org.geomajas.gwt.client.gfx.context.VmlStyleUtil.java Source code

Introduction

Here is the source code for org.geomajas.gwt.client.gfx.context.VmlStyleUtil.java

Source

/*
 * This is part of Geomajas, a GIS framework, http://www.geomajas.org/.
 *
 * Copyright 2008-2013 Geosparc nv, http://www.geosparc.com/, Belgium.
 *
 * The program is available in open source according to the GNU Affero
 * General Public License. All contributions in this program are covered
 * by the Geomajas Contributors License Agreement. For full licensing
 * details, see LICENSE.txt in the project root.
 */

package org.geomajas.gwt.client.gfx.context;

import org.geomajas.gwt.client.gfx.style.FontStyle;
import org.geomajas.gwt.client.gfx.style.PictureStyle;
import org.geomajas.gwt.client.gfx.style.ShapeStyle;
import org.geomajas.gwt.client.gfx.style.Style;
import org.geomajas.gwt.client.util.Dom;

import com.google.gwt.dom.client.Element;
import com.google.gwt.dom.client.NodeList;
import com.smartgwt.client.util.SC;

/**
 * <p>
 * Decoder for style objects in Internet Explorer (VML). Is able to decode styles, but also to apply styles on DOM
 * elements and to retrieve them again (from DOM elements).
 * </p>
 * TODO: we could use a visitor pattern here for the different style implementations.
 *
 * @author Pieter De Graef
 */
public final class VmlStyleUtil {

    private VmlStyleUtil() {
    }

    /**
     * Apply the given style onto a DOM element. This decoder will decide how to handle all the details.
     *
     * @param element
     *            The target element onto whom we apply a style object.
     * @param style
     *            The style object to be applied.
     */
    public static void applyStyle(Element element, Style style) {
        if (style != null && element != null) {
            if (style instanceof ShapeStyle) {
                applyShapeStyle(element, (ShapeStyle) style);
            } else if (style instanceof FontStyle) {
                FontStyle fontStyle = (FontStyle) style;
                element.getStyle().setProperty("fontSize", "" + fontStyle.getFontSize());
                element.getStyle().setProperty("color", fontStyle.getFillColor());
                element.getStyle().setProperty("fontFamily", fontStyle.getFontFamily());
                element.getStyle().setProperty("fontWeight", fontStyle.getFontWeight());
                element.getStyle().setProperty("fontStyle", fontStyle.getFontStyle());
            } else if (style instanceof PictureStyle) {
                PictureStyle picturStyle = (PictureStyle) style;
                if (SC.isIE()) { //TODO: it's a VML decoder, why make this check?
                    element.getStyle().setProperty("filter",
                            "alpha(opacity=" + 100 * picturStyle.getOpacity() + ")");
                } else {
                    element.setAttribute("style", "opacity:" + picturStyle.getOpacity() + ";");
                }
            }
        }
    }

    /**
     * Retrieve a ShapeStyle object from a DOM element. Note that this function will always return a shapestyle object,
     * even if nothing is in it.
     *
     * @param element
     *            The element to retrieve the style from.
     * @return The ShapeStyle object retrieved from the element.
     */
    public static ShapeStyle retrieveShapeStyle(Element element) {
        ShapeStyle style = new ShapeStyle();

        // Check the "fill" child-element:
        String filled = element.getAttribute("filled");
        if ("true".equals(filled)) {
            Element fill = element.getElementsByTagName("fill").getItem(0);
            style.setFillColor(fill.getAttribute("color"));
            style.setFillOpacity(Float.parseFloat(fill.getAttribute("opacity")));
        }

        // Check the "stroke" child-element:
        String stroked = element.getAttribute("stroked");
        if ("true".equals(stroked)) {
            Element stroke = element.getElementsByTagName("stroke").getItem(0);
            style.setFillColor(stroke.getAttribute("color"));
            style.setFillOpacity(Float.parseFloat(stroke.getAttribute("opacity")));
            style.setStrokeWidth(Integer.parseInt(stroke.getAttribute("strokeweight")));
        }
        return style;
    }

    // -------------------------------------------------------------------------
    // Private functions for DOM element manipulation:
    // -------------------------------------------------------------------------

    /**
     * When applying ShapeStyles, we create child elements for fill and stroke. According to Microsoft, this is the
     * proper way to go.
     */
    private static void applyShapeStyle(Element element, ShapeStyle style) {
        // First check the presence of the fill and stroke elements:
        NodeList<Element> fills = element.getElementsByTagName("fill");
        if (fills.getLength() == 0) {
            Element stroke = Dom.createElementNS(Dom.NS_VML, "stroke");
            element.appendChild(stroke);
            Element fill = Dom.createElementNS(Dom.NS_VML, "fill");
            element.appendChild(fill);
            fills = element.getElementsByTagName("fill");
        }

        // Then if fill-color then filled=true:
        if (style.getFillColor() != null) {
            element.setAttribute("filled", "true");
            fills.getItem(0).setAttribute("color", style.getFillColor());
            fills.getItem(0).setAttribute("opacity", Float.toString(style.getFillOpacity()));
        } else {
            element.setAttribute("filled", "false");
        }

        // Then if stroke-color then stroke=true:
        if (style.getStrokeColor() != null) {
            element.setAttribute("stroked", "true");
            NodeList<Element> strokes = element.getElementsByTagName("stroke");
            strokes.getItem(0).setAttribute("color", style.getStrokeColor());
            strokes.getItem(0).setAttribute("opacity", Float.toString(style.getStrokeOpacity()));
            element.setAttribute("strokeweight", Float.toString(style.getStrokeWidth()));
        } else {
            element.setAttribute("stroked", "false");
        }
    }
}