| /******************************************************************************* |
| * Copyright (c) 2000, 2003 IBM Corporation and others. |
| * All rights reserved. This program and the accompanying materials |
| * are 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 |
| * |
| * Contributors: |
| * IBM Corporation - initial API and implementation |
| *******************************************************************************/ |
| package org.eclipse.swt.widgets; |
| |
| |
| import org.eclipse.swt.internal.carbon.*; |
| |
| import org.eclipse.swt.*; |
| import org.eclipse.swt.graphics.*; |
| |
| /** |
| * Instances of this class provide a surface for drawing |
| * arbitrary graphics. |
| * <dl> |
| * <dt><b>Styles:</b></dt> |
| * <dd>(none)</dd> |
| * <dt><b>Events:</b></dt> |
| * <dd>(none)</dd> |
| * </dl> |
| * <p> |
| * This class may be subclassed by custom control implementors |
| * who are building controls that are <em>not</em> constructed |
| * from aggregates of other controls. That is, they are either |
| * painted using SWT graphics calls or are handled by native |
| * methods. |
| * </p> |
| * |
| * @see Composite |
| */ |
| public class Canvas extends Composite { |
| Caret caret; |
| |
| Canvas () { |
| /* Do nothing */ |
| } |
| |
| /** |
| * Constructs a new instance of this class given its parent |
| * and a style value describing its behavior and appearance. |
| * <p> |
| * The style value is either one of the style constants defined in |
| * class <code>SWT</code> which is applicable to instances of this |
| * class, or must be built by <em>bitwise OR</em>'ing together |
| * (that is, using the <code>int</code> "|" operator) two or more |
| * of those <code>SWT</code> style constants. The class description |
| * lists the style constants that are applicable to the class. |
| * Style bits are also inherited from superclasses. |
| * </p> |
| * |
| * @param parent a composite control which will be the parent of the new instance (cannot be null) |
| * @param style the style of control to construct |
| * |
| * @exception IllegalArgumentException <ul> |
| * <li>ERROR_NULL_ARGUMENT - if the parent is null</li> |
| * </ul> |
| * @exception SWTException <ul> |
| * <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the parent</li> |
| * <li>ERROR_INVALID_SUBCLASS - if this class is not an allowed subclass</li> |
| * </ul> |
| * |
| * @see SWT |
| * @see Widget#checkSubclass |
| * @see Widget#getStyle |
| */ |
| public Canvas (Composite parent, int style) { |
| super (parent, style); |
| } |
| |
| /** |
| * Returns the caret. |
| * <p> |
| * The caret for the control is automatically hidden |
| * and shown when the control is painted or resized, |
| * when focus is gained or lost and when an the control |
| * is scrolled. To avoid drawing on top of the caret, |
| * the programmer must hide and show the caret when |
| * drawing in the window any other time. |
| * </p> |
| * |
| * @return the caret |
| * |
| * @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 Caret getCaret () { |
| checkWidget(); |
| return caret; |
| } |
| |
| int kEventControlDraw (int nextHandler, int theEvent, int userData) { |
| int [] theControl = new int [1]; |
| OS.GetEventParameter (theEvent, OS.kEventParamDirectObject, OS.typeControlRef, null, 4, null, theControl); |
| boolean isFocus = theControl [0] == handle && caret != null && caret.isFocusCaret (); |
| if (isFocus) caret.killFocus (); |
| int result = super.kEventControlDraw (nextHandler, theEvent, userData); |
| if (isFocus) caret.setFocus (); |
| return result; |
| } |
| |
| int kEventControlSetFocusPart (int nextHandler, int theEvent, int userData) { |
| int result = super.kEventControlSetFocusPart (nextHandler, theEvent, userData); |
| if (caret != null) { |
| short [] part = new short [1]; |
| OS.GetEventParameter (theEvent, OS.kEventParamControlPart, OS.typeControlPartCode, null, 2, null, part); |
| if (part [0] != 0) { |
| caret.setFocus (); |
| } else { |
| caret.killFocus (); |
| } |
| } |
| return result; |
| } |
| |
| void releaseWidget () { |
| if (caret != null) caret.releaseResources (); |
| caret = null; |
| super.releaseWidget (); |
| } |
| |
| /** |
| * Scrolls a rectangular area of the receiver by first copying |
| * the source area to the destination and then causing the area |
| * of the source which is not covered by the destination to |
| * be repainted. Children that intersect the rectangle are |
| * optionally moved during the operation. In addition, outstanding |
| * paint events are flushed before the source area is copied to |
| * ensure that the contents of the canvas are drawn correctly. |
| * |
| * @param destX the x coordinate of the destination |
| * @param destY the y coordinate of the destination |
| * @param x the x coordinate of the source |
| * @param y the y coordinate of the source |
| * @param width the width of the area |
| * @param height the height of the area |
| * @param all <code>true</code>if children should be scrolled, and <code>false</code> otherwise |
| * |
| * @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 scroll (int destX, int destY, int x, int y, int width, int height, boolean all) { |
| checkWidget(); |
| if (width <= 0 || height <= 0) return; |
| int deltaX = destX - x, deltaY = destY - y; |
| if (deltaX == 0 && deltaY == 0) return; |
| if (!isDrawing (handle)) return; |
| boolean isFocus = caret != null && caret.isFocusCaret (); |
| if (isFocus) caret.killFocus (); |
| update (all); |
| GC gc = new GC (this); |
| gc.copyArea (x, y, width, height, destX, destY); |
| gc.dispose (); |
| if (isFocus) caret.setFocus (); |
| } |
| |
| /** |
| * Sets the receiver's caret. |
| * <p> |
| * The caret for the control is automatically hidden |
| * and shown when the control is painted or resized, |
| * when focus is gained or lost and when an the control |
| * is scrolled. To avoid drawing on top of the caret, |
| * the programmer must hide and show the caret when |
| * drawing in the window any other time. |
| * </p> |
| * @param caret the new caret for the receiver, may be null |
| * |
| * @exception IllegalArgumentException <ul> |
| * <li>ERROR_INVALID_ARGUMENT - if the caret has been disposed</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> |
| */ |
| public void setCaret (Caret caret) { |
| checkWidget(); |
| Caret newCaret = caret; |
| Caret oldCaret = this.caret; |
| this.caret = newCaret; |
| if (hasFocus ()) { |
| if (oldCaret != null) oldCaret.killFocus (); |
| if (newCaret != null) { |
| if (newCaret.isDisposed()) error(SWT.ERROR_INVALID_ARGUMENT); |
| newCaret.setFocus (); |
| } |
| } |
| } |
| |
| } |