org.primaresearch.web.gwt.client.ui.page.tool.drawing.RectangleTool.java Source code

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Here is the source code for org.primaresearch.web.gwt.client.ui.page.tool.drawing.RectangleTool.java

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/*
 * Copyright 2014 PRImA Research Lab, University of Salford, United Kingdom
 *
 * 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.primaresearch.web.gwt.client.ui.page.tool.drawing;

import org.primaresearch.maths.geometry.Point;
import org.primaresearch.maths.geometry.Rect;
import org.primaresearch.web.gwt.client.ui.page.PageScrollView;
import org.primaresearch.web.gwt.client.ui.page.renderer.PageRenderer;

import com.google.gwt.canvas.dom.client.Context2d;
import com.google.gwt.canvas.dom.client.CssColor;
import com.google.gwt.dom.client.Style.Cursor;
import com.google.gwt.event.dom.client.MouseDownEvent;
import com.google.gwt.event.dom.client.MouseMoveEvent;
import com.google.gwt.event.dom.client.MouseOutEvent;
import com.google.gwt.event.dom.client.MouseUpEvent;

/**
 * Tool that allows drawing a rectangle on the document.
 * 
 * @author Christian Clausner
 *
 */
public class RectangleTool extends BasePageViewTool implements PageViewTool {

    Point p1 = null;
    Point p2 = null;
    PageScrollView view;

    /**
     * Constructor
     * @param view The document page view.
     */
    public RectangleTool(PageScrollView view) {
        this.view = view;
        //Change cursor
        view.getViewPanel().getElement().getStyle().setCursor(Cursor.CROSSHAIR);
    }

    /**
     * Returns the rectangle that has been drawn by the user.
     * @return A rectangle or <code>null</code>
     */
    public Rect getRect() {
        if (p1 == null)
            return null;
        int x1 = Math.min(p1.x, p2.x);
        int x2 = Math.max(p1.x, p2.x);
        int y1 = Math.min(p1.y, p2.y);
        int y2 = Math.max(p1.y, p2.y);
        return new Rect(x1, y1, x2, y2);
    }

    @Override
    public void render(PageRenderer renderer) {
        if (p1 == null || !isEnabled())
            return;
        Context2d context = renderer.getContext();

        //Blue rectangle
        context.setStrokeStyle(CssColor.make(0, 128, 255));
        context.setLineWidth(1.0 / renderer.getZoomFactor());

        int x1 = Math.min(p1.x, p2.x);
        int x2 = Math.max(p1.x, p2.x);
        int y1 = Math.min(p1.y, p2.y);
        int y2 = Math.max(p1.y, p2.y);

        context.beginPath();
        context.rect(x1, y1, x2 - x1 + 1, y2 - y1 + 1);
        context.stroke();
    }

    @Override
    public boolean onMouseMove(MouseMoveEvent event) {
        //Dragging?
        if (p1 != null) {
            int x = view.clientToDocumentCoordsX(event.getRelativeX(view.asWidget().getElement()));
            int y = view.clientToDocumentCoordsY(event.getRelativeY(view.asWidget().getElement()));
            p2.x = x;
            p2.y = y;
            view.getRenderer().refresh();
            return true; //Forbid scrolling
        }
        return false; //Allow scrolling
    }

    @Override
    public boolean onMouseOut(MouseOutEvent event) {
        if (p1 != null) {
            enable(false);
            p1 = p2 = null;
            notifyListenersToolFinished(false);
            return true;
        }
        return false;
    }

    @Override
    public boolean onMouseUp(MouseUpEvent event) {
        if (p1 != null) {
            enable(false);
            notifyListenersToolFinished(true);
            p1 = p2 = null;
            return true;
        }
        return false;
    }

    @Override
    public boolean onMouseDown(MouseDownEvent event) {
        if (p1 == null) {
            //Start dragging
            int x = view.clientToDocumentCoordsX(event.getRelativeX(view.asWidget().getElement()));
            int y = view.clientToDocumentCoordsY(event.getRelativeY(view.asWidget().getElement()));
            p1 = new Point(x, y);
            p2 = new Point(x, y);
            return true; //Forbid scrolling
        }
        return false; //Allow scrolling
    }

    @Override
    protected void notifyListenersToolFinished(boolean success) {
        view.getViewPanel().getElement().getStyle().setCursor(Cursor.AUTO);
        super.notifyListenersToolFinished(success);
    }

}