swtscrolledcomposite.java

一个基于PlaceLab的室内和室外的智能导航系统

	Rectangle hostRect = getBounds();
	int border = getBorderWidth();
	hostRect.width -= 2*border;
	ScrollBar vBar = getVerticalBar();
	if (vVisible && vBar != null) hostRect.width -= vBar.getSize().x;
	
	if (!expandHorizontal && contentRect.width > hostRect.width) return true;
	if (expandHorizontal && minWidth > hostRect.width) return true;
	return false;
}

private boolean needVScroll(Rectangle contentRect, boolean hVisible) {
	ScrollBar vBar = getVerticalBar();
	if (vBar == null) return false;
	
	Rectangle hostRect = getBounds();
	int border = getBorderWidth();
	hostRect.height -= 2*border;
	ScrollBar hBar = getHorizontalBar();
	if (hVisible && hBar != null) hostRect.height -= hBar.getSize().y;
	
	if (!expandHorizontal && contentRect.height > hostRect.height) return true;
	if (expandHorizontal && minHeight > hostRect.height) return true;
	return false;
}

private void resize() {
	if (inResize) return;
	inResize = true;
	layout();
	inResize = false;
}
/**
 * Return the point in the content that currenly appears in the top left 
 * corner of the scrolled composite.
 * 
 * @return the point in the content that currenly appears in the top left 
 * corner of the scrolled composite.  If no content has been set, this returns
 * (0, 0).
 * 
 * @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>
 * 
 * @since 2.0
 */
public Point getOrigin() {
	checkWidget();
	if (content == null) return new Point(0, 0);
	Point location = content.getLocation();
	return new Point(-location.x, -location.y);
}
/**
 * Scrolls the content so that the specified point in the content is in the top 
 * left corner.  If no content has been set, nothing will occur.  
 * 
 * Negative values will be ignored.  Values greater than the maximum scroll 
 * distance will result in scrolling to the end of the scrollbar.
 *
 * @param origin the point on the content to appear in the top left corner 
 * 
 * @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>
 *    <li>ERROR_INVALID_ARGUMENT - value of origin is outside of content
 * </ul>
 * @since 2.0
 */
public void setOrigin(Point origin) {
	setOrigin(origin.x, origin.y);
}
/**
 * Scrolls the content so that the specified point in the content is in the top 
 * left corner.  If no content has been set, nothing will occur.  
 * 
 * Negative values will be ignored.  Values greater than the maximum scroll 
 * distance will result in scrolling to the end of the scrollbar.
 *
 * @param x the x coordinate of the content to appear in the top left corner 
 * 
 * @param y the y coordinate of the content to appear in the top left corner 
 * 
 * @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>
 * 
 * @since 2.0
 */
public void setOrigin(int x, int y) {
	checkWidget();
	if (content == null) return;
	ScrollBar hBar = getHorizontalBar ();
	if (hBar != null) {
		hBar.setSelection(x);
		x = -hBar.getSelection ();
	} else {
		x = 0;
	}
	ScrollBar vBar = getVerticalBar ();
	if (vBar != null) {
		vBar.setSelection(y);
		y = -vBar.getSelection ();
	} else {
		y = 0;
	}
	content.setLocation(x, y);
}
/**
 * Set the Always Show Scrollbars flag.  True if the scrollbars are 
 * always shown even if they are not required.  False if the scrollbars are only 
 * visible when some part of the composite needs to be scrolled to be seen.
 * The H_SCROLL and V_SCROLL style bits are also required to enable scrollbars in the 
 * horizontal and vertical directions.
 * 
 * @param show true to show the scrollbars even when not required, false to show scrollbars only when required
 * 
 * @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 setAlwaysShowScrollBars(boolean show) {
	checkWidget();
	if (show == alwaysShowScroll) return;
	alwaysShowScroll = show;
	ScrollBar hBar = getHorizontalBar ();
	if (hBar != null && alwaysShowScroll) hBar.setVisible(true);
	ScrollBar vBar = getVerticalBar ();
	if (vBar != null && alwaysShowScroll) vBar.setVisible(true);
	layout();
}

/**
 * Set the content that will be scrolled.
 * 
 * @param content the control to be displayed in the content area
 * 
 * @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 setContent(Control content) {
	checkWidget();
	if (this.content != null && !this.content.isDisposed()) {
		this.content.removeListener(SWT.Resize, contentListener);
		this.content.setBounds(new Rectangle(-200, -200, 0, 0));	
	}
	
	this.content = content;
	ScrollBar vBar = getVerticalBar ();
	ScrollBar hBar = getHorizontalBar ();
	if (this.content != null) {
		if (vBar != null) {
			vBar.setMaximum (0);
			vBar.setThumb (0);
			vBar.setSelection(0);
		}
		if (hBar != null) {
			hBar.setMaximum (0);
			hBar.setThumb (0);
			hBar.setSelection(0);
		}
		content.setLocation(0, 0);
		layout();
		this.content.addListener(SWT.Resize, contentListener);
	} else {
		if (hBar != null) hBar.setVisible(alwaysShowScroll);
		if (vBar != null) vBar.setVisible(alwaysShowScroll);
	}
}
/**
 * Configure the ScrolledComposite to resize the content object to be as wide as the 
 * ScrolledComposite when the width of the ScrolledComposite is greater than the
 * minimum width specified in setMinWidth.  If the ScrolledComposite is less than the
 * minimum width, the content will not resized and instead the horizontal scroll bar will be
 * used to view the entire width.
 * If expand is false, this behaviour is turned off.  By default, this behaviour is turned off.
 * 
 * @param expand true to expand the content control to fill available horizontal space
 * 
 * @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 setExpandHorizontal(boolean expand) {
	checkWidget();
	if (expand == expandHorizontal) return;
	expandHorizontal = expand;
	layout();
}
/**
 * Configure the ScrolledComposite to resize the content object to be as tall as the 
 * ScrolledComposite when the height of the ScrolledComposite is greater than the
 * minimum height specified in setMinHeight.  If the ScrolledComposite is less than the
 * minimum height, the content will not resized and instead the vertical scroll bar will be
 * used to view the entire height.
 * If expand is false, this behaviour is turned off.  By default, this behaviour is turned off.
 * 
 * @param expand true to expand the content control to fill available vertical space
 * 
 * @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 setExpandVertical(boolean expand) {
	checkWidget();
	if (expand == expandVertical) return;
	expandVertical = expand;
	layout();
}
public void setLayout (Layout layout) {
	// do not allow a layout to be set on this class because layout is being handled by the resize listener
	checkWidget();
	return;
}
/**
 * Specify the minimum height at which the ScrolledComposite will begin scrolling the
 * content with the vertical scroll bar.  This value is only relevant if  
 * setExpandVertical(true) has been set.
 * 
 * @param height the minimum height or 0 for default height
 * 
 * @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 setMinHeight(int height) {
	setMinSize(minWidth, height);
}
/**
 * Specify the minimum width and height at which the ScrolledComposite will begin scrolling the
 * content with the horizontal scroll bar.  This value is only relevant if  
 * setExpandHorizontal(true) and setExpandVertical(true) have been set.
 * 
 * @param size the minimum size or null for the default size
 * 
 * @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 setMinSize(Point size) {
	if (size == null) {
		setMinSize(0, 0);
	} else {
		setMinSize(size.x, size.y);
	}
}
/**
 * Specify the minimum width and height at which the ScrolledComposite will begin scrolling the
 * content with the horizontal scroll bar.  This value is only relevant if  
 * setExpandHorizontal(true) and setExpandVertical(true) have been set.
 * 
 * @param width the minimum width or 0 for default width
 * @param height the minimum height or 0 for default height
 * 
 * @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 setMinSize(int width, int height) {
	checkWidget();
	if (width == minWidth && height == minHeight) return;
	minWidth = Math.max(0, width);
	minHeight = Math.max(0, height);
	layout();
}
/**
 * Specify the minimum width at which the ScrolledComposite will begin scrolling the
 * content with the horizontal scroll bar.  This value is only relevant if  
 * setExpandHorizontal(true) has been set.
 * 
 * @param width the minimum width or 0 for default width
 * 
 * @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 setMinWidth(int width) {
	setMinSize(width, minHeight);
}

private void vScroll() {
	if (content == null) return;
	Point location = content.getLocation ();
	ScrollBar vBar = getVerticalBar ();
	int vSelection = vBar.getSelection ();
	content.setLocation (location.x, -vSelection);
}
}