com.globalmentor.swing.text.ZeroSpanView Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of globalmentor-swing Show documentation
GlobalMentor Java Swing library.
The newest version!
/*
 * Copyright © 1996-2009 GlobalMentor, Inc. 
 *
 * 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 com.globalmentor.swing.text;

import java.awt.*;
import javax.swing.text.*;

/**
 * View class with no span that paints no content, but that nevertheless is considered visible.
 * @author Garret Wilson
 */
public abstract class ZeroSpanView extends View {

	/**
	 * Constructor which specifies an element.
	 * @param element The element this view represents.
	 */
	public ZeroSpanView(Element element) {
		super(element); //construct the parent class
	}

	/**
	 * Performs no rendering for the hidden view.
	 * @param graphics The rendering surface to use.
	 * @param allocation The allocated region to render into.
	 * @see View#paint
	 */
	public void paint(Graphics graphics, Shape allocation) {
	}

	/**
	 * Determines the preferred span for this view. Returns 0.
	 * @param axis The axis (View.X_AXIS or View.Y_AXIS).
	 * @return The span the view would like to be rendered into.
	 * @see View#getPreferredSpan
	 */
	public float getPreferredSpan(int axis) {
		return 0; //return 0 because the view isn't visible
	}

	/**
	 * Determines the minimum span for this view along an axis. Returns 0.
	 * @param axis The axis (View.X_AXIS or View.Y_AXIS).
	 * @return The minimum span the view can be rendered into.
	 * @see View#getMinimumSpan
	 */
	public float getMinimumSpan(int axis) {
		return 0; //return no span
	}

	/**
	 * Determines the maximum span for this view along an axis. Returns 0.
	 * @param axis The axis (View.X_AXIS or View.Y_AXIS).
	 * @return The maximum span the view can be rendered into.
	 * @see View#getMaximumSpan
	 */
	public float getMaximumSpan(int axis) {
		return 0; //return no span
	}

	/**
	 * Provides a mapping from the view coordinate space to the logical coordinate space of the model.
	 * @param x The X coordinate (>= 0).
	 * @param y The Y coordinate (>= 0).
	 * @param allocation The allocated region to render into.
	 * @return The location within the model that best represents the given point in the view
	 * @see View#viewToModel
	 */
	public int viewToModel(final float x, final float y, final Shape allocation, final Position.Bias[] bias) {
		final Rectangle rectangle = allocation instanceof Rectangle ? (Rectangle)allocation : allocation.getBounds(); //get the allocation rectangle
		if(x < rectangle.x + rectangle.width / 2) //if the position is on the left side of this view
		{
			bias[0] = Position.Bias.Forward; //set the bias forward
			return getStartOffset(); //return the start offset
		} else { //if the position is to the right side of the object
			bias[0] = Position.Bias.Backward; //set the bias backward
			return getEndOffset(); //return the ending offset
		}
	}

	/**
	 * Provides a mapping from the coordinate space of the model to that of the view.
	 * @param pos The position to convert (>=0).
	 * @param allocation The allocated region to render into.
	 * @return The bounding box of the given position.
	 * @throws BadLocationException Thrown if the given position does not represent a valid location governed by the view in the associated document.
	 * @see View#modelToView
	 */
	public Shape modelToView(final int pos, final Shape allocation, final Position.Bias b) throws BadLocationException {
		final int p0 = getStartOffset(); //get the starting offset of the view
		final int p1 = getEndOffset(); //get the ending offset of the view
		if((pos >= p0) && (pos <= p1)) { //if the given position is valid
			final Rectangle rectangle = (allocation instanceof Rectangle) ? (Rectangle)allocation : allocation.getBounds(); //get the bounding rectangle of the painting area
			if(pos == p1) { //if the position given is the last position we govern
				rectangle.x += rectangle.width; //move the rectangle to the right
			}
			rectangle.width = 0; //set the width of the rectangle to zero
			return rectangle; //return the rectangle
		} else
			//if the position isn't valid
			throw new BadLocationException(pos + " not in range " + p0 + "," + p1, pos); //report that we don't recognize the position
	}

}