EDIT

/**

* Copyright (C) 2007 EDIT

* European Distributed Institute of Taxonomy 

* http://www.e-taxonomy.eu

* 

* The contents of this file are subject to the Mozilla Public License Version 1.1

* See LICENSE.TXT at the top of this package for the full license terms.

*/

package eu.etaxonomy.taxeditor.editor.name.container;

import org.eclipse.jface.text.source.Annotation;

import org.eclipse.jface.text.source.AnnotationPainter.SquigglesStrategy;

import org.eclipse.swt.SWT;

import org.eclipse.swt.custom.StyledText;

import org.eclipse.swt.graphics.Color;

import org.eclipse.swt.graphics.GC;

import org.eclipse.swt.graphics.Point;

/**

 * Adds ability to draw multiline squiggles when a <code>StyledText</code>

 * contains line-wrapping.

 *

 * @author p.ciardelli

 * @created 21.11.2008

 * @version 1.0

 */

public class LineWrapSquigglesStrategy extends SquigglesStrategy {

	/** Constant <code>ID="linewrap_squigglesstrategy"</code> */

	public static final String ID = "linewrap_squigglesstrategy"; //$NON-NLS-1$

	private GC gc;

	private Color color;

	private int lineHeight;

	private int baseline;

	private StyledText textWidget;

	private int offset;

	/* (non-Javadoc)

	 * @see org.eclipse.jface.text.source.AnnotationPainter$SquigglesStrategy#draw(org.eclipse.jface.text.source.Annotation, org.eclipse.swt.graphics.GC, org.eclipse.swt.custom.StyledText, int, int, org.eclipse.swt.graphics.Color)

	 */

	/** {@inheritDoc} */

	public void draw(Annotation annotation, GC gc, StyledText textWidget, int offset, int length, Color color) {

		this.gc = gc;

		this.color = color;

		this.textWidget = textWidget;

		this.offset = offset;

		if (gc != null) {

			if (length < 1)

				return;

			baseline = textWidget.getBaseline(offset);

			lineHeight = textWidget.getLineHeight(offset);

			Point right = null;

			int offsetNewline = offset;

			int end = offset + length;

			// Go through the length one character at a time

			for (int i = offset; i <= end; i++) {

				// If the y of the current offset is different from that of the last offset,

				//	we are on a new line

				if (right != null && textWidget.getLocationAtOffset(i).y > right.y) {

					// Draw a line of squigglies

					drawPolyline(offsetNewline, right);

					// Save offset of line break

					offsetNewline = i;

				}

				// Get x,y position in case the next char is on a new line

				right = textWidget.getLocationAtOffset(i);					

			}

			// Draw the last line of squigglies 

			drawPolyline(offsetNewline, right);

		} else {

			textWidget.redrawRange(offset, length, true);

		}

	}

	/**

	 * Draws a squiggly line from the offset <code>offsetNewline</code> to

	 * the x,y coordinates at <code>right</code>.

	 * 

	 * @param offsetNewline

	 * @param right

	 */

	private void drawPolyline(int offsetNewline, Point right) {

		// Get offset at last line break

		Point left = textWidget.getLocationAtOffset(offsetNewline);

		// Prevent solitary red dot from appearing at EOL

		if (left.equals(right)) {

			return;

		}

		// Only start drawing from 0 if not on the first line

		if (offsetNewline != offset) {

			// Offset.x is at the end of the first letter of the new line, not at 0

			left.x = 0;

		}

		int[] polyline= computePolyline(left, right, baseline, lineHeight);

		gc.setLineWidth(0); // NOTE: 0 means width is 1 but with optimized performance

		gc.setLineStyle(SWT.LINE_SOLID);

		gc.setForeground(color);

		gc.drawPolyline(polyline);

	}

	/**

	 * Copied verbatim from {@link org.eclipse.jface.text.source.AnnotationPainter$SquigglesStrategy} 

	 * 

	 * @see org.eclipse.jface.text.source.AnnotationPainter$SquigglesStrategy

	 *  

	 * @param left

	 * @param right

	 * @param baseline

	 * @param lineHeight

	 * @return

	 */

	private int[] computePolyline(Point left, Point right, int baseline, int lineHeight) {

		final int WIDTH= 4; // must be even

		final int HEIGHT= 2; // can be any number

		int peaks= (right.x - left.x) / WIDTH;

		if (peaks == 0 && right.x - left.x > 2)

			peaks= 1;

		int leftX= left.x;

		// compute (number of point) * 2

		int length= ((2 * peaks) + 1) * 2;

		if (length < 0)

			return new int[0];

		int[] coordinates= new int[length];

		// cache peeks' y-coordinates

		int top= left.y + Math.min(baseline + 1, lineHeight - HEIGHT - 1);

		int bottom= top + HEIGHT;

		// populate array with peek coordinates

		for (int i= 0; i < peaks; i++) {

			int index= 4 * i;

			coordinates[index]= leftX + (WIDTH * i);

			coordinates[index+1]= bottom;

			coordinates[index+2]= coordinates[index] + WIDTH/2;

			coordinates[index+3]= top;

		}

		// the last down flank is missing

		coordinates[length-2]= Math.min(Math.max(0, right.x - 1), left.x + (WIDTH * peaks));

		coordinates[length-1]= bottom;

		return coordinates;

	}

}