ElementInteractionMoveHandler.java

package de.lessvoid.nifty.elements;

import de.lessvoid.nifty.Nifty;
import de.lessvoid.nifty.elements.events.NiftyMouseEvent;
import de.lessvoid.nifty.elements.events.NiftyMouseMovedEvent;
import de.lessvoid.nifty.elements.events.NiftyMouseWheelEvent;
import de.lessvoid.nifty.input.NiftyMouseInputEvent;

import javax.annotation.Nonnull;

public class ElementInteractionMoveHandler {
  @Nonnull
  private final Nifty nifty;
  @Nonnull
  private final Element element;
  private int lastMouseX;
  private int lastMouseY;
  private boolean lastButton0Down;
  private boolean lastButton1Down;
  private boolean lastButton2Down;

  public ElementInteractionMoveHandler(@Nonnull final Nifty nifty, @Nonnull final Element element) {
    this.nifty = nifty;
    this.element = element;
    this.lastMouseX = 0;
    this.lastMouseY = 0;
    this.lastButton0Down = false;
    this.lastButton1Down = false;
    this.lastButton2Down = false;
  }

  public boolean process(
      final boolean canHandleInteraction, final boolean mouseInside, final boolean hasMouseAccess,
      @Nonnull final NiftyMouseInputEvent mouseEvent) {
    if (canHandleInteraction && mouseInside) {
      final boolean moved = handleMoveEvent(mouseEvent);
      final boolean wheel = handleWheelEvent(mouseEvent);
      if (moved || wheel) {
        handleGeneralEvent(mouseEvent);
        return true;
      }

      boolean generateEvent = false;
      if (mouseEvent.isButton0Down() != lastButton0Down) {
        lastButton0Down = mouseEvent.isButton0Down();
        generateEvent = true;
      }
      if (mouseEvent.isButton1Down() != lastButton1Down) {
        lastButton1Down = mouseEvent.isButton1Down();
        generateEvent = true;
      }
      if (mouseEvent.isButton2Down() != lastButton2Down) {
        lastButton2Down = mouseEvent.isButton2Down();
        generateEvent = true;
      }
      if (generateEvent) {
        handleGeneralEvent(mouseEvent);
        return true;
      }
    }

    return false;
  }

  private boolean handleMoveEvent(@Nonnull final NiftyMouseInputEvent mouseEvent) {
    String id = element.getId();
    if (id != null && ((mouseEvent.getMouseX() != lastMouseX) || (mouseEvent.getMouseY() != lastMouseY))) {
      lastMouseX = mouseEvent.getMouseX();
      lastMouseY = mouseEvent.getMouseY();
      nifty.publishEvent(id, new NiftyMouseMovedEvent(element, mouseEvent));
      return true;
    }
    return false;
  }

  private boolean handleWheelEvent(@Nonnull final NiftyMouseInputEvent mouseEvent) {
    String id = element.getId();
    if (id != null && mouseEvent.getMouseWheel() != 0) {
      nifty.publishEvent(id, new NiftyMouseWheelEvent(element, mouseEvent));
      return true;
    }
    return false;
  }

  private void handleGeneralEvent(@Nonnull final NiftyMouseInputEvent mouseEvent) {
    String id = element.getId();
    if (id != null) {
      nifty.publishEvent(id, new NiftyMouseEvent(element, mouseEvent));
    }
  }
}