!include once #1027304 // eclipse collections

import org.eclipse.collections.impl.map.mutable.primitive.*;

static IBWImage lazyBWImage(int w, int h, IF2<Int, Int, Float> getFloatPixel) {
  ret new IBWImage {
    new IntFloatHashMap knownPixels;
    
    public int getWidth() { ret w; }
    public int getHeight() { ret h; }
    
    public float getFloatPixel(int x, int y) {
      int i = x*w+h;
      Float f = knownPixels.getIfAbsent(i, Float.NaN);
      if (!isNaN(f)) ret f;
        knownPixels.put(i, f = getFloatPixel.get(x, y));
      ret f;
    }
  };
}