org.openxdata.designer.client.controller.FormDesignerDropController.java Source code

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Here is the source code for org.openxdata.designer.client.controller.FormDesignerDropController.java

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package org.openxdata.designer.client.controller;

import java.util.ArrayList;

import org.openxdata.designer.client.widget.DesignWidgetWrapper;
import org.openxdata.sharedlib.client.OpenXdataConstants;

import com.allen_sauer.gwt.dnd.client.DragContext;
import com.allen_sauer.gwt.dnd.client.drop.AbstractPositioningDropController;
import com.allen_sauer.gwt.dnd.client.util.DOMUtil;
import com.allen_sauer.gwt.dnd.client.util.WidgetLocation;
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;

/**
 * 
 *  www.openxdata.org - Licensed as written in license.txt and original sources of this file and its authors are found in sources.txt.
 *
 */

public class FormDesignerDropController 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;

    private DragDropListener dragDropListener;

    public FormDesignerDropController(AbsolutePanel dropTarget, DragDropListener dragDropListener) {
        super(dropTarget);
        this.dropTarget = dropTarget;
        this.dragDropListener = dragDropListener;
    }

    /**
     * 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) {
            if (draggable.widget instanceof DesignWidgetWrapper) {
                draggable.positioner.removeFromParent();
                dropTarget.add(draggable.widget, draggable.desiredX, draggable.desiredY);
            } else if (dragDropListener != null)
                dragDropListener.onDrop(draggable.widget, context.mouseX, context.mouseY);
        }
        super.onDrop(context);
    }

    @Override
    public void onEnter(DragContext context) {
        assert draggableList.size() == 0;

        dropTargetClientWidth = DOMUtil.getClientWidth(dropTarget.getElement());
        dropTargetClientHeight = DOMUtil.getClientHeight(dropTarget.getElement());
        WidgetLocation dropTargetLocation = new WidgetLocation(dropTarget, null);
        dropTargetOffsetX = dropTargetLocation.getLeft() + DOMUtil.getBorderLeft(dropTarget.getElement());
        dropTargetOffsetY = dropTargetLocation.getTop() + DOMUtil.getBorderTop(dropTarget.getElement());

        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();
    }

    @Override
    public void onMove(DragContext context) {
        super.onMove(context);

        int count = draggableList.size();

        for (Draggable draggable : draggableList) {

            if (count == 1) {
                draggable.desiredX = draggable.widget.getAbsoluteLeft() - dropTargetOffsetX + draggable.relativeX;
                draggable.desiredY = draggable.widget.getAbsoluteTop() - dropTargetOffsetY + draggable.relativeY;
            } else {
                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);
        }
    }

    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.getElement().getStyle().setProperty("margin", "0" + OpenXdataConstants.UNITS);

        // place off screen for border calculation
        RootPanel.get().add(outer, -500, -500);

        outer.setWidget(DUMMY_LABEL_IE_QUIRKS_MODE_OFFSET_HEIGHT);

        SimplePanel inner = new SimplePanel();
        inner.getElement().getStyle().setProperty("margin", "0" + OpenXdataConstants.UNITS);
        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;
    }
}