~repos /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());
      }
    }

  }
}