/******************************************************************************* * 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 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.graphics;import org.eclipse.swt.internal.*;import org.eclipse.swt.internal.win32.*;import org.eclipse.swt.*;/** * Class <code>GC</code> is where all of the drawing capabilities that are  * supported by SWT are located. Instances are used to draw on either an  * <code>Image</code>, a <code>Control</code>, or directly on a <code>Display</code>. * <dl> * <dt><b>Styles:</b></dt> * <dd>LEFT_TO_RIGHT, RIGHT_TO_LEFT</dd> * </dl> *  * <p> * The SWT drawing coordinate system is the two-dimensional space with the origin * (0,0) at the top left corner of the drawing area and with (x,y) values increasing * to the right and downward respectively. * </p> *  * <p> * Application code must explicitly invoke the <code>GC.dispose()</code>  * method to release the operating system resources managed by each instance * when those instances are no longer required. This is <em>particularly</em> * important on Windows95 and Windows98 where the operating system has a limited * number of device contexts available. * </p> *  * <p> * Note: Only one of LEFT_TO_RIGHT and RIGHT_TO_LEFT may be specified. * </p> * * @see org.eclipse.swt.events.PaintEvent */public final class GC {		/**	 * the handle to the OS device context	 * (Warning: This field is platform dependent)	 */	public int handle;	Drawable drawable;	GCData data;/** * Prevents uninitialized instances from being created outside the package. */GC() {}/**	  * Constructs a new instance of this class which has been * configured to draw on the specified drawable. Sets the * foreground and background color in the GC to match those * in the drawable. * <p> * You must dispose the graphics context when it is no longer required.  * </p> * @param drawable the drawable to draw on * @exception IllegalArgumentException <ul> *    <li>ERROR_NULL_ARGUMENT - if the drawable is null</li> *    <li>ERROR_NULL_ARGUMENT - if there is no current device</li> *    <li>ERROR_INVALID_ARGUMENT *          - if the drawable is an image that is not a bitmap or an icon *          - if the drawable is an image or printer that is already selected *            into another graphics context</li> * </ul> * @exception SWTError <ul> *    <li>ERROR_NO_HANDLES if a handle could not be obtained for gc creation</li> * </ul> */public GC(Drawable drawable) {	this(drawable, SWT.NONE);}/**	  * Constructs a new instance of this class which has been * configured to draw on the specified drawable. Sets the * foreground and background color in the GC to match those * in the drawable. * <p> * You must dispose the graphics context when it is no longer required.  * </p> *  * @param drawable the drawable to draw on * @param style the style of GC to construct *  * @exception IllegalArgumentException <ul> *    <li>ERROR_NULL_ARGUMENT - if the drawable is null</li> *    <li>ERROR_NULL_ARGUMENT - if there is no current device</li> *    <li>ERROR_INVALID_ARGUMENT *          - if the drawable is an image that is not a bitmap or an icon *          - if the drawable is an image or printer that is already selected *            into another graphics context</li> * </ul> * @exception SWTError <ul> *    <li>ERROR_NO_HANDLES if a handle could not be obtained for gc creation</li> * </ul> *   * @since 2.1.2 */public GC(Drawable drawable, int style) {	if (drawable == null) SWT.error(SWT.ERROR_NULL_ARGUMENT);	GCData data = new GCData ();	data.style = checkStyle(style);	int hDC = drawable.internal_new_GC(data);	Device device = data.device;	if (device == null) device = Device.getDevice();	if (device == null) SWT.error(SWT.ERROR_NULL_ARGUMENT);	data.device = device;	init (drawable, data, hDC);	if (device.tracking) device.new_Object(this);	}static int checkStyle(int style) {	if ((style & SWT.LEFT_TO_RIGHT) != 0) style &= ~SWT.RIGHT_TO_LEFT;	return style & (SWT.LEFT_TO_RIGHT | SWT.RIGHT_TO_LEFT);}/** * Copies a rectangular area of the receiver at the specified * position into the image, which must be of type <code>SWT.BITMAP</code>. * * @param image the image to copy into * @param x the x coordinate in the receiver of the area to be copied * @param y the y coordinate in the receiver of the area to be copied * * @exception IllegalArgumentException <ul> *    <li>ERROR_NULL_ARGUMENT - if the image is null</li> *    <li>ERROR_INVALID_ARGUMENT - if the image is not a bitmap or has been disposed</li>  * </ul> * @exception SWTException <ul> *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li> * </ul> */public void copyArea(Image image, int x, int y) {	if (handle == 0) SWT.error(SWT.ERROR_GRAPHIC_DISPOSED);	if (image == null) SWT.error(SWT.ERROR_NULL_ARGUMENT);	if (image.type != SWT.BITMAP || image.isDisposed()) SWT.error(SWT.ERROR_INVALID_ARGUMENT);		/* Get the HDC for the device */	Device device = data.device; 	int hDC = device.internal_new_GC(null); 	 	/* Copy the bitmap area */	Rectangle rect = image.getBounds(); 		int memHdc = OS.CreateCompatibleDC(hDC);	int hOldBitmap = OS.SelectObject(memHdc, image.handle);	OS.BitBlt(memHdc, 0, 0, rect.width, rect.height, handle, x, y, OS.SRCCOPY);	OS.SelectObject(memHdc, hOldBitmap);	OS.DeleteDC(memHdc);		/* Release the HDC for the device */	device.internal_dispose_GC(hDC, null);}/** * Copies a rectangular area of the receiver at the source * position onto the receiver at the destination position. * * @param srcX the x coordinate in the receiver of the area to be copied * @param srcY the y coordinate in the receiver of the area to be copied * @param width the width of the area to copy * @param height the height of the area to copy * @param destX the x coordinate in the receiver of the area to copy to * @param destY the y coordinate in the receiver of the area to copy to * * @exception SWTException <ul> *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li> * </ul> */public void copyArea(int srcX, int srcY, int width, int height, int destX, int destY) {	if (handle == 0) SWT.error(SWT.ERROR_GRAPHIC_DISPOSED);	/*	* Feature in WinCE.  The function WindowFromDC is not part of the	* WinCE SDK.  The fix is to remember the HWND.	*/	int hwnd = data.hwnd;	if (hwnd == 0) {		OS.BitBlt(handle, destX, destY, width, height, handle, srcX, srcY, OS.SRCCOPY);	} else {		RECT lprcClip = null;		int hrgn = OS.CreateRectRgn(0, 0, 0, 0);		if (OS.GetClipRgn(handle, hrgn) == 1) {			lprcClip = new RECT();			OS.GetRgnBox(hrgn, lprcClip);		}		OS.DeleteObject(hrgn);		RECT lprcScroll = new RECT();		OS.SetRect(lprcScroll, srcX, srcY, srcX + width, srcY + height);		int res = OS.ScrollWindowEx(hwnd, destX - srcX, destY - srcY, lprcScroll, lprcClip, 0, null, OS.SW_INVALIDATE | OS.SW_ERASE); 		/*		* Feature in WinCE.  ScrollWindowEx does not accept combined		* vertical and horizontal scrolling.  The fix is to do a		* BitBlt and invalidate the appropriate source area.		*/		if (res == 0 && OS.IsWinCE) {			OS.BitBlt(handle, destX, destY, width, height, handle, srcX, srcY, OS.SRCCOPY);			int deltaX = destX - srcX, deltaY = destY - srcY;			boolean disjoint = (destX + width < srcX) || (srcX + width < destX) || (destY + height < srcY) || (srcY + height < destY);			if (disjoint) {				OS.InvalidateRect(hwnd, lprcScroll, true);			} else {				if (deltaX != 0) {					int newX = destX - deltaX;					if (deltaX < 0) newX = destX + width;					OS.SetRect(lprcScroll, newX, srcY, newX + Math.abs(deltaX), srcY + height);					OS.InvalidateRect(hwnd, lprcScroll, true);				}				if (deltaY != 0) {					int newY = destY - deltaY;					if (deltaY < 0) newY = destY + height;					OS.SetRect(lprcScroll, srcX, newY, srcX + width, newY + Math.abs(deltaY));					OS.InvalidateRect(hwnd, lprcScroll, true);				}			}		}	}}int createDIB(int width, int height) {	short depth = 32;	BITMAPINFOHEADER bmiHeader = new BITMAPINFOHEADER();	bmiHeader.biSize = BITMAPINFOHEADER.sizeof;	bmiHeader.biWidth = width;	bmiHeader.biHeight = -height;	bmiHeader.biPlanes = 1;	bmiHeader.biBitCount = depth;	if (OS.IsWinCE) bmiHeader.biCompression = OS.BI_BITFIELDS;	else bmiHeader.biCompression = OS.BI_RGB;	byte[]	bmi = new byte[BITMAPINFOHEADER.sizeof + (OS.IsWinCE ? 12 : 0)];	OS.MoveMemory(bmi, bmiHeader, BITMAPINFOHEADER.sizeof);	/* Set the rgb colors into the bitmap info */	if (OS.IsWinCE) {		int redMask = 0xFF00;		int greenMask = 0xFF0000;		int blueMask = 0xFF000000;		/* big endian */		int offset = BITMAPINFOHEADER.sizeof;		bmi[offset] = (byte)((redMask & 0xFF000000) >> 24);		bmi[offset + 1] = (byte)((redMask & 0xFF0000) >> 16);		bmi[offset + 2] = (byte)((redMask & 0xFF00) >> 8);		bmi[offset + 3] = (byte)((redMask & 0xFF) >> 0);		bmi[offset + 4] = (byte)((greenMask & 0xFF000000) >> 24);		bmi[offset + 5] = (byte)((greenMask & 0xFF0000) >> 16);		bmi[offset + 6] = (byte)((greenMask & 0xFF00) >> 8);		bmi[offset + 7] = (byte)((greenMask & 0xFF) >> 0);		bmi[offset + 8] = (byte)((blueMask & 0xFF000000) >> 24);		bmi[offset + 9] = (byte)((blueMask & 0xFF0000) >> 16);		bmi[offset + 10] = (byte)((blueMask & 0xFF00) >> 8);		bmi[offset + 11] = (byte)((blueMask & 0xFF) >> 0);	}	int[] pBits = new int[1];	int hDib = OS.CreateDIBSection(0, bmi, OS.DIB_RGB_COLORS, pBits, 0, 0);	if (hDib == 0) SWT.error(SWT.ERROR_NO_HANDLES);	return hDib;}/** * Disposes of the operating system resources associated with * the graphics context. Applications must dispose of all GCs * which they allocate. */public void dispose() {	if (handle == 0) return;	if (data.device.isDisposed()) return;		/* Select stock pen and brush objects and free resources */	if (data.hPen != 0) {		int nullPen = OS.GetStockObject(OS.NULL_PEN);		OS.SelectObject(handle, nullPen);		OS.DeleteObject(data.hPen);		data.hPen = 0;	}	if (data.hBrush != 0) {		int nullBrush = OS.GetStockObject(OS.NULL_BRUSH);		OS.SelectObject(handle, nullBrush);		OS.DeleteObject(data.hBrush);		data.hBrush = 0;	}		/*	* Put back the original bitmap into the device context.	* This will ensure that we have not left a bitmap	* selected in it when we delete the HDC.	*/	int hNullBitmap = data.hNullBitmap;	if (hNullBitmap != 0) {		OS.SelectObject(handle, hNullBitmap);		data.hNullBitmap = 0;	}	Image image = data.image;	if (image != null) image.memGC = null;		/*	* Dispose the HDC.	*/	Device device = data.device;	if (drawable != null) drawable.internal_dispose_GC(handle, data);	drawable = null;	handle = 0;	data.image = null;	data.ps = null;	if (device.tracking) device.dispose_Object(this);	data.device = null;	data = null;}/** * Draws the outline of a circular or elliptical arc  * within the specified rectangular area. * <p> * The resulting arc begins at <code>startAngle</code> and extends   * for <code>arcAngle</code> degrees, using the current color. * Angles are interpreted such that 0 degrees is at the 3 o'clock * position. A positive value indicates a counter-clockwise rotation * while a negative value indicates a clockwise rotation. * </p><p> * The center of the arc is the center of the rectangle whose origin  * is (<code>x</code>, <code>y</code>) and whose size is specified by the  * <code>width</code> and <code>height</code> arguments.  * </p><p> * The resulting arc covers an area <code>width + 1</code> pixels wide * by <code>height + 1</code> pixels tall. * </p>