swt/graphics/Region.java

/*******************************************************************************
 * Copyright (c) 2000, 2014 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.swt.graphics;


import org.eclipse.swt.*;
import org.eclipse.swt.internal.*;
import org.eclipse.swt.internal.win32.*;

/**
 * Instances of this class represent areas of an x-y coordinate
 * system that are aggregates of the areas covered by a number
 * of polygons.
 * <p>
 * Application code must explicitly invoke the <code>Region.dispose()</code>
 * method to release the operating system resources managed by each instance
 * when those instances are no longer required.
 * </p>
 *
 * @see <a href="http://www.eclipse.org/swt/examples.php">SWT Example: GraphicsExample</a>
 * @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a>
 */
public final class Region extends Resource {

	/**
	 * the OS resource for the region
	 * (Warning: This field is platform dependent)
	 * <p>
	 * <b>IMPORTANT:</b> This field is <em>not</em> part of the SWT
	 * public API. It is marked public only so that it can be shared
	 * within the packages provided by SWT. It is not available on all
	 * platforms and should never be accessed from application code.
	 * </p>
	 *
	 * @noreference This field is not intended to be referenced by clients.
	 */
	public long handle;

/**
 * Constructs a new empty region.
 * <p>
 * You must dispose the region when it is no longer required.
 * </p>
 *
 * @exception SWTError <ul>
 *    <li>ERROR_NO_HANDLES if a handle could not be obtained for region creation</li>
 * </ul>
 *
 * @see #dispose()
 */
public Region () {
	this(null);
}

/**
 * Constructs a new empty region.
 * <p>
 * You must dispose the region when it is no longer required.
 * </p>
 *
 * @param device the device on which to allocate the region
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if device is null and there is no current device</li>
 * </ul>
 * @exception SWTError <ul>
 *    <li>ERROR_NO_HANDLES if a handle could not be obtained for region creation</li>
 * </ul>
 *
 * @see #dispose()
 *
 * @since 3.0
 */
public Region (Device device) {
	super(device);
	handle = OS.CreateRectRgn (0, 0, 0, 0);
	if (handle == 0) SWT.error(SWT.ERROR_NO_HANDLES);
	init();
}

/**
 * Constructs a new region given a handle to the operating
 * system resources that it should represent.
 *
 * @param handle the handle for the result
 */
Region(Device device, int handle) {
	super(device);
	this.handle = handle;
}

/**
 * Adds the given polygon to the collection of polygons
 * the receiver maintains to describe its area.
 *
 * @param pointArray points that describe the polygon to merge with the receiver
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the argument is null</li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 *
 * @since 3.0
 *
 */
public void add (int[] pointArray) {
	if (isDisposed()) SWT.error(SWT.ERROR_GRAPHIC_DISPOSED);
	if (pointArray == null) SWT.error(SWT.ERROR_NULL_ARGUMENT);
	addInPixels(DPIUtil.autoScaleUp(pointArray));
}

void addInPixels (int[] pointArray) {
	long polyRgn = OS.CreatePolygonRgn(pointArray, pointArray.length / 2, OS.ALTERNATE);
	OS.CombineRgn (handle, handle, polyRgn, OS.RGN_OR);
	OS.DeleteObject (polyRgn);
}

/**
 * Adds the given rectangle to the collection of polygons
 * the receiver maintains to describe its area.
 *
 * @param rect the rectangle to merge with the receiver
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the argument is null</li>
 *    <li>ERROR_INVALID_ARGUMENT - if the rectangle's width or height is negative</li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 */
public void add (Rectangle rect) {
	if (isDisposed()) SWT.error(SWT.ERROR_GRAPHIC_DISPOSED);
	if (rect == null) SWT.error(SWT.ERROR_NULL_ARGUMENT);
	rect = DPIUtil.autoScaleUp(rect);
	addInPixels(rect.x, rect.y, rect.width, rect.height);
}

/**
 * Adds the given rectangle to the collection of polygons
 * the receiver maintains to describe its area.
 *
 * @param x the x coordinate of the rectangle
 * @param y the y coordinate of the rectangle
 * @param width the width coordinate of the rectangle
 * @param height the height coordinate of the rectangle
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_INVALID_ARGUMENT - if the rectangle's width or height is negative</li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 *
 * @since 3.1
 */
public void add (int x, int y, int width, int height) {
	if (isDisposed()) SWT.error(SWT.ERROR_GRAPHIC_DISPOSED);
	addInPixels(DPIUtil.autoScaleUp(x), DPIUtil.autoScaleUp(y), DPIUtil.autoScaleUp(width), DPIUtil.autoScaleUp(height));
}

void addInPixels (int x, int y, int width, int height) {
	if (width < 0 || height < 0) SWT.error(SWT.ERROR_INVALID_ARGUMENT);
	long rectRgn = OS.CreateRectRgn (x, y, x + width, y + height);
	OS.CombineRgn (handle, handle, rectRgn, OS.RGN_OR);
	OS.DeleteObject (rectRgn);
}

/**
 * Adds all of the polygons which make up the area covered
 * by the argument to the collection of polygons the receiver
 * maintains to describe its area.
 *
 * @param region the region to merge
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the argument is null</li>
 *    <li>ERROR_INVALID_ARGUMENT - if the argument has been disposed</li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 */
public void add (Region region) {
	if (isDisposed()) SWT.error(SWT.ERROR_GRAPHIC_DISPOSED);
	if (region == null) SWT.error(SWT.ERROR_NULL_ARGUMENT);
	if (region.isDisposed()) SWT.error(SWT.ERROR_INVALID_ARGUMENT);
	OS.CombineRgn (handle, handle, region.handle, OS.RGN_OR);
}

/**
 * Returns <code>true</code> if the point specified by the
 * arguments is inside the area specified by the receiver,
 * and <code>false</code> otherwise.
 *
 * @param x the x coordinate of the point to test for containment
 * @param y the y coordinate of the point to test for containment
 * @return <code>true</code> if the region contains the point and <code>false</code> otherwise
 *
 * @exception SWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 */
public boolean contains (int x, int y) {
	if (isDisposed()) SWT.error(SWT.ERROR_GRAPHIC_DISPOSED);
	return containsInPixels(DPIUtil.autoScaleUp(x), DPIUtil.autoScaleUp(y));
}

boolean containsInPixels (int x, int y) {
	return OS.PtInRegion (handle, x, y);
}

/**
 * Returns <code>true</code> if the given point is inside the
 * area specified by the receiver, and <code>false</code>
 * otherwise.
 *
 * @param pt the point to test for containment
 * @return <code>true</code> if the region contains the point and <code>false</code> otherwise
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the argument is null</li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 */
public boolean contains (Point pt) {
	if (isDisposed()) SWT.error(SWT.ERROR_GRAPHIC_DISPOSED);
	if (pt == null) SWT.error(SWT.ERROR_NULL_ARGUMENT);
	pt = DPIUtil.autoScaleUp(pt);
	return containsInPixels(pt.x, pt.y);
}

@Override
void destroy () {
	OS.DeleteObject(handle);
	handle = 0;
}

/**
 * Compares the argument to the receiver, and returns true
 * if they represent the <em>same</em> object using a class
 * specific comparison.
 *
 * @param object the object to compare with this object
 * @return <code>true</code> if the object is the same as this object and <code>false</code> otherwise
 *
 * @see #hashCode
 */
@Override
public boolean equals (Object object) {
	if (this == object) return true;
	if (!(object instanceof Region)) return false;
	Region rgn = (Region)object;
	return handle == rgn.handle;
}

/**
 * Returns a rectangle which represents the rectangular
 * union of the collection of polygons the receiver
 * maintains to describe its area.
 *
 * @return a bounding rectangle for the region
 *
 * @exception SWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 *
 * @see Rectangle#union
 */
public Rectangle getBounds () {
	if (isDisposed()) SWT.error(SWT.ERROR_GRAPHIC_DISPOSED);
	return DPIUtil.autoScaleDown(getBoundsInPixels());
}

Rectangle getBoundsInPixels() {
	RECT rect = new RECT();
	OS.GetRgnBox(handle, rect);
	return new Rectangle(rect.left, rect.top, rect.right - rect.left, rect.bottom - rect.top);
}

/**
 * Returns an integer hash code for the receiver. Any two
 * objects that return <code>true</code> when passed to
 * <code>equals</code> must return the same value for this
 * method.
 *
 * @return the receiver's hash
 *
 * @see #equals
 */
@Override
public int hashCode () {
	return (int)handle;
}

/**
 * Intersects the given rectangle to the collection of polygons
 * the receiver maintains to describe its area.
 *
 * @param rect the rectangle to intersect with the receiver
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the argument is null</li>
 *    <li>ERROR_INVALID_ARGUMENT - if the rectangle's width or height is negative</li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 *
 * @since 3.0
 */
public void intersect (Rectangle rect) {
	if (isDisposed()) SWT.error(SWT.ERROR_GRAPHIC_DISPOSED);
	if (rect == null) SWT.error(SWT.ERROR_NULL_ARGUMENT);
	rect = DPIUtil.autoScaleUp(rect);
	intersectInPixels(rect.x, rect.y, rect.width, rect.height);
}

/**
 * Intersects the given rectangle to the collection of polygons
 * the receiver maintains to describe its area.
 *
 * @param x the x coordinate of the rectangle
 * @param y the y coordinate of the rectangle
 * @param width the width coordinate of the rectangle
 * @param height the height coordinate of the rectangle
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_INVALID_ARGUMENT - if the rectangle's width or height is negative</li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 *
 * @since 3.1
 */
public void intersect (int x, int y, int width, int height) {
	if (isDisposed()) SWT.error(SWT.ERROR_GRAPHIC_DISPOSED);
	intersectInPixels(DPIUtil.autoScaleUp(x), DPIUtil.autoScaleUp(y), DPIUtil.autoScaleUp(width), DPIUtil.autoScaleUp(height));
}

void intersectInPixels (int x, int y, int width, int height) {
	if (width < 0 || height < 0) SWT.error(SWT.ERROR_INVALID_ARGUMENT);
	long rectRgn = OS.CreateRectRgn (x, y, x + width, y + height);
	OS.CombineRgn (handle, handle, rectRgn, OS.RGN_AND);
	OS.DeleteObject (rectRgn);
}

/**
 * Intersects all of the polygons which make up the area covered
 * by the argument to the collection of polygons the receiver
 * maintains to describe its area.
 *
 * @param region the region to intersect
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the argument is null</li>
 *    <li>ERROR_INVALID_ARGUMENT - if the argument has been disposed</li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 *
 * @since 3.0
 */
public void intersect (Region region) {
	if (isDisposed()) SWT.error(SWT.ERROR_GRAPHIC_DISPOSED);
	if (region == null) SWT.error(SWT.ERROR_NULL_ARGUMENT);
	if (region.isDisposed()) SWT.error(SWT.ERROR_INVALID_ARGUMENT);
	OS.CombineRgn (handle, handle, region.handle, OS.RGN_AND);
}

/**
 * Returns <code>true</code> if the rectangle described by the
 * arguments intersects with any of the polygons the receiver
 * maintains to describe its area, and <code>false</code> otherwise.
 *
 * @param x the x coordinate of the origin of the rectangle
 * @param y the y coordinate of the origin of the rectangle
 * @param width the width of the rectangle
 * @param height the height of the rectangle
 * @return <code>true</code> if the rectangle intersects with the receiver, and <code>false</code> otherwise
 *
 * @exception SWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 *
 * @see Rectangle#intersects(Rectangle)
 */
public boolean intersects (int x, int y, int width, int height) {
	if (isDisposed()) SWT.error(SWT.ERROR_GRAPHIC_DISPOSED);
	return 	intersectsInPixels(DPIUtil.autoScaleUp(x), DPIUtil.autoScaleUp(y), DPIUtil.autoScaleUp(width), DPIUtil.autoScaleUp(height));
}

boolean intersectsInPixels (int x, int y, int width, int height) {
	RECT r = new RECT ();
	OS.SetRect (r, x, y, x + width, y + height);
	return OS.RectInRegion (handle, r);
}

/**
 * Returns <code>true</code> if the given rectangle intersects
 * with any of the polygons the receiver maintains to describe
 * its area and <code>false</code> otherwise.
 *
 * @param rect the rectangle to test for intersection
 * @return <code>true</code> if the rectangle intersects with the receiver, and <code>false</code> otherwise
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the argument is null</li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 *
 * @see Rectangle#intersects(Rectangle)
 */
public boolean intersects (Rectangle rect) {
	if (isDisposed()) SWT.error(SWT.ERROR_GRAPHIC_DISPOSED);
	if (rect == null) SWT.error(SWT.ERROR_NULL_ARGUMENT);
	rect = DPIUtil.autoScaleUp(rect);
	return intersectsInPixels(rect.x, rect.y, rect.width, rect.height);
}

/**
 * Returns <code>true</code> if the region has been disposed,
 * and <code>false</code> otherwise.
 * <p>
 * This method gets the dispose state for the region.
 * When a region has been disposed, it is an error to
 * invoke any other method (except {@link #dispose()}) using the region.
 *
 * @return <code>true</code> when the region is disposed, and <code>false</code> otherwise
 */
@Override
public boolean isDisposed() {
	return handle == 0;
}

/**
 * Returns <code>true</code> if the receiver does not cover any
 * area in the (x, y) coordinate plane, and <code>false</code> if
 * the receiver does cover some area in the plane.
 *
 * @return <code>true</code> if the receiver is empty, and <code>false</code> otherwise
 *
 * @exception SWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 */
public boolean isEmpty () {
	if (isDisposed()) SWT.error(SWT.ERROR_GRAPHIC_DISPOSED);
	RECT rect = new RECT ();
	int result = OS.GetRgnBox (handle, rect);
	if (result == OS.NULLREGION) return true;
	return ((rect.right - rect.left) <= 0) || ((rect.bottom - rect.top) <= 0);
}

/**
 * Subtracts the given polygon from the collection of polygons
 * the receiver maintains to describe its area.
 *
 * @param pointArray points that describe the polygon to merge with the receiver
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the argument is null</li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 *
 * @since 3.0
 */
public void subtract (int[] pointArray) {
	if (isDisposed()) SWT.error(SWT.ERROR_GRAPHIC_DISPOSED);
	if (pointArray == null) SWT.error(SWT.ERROR_NULL_ARGUMENT);
	subtractInPixels(DPIUtil.autoScaleUp(pointArray));
}

void subtractInPixels (int[] pointArray) {
	long polyRgn = OS.CreatePolygonRgn(pointArray, pointArray.length / 2, OS.ALTERNATE);
	OS.CombineRgn (handle, handle, polyRgn, OS.RGN_DIFF);
	OS.DeleteObject (polyRgn);
}

/**
 * Subtracts the given rectangle from the collection of polygons
 * the receiver maintains to describe its area.
 *
 * @param rect the rectangle to subtract from the receiver
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the argument is null</li>
 *    <li>ERROR_INVALID_ARGUMENT - if the rectangle's width or height is negative</li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 *
 * @since 3.0
 */
public void subtract (Rectangle rect) {
	if (isDisposed()) SWT.error(SWT.ERROR_GRAPHIC_DISPOSED);
	if (rect == null) SWT.error(SWT.ERROR_NULL_ARGUMENT);
	rect = DPIUtil.autoScaleUp(rect);
	subtractInPixels(rect.x, rect.y, rect.width, rect.height);
}

/**
 * Subtracts the given rectangle from the collection of polygons
 * the receiver maintains to describe its area.
 *
 * @param x the x coordinate of the rectangle
 * @param y the y coordinate of the rectangle
 * @param width the width coordinate of the rectangle
 * @param height the height coordinate of the rectangle
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_INVALID_ARGUMENT - if the rectangle's width or height is negative</li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 *
 * @since 3.1
 */
public void subtract (int x, int y, int width, int height) {
	if (isDisposed()) SWT.error(SWT.ERROR_GRAPHIC_DISPOSED);
	subtractInPixels(DPIUtil.autoScaleUp(x), DPIUtil.autoScaleUp(y), DPIUtil.autoScaleUp(width), DPIUtil.autoScaleUp(height));
}

void subtractInPixels (int x, int y, int width, int height) {
	if (width < 0 || height < 0) SWT.error(SWT.ERROR_INVALID_ARGUMENT);
	long rectRgn = OS.CreateRectRgn (x, y, x + width, y + height);
	OS.CombineRgn (handle, handle, rectRgn, OS.RGN_DIFF);
	OS.DeleteObject (rectRgn);
}

/**
 * Subtracts all of the polygons which make up the area covered
 * by the argument from the collection of polygons the receiver
 * maintains to describe its area.
 *
 * @param region the region to subtract
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the argument is null</li>
 *    <li>ERROR_INVALID_ARGUMENT - if the argument has been disposed</li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 *
 * @since 3.0
 */
public void subtract (Region region) {
	if (isDisposed()) SWT.error(SWT.ERROR_GRAPHIC_DISPOSED);
	if (region == null) SWT.error(SWT.ERROR_NULL_ARGUMENT);
	if (region.isDisposed()) SWT.error(SWT.ERROR_INVALID_ARGUMENT);
	OS.CombineRgn (handle, handle, region.handle, OS.RGN_DIFF);
}

/**
 * Translate all of the polygons the receiver maintains to describe
 * its area by the specified point.
 *
 * @param x the x coordinate of the point to translate
 * @param y the y coordinate of the point to translate
 *
 * @exception SWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 *
 * @since 3.1
 */
public void translate (int x, int y) {
	if (isDisposed()) SWT.error(SWT.ERROR_GRAPHIC_DISPOSED);
	translateInPixels(DPIUtil.autoScaleUp(x), DPIUtil.autoScaleUp(y));
}

void translateInPixels (int x, int y) {
	OS.OffsetRgn (handle, x, y);
}

/**
 * Translate all of the polygons the receiver maintains to describe
 * its area by the specified point.
 *
 * @param pt the point to translate
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the argument is null</li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 *
 * @since 3.1
 */
public void translate (Point pt) {
	if (isDisposed()) SWT.error(SWT.ERROR_GRAPHIC_DISPOSED);
	if (pt == null) SWT.error(SWT.ERROR_NULL_ARGUMENT);
	pt = DPIUtil.autoScaleUp(pt);
	translateInPixels(pt.x, pt.y);
}

/**
 * Returns a string containing a concise, human-readable
 * description of the receiver.
 *
 * @return a string representation of the receiver
 */
@Override
public String toString () {
	if (isDisposed()) return "Region {*DISPOSED*}";
	return "Region {" + handle + "}";
}

/**
 * Invokes platform specific functionality to allocate a new region.
 * <p>
 * <b>IMPORTANT:</b> This method is <em>not</em> part of the public
 * API for <code>Region</code>. It is marked public only so that it
 * can be shared within the packages provided by SWT. It is not
 * available on all platforms, and should never be called from
 * application code.
 * </p>
 *
 * @param device the device on which to allocate the region
 * @param handle the handle for the region
 * @return a new region object containing the specified device and handle
 *
 * @noreference This method is not intended to be referenced by clients.
 */
public static Region win32_new(Device device, int handle) {
	return new Region(device, handle);
}

}