ClientSessionUtils.java

/*
 * Copyright 2016 Red Hat, Inc. and/or its affiliates.
 * 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.kie.workbench.common.stunner.core.client.util;

import javax.enterprise.context.Dependent;
import javax.inject.Inject;

import org.kie.workbench.common.stunner.core.client.canvas.Canvas;
import org.kie.workbench.common.stunner.core.client.canvas.CanvasHandler;
import org.kie.workbench.common.stunner.core.client.canvas.Layer;
import org.kie.workbench.common.stunner.core.client.canvas.controls.select.SelectionControl;
import org.kie.workbench.common.stunner.core.client.session.ClientReadOnlySession;
import org.kie.workbench.common.stunner.core.client.session.ClientSession;
import org.kie.workbench.common.stunner.core.diagram.Diagram;
import org.kie.workbench.common.stunner.core.graph.Element;
import org.kie.workbench.common.stunner.core.graph.Graph;
import org.kie.workbench.common.stunner.core.graph.processing.index.bounds.GraphBoundsIndexer;

@Dependent
public class ClientSessionUtils {

    private GraphBoundsIndexer graphBoundsIndexer;

    protected ClientSessionUtils() {
        this(null);
    }

    @Inject
    public ClientSessionUtils(final GraphBoundsIndexer graphBoundsIndexer) {
        this.graphBoundsIndexer = graphBoundsIndexer;
    }

    @SuppressWarnings("unchecked")
    public String canvasToImageData(final ClientSession session) {
        if (session instanceof ClientReadOnlySession) {
            final SelectionControl<CanvasHandler<?, Canvas<?>>, Element> selectionControl = ((ClientReadOnlySession) session).getSelectionControl();
            if (null != selectionControl) {
                // Ensure no selection present before creating the image data for the canvas.
                selectionControl.clearSelection();
            }
        }
        final CanvasHandler<?, Canvas<?>> canvasHandler = session.getCanvasHandler();
        return canvasToImageData(canvasHandler);
    }

    @SuppressWarnings("unchecked")
    private String canvasToImageData(final CanvasHandler<?, Canvas<?>> canvasHandler) {
        final Diagram diagram = canvasHandler.getDiagram();
        final Graph graph = diagram.getGraph();
        final double[] dBounds = graphBoundsIndexer
                .build(graph)
                .getTrimmedBounds();
        String thumbData = null;
        if (dBounds[2] > 0 && dBounds[3] > 0) {
            final Layer layer = canvasHandler.getCanvas().getLayer();
            if (null != layer) {
                thumbData = layer.toDataURL((int) dBounds[0],
                                            (int) dBounds[1],
                                            (int) dBounds[2],
                                            (int) dBounds[3]);
            }
        }
        return thumbData;
    }
}