ScalableRenderableImage.java

/*
 * Copyright 2016 Igor Maznitsa.
 *
 * 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.igormaznitsa.mindmap.plugins.attributes.images;

import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.RenderingHints;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import java.lang.ref.SoftReference;
import javax.annotation.Nonnull;
import com.igormaznitsa.mindmap.plugins.api.Renderable;
import com.igormaznitsa.mindmap.swing.panel.MindMapPanelConfig;
import com.igormaznitsa.mindmap.swing.panel.ui.gfx.MMGraphics;

final class ScalableRenderableImage implements Renderable {

  private final Image baseImage;
  private final int width;
  private final int height;
  private SoftReference<Image> scaledImage;
  private double cachedScale = Double.MIN_VALUE; 
  
  public ScalableRenderableImage(@Nonnull final Image baseImage){
    this.baseImage = baseImage;
    this.width = baseImage.getWidth(null);
    this.height = baseImage.getHeight(null);
  }
  
  @Override
  public int getWidth(final double scale) {
    return (int)Math.round(this.width*scale);
  }

  @Override
  public int getHeight(final double scale) {
    return (int) Math.round(this.height * scale);
  }

  @Nonnull
  private Image getCached(final double scale){
    Image result = this.scaledImage == null ? null : this.scaledImage.get();
    if (result == null || Double.compare(this.cachedScale,scale)!=0){
      final int sw = getWidth(scale);
      final int sh = getHeight(scale);
      final BufferedImage scaled  = new BufferedImage(sw, sh, BufferedImage.TYPE_INT_ARGB);
      final Graphics2D gfx = scaled.createGraphics();
      
      gfx.setRenderingHint(RenderingHints.KEY_ALPHA_INTERPOLATION, RenderingHints.VALUE_ALPHA_INTERPOLATION_QUALITY);
      gfx.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
      gfx.setRenderingHint(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY);
      gfx.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BICUBIC);
      gfx.setRenderingHint(RenderingHints.KEY_COLOR_RENDERING, RenderingHints.VALUE_COLOR_RENDER_QUALITY);
      
      gfx.drawImage(this.baseImage, AffineTransform.getScaleInstance(scale, scale), null);
      gfx.dispose();
      result = scaled;
      this.scaledImage = new SoftReference<Image>(result);
      this.cachedScale = scale;
    }
    return result;
  }
  
  @Override
  public void renderAt(@Nonnull final MMGraphics gfx, @Nonnull final MindMapPanelConfig config, final int x, final int y) {
    gfx.drawImage(getCached(config.getScale()), x, y);
  }
  
}