CPlatformResponder.java 文件源码

/**
 * Handles scroll events.
 */
void handleScrollEvent(final int x, final int y, final int modifierFlags,
                       final double deltaX, final double deltaY) {
    final int buttonNumber = CocoaConstants.kCGMouseButtonCenter;
    int jmodifiers = NSEvent.nsToJavaMouseModifiers(buttonNumber,
                                                    modifierFlags);
    final boolean isShift = (jmodifiers & InputEvent.SHIFT_DOWN_MASK) != 0;

    // Vertical scroll.
    if (!isShift && deltaY != 0.0) {
        dispatchScrollEvent(x, y, jmodifiers, deltaY);
    }
    // Horizontal scroll or shirt+vertical scroll.
    final double delta = isShift && deltaY != 0.0 ? deltaY : deltaX;
    if (delta != 0.0) {
        jmodifiers |= InputEvent.SHIFT_DOWN_MASK;
        dispatchScrollEvent(x, y, jmodifiers, delta);
    }
}