gdx-studio

/*******************************************************************************

 * Copyright 2011 See AUTHORS file.

 * 

 * 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.badlogic.gdx.tools.hiero.unicodefont.effects;

import java.awt.Color;

import java.awt.Graphics2D;

import java.awt.RenderingHints;

import java.awt.geom.AffineTransform;

import java.awt.image.BufferedImage;

import java.util.ArrayList;

import java.util.Iterator;

import java.util.List;

import com.badlogic.gdx.tools.hiero.unicodefont.Glyph;

import com.badlogic.gdx.tools.hiero.unicodefont.UnicodeFont;

/**

 * A filter to create a distance field. The resulting font can be rendered

 * with a simple custom shader to draw bitmap fonts that remain crisp

 * even under high magnification.

 * 

 * <p> An example of the use of such a font is included in the libgdx test suite

 * under the name {@code BitmapFontDistanceFieldTest}.

 * 

 * @see DistanceFieldGenerator

 * 

 * @author Thomas ten Cate

 */

public class DistanceFieldEffect implements ConfigurableEffect

{

	private Color color = Color.WHITE;

	private int scale = 1;

	private float spread = 1;

	/**

	 * Draws the glyph to the given image, upscaled by a factor of {@link #scale}.

	 * 

	 * @param image the image to draw to

	 * @param glyph the glyph to draw

	 */

	private void drawGlyph(BufferedImage image, Glyph glyph) {

		Graphics2D inputG = (Graphics2D) image.getGraphics();

		inputG.setTransform(AffineTransform.getScaleInstance(scale, scale));

		// We don't really want anti-aliasing (we'll discard it anyway),

		// but accurate positioning might improve the result slightly

		inputG.setRenderingHint(RenderingHints.KEY_FRACTIONALMETRICS, RenderingHints.VALUE_FRACTIONALMETRICS_ON);

		inputG.setColor(Color.WHITE);

		inputG.fill(glyph.getShape());

	}

	@Override

	public void draw(BufferedImage image, Graphics2D g, UnicodeFont unicodeFont, Glyph glyph) {

		BufferedImage input = new BufferedImage(

			scale * glyph.getWidth(),

			scale * glyph.getHeight(),

			BufferedImage.TYPE_BYTE_BINARY);

		drawGlyph(input, glyph);

		DistanceFieldGenerator generator = new DistanceFieldGenerator();

		generator.setColor(color);

		generator.setDownscale(scale);

		// We multiply spread by the scale, so that changing scale will only affect accuracy

		// and not spread in the output image.

		generator.setSpread(scale * spread);

		BufferedImage distanceField = generator.generateDistanceField(input);

		g.drawImage(distanceField, new AffineTransform(), null);

	}

	@Override

	public String toString() {

		return "Distance field";

	}

	@Override

	public List getValues() {

		List values = new ArrayList();

		values.add(EffectUtil.colorValue("Color", color));

		values.add(EffectUtil.intValue("Scale", scale, "The distance field is computed from an image larger than the output glyph by this factor. Set this to a higher value for more accuracy, but slower font generation."));

		values.add(EffectUtil.floatValue("Spread", spread, 1.0f, Float.MAX_VALUE, "The maximum distance from edges where the effect of the distance field is seen. Set this to about half the width of lines in your output font."));

		return values;

	}

	@Override

	public void setValues(List values) {

		for (Iterator iter = values.iterator(); iter.hasNext();) {

			Value value = (Value)iter.next();

			if ("Color".equals(value.getName())) {

				color = (Color)value.getObject();

			} else if ("Scale".equals(value.getName())) {

				scale = Math.max(1, (Integer)value.getObject());

			} else if ("Spread".equals(value.getName())) {

				spread = Math.max(0, (Float)value.getObject());

			}

		}

	}

}