PanningHandler.java

/*
 * Copyright 2006-2017 ICEsoft Technologies Canada Corp.
 *
 * 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 org.icepdf.ri.common.tools;

import org.icepdf.ri.common.views.AbstractDocumentView;
import org.icepdf.ri.common.views.DocumentViewController;
import org.icepdf.ri.common.views.DocumentViewModel;

import java.awt.*;
import java.awt.event.MouseEvent;

/**
 * Container logic used for view panning via mouse dragging for page views.
 * Panning can be handle in the view and doesn't need to be handled by the
 * page components.
 *
 * @since 4.0
 */
public class PanningHandler implements ToolHandler {


    // page mouse event manipulation
    private Point lastMousePosition = new Point();

    private DocumentViewController documentViewController;
    private DocumentViewModel documentViewModel;
    private AbstractDocumentView parentComponent;

    public PanningHandler(DocumentViewController documentViewController,
                          DocumentViewModel documentViewModel,
                          AbstractDocumentView parentComponent) {
        this.documentViewController = documentViewController;
        this.documentViewModel = documentViewModel;
        this.parentComponent = parentComponent;
    }

    /**
     * Mouse dragged, initiates page panning if the tool is selected.
     *
     * @param e awt mouse event
     */
    public void mouseDragged(MouseEvent e) {
        if (documentViewController != null) {

            // Get data about the current view port position
            Adjustable verticalScrollbar =
                    documentViewController.getVerticalScrollBar();
            Adjustable horizontalScrollbar =
                    documentViewController.getHorizontalScrollBar();

            if (verticalScrollbar != null && horizontalScrollbar != null) {
                // calculate how much the view port should be moved
                Point p = new Point(
                        (int) e.getPoint().getX() - horizontalScrollbar.getValue(),
                        (int) e.getPoint().getY() - verticalScrollbar.getValue());
                int x = (int) (horizontalScrollbar.getValue() - (p.getX() - lastMousePosition.getX()));
                int y = (int) (verticalScrollbar.getValue() - (p.getY() - lastMousePosition.getY()));

                // apply the pan
                horizontalScrollbar.setValue(x);
                verticalScrollbar.setValue(y);

                // update last position holder
                lastMousePosition.setLocation(p);
            }
        }
    }

    public void mouseMoved(MouseEvent e) {
        if (documentViewController != null) {

            Adjustable verticalScrollbar =
                    documentViewController.getVerticalScrollBar();
            Adjustable horizontalScrollbar =
                    documentViewController.getHorizontalScrollBar();

            lastMousePosition.setLocation(
                    e.getPoint().getX() - horizontalScrollbar.getValue(),
                    e.getPoint().getY() - verticalScrollbar.getValue());
        }
    }

    /**
     * Invoked when the mouse button has been clicked (pressed
     * and released) on a component.
     */
    public void mouseClicked(MouseEvent e) {
        documentViewController.clearSelectedAnnotations();
        if (parentComponent != null) {
            parentComponent.requestFocus();
        }
    }

    /**
     * Invoked when a mouse button has been pressed on a component.
     */
    public void mousePressed(MouseEvent e) {

        if (documentViewController != null &&
                documentViewController.getDocumentViewModel()
                        .isViewToolModeSelected(DocumentViewModel.DISPLAY_TOOL_PAN)) {
            documentViewController.setViewCursor(DocumentViewController.CURSOR_HAND_CLOSE);
        }
    }

    /**
     * Invoked when a mouse button has been released on a component.
     */
    public void mouseReleased(MouseEvent e) {
        if (documentViewController != null &&
                documentViewController.getDocumentViewModel().getViewToolMode()
                        == DocumentViewModel.DISPLAY_TOOL_PAN) {
            documentViewController.setViewCursor(DocumentViewController.CURSOR_HAND_OPEN);
        }
    }

    /**
     * Invoked when the mouse enters a component.
     */
    public void mouseEntered(MouseEvent e) {

    }

    /**
     * Invoked when the mouse exits a component.
     */
    public void mouseExited(MouseEvent e) {

    }

    public void paintTool(Graphics g) {
        // nothing to paint for paning.
    }

    public void installTool() {

    }

    public void uninstallTool() {

    }
}