sclass JPaintTool is Swingable {
  transient gettable BufferedImage image;
  transient ImageSurface imageSurface;
  settable File autoPersistFile;
  bool autoPersistInstalled;
  volatile bool dirty;
  double autoPersistInterval = 10.0;
  ReliableSingleThread rstPersist = new(r _persist);
  transient JPanel buttons;
  transient ImageSurfaceScribbleTool scribbler;
  //transient JColorChooser colorChooser;
  
  void init {
    imageSurface if null = makeImageSurface();
    
    if (image == null) {
      setImage(makeNewImage());
      
      if (autoPersistFile != null) {
        pcall {
          var img = loadImage2(autoPersistFile);
          if (img != null)
            setImage(img);
          else
            set dirty;
        }
                      
        if (!autoPersistInstalled) {
          set autoPersistInstalled;
          awtEvery(imageSurface, autoPersistInterval, rstPersist);
          bindToComponent(imageSurface, null, rstPersist);
        }
      }

    }
  }
  
  BufferedImage makeNewImage() {
    ret main newImage(defaultImageSize);
  }
  
  visualize {
    init();
    ret withTopMargin(northAndCenterWithMargin(buttons = jcenteredline(flattenToList(
      jbutton("New image", rThread newImage),
      cbImageSize = jTypedComboBox(imageSizes())
      map colorSelectButton(colors())
    )),
      jscroll_center_borderless(imageSurface)));
  }
  
  void setImage(BufferedImage image) {
    this.image = image;
    imageSurface.setImage(image);
  }

  swappable ImageSurface makeImageSurface() {  
    var is = pixelatedImageSurface();
    //is.setAutoZoomToDisplay(true);
    //is.specialPurposed = true;
    is.zoomable(false);
    is.removeAllTools();
    scribbler = new ImageSurfaceScribbleTool(is);
    scribbler.onPainted(-> { set dirty; });
    
    ret is;
  }
  
  void _persist {
    if (autoPersistFile != null && dirty) {
      dirty = false;
      savePNGVerbose(autoPersistFile, image);
    }
  }
  
  void newImage {
    setImage(makeNewImage());
    set dirty;
  }
  
  JButton colorSelectButton(Color color) {
    ret jImageButton(main newImage(16, color),
      "Select color to draw with", -> scribbler.setColor(color));
  }
  
  L<Color> colors() {
    ret colorPaletteByBits(1); // 8 primary colors
  }
  
  L<> imageSizes() {
    ret mapLL sixteenToNine_(
      240, 360, 480, 720
    );
  }
}