abstract sclass DynImageSurface extends DynModule {

  transient ImageSurface imageSurface;

  transient BufferedImage image;

  transient S imageID;

  transient bool useUpdateHack, zoomToWindowOnSetImage;

  transient O onNewImage;

  switchable bool autoSaveToDisk = autoSaveToDiskDefault(); // dev.

  switchable bool pixelate;

  visualize { ret _visualize(); }

  final private JComponent _visualize() {

    imageSurface = imageSurface(image);

    imageSurface.onNewImage = r newImageFromSurface;

    imageSurface_pixelated(imageSurface, pixelate);

    ret jscroll_center(imageSurface);

  }

  // call after visualize

  void enableDoubleBuffering {

    if (imageSurface != null) imageSurface.setDoubleBuffered(true);

  }

  JComponent visualizeWithDoubleBuffering() {  

    JComponent c = _visualize();

    enableDoubleBuffering();

    ret c;

  }

  // hold image during reload (not during reboot yet)

  O _getReloadData() { ret image; }

  void _setReloadData(BufferedImage image) { this.image = image; }

  start {

    dm_watchField pixelate(-> imageSurface_pixelated(imageSurface, pixelate));

    if (autoSaveToDisk)

      autoLoadNow();

  }

  void autoLoadNow enter {

    pcall {

      File f = autoSaveImageFile();

      if (fileExists(f)) {

        print("Auto-loading " + f);

        setImage(loadImage2(f), true);

      }

    }

  }

  void autoSaveNow enter {  

    pcall {

      File f = autoSaveImageFile();

      savePNG(f, image);

      infoBox("Auto-saved " + renderFileInfo(f));

    }

  }

  bool autoSaveToDiskDefault() { false; }

  enhanceFrame {

    internalFramePopupMenuItem(f, "Auto-save now", rThread autoSaveNow);

  }

  // API

  void setImage(MakesBufferedImage image) { imageID = null; setImage(image == null ? null : image.getBufferedImage()); }

  void newImageFromSurface {

    setImage(imageSurface.getImage());

  }

  void setImage(BufferedImage image, bool loadingFromAutoSave default false) {

    this.image = image; imageID = null;

    if (imageSurface != null) {

      temp tempSetField(imageSurface, onNewImage := null); // avoid recursion

      imageSurface.setImage(image);

      if (zoomToWindowOnSetImage) imageSurface.zoomToWindow();

      if (autoSaveToDisk && !loadingFromAutoSave)

        autoSaveNow();

    }

    vmBus_send('newImage, this);

    pcallF(onNewImage, image);

  }

  void setImage(S imageID) {

    if (sameSnippetID(this.imageID, imageID)) ret;

    setImage(loadImage2(imageID));

    this.imageID = imageID;

  }

  File autoSaveImageFile() {

    S id = dm_moduleID(me());

    ret javaxDataDir("Image Autosaves/" + id + "-autosave.png");

  }

  BufferedImage getImage() {

    if (useUpdateHack) {

      // HACKY: to get changes in ImageSurface (e.g. images drag&dropped in there directly)

      ImageSurface is = imageSurface;

      if (is != null && is.getImage() != image) setImage(is.getImage());

    }

    ret image;

  }

  bool hasImage() { ret image != null; }

  void setZoom(double zoom) { if (imageSurface != null) imageSurface.setZoom(zoom); }

  Rect getSelection() { ret imageSurface == null ? null : toRect(imageSurface.getSelection()); }

  void setSelection(Rect r) { if (imageSurface != null) imageSurface.setSelection(toRectangle(r)); }

  int imageWidth() { ret imageSurface.getImage().getWidth(); }

  int imageHeight() { ret imageSurface.getImage().getHeight(); }

  void pixelate() {

    setField(pixelate := true);

  }

}