/*
* Copyright 2009 Fred Sauer
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
* in compliance with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software distributed under the License
* is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
* or implied. See the License for the specific language governing permissions and limitations under
* the License.
*/
package com.allen_sauer.gwt.dnd.client.drop;
import com.google.gwt.user.client.ui.AbsolutePanel;
import com.google.gwt.user.client.ui.Label;
import com.google.gwt.user.client.ui.RootPanel;
import com.google.gwt.user.client.ui.SimplePanel;
import com.google.gwt.user.client.ui.Widget;
import com.allen_sauer.gwt.dnd.client.DragContext;
import com.allen_sauer.gwt.dnd.client.util.DOMUtil;
import com.allen_sauer.gwt.dnd.client.util.DragClientBundle;
import com.allen_sauer.gwt.dnd.client.util.WidgetLocation;
import java.util.ArrayList;
/**
* A {@link DropController} which allows a draggable widget to be placed at specific (absolute)
* locations on an {@link com.google.gwt.user.client.ui.AbsolutePanel} drop target.
*/
public class AbsolutePositionDropController extends AbstractPositioningDropController {
static class Draggable {
public int desiredX;
public int desiredY;
public int relativeX;
public int relativeY;
final int offsetHeight;
final int offsetWidth;
Widget positioner = null;
final Widget widget;
public Draggable(Widget widget) {
this.widget = widget;
offsetWidth = widget.getOffsetWidth();
offsetHeight = widget.getOffsetHeight();
}
}
private static final Label DUMMY_LABEL_IE_QUIRKS_MODE_OFFSET_HEIGHT = new Label("x");
final ArrayList<Draggable> draggableList = new ArrayList<Draggable>();
final AbsolutePanel dropTarget;
int dropTargetClientHeight;
int dropTargetClientWidth;
int dropTargetOffsetX;
int dropTargetOffsetY;
public AbsolutePositionDropController(AbsolutePanel dropTarget) {
super(dropTarget);
this.dropTarget = dropTarget;
}
/**
* Programmatically drop a widget on our drop target while obeying the constraints of this
* controller.
*
* @param widget the widget to be dropped
* @param left the desired absolute horizontal location relative to our drop target
* @param top the desired absolute vertical location relative to our drop target
*/
public void drop(Widget widget, int left, int top) {
left = Math.max(0, Math.min(left, dropTarget.getOffsetWidth() - widget.getOffsetWidth()));
top = Math.max(0, Math.min(top, dropTarget.getOffsetHeight() - widget.getOffsetHeight()));
dropTarget.add(widget, left, top);
}
@Override
public void onDrop(DragContext context) {
for (Draggable draggable : draggableList) {
draggable.positioner.removeFromParent();
dropTarget.add(draggable.widget, draggable.desiredX, draggable.desiredY);
}
super.onDrop(context);
}
@Override
public void onEnter(DragContext context) {
super.onEnter(context);
assert draggableList.size() == 0;
dropTargetClientWidth = DOMUtil.getClientWidth(dropTarget.getElement());
dropTargetClientHeight = DOMUtil.getClientHeight(dropTarget.getElement());
calcDropTargetOffset();
int draggableAbsoluteLeft = context.draggable.getAbsoluteLeft();
int draggableAbsoluteTop = context.draggable.getAbsoluteTop();
for (Widget widget : context.selectedWidgets) {
Draggable draggable = new Draggable(widget);
draggable.positioner = makePositioner(widget);
draggable.relativeX = widget.getAbsoluteLeft() - draggableAbsoluteLeft;
draggable.relativeY = widget.getAbsoluteTop() - draggableAbsoluteTop;
draggableList.add(draggable);
}
}
@Override
public void onLeave(DragContext context) {
for (Draggable draggable : draggableList) {
draggable.positioner.removeFromParent();
}
draggableList.clear();
super.onLeave(context);
}
@Override
public void onMove(DragContext context) {
super.onMove(context);
for (Draggable draggable : draggableList) {
draggable.desiredX = context.desiredDraggableX - dropTargetOffsetX + draggable.relativeX;
draggable.desiredY = context.desiredDraggableY - dropTargetOffsetY + draggable.relativeY;
draggable.desiredX = Math.max(0, Math.min(draggable.desiredX, dropTargetClientWidth
- draggable.offsetWidth));
draggable.desiredY = Math.max(0, Math.min(draggable.desiredY, dropTargetClientHeight
- draggable.offsetHeight));
dropTarget.add(draggable.positioner, draggable.desiredX, draggable.desiredY);
}
if (context.dragController.getBehaviorScrollIntoView()) {
draggableList.get(draggableList.size() - 1).positioner.getElement().scrollIntoView();
}
// may have changed due to scrollIntoView() or user driven scrolling
calcDropTargetOffset();
}
Widget makePositioner(Widget reference) {
// Use two widgets so that setPixelSize() consistently affects dimensions
// excluding positioner border in quirks and strict modes
SimplePanel outer = new SimplePanel();
outer.addStyleName(DragClientBundle.INSTANCE.css().positioner());
outer.getElement().getStyle().setProperty("margin", "0px");
// place off screen for border calculation
RootPanel.get().add(outer, -500, -500);
// Ensure IE quirks mode returns valid outer.offsetHeight, and thus valid
// DOMUtil.getVerticalBorders(outer)
outer.setWidget(DUMMY_LABEL_IE_QUIRKS_MODE_OFFSET_HEIGHT);
SimplePanel inner = new SimplePanel();
inner.getElement().getStyle().setProperty("margin", "0px");
inner.getElement().getStyle().setProperty("border", "none");
int offsetWidth = reference.getOffsetWidth() - DOMUtil.getHorizontalBorders(outer);
int offsetHeight = reference.getOffsetHeight() - DOMUtil.getVerticalBorders(outer);
inner.setPixelSize(offsetWidth, offsetHeight);
outer.setWidget(inner);
return outer;
}
private void calcDropTargetOffset() {
WidgetLocation dropTargetLocation = new WidgetLocation(dropTarget, null);
dropTargetOffsetX = dropTargetLocation.getLeft()
+ DOMUtil.getBorderLeft(dropTarget.getElement());
dropTargetOffsetY = dropTargetLocation.getTop() + DOMUtil.getBorderTop(dropTarget.getElement());
// System.out.println(dropTargetOffsetX + ", " + dropTargetOffsetY);
}
}