ChartBar.java

/*
 *  Copyright 2012 Axel Winkler, Daniel Dunér
 * 
 *  This file is part of Daxplore Presenter.
 *
 *  Daxplore Presenter is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU Lesser General Public License as published by
 *  the Free Software Foundation, either version 2.1 of the License, or
 *  (at your option) any later version.
 *
 *  Daxplore Presenter is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public License
 *  along with Daxplore Presenter.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.daxplore.presenter.chart.display;

import org.daxplore.presenter.chart.resources.ChartTexts;

import com.googlecode.gchart.client.GChart.AnnotationLocation;
import com.googlecode.gchart.client.GChart.Curve;
import com.googlecode.gchart.client.GChart.Symbol;
import com.googlecode.gchart.client.GChart.SymbolType;

/**
 * An abstract class for creating a bar in a barchart.
 * 
 * <p>Instead of using Gchart's built in bars, this class is used. It allows
 * bars to overlap, but still be hovered over properly. Each bar should be
 * mapped against a GChart curve, and each curve should (at most) have one
 * bar.</p>
 * 
 */
abstract class ChartBar {

	protected final ChartTexts chartTexts;

	/**
	 * The curve belonging to this bar.
	 */
	protected final Curve curve;

	/**
	 * The color set used to color this bar.
	 */
	protected final BarColors color;

	/**
	 * Display the chart bar in a printer-friendly mode.
	 */
	protected boolean printerMode;

	protected double annotationCharacterCount = 10;

	/**
	 * Create a new bar.
	 * 
	 * <p>Each bar should be mapped against a GChart curve, and each curve
	 * should (at most) have one bar.</p>
	 * 
	 * <p> Use GChart.formatAsHovertext(String plainTextLabel) to format the
	 * hover text. </p>
	 * 
	 * @param barCurve
	 *            The Gchart curve that this bar is mapped to.
	 * @param color
	 *            The color set, used to color this bar.
	 * @param hoverText
	 *            The GChart-formatted text to display when the bar is hovered.
	 */
	ChartBar(ChartTexts chartTexts, Curve barCurve, BarColors color, boolean printerMode, AnnotationLocation hoverLocation) {
		this.curve = barCurve;
		this.color = color;
		this.chartTexts = chartTexts;
		this.printerMode = printerMode;

		Symbol symbol = curve.getSymbol();
		symbol.setBorderStyle("none");
		symbol.setBorderWidth(0);
		symbol.setSymbolType(SymbolType.VBAR_SOUTHWEST);
		symbol.setModelWidth(1.0);
		symbol.setDistanceMetric(0, 0);
		symbol.setHoverSelectionEnabled(false);
		
		symbol.setHoverLocation(hoverLocation);
		if(hoverLocation==AnnotationLocation.SOUTHWEST) {
			symbol.setHoverXShift(20);
		} else if(hoverLocation==AnnotationLocation.SOUTHEAST) {
			symbol.setHoverXShift(-20);
		}

		symbol.setHoverAnnotationEnabled(!printerMode);
	}

	/**
	 * Get the curve that this bar is mapped against.
	 * 
	 * @return The curve that this bar is mapped against.
	 */
	Curve getCurve() {
		return curve;
	}

	/**
	 * Get the color set used to color this bar.
	 * 
	 * @return The color set used to color this bar.
	 */
	BarColors getColor() {
		return color;
	}

	/**
	 * Specify the position of the bar in the GChart.
	 * 
	 * @param x
	 *            Where to put this bar on the X-axis of the G-chart.
	 * @param y
	 *            How high to make this bar, in the GChart.
	 */
	void setDataPoint(double x, double y) {
		// Optionally use:
		// curve.clearPoints();
		curve.addPoint(x, y);
	}

	/**
	 * This method is called when the user hovers the mouse over the bar.
	 * 
	 * <p>Use it to change the appearance of the bar, making it stand out.</p>
	 */
	abstract void hover();

	/**
	 * This method is called when the user stops hovering the bar.
	 * 
	 * <p>Use it to change the appearance of the bar, restoring the original
	 * appearance.</p>
	 */
	abstract void unhover();

	/**
	 * Use instead of GChart.formatAsHovertext(plainTextLabel) and use css on
	 * .daxplore-BarAnnotation to format the label instead.
	 */
	protected String formatAsHoverText(String annotation) {
		return "<html><div class=\"daxplore-BarAnnotation\"" + "style=\"background-color:" + color.getAnnotation() + "\">" + annotation + "</div>";
	}

	/**
	 * Get a rough estimate of the annotation width.
	 * 
	 * @return The annotation width in pixels.
	 */
	public double getAnnotationWidth() {
		return annotationCharacterCount * 7.5;
	}
}