packages/serverless-workflow-diagram-editor/lienzo-core/src/main/java/com/ait/lienzo/client/widget/panel/util/PanelTransformUtils.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.ait.lienzo.client.widget.panel.util;

import com.ait.lienzo.client.core.shape.Viewport;
import com.ait.lienzo.client.core.types.Transform;
import com.ait.lienzo.client.widget.panel.Bounds;
import com.ait.lienzo.client.widget.panel.LienzoBoundsPanel;
import com.ait.lienzo.client.widget.panel.impl.ScrollablePanel;

public class PanelTransformUtils {

    public final static double HORIZONTAL_OFFSET = 30d;
    public final static double VERTICAL_OFFSET = 30d;

    private PanelTransformUtils() {

    }

    public static void setScaleLevel(final Viewport viewport,
                                     final double level) {
        final Transform viewportTransform = viewport.getTransform();
        final Transform transform = new Transform();
        transform.translate(viewportTransform.getTranslateX(),
                            viewportTransform.getTranslateY());
        transform.scale(level);
        viewport.setTransform(transform);
    }

    public static void reset(final Viewport viewport) {
        viewport.setTransform(new Transform());
    }

    public static double scaleToFitPanel(ScrollablePanel scrollablePanel) {
        double scale = PanelTransformUtils.computeZoomLevelFitToWidth(scrollablePanel);
        scale(scrollablePanel, scale);
        return scale;
    }

    public static void scale(ScrollablePanel scrollablePanel, double scale) {
        if (scale > 0) {
            PanelTransformUtils.setScaleLevel(scrollablePanel.getViewport(), scale);
            scrollablePanel.resetScrollPositionToZero();
        }
    }

    public static double computeZoomLevelFitToWidth(final LienzoBoundsPanel panel) {
        final double panelWidth = panel.getWidePx();
        final double panelHeight = panel.getHighPx();
        return computeZoomLevelFitToWidth(panelWidth, panelHeight, panel);
    }

    public static double computeZoomLevelFitToWidth(final double width,
                                                    final double height,
                                                    final LienzoBoundsPanel panel) {
        final Bounds layerBounds = panel.getLayerBounds();
        final double layerWidth = layerBounds.getWidth();
        final double layerHeight = layerBounds.getHeight();
        double widthRatio = (width - HORIZONTAL_OFFSET) / layerWidth;
        double heightRatio = (height - VERTICAL_OFFSET) / layerHeight;
        final double level = Math.min(widthRatio, heightRatio);
        return level < 1 ? level : 1;
    }

    public static double computeLevel(final Viewport viewport) {
        final Transform transform = viewport.getTransform();
        final double scaleX = transform.getScaleX();
        final double scaleY = transform.getScaleY();
        return scaleX < scaleY ? scaleX : scaleY;
    }
}