEffect(Tree tree) {
this.tree = tree;
}
void show(int effect, int x, int y) {
effect = checkEffect(effect);
TreeItem item = findItem(x, y);
if (item == null) effect = DND.FEEDBACK_NONE;
if (currentEffect == DND.FEEDBACK_NONE && effect != DND.FEEDBACK_NONE) {
selection = tree.getSelection();
tree.deselectAll();
}
scrollHover(effect, item, x, y);
expandHover(effect, item, x, y);
setDragUnderEffect(effect, item);
if (currentEffect != DND.FEEDBACK_NONE && effect == DND.FEEDBACK_NONE) {
for (int i = 0; i < selection.length; i++) {
TVITEM tvItem = new TVITEM ();
tvItem.mask = OS.TVIF_STATE;
tvItem.state = OS.TVIS_SELECTED;
tvItem.stateMask = OS.TVIS_SELECTED;
tvItem.hItem = selection[i].handle;
OS.SendMessage (tree.handle, OS.TVM_SETITEM, 0, tvItem);
}
selection = new TreeItem[0];
}
currentEffect = effect;
}
private int checkEffect(int effect) {
// Some effects are mutually exclusive. Make sure that only one of the mutually exclusive effects has been specified.
int mask = DND.FEEDBACK_INSERT_AFTER | DND.FEEDBACK_INSERT_BEFORE | DND.FEEDBACK_SELECT;
int bits = effect & mask;
if (bits == DND.FEEDBACK_INSERT_AFTER || bits == DND.FEEDBACK_INSERT_BEFORE || bits == DND.FEEDBACK_SELECT) return effect;
return (effect & ~mask);
}
private TreeItem findItem(int x, int y){
Point coordinates = new Point(x, y);
coordinates = tree.toControl(coordinates);
Rectangle area = tree.getClientArea();
if (!area.contains(coordinates)) return null;
TreeItem item = tree.getItem(coordinates);
if (item != null) return item;
// Scan across the width of the tree.
for (int x1 = area.x; x1 < area.x + area.width; x1++) {
Point pt = new Point(x1, coordinates.y);
item = tree.getItem(pt);
if (item != null) return item;
}
// Check if we are just below the last item of the tree
if (coordinates.y > area.y + area.height - tree.getItemHeight()) {
int y1 = area.y + area.height - tree.getItemHeight();
Point pt = new Point(coordinates.x, y1);
item = tree.getItem(pt);
if (item != null) return item;
// Scan across the width of the tree just above the bottom..
for (int x1 = area.x; x1 < area.x + area.width; x1++) {
pt = new Point(x1, y1);
item = tree.getItem(pt);
if (item != null) return item;
}
}
return null;
}
private void setDragUnderEffect(int effect, TreeItem item) {
if ((effect & DND.FEEDBACK_SELECT) != 0) {
if ((currentEffect & DND.FEEDBACK_INSERT_AFTER) != 0 ||
(currentEffect & DND.FEEDBACK_INSERT_BEFORE) != 0) {
tree.setInsertMark(null, false);
}
setDropSelection(item);
return;
}
if ((effect & DND.FEEDBACK_INSERT_AFTER) != 0 ||
(effect & DND.FEEDBACK_INSERT_BEFORE) != 0) {
if ((currentEffect & DND.FEEDBACK_SELECT) != 0) {
setDropSelection(null);
}
setInsertMark(item, (effect & DND.FEEDBACK_INSERT_BEFORE) != 0);
return;
}
if ((currentEffect & DND.FEEDBACK_INSERT_AFTER) != 0 ||
(currentEffect & DND.FEEDBACK_INSERT_BEFORE) != 0) {
tree.setInsertMark(null, false);
}
if ((currentEffect & DND.FEEDBACK_SELECT) != 0) {
setDropSelection(null);
}
}
private void setDropSelection (TreeItem item) {
int hItem = (item != null) ? item.handle : 0;
OS.SendMessage (tree.handle, OS.TVM_SELECTITEM, OS.TVGN_DROPHILITED, hItem);
}
private void setInsertMark(TreeItem item, boolean before) {
int hItem = (item != null) ? item.handle : 0;
OS.SendMessage (tree.handle, OS.TVM_SETINSERTMARK, (before) ? 0 : 1, hItem);
}
private void scrollHover (int effect, TreeItem item, int x, int y) {
if ((effect & DND.FEEDBACK_SCROLL) == 0) {
scrollBeginTime = 0;
scrollItem = null;
return;
}
if (scrollItem == item && scrollBeginTime != 0) {
if (System.currentTimeMillis() >= scrollBeginTime) {
scroll(item, x, y);
scrollBeginTime = 0;
scrollItem = null;
}
return;
}
scrollBeginTime = System.currentTimeMillis() + SCROLL_HYSTERESIS;
scrollItem = item;
}
private void scroll(TreeItem item, int x, int y) {
if (item == null) return;
Point coordinates = new Point(x, y);
coordinates = tree.toControl(coordinates);
Rectangle area = tree.getClientArea();
TreeItem top = tree.getTopItem();
TreeItem newTop = null;
// scroll if two lines from top or bottom
int scroll_width = 2*tree.getItemHeight();
if (coordinates.y < area.y + scroll_width) {
newTop = getPreviousVisibleItem(top);
} else if (coordinates.y > area.y + area.height - scroll_width) {
newTop = getNextVisibleItem(top, true);
}
if (newTop != null && newTop != top) {
tree.setTopItem(newTop);
}
}
private void expandHover (int effect, TreeItem item, int x, int y) {
if ((effect & DND.FEEDBACK_EXPAND) == 0) {
expandBeginTime = 0;
expandItem = null;
return;
}
if (expandItem == item && expandBeginTime != 0) {
if (System.currentTimeMillis() >= expandBeginTime) {
expand(item, x, y);
expandBeginTime = 0;
expandItem = null;
}
return;
}
expandBeginTime = System.currentTimeMillis() + EXPAND_HYSTERESIS;
expandItem = item;
}
private void expand(TreeItem item, int x, int y) {
if (item == null || item.getExpanded()) return;
Event event = new Event();
event.x = x;
event.y = y;
event.item = item;
event.time = (int) System.currentTimeMillis();
tree.notifyListeners(SWT.Expand, event);
if (item.isDisposed()) return;
item.setExpanded(true);
}
private TreeItem getNextVisibleItem(TreeItem item, boolean includeChildren) {
// look down
// neccesary on the first pass only
if (includeChildren && item.getItemCount() > 0 && item.getExpanded()) {
return item.getItems()[0];
}
// look sideways
TreeItem parent = item.getParentItem();
TreeItem[] peers = (parent != null) ? parent.getItems() : tree.getItems();
for (int i = 0; i < peers.length - 1; i++) {
if (peers[i] == item) return peers[i + 1];
}
// look up
if (parent != null) return getNextVisibleItem(parent, false);
return null;
}
private TreeItem getPreviousVisibleItem(TreeItem item) {
// look sideways
TreeItem parent = item.getParentItem();
TreeItem[] peers = (parent != null) ? parent.getItems() : tree.getItems();
for (int i = peers.length - 1; i > 0; i--) {
if (peers[i] == item) {
TreeItem peer = peers[i-1];
if (!peer.getExpanded() || peer.getItemCount() == 0) return peer;
TreeItem[] peerItems = peer.getItems();
return peerItems[peerItems.length - 1];
}
}
// look up
return parent;
}
}
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