package org.eclipse.swt.examples.paint;
/*
 * (c) Copyright IBM Corp. 2000, 2002.
 * This file is made available under the terms of the Common Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/cpl-v10.html
 */
import org.eclipse.swt.events.*;import org.eclipse.swt.graphics.*;import org.eclipse.swt.widgets.*;
/** * Manages a simple drawing surface. */
public class PaintSurface {	private Point currentPosition = new Point(0, 0);
	private Canvas paintCanvas;	private PaintSession paintSession;	private Image image;	private Image paintImage; // buffer for refresh blits	private int   imageWidth, imageHeight;	private int   visibleWidth, visibleHeight;	private FigureDrawContext displayFDC = new FigureDrawContext();	private FigureDrawContext imageFDC = new FigureDrawContext();	private FigureDrawContext paintFDC = new FigureDrawContext();	/* Rubberband */	private ContainerFigure rubberband = new ContainerFigure();		// the active rubberband selection	private int rubberbandHiddenNestingCount = 0;		// always >= 0, if > 0 rubberband has been hidden	/* Status */	private Text statusText;	private String statusActionInfo, statusMessageInfo, statusCoordInfo;	/**	 * Constructs a PaintSurface.	 * <p>	 * paintCanvas must have SWT.NO_REDRAW_RESIZE and SWT.NO_BACKGROUND styles,	 *     and may have SWT.V_SCROLL and/or SWT.H_SCROLL.	 * </p>	 * @param paintCanvas the Canvas object in which to render	 * @param paintStatus the PaintStatus object to use for providing user feedback	 * @param fillColor the color to fill the canvas with initially	 */
	public PaintSurface(Canvas paintCanvas, Text statusText, Color fillColor) {		this.paintCanvas = paintCanvas;		this.statusText = statusText;		clearStatus();		/* Set up the drawing surface */		Rectangle displayRect = paintCanvas.getDisplay().getClientArea();		imageWidth = displayRect.width;		imageHeight = displayRect.height;		image = new Image(paintCanvas.getDisplay(), imageWidth, imageHeight);		imageFDC.gc = new GC(image);		imageFDC.gc.setBackground(fillColor);		imageFDC.gc.fillRectangle(0, 0, imageWidth, imageHeight);		displayFDC.gc = new GC(paintCanvas);		/* Initialize the session */		setPaintSession(null);		/* Add our listeners */		paintCanvas.addDisposeListener(new DisposeListener() {			public void widgetDisposed(DisposeEvent e) {				displayFDC.gc.dispose();			}					});		paintCanvas.addMouseListener(new MouseAdapter() {			public void mouseDown(MouseEvent event) {				processMouseEventCoordinates(event);				if (paintSession != null) paintSession.mouseDown(event);			}			public void mouseUp(MouseEvent event) {				processMouseEventCoordinates(event);				if (paintSession != null) paintSession.mouseUp(event);			}			public void mouseDoubleClick(MouseEvent event) {				processMouseEventCoordinates(event);				if (paintSession != null) paintSession.mouseDoubleClick(event);			}					});		paintCanvas.addMouseMoveListener(new MouseMoveListener() {			public void mouseMove(MouseEvent event) {				processMouseEventCoordinates(event);				if (paintSession != null) paintSession.mouseMove(event);			}		});		paintCanvas.addPaintListener(new PaintListener() {			public void paintControl(PaintEvent event) {				if (rubberband.isEmpty()) {					// Nothing to merge, so we just refresh					event.gc.drawImage(image,						displayFDC.xOffset + event.x, displayFDC.yOffset + event.y, event.width, event.height,						event.x, event.y, event.width, event.height);				} else {					/*					 * Avoid flicker when merging overlayed objects by constructing the image on					 * a backbuffer first, then blitting it to the screen.					 */					// Check that the backbuffer is large enough					if (paintImage != null) {						Rectangle rect = paintImage.getBounds();						if ((event.width + event.x > rect.width) ||							(event.height + event.y > rect.height)) {							paintFDC.gc.dispose();							paintImage.dispose();							paintImage = null;						}					}					if (paintImage == null) {						Display display = getDisplay();						Rectangle rect = display.getClientArea();						paintImage = new Image(display,							Math.max(rect.width, event.width + event.x),							Math.max(rect.height, event.height + event.y));						paintFDC.gc = new GC(paintImage);					}					// Setup clipping and the FDC					Region clipRegion = new Region();					event.gc.getClipping(clipRegion);										paintFDC.gc.setClipping(clipRegion);					clipRegion.dispose();					paintFDC.xOffset = displayFDC.xOffset;					paintFDC.yOffset = displayFDC.yOffset;					paintFDC.xScale = displayFDC.xScale;					paintFDC.yScale = displayFDC.yScale;										// Merge the overlayed objects into the image, then blit					paintFDC.gc.drawImage(image,						displayFDC.xOffset + event.x, displayFDC.yOffset + event.y, event.width, event.height,						event.x, event.y, event.width, event.height);					rubberband.draw(paintFDC);					event.gc.drawImage(paintImage,						event.x, event.y, event.width, event.height,						event.x, event.y, event.width, event.height);				}			}		});		paintCanvas.addControlListener(new ControlAdapter() {			public void controlResized(ControlEvent event) {				handleResize();			}					});		/* Set up the paint canvas scroll bars */		ScrollBar horizontal = paintCanvas.getHorizontalBar();		horizontal.setVisible(true);		horizontal.addSelectionListener(new SelectionAdapter() {			public void widgetSelected(SelectionEvent event) {				scrollHorizontally((ScrollBar)event.widget);			}		});		ScrollBar vertical = paintCanvas.getVerticalBar();		vertical.setVisible(true);		vertical.addSelectionListener(new SelectionAdapter() {			public void widgetSelected(SelectionEvent event) {				scrollVertically((ScrollBar)event.widget);			}		});		handleResize();	}		/**	 * Disposes of the PaintSurface's resources.	 */	public void dispose() {		imageFDC.gc.dispose();		image.dispose();		if (paintImage != null) {			paintImage.dispose();			paintFDC.gc.dispose();		}		currentPosition = null;		paintCanvas = null;		paintSession = null;		image = null;		paintImage = null;		displayFDC = null;		imageFDC = null;		paintFDC = null;		rubberband = null;		statusText = null;		statusActionInfo = null;		statusMessageInfo = null;		statusCoordInfo = null;	}	/**	 * Called when we must grab focus.	 */	public void setFocus()  {		paintCanvas.setFocus();	}	/**	 * Returns the Display on which the PaintSurface resides.	 * @return the Display	 */	public Display getDisplay() {		return paintCanvas.getDisplay();	}	/**	 * Returns the Shell in which the PaintSurface resides.	 * @return the Shell	 */	public Shell getShell() {		return paintCanvas.getShell();	}	/**
	 * Sets the current paint session.	 * <p>
	 * If oldPaintSession != paintSession calls oldPaintSession.end()	 * and paintSession.begin()	 * </p>	 * 
	 * @param paintSession the paint session to activate; null to disable all sessions
	 */
	public void setPaintSession(PaintSession paintSession) {
		if (this.paintSession != null) {			if (this.paintSession == paintSession) return;
			this.paintSession.endSession();		}
		this.paintSession = paintSession;
		clearStatus();		if (paintSession != null) {			setStatusAction(paintSession.getDisplayName());			paintSession.beginSession();		} else {			setStatusAction(PaintPlugin.getResourceString("tool.Null.label"));			setStatusMessage(PaintPlugin.getResourceString("session.Null.message"));		}	}

	/**
	 * Returns the current paint session.
	 * 
	 * @return the current paint session, null if none is active
	 */
	public PaintSession getPaintSession() {
		return paintSession;
	}
	/**	 * Returns the current paint tool.	 * 	 * @return the current paint tool, null if none is active (though some other session	 *         might be)	 */	public PaintTool getPaintTool() {		return (paintSession != null && paintSession instanceof PaintTool) ?			(PaintTool)paintSession : null;	}	/**	 * Returns the current position in an interactive operation.	 *	 * @return the last known position of the pointer	 */	public Point getCurrentPosition() {		return currentPosition;	}	/**	 * Draws a Figure object to the screen and to the backing store permanently.	 * 	 * @param object the object to draw onscreen	 */	public void drawFigure(Figure object) {		object.draw(imageFDC);		object.draw(displayFDC);	}	/**	 * Adds a Figure object to the active rubberband selection.	 * <p>	 * This object will be drawn to the screen as a preview and refreshed appropriately	 * until the selection is either cleared or committed.	 * </p>	 * 	 * @param object the object to add to the selection	 */	public void addRubberbandSelection(Figure object) {		rubberband.add(object);		if (! isRubberbandHidden()) object.draw(displayFDC);	}	/**	 * Clears the active rubberband selection.	 * <p>	 * Erases any rubberband objects on the screen then clears the selection.	 * </p>	 */	public void clearRubberbandSelection() {		if (! isRubberbandHidden()) {			Region region = new Region();			rubberband.addDamagedRegion(displayFDC, region);			Rectangle r = region.getBounds();			paintCanvas.redraw(r.x, r.y, r.width, r.height, true);			region.dispose();		}		rubberband.clear();	}	/**	 * Commits the active rubberband selection.	 * <p>	 * Redraws any rubberband objects on the screen as permanent objects then clears the selection.	 * </p>	 */	public void commitRubberbandSelection() {		rubberband.draw(imageFDC);		if (isRubberbandHidden()) rubberband.draw(displayFDC);		rubberband.clear();	}		/**	 * Hides the rubberband (but does not eliminate it).	 * <p>	 * Increments by one the rubberband "hide" nesting count.  The rubberband	 * is hidden from view (but remains active) if it wasn't already hidden.	 * </p>	 */	public void hideRubberband() {		if (rubberbandHiddenNestingCount++ <= 0) {			Region region = new Region();			rubberband.addDamagedRegion(displayFDC, region);			Rectangle r = region.getBounds();			paintCanvas.redraw(r.x, r.y, r.width, r.height, true);			region.dispose();		}	}			/**	 * Shows (un-hides) the rubberband.	 * <p>	 * Decrements by one the rubberband "hide" nesting count.  The rubberband	 * is only made visible when showRubberband() has been called once for each	 * previous hideRubberband().  It is not permitted to call showRubberband() if	 * the rubber band is not presently hidden.	 * </p>	 */	public void showRubberband() {		if (rubberbandHiddenNestingCount <= 0)			throw new IllegalStateException("rubberbandHiddenNestingCount > 0");		if (--rubberbandHiddenNestingCount == 0) {			rubberband.draw(displayFDC);		}	}		/**	 * Determines if the rubberband is hidden.	 * 	 * @return true iff the rubber is hidden	 */	public boolean isRubberbandHidden() {		return rubberbandHiddenNestingCount > 0;	}	/**	 * Handles a horizontal scroll event	 * 	 * @param scrollbar the horizontal scroll bar that posted this event	 */	public void scrollHorizontally(ScrollBar scrollBar) {		if (image == null) return;		if (imageWidth > visibleWidth) {			final int oldOffset = displayFDC.xOffset;			final int newOffset = Math.min(scrollBar.getSelection(), imageWidth - visibleWidth);			if (oldOffset != newOffset) {				paintCanvas.update();				displayFDC.xOffset = newOffset;				paintCanvas.scroll(Math.max(oldOffset - newOffset, 0), 0, Math.max(newOffset - oldOffset, 0), 0,					visibleWidth, visibleHeight, false);			}		}	}	/**	 * Handles a vertical scroll event	 * 	 * @param scrollbar the vertical scroll bar that posted this event	 */	public void scrollVertically(ScrollBar scrollBar) {		if (image == null) return;		if (imageHeight > visibleHeight) {			final int oldOffset = displayFDC.yOffset;			final int newOffset = Math.min(scrollBar.getSelection(), imageHeight - visibleHeight);			if (oldOffset != newOffset) {				paintCanvas.update();				displayFDC.yOffset = newOffset;				paintCanvas.scroll(0, Math.max(oldOffset - newOffset, 0), 0, Math.max(newOffset - oldOffset, 0),					visibleWidth, visibleHeight, false);			}		}	}		/**	 * Handles resize events	 */	private void handleResize() {		paintCanvas.update();		Rectangle visibleRect = paintCanvas.getClientArea();		visibleWidth = visibleRect.width;		visibleHeight = visibleRect.height;		ScrollBar horizontal = paintCanvas.getHorizontalBar();		if (horizontal != null) {			displayFDC.xOffset = Math.min(horizontal.getSelection(), imageWidth - visibleWidth);			if (imageWidth <= visibleWidth) {				horizontal.setEnabled(false);				horizontal.setSelection(0);			} else {				final int max = imageWidth - visibleWidth;				horizontal.setEnabled(true);				horizontal.setValues(displayFDC.xOffset, 0, imageWidth, visibleWidth,					8, visibleWidth);			}		}		ScrollBar vertical = paintCanvas.getVerticalBar();		if (vertical != null) {			displayFDC.yOffset = Math.min(vertical.getSelection(), imageHeight - visibleHeight);			if (imageHeight <= visibleHeight) {				vertical.setEnabled(false);				vertical.setSelection(0);			} else {				final int max = imageHeight - visibleHeight;				vertical.setEnabled(true);				vertical.setValues(displayFDC.yOffset, 0, imageHeight, visibleHeight,					8, visibleHeight);			}		}	}	/**	 * Virtualizes MouseEvent coordinates and stores the current position.	 */	private void processMouseEventCoordinates(MouseEvent event) {		currentPosition.x = event.x =			Math.min(Math.max(event.x, 0), visibleWidth - 1) + displayFDC.xOffset;		currentPosition.y = event.y =			Math.min(Math.max(event.y, 0), visibleHeight - 1) + displayFDC.yOffset;	}		/**	 * Clears the status bar.	 */	public void clearStatus() {		statusActionInfo = "";		statusMessageInfo = "";		statusCoordInfo = "";		updateStatus();	}	/**	 * Sets the status bar action text.	 *	 * @param action the action in progress, null to clear	 */	public void setStatusAction(String action) {		statusActionInfo = (action != null) ? action : "";		updateStatus();	}		/**	 * Sets the status bar message text.	 * 	 * @param message the message to display, null to clear	 */	public void setStatusMessage(String message) {		statusMessageInfo = (message != null) ? message : "";		updateStatus();	}	/**	 * Sets the coordinates in the status bar.	 * 	 * @param coord the coordinates to display, null to clear	 */	public void setStatusCoord(Point coord) {		statusCoordInfo = (coord != null) ? PaintPlugin.getResourceString("status.Coord.format", new Object[]			{ new Integer(coord.x), new Integer(coord.y)}) : "";		updateStatus();	}	/**	 * Sets the coordinate range in the status bar.	 * 	 * @param a the "from" coordinate, must not be null	 * @param b the "to" coordinate, must not be null	 */	public void setStatusCoordRange(Point a, Point b) {		statusCoordInfo = PaintPlugin.getResourceString("status.CoordRange.format", new Object[]			{ new Integer(a.x), new Integer(a.y), new Integer(b.x), new Integer(b.y)});		updateStatus();	}	/**	 * Updates the display.	 */	private void updateStatus() {		statusText.setText(			PaintPlugin.getResourceString("status.Bar.format", new Object[]			{ statusActionInfo, statusMessageInfo, statusCoordInfo }));	}}