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package org.eclipse.swt.dnd;
/*
* Copyright (c) 2000, 2002 IBM Corp. All rights reserved.
* This file is 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
*/
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.widgets.*;
class TableDragUnderEffect extends DragUnderEffect {
private Table table;
private TableItem[] selection = new TableItem[0];
private int currentEffect = DND.FEEDBACK_NONE;
private TableItem dropSelection;
private TableItem scrollItem;
private long scrollBeginTime;
private static final int SCROLL_HYSTERESIS = 400; // milli seconds
private static final int SCROLL_WIDTH = 100; // pixels
TableDragUnderEffect(Table table) {
this.table = table;
}
void show(int effect, int x, int y) {
TableItem item = findItem(x, y);
if (item == null) effect = DND.FEEDBACK_NONE;
if (currentEffect == DND.FEEDBACK_NONE && effect != DND.FEEDBACK_NONE) {
selection = table.getSelection();
table.deselectAll();
}
scrollHover(effect, item, x, y);
setDragUnderEffect(effect, item);
if (currentEffect != DND.FEEDBACK_NONE && effect == DND.FEEDBACK_NONE) {
table.setSelection(selection);
selection = new TableItem[0];
}
currentEffect = effect;
}
private TableItem findItem(int x, int y){
if (table == null) return null;
Point coordinates = new Point(x, y);
coordinates = table.toControl(coordinates);
TableItem item = table.getItem(coordinates);
if (item != null) return item;
Rectangle area = table.getClientArea();
for (int x1 = area.x; x1 < area.x + area.width; x1++) {
coordinates = new Point(x1, y);
coordinates = table.toControl(coordinates);
item = table.getItem(coordinates);
if (item != null) return item;
}
return null;
}
private void setDragUnderEffect(int effect, TableItem item) {
if ((effect & DND.FEEDBACK_SELECT) != 0) {
setDropSelection(item);
return;
}
if ((currentEffect & DND.FEEDBACK_SELECT) != 0) setDropSelection(null);
}
private void setDropSelection (TableItem item) {
if (item == dropSelection) return;
if (dropSelection != null) table.deselectAll();
dropSelection = item;
if (dropSelection != null) table.setSelection(new TableItem[]{dropSelection});
}
private void scrollHover (int effect, TableItem 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(TableItem item, int x, int y) {
if (item == null) return;
Point coordinates = new Point(x, y);
coordinates = table.toControl(coordinates);
Rectangle area = table.getClientArea();
TableItem showItem = null;
int itemIndex = table.indexOf(item);
if (coordinates.y - area.y < SCROLL_WIDTH) {
showItem = table.getItem(Math.max(0, itemIndex - 1));
} else if ((area.y + area.height - coordinates.y) < SCROLL_WIDTH) {
showItem = table.getItem(Math.min(table.getItemCount() - 1, itemIndex + 1));
}
if (showItem != null) {
table.showItem(showItem);
}
}
}
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