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/*******************************************************************************
* Copyright (c) 2000, 2004 IBM Corporation and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* IBM Corporation - initial API and implementation
*******************************************************************************/
package org.eclipse.swt.widgets;
import org.eclipse.swt.internal.motif.*;
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;
}
Caret getIMCaret () {
return caret;
}
void redrawWidget (int x, int y, int width, int height, boolean all) {
boolean isFocus = caret != null && caret.isFocusCaret ();
if (isFocus) caret.killFocus ();
super.redrawWidget (x, y, width, height, all);
if (isFocus) caret.setFocus ();
}
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 (!isVisible ()) return;
boolean isFocus = caret != null && caret.isFocusCaret ();
if (isFocus) caret.killFocus ();
int xDisplay = OS.XtDisplay (handle);
if (xDisplay == 0) return;
int xWindow = OS.XtWindow (handle);
if (xWindow == 0) return;
int [] argList = {OS.XmNwidth, 0, OS.XmNheight, 0};
OS.XtGetValues (handle, argList, argList.length / 2);
if (Math.min(x + width, argList [1]) >= Math.max (x, 0) && Math.min(y + height, 0 + argList [3]) >= Math.max (y, 0)) {
int xEvent = OS.XtMalloc (XEvent.sizeof);
OS.XSync (xDisplay, false);
OS.XSync (xDisplay, false);
while (OS.XCheckWindowEvent (xDisplay, xWindow, OS.ExposureMask, xEvent)) {
OS.XtDispatchEvent (xEvent);
}
OS.XtFree (xEvent);
}
int xGC = OS.XCreateGC (xDisplay, xWindow, 0, null);
OS.XCopyArea (xDisplay, xWindow, xWindow, xGC, x, y, width, height, destX, destY);
OS.XFreeGC (xDisplay, xGC);
boolean disjoint = (destX + width < x) || (x + width < destX) || (destY + height < y) || (y + height < destY);
if (disjoint) {
OS.XClearArea (xDisplay, xWindow, x, y, width, height, true);
} else {
if (deltaX != 0) {
int newX = destX - deltaX;
if (deltaX < 0) newX = destX + width;
OS.XClearArea (xDisplay, xWindow, newX, y, Math.abs (deltaX), height, true);
}
if (deltaY != 0) {
int newY = destY - deltaY;
if (deltaY < 0) newY = destY + height;
OS.XClearArea (xDisplay, xWindow, x, newY, width, Math.abs (deltaY), true);
}
}
if (all) {
Control [] children = _getChildren ();
for (int i=0; i<children.length; i++) {
Control child = children [i];
Rectangle rect = child.getBounds ();
if (Math.min(x + width, rect.x + rect.width) >= Math.max (x, rect.x) &&
Math.min(y + height, rect.y + rect.height) >= Math.max (y, rect.y)) {
child.setLocation (rect.x + deltaX, rect.y + deltaY);
}
}
}
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 ();
}
}
}
boolean setBounds (int x, int y, int width, int height, boolean move, boolean resize) {
boolean isFocus = caret != null && caret.isFocusCaret ();
if (isFocus) caret.killFocus ();
boolean changed = super.setBounds (x, y, width, height, move, resize);
if (isFocus) caret.setFocus ();
return changed;
}
public void setFont (Font font) {
checkWidget();
if (caret != null) caret.setFont (font);
super.setFont (font);
}
int XExposure (int w, int client_data, int call_data, int continue_to_dispatch) {
boolean isFocus = caret != null && caret.isFocusCaret ();
if (isFocus) caret.killFocus ();
int result = super.XExposure (w, client_data, call_data, continue_to_dispatch);
if (isFocus) caret.setFocus ();
return result;
}
int xFocusIn (XFocusChangeEvent xEvent) {
int result = super.xFocusIn (xEvent);
if (caret != null) caret.setFocus ();
return result;
}
int xFocusOut (XFocusChangeEvent xEvent) {
int result = super.xFocusOut (xEvent);
if (caret != null) caret.killFocus ();
return result;
}
}
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