scale.java

源码为Eclipse开源开发平台桌面开发工具SWT的源代码,

 * @return the page increment
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public int getPageIncrement () {
	checkWidget ();
	return OS.SendMessage (handle, OS.TBM_GETPAGESIZE, 0, 0);
}

/**
 * Returns the single <em>selection</em> that is the receiver's position.
 *
 * @return the selection
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public int getSelection () {
	checkWidget ();
	return OS.SendMessage (handle, OS.TBM_GETPOS, 0, 0);
}

/**
 * Removes the listener from the collection of listeners who will
 * be notified when the receiver's value changes.
 *
 * @param listener the listener which should no longer be notified
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the listener is null</li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 *
 * @see SelectionListener
 * @see #addSelectionListener
 */
public void removeSelectionListener(SelectionListener listener) {
	checkWidget ();
	if (listener == null) error (SWT.ERROR_NULL_ARGUMENT);
	if (eventTable == null) return;
	eventTable.unhook (SWT.Selection, listener);
	eventTable.unhook (SWT.DefaultSelection,listener);	
}

void setBackgroundPixel (int pixel) {
	if (background == pixel) return;
	super.setBackgroundPixel (pixel);
	/*
	* Bug in Windows.  Changing the background color of the Scale
	* widget and calling InvalidateRect still draws with the old color.
	* The fix is to post a fake WM_SETFOCUS event to cause it to redraw
	* with the new background color.
	* 
	* Note.  This WM_SETFOCUS message causes recursion when
	* setBackground is called from within the focus event listener.
	*/
	OS.PostMessage (handle, OS.WM_SETFOCUS, 0, 0);
}

/**
 * Sets the amount that the receiver's value will be
 * modified by when the up/down (or right/left) arrows
 * are pressed to the argument, which must be at least 
 * one.
 *
 * @param increment the new increment (must be greater than zero)
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public void setIncrement (int increment) {
	checkWidget ();
	if (increment < 1) return;
	int minimum = OS.SendMessage (handle, OS.TBM_GETRANGEMIN, 0, 0);
	int maximum = OS.SendMessage (handle, OS.TBM_GETRANGEMAX, 0, 0);
	if (increment > maximum - minimum) return;
	OS.SendMessage (handle, OS.TBM_SETLINESIZE, 0, increment);
}

/**
 * Sets the maximum value that the receiver will allow.  This new
 * value will be ignored if it is not greater than the receiver's current
 * minimum value.  If the new maximum is applied then the receiver's
 * selection value will be adjusted if necessary to fall within its new range.
 *
 * @param value the new maximum, which must be greater than the current minimum
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public void setMaximum (int value) {
	checkWidget ();
	int minimum = OS.SendMessage (handle, OS.TBM_GETRANGEMIN, 0, 0);
	if (0 <= minimum && minimum < value) {
		OS.SendMessage (handle, OS.TBM_SETRANGEMAX, 1, value);
	}
}

/**
 * Sets the minimum value that the receiver will allow.  This new
 * value will be ignored if it is negative or is not less than the receiver's
 * current maximum value.  If the new minimum is applied then the receiver's
 * selection value will be adjusted if necessary to fall within its new range.
 *
 * @param value the new minimum, which must be nonnegative and less than the current maximum
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public void setMinimum (int value) {
	checkWidget ();
	int maximum = OS.SendMessage (handle, OS.TBM_GETRANGEMAX, 0, 0);
	if (0 <= value && value < maximum) {
		OS.SendMessage (handle, OS.TBM_SETRANGEMIN, 1, value);
	}
}

/**
 * Sets the amount that the receiver's value will be
 * modified by when the page increment/decrement areas
 * are selected to the argument, which must be at least
 * one.
 *
 * @param pageIncrement the page increment (must be greater than zero)
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public void setPageIncrement (int pageIncrement) {
	checkWidget ();
	if (pageIncrement < 1) return;
	int minimum = OS.SendMessage (handle, OS.TBM_GETRANGEMIN, 0, 0);
	int maximum = OS.SendMessage (handle, OS.TBM_GETRANGEMAX, 0, 0);
	if (pageIncrement > maximum - minimum) return;
	OS.SendMessage (handle, OS.TBM_SETPAGESIZE, 0, pageIncrement);
	OS.SendMessage (handle, OS.TBM_SETTICFREQ, pageIncrement, 0);
}

/**
 * Sets the single <em>selection</em> that is the receiver's
 * value to the argument which must be greater than or equal
 * to zero.
 *
 * @param value the new selection (must be zero or greater)
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public void setSelection (int value) {
	checkWidget ();
	OS.SendMessage (handle, OS.TBM_SETPOS, 1, value);
}

int widgetStyle () {
	int bits = super.widgetStyle () | OS.WS_TABSTOP | OS.TBS_BOTH | OS.TBS_AUTOTICKS;
	if ((style & SWT.HORIZONTAL) != 0) return bits | OS.TBS_HORZ;
	return bits | OS.TBS_VERT;
}

TCHAR windowClass () {
	return TrackBarClass;
}

int windowProc () {
	return TrackBarProc;
}

LRESULT wmScrollChild (int wParam, int lParam) {
	
	/* Do nothing when scrolling is ending */
	int code = wParam & 0xFFFF;
	if (code == OS.TB_ENDTRACK) return null;
	
	/*
	* This code is intentionally commented.  The event
	* detail field is not currently supported on all
	* platforms.
	*/
	Event event = new Event ();
//	switch (code) {
//		/*
//		* This line is intentionally commented.  Do not set the detail
//		* field to DRAG to indicate that the dragging has ended when the
//		* scroll bar is finally positioned in TB_THUMBPOSITION.
//		*/
////		case OS.TB_THUMBPOSITION: 	break;
//		case OS.TB_THUMBTRACK:		event.detail = SWT.DRAG;  break;
//		case OS.TB_TOP: 			event.detail = SWT.HOME;  break;
//		case OS.TB_BOTTOM:		event.detail = SWT.END;  break;
//		case OS.TB_LINEDOWN:		event.detail = SWT.ARROW_DOWN;  break;
//		case OS.TB_LINEUP: 		event.detail = SWT.ARROW_UP;  break;
//		case OS.TB_PAGEDOWN: 		event.detail = SWT.PAGE_DOWN;  break;
//		case OS.TB_PAGEUP: 		event.detail = SWT.PAGE_UP;  break;
//	}
	
	/*
	* Send the event because WM_HSCROLL and WM_VSCROLL
	* are sent from a modal message loop in windows that
	* is active when the user is scrolling.
	*/
	sendEvent (SWT.Selection, event);
	// widget could be disposed at this point
	return null;
}

}