SWTGraphics.java

/*******************************************************************************
 * Copyright (c) 2000, 2024 IBM Corporation and others.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License 2.0 which is available at
 * http://www.eclipse.org/legal/epl-2.0.
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.draw2d;

import java.util.ArrayList;
import java.util.List;

import org.eclipse.swt.SWT;
import org.eclipse.swt.graphics.Color;
import org.eclipse.swt.graphics.Font;
import org.eclipse.swt.graphics.FontMetrics;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.graphics.LineAttributes;
import org.eclipse.swt.graphics.Path;
import org.eclipse.swt.graphics.PathData;
import org.eclipse.swt.graphics.Pattern;
import org.eclipse.swt.graphics.Region;
import org.eclipse.swt.graphics.TextLayout;
import org.eclipse.swt.graphics.Transform;
import org.eclipse.swt.widgets.Display;

import org.eclipse.draw2d.geometry.PointList;
import org.eclipse.draw2d.geometry.Rectangle;

/**
 * A concrete implementation of <code>Graphics</code> using an SWT
 * <code>GC</code>. There are 2 states contained in this graphics class -- the
 * applied state which is the actual state of the GC and the current state which
 * is the current state of this graphics object. Certain properties can be
 * changed multiple times and the GC won't be updated until it's actually used.
 * <P>
 * WARNING: This class is not intended to be subclassed.
 */
public class SWTGraphics extends Graphics {

	/**
	 * An internal type used to represent and update the GC's clipping.
	 *
	 * @since 3.1
	 */
	interface Clipping {
		/**
		 * Sets the clip's bounding rectangle into the provided argument and returns it
		 * for convenince.
		 *
		 * @param rect the rect
		 * @return the given rect
		 * @since 3.1
		 */
		Rectangle getBoundingBox(Rectangle rect);

		Clipping getCopy();

		void intersect(int left, int top, int right, int bottom);

		void scale(float horizontal, float vertical);

		void setOn(GC gc, int translateX, int translateY);

		void translate(float dx, float dy);
	}

	/**
	 * Any state stored in this class is only applied when it is needed by a
	 * specific graphics call.
	 *
	 * @since 3.1
	 */
	static class LazyState {
		Color bgColor;
		Color fgColor;
		Font font;
		int graphicHints;
		LineAttributes lineAttributes;
		Clipping relativeClip;
	}

	static class RectangleClipping implements Clipping {

		private float top;
		private float left;
		private float bottom;
		private float right;

		RectangleClipping(float left, float top, float right, float bottom) {
			this.left = left;
			this.right = right;
			this.bottom = bottom;
			this.top = top;
		}

		RectangleClipping(org.eclipse.swt.graphics.Rectangle rect) {
			left = rect.x;
			top = rect.y;
			right = rect.x + rect.width;
			bottom = rect.y + rect.height;
		}

		RectangleClipping(Rectangle rect) {
			left = rect.x;
			top = rect.y;
			right = rect.right();
			bottom = rect.bottom();
		}

		@Override
		public Rectangle getBoundingBox(Rectangle rect) {
			rect.x = (int) left;
			rect.y = (int) top;
			rect.width = (int) Math.ceil(right) - rect.x;
			rect.height = (int) Math.ceil(bottom) - rect.y;
			return rect;
		}

		@Override
		public Clipping getCopy() {
			return new RectangleClipping(left, top, right, bottom);
		}

		@Override
		public void intersect(int left, int top, final int right, final int bottom) {
			this.left = Math.max(this.left, left);
			this.right = Math.min(this.right, right);
			this.top = Math.max(this.top, top);
			this.bottom = Math.min(this.bottom, bottom);
			// use left/top -1 to ensure ceiling function doesn't add a pixel
			if (this.right < this.left || this.bottom < this.top) {
				this.right = this.left - 1;
				this.bottom = this.top - 1;
			}
		}

		@Override
		public void scale(float horz, float vert) {
			left /= horz;
			right /= horz;
			top /= vert;
			bottom /= vert;
		}

		@Override
		public void setOn(GC gc, int translateX, int translateY) {
			int xInt = (int) Math.floor(left);
			int yInt = (int) Math.floor(top);
			gc.setClipping(xInt + translateX, yInt + translateY, (int) Math.ceil(right) - xInt,
					(int) Math.ceil(bottom) - yInt);
		}

		@Override
		public void translate(float dx, float dy) {
			left += dx;
			right += dx;
			top += dy;
			bottom += dy;
		}
	}

	/**
	 * Contains the entire state of the Graphics.
	 */
	static class State extends LazyState implements Cloneable {
		float[] affineMatrix;
		int alpha;
		Pattern bgPattern;
		int dx;
		int dy;

		Pattern fgPattern;

		@Override
		public State clone() throws CloneNotSupportedException {
			State clone = (State) super.clone();
			clone.lineAttributes = SWTGraphics.clone(clone.lineAttributes);
			return clone;
		}

		/**
		 * Copies all state information from the given State to this State
		 *
		 * @param state The State to copy from
		 */
		public void copyFrom(State state) {
			bgColor = state.bgColor;
			fgColor = state.fgColor;
			lineAttributes = SWTGraphics.clone(state.lineAttributes);
			dx = state.dx;
			dy = state.dy;
			bgPattern = state.bgPattern;
			fgPattern = state.fgPattern;
			font = state.font;
			graphicHints = state.graphicHints;
			affineMatrix = state.affineMatrix;
			relativeClip = state.relativeClip;
			alpha = state.alpha;
		}
	}

	static final int AA_MASK;
	static final int AA_SHIFT;
	static final int AA_WHOLE_NUMBER = 1;
	static final int ADVANCED_GRAPHICS_MASK;
	static final int ADVANCED_HINTS_DEFAULTS;
	static final int ADVANCED_HINTS_MASK;
	static final int ADVANCED_SHIFT;
	static final int FILL_RULE_MASK;
	static final int FILL_RULE_SHIFT;
	static final int FILL_RULE_WHOLE_NUMBER = -1;
	static final int INTERPOLATION_MASK;
	static final int INTERPOLATION_SHIFT;
	static final int INTERPOLATION_WHOLE_NUMBER = 1;

	static final int TEXT_AA_MASK;
	static final int TEXT_AA_SHIFT;
	static final int XOR_MASK;
	static final int XOR_SHIFT;

	static {
		XOR_SHIFT = 3;
		AA_SHIFT = 8;
		TEXT_AA_SHIFT = 10;
		INTERPOLATION_SHIFT = 12;
		FILL_RULE_SHIFT = 14;
		ADVANCED_SHIFT = 15;

		AA_MASK = 3 << AA_SHIFT;
		FILL_RULE_MASK = 1 << FILL_RULE_SHIFT; // If changed to more than 1-bit,
												// check references!
		INTERPOLATION_MASK = 3 << INTERPOLATION_SHIFT;
		TEXT_AA_MASK = 3 << TEXT_AA_SHIFT;
		XOR_MASK = 1 << XOR_SHIFT;
		ADVANCED_GRAPHICS_MASK = 1 << ADVANCED_SHIFT;

		ADVANCED_HINTS_MASK = TEXT_AA_MASK | AA_MASK | INTERPOLATION_MASK;
		ADVANCED_HINTS_DEFAULTS = ((SWT.DEFAULT + AA_WHOLE_NUMBER) << TEXT_AA_SHIFT)
				| ((SWT.DEFAULT + AA_WHOLE_NUMBER) << AA_SHIFT)
				| ((SWT.DEFAULT + INTERPOLATION_WHOLE_NUMBER) << INTERPOLATION_SHIFT);
	}

	private final LazyState appliedState = new LazyState();
	private final State currentState = new State();

	private boolean elementsNeedUpdate;
	private final GC gc;

	private boolean sharedClipping;
	private final List<State> stack = new ArrayList<>();

	private int stackPointer = 0;
	Transform transform;
	private int translateX = 0;
	private int translateY = 0;

	/**
	 * Constructs a new SWTGraphics that draws to the Canvas using the given GC.
	 *
	 * @param gc the GC
	 */
	public SWTGraphics(GC gc) {
		this.gc = gc;
		init();
	}

	/**
	 * If the background color has changed, this change will be pushed to the GC.
	 * Also calls {@link #checkGC()}.
	 */
	protected final void checkFill() {
		if (!currentState.bgColor.equals(appliedState.bgColor) && currentState.bgPattern == null) {
			appliedState.bgColor = currentState.bgColor;
			gc.setBackground(appliedState.bgColor);
		}
		checkGC();
	}

	/**
	 * If the rendering hints or the clip region has changed, these changes will be
	 * pushed to the GC. Rendering hints include anti-alias, xor, join, cap, line
	 * style, fill rule, interpolation, and other settings.
	 */
	protected final void checkGC() {
		if (appliedState.relativeClip != currentState.relativeClip) {
			appliedState.relativeClip = currentState.relativeClip;
			currentState.relativeClip.setOn(gc, translateX, translateY);
		}

		if (appliedState.graphicHints != currentState.graphicHints) {
			reconcileHints(gc, appliedState.graphicHints, currentState.graphicHints);
			appliedState.graphicHints = currentState.graphicHints;
		}
	}

	/**
	 * If the line width, line style, foreground or background colors have changed,
	 * these changes will be pushed to the GC. Also calls {@link #checkGC()}.
	 */
	protected final void checkPaint() {
		checkGC();
		if (!currentState.fgColor.equals(appliedState.fgColor) && currentState.fgPattern == null) {
			gc.setForeground(appliedState.fgColor = currentState.fgColor);
		}

		LineAttributes lineAttributes = currentState.lineAttributes;
		if (!appliedState.lineAttributes.equals(lineAttributes)) {
			if (getAdvanced()) {
				gc.setLineAttributes(clone(lineAttributes)); // Clone lineAttributes because on Windows hi-dpi the line
																// width may be increased
			} else {
				gc.setLineWidth((int) lineAttributes.width);
				gc.setLineCap(lineAttributes.cap);
				gc.setLineJoin(lineAttributes.join);
				gc.setLineStyle(lineAttributes.style);
				if (lineAttributes.dash != null) {
					gc.setLineDash(convertFloatArrayToInt(lineAttributes.dash));
				}
			}
			appliedState.lineAttributes = clone(lineAttributes);
		}

		if (!currentState.bgColor.equals(appliedState.bgColor) && currentState.bgPattern == null) {
			appliedState.bgColor = currentState.bgColor;
			gc.setBackground(appliedState.bgColor);
		}
	}

	/**
	 * @since 3.1
	 */
	private void checkSharedClipping() {
		if (sharedClipping) {
			sharedClipping = false;

			boolean previouslyApplied = (appliedState == currentState.relativeClip);
			// Fix: currentState.relativeClip can be null and lead to NPE
			if (currentState.relativeClip != null) {
				currentState.relativeClip = currentState.relativeClip.getCopy();
			}
			if (previouslyApplied) {
				appliedState.relativeClip = currentState.relativeClip;
			}
		}
	}

	/**
	 * If the font has changed, this change will be pushed to the GC. Also calls
	 * {@link #checkPaint()} and {@link #checkFill()}.
	 */
	protected final void checkText() {
		checkPaint();
		if (!appliedState.font.equals(currentState.font)) {
			appliedState.font = currentState.font;
			gc.setFont(appliedState.font);
		}
	}

	/**
	 * @see Graphics#clipRect(Rectangle)
	 */
	@Override
	public void clipRect(Rectangle rect) {
		if (currentState.relativeClip == null) {
			throw new IllegalStateException("The current clipping area does not " + //$NON-NLS-1$
					"support intersection."); //$NON-NLS-1$
		}

		checkSharedClipping();
		currentState.relativeClip.intersect(rect.x, rect.y, rect.right(), rect.bottom());
		appliedState.relativeClip = null;
	}

	/**
	 * @see Graphics#dispose()
	 */
	@Override
	public void dispose() {
		while (stackPointer > 0) {
			popState();
		}

		if (transform != null) {
			transform.dispose();
		}
	}

	/**
	 * @see Graphics#drawArc(int, int, int, int, int, int)
	 */
	@Override
	public void drawArc(int x, int y, int width, int height, int offset, int length) {
		checkPaint();
		gc.drawArc(x + translateX, y + translateY, width, height, offset, length);
	}

	/**
	 * @see Graphics#drawFocus(int, int, int, int)
	 */
	@Override
	public void drawFocus(int x, int y, int w, int h) {
		checkPaint();
		gc.drawFocus(x + translateX, y + translateY, w + 1, h + 1);
	}

	/**
	 * @see Graphics#drawImage(Image, int, int)
	 */
	@Override
	public void drawImage(Image srcImage, int x, int y) {
		checkGC();
		gc.drawImage(srcImage, x + translateX, y + translateY);
	}

	/**
	 * @see Graphics#drawImage(Image, int, int, int, int, int, int, int, int)
	 */
	@Override
	public void drawImage(Image srcImage, int x1, int y1, int w1, int h1, int x2, int y2, int w2, int h2) {
		checkGC();
		gc.drawImage(srcImage, x1, y1, w1, h1, x2 + translateX, y2 + translateY, w2, h2);
	}

	/**
	 * @see Graphics#drawLine(int, int, int, int)
	 */
	@Override
	public void drawLine(int x1, int y1, int x2, int y2) {
		checkPaint();
		gc.drawLine(x1 + translateX, y1 + translateY, x2 + translateX, y2 + translateY);
	}

	/**
	 * @see Graphics#drawOval(int, int, int, int)
	 */
	@Override
	public void drawOval(int x, int y, int width, int height) {
		checkPaint();
		gc.drawOval(x + translateX, y + translateY, width, height);
	}

	/**
	 * This method requires advanced graphics support. A check should be made to
	 * ensure advanced graphics is supported in the user's environment before
	 * calling this method. See {@link GC#getAdvanced()}.
	 *
	 * @see Graphics#drawPath(Path)
	 */
	@Override
	public void drawPath(Path path) {
		checkPaint();
		initTransform(false);
		gc.drawPath(path);
	}

	/**
	 * @see Graphics#drawPoint(int, int)
	 */
	@Override
	public void drawPoint(int x, int y) {
		checkPaint();
		gc.drawPoint(x + translateX, y + translateY);
	}

	/**
	 * @see Graphics#drawPolygon(int[])
	 */
	@Override
	public void drawPolygon(int[] points) {
		checkPaint();
		try {
			translatePointArray(points, translateX, translateY);
			gc.drawPolygon(points);
		} finally {
			translatePointArray(points, -translateX, -translateY);
		}
	}

	/**
	 * @see Graphics#drawPolygon(PointList)
	 */
	@Override
	public void drawPolygon(PointList points) {
		drawPolygon(points.toIntArray());
	}

	/**
	 * @see Graphics#drawPolyline(int[])
	 */
	@Override
	public void drawPolyline(int[] points) {
		checkPaint();
		try {
			translatePointArray(points, translateX, translateY);
			gc.drawPolyline(points);
		} finally {
			translatePointArray(points, -translateX, -translateY);
		}
	}

	/**
	 * @see Graphics#drawPolyline(PointList)
	 */
	@Override
	public void drawPolyline(PointList points) {
		drawPolyline(points.toIntArray());
	}

	/**
	 * @see Graphics#drawRectangle(int, int, int, int)
	 */
	@Override
	public void drawRectangle(int x, int y, int width, int height) {
		checkPaint();
		gc.drawRectangle(x + translateX, y + translateY, width, height);
	}

	/**
	 * @see Graphics#drawRoundRectangle(Rectangle, int, int)
	 */
	@Override
	public void drawRoundRectangle(Rectangle r, int arcWidth, int arcHeight) {
		checkPaint();
		gc.drawRoundRectangle(r.x + translateX, r.y + translateY, r.width, r.height, arcWidth, arcHeight);
	}

	/**
	 * @see Graphics#drawString(String, int, int)
	 */
	@Override
	public void drawString(String s, int x, int y) {
		checkText();
		gc.drawString(s, x + translateX, y + translateY, true);
	}

	/**
	 * @see Graphics#drawText(String, int, int)
	 */
	@Override
	public void drawText(String s, int x, int y) {
		checkText();
		gc.drawText(s, x + translateX, y + translateY, true);
	}

	/**
	 * @see Graphics#drawTextLayout(TextLayout, int, int, int, int, Color, Color)
	 */
	@Override
	public void drawTextLayout(TextLayout layout, int x, int y, int selectionStart, int selectionEnd,
			Color selectionForeground, Color selectionBackground) {
		// $TODO probably just call checkPaint since Font and BG color don't
		// apply
		checkText();
		layout.draw(gc, x + translateX, y + translateY, selectionStart, selectionEnd, selectionForeground,
				selectionBackground);
	}

	/**
	 * @see Graphics#fillArc(int, int, int, int, int, int)
	 */
	@Override
	public void fillArc(int x, int y, int width, int height, int offset, int length) {
		checkFill();
		gc.fillArc(x + translateX, y + translateY, width, height, offset, length);
	}

	/**
	 * @see Graphics#fillGradient(int, int, int, int, boolean)
	 */
	@Override
	public void fillGradient(int x, int y, int w, int h, boolean vertical) {
		checkPaint();
		gc.fillGradientRectangle(x + translateX, y + translateY, w, h, vertical);
	}

	/**
	 * @see Graphics#fillOval(int, int, int, int)
	 */
	@Override
	public void fillOval(int x, int y, int width, int height) {
		checkFill();
		gc.fillOval(x + translateX, y + translateY, width, height);
	}

	/**
	 * This method requires advanced graphics support. A check should be made to
	 * ensure advanced graphics is supported in the user's environment before
	 * calling this method. See {@link GC#getAdvanced()}.
	 *
	 * @see Graphics#fillPath(Path)
	 */
	@Override
	public void fillPath(Path path) {
		checkFill();
		initTransform(false);
		gc.fillPath(path);
	}

	/**
	 * @see Graphics#fillPolygon(int[])
	 */
	@Override
	public void fillPolygon(int[] points) {
		checkFill();
		try {
			translatePointArray(points, translateX, translateY);
			gc.fillPolygon(points);
		} finally {
			translatePointArray(points, -translateX, -translateY);
		}
	}

	/**
	 * @see Graphics#fillPolygon(PointList)
	 */
	@Override
	public void fillPolygon(PointList points) {
		fillPolygon(points.toIntArray());
	}

	/**
	 * @see Graphics#fillRectangle(int, int, int, int)
	 */
	@Override
	public void fillRectangle(int x, int y, int width, int height) {
		checkFill();
		gc.fillRectangle(x + translateX, y + translateY, width, height);
	}

	/**
	 * @see Graphics#fillRoundRectangle(Rectangle, int, int)
	 */
	@Override
	public void fillRoundRectangle(Rectangle r, int arcWidth, int arcHeight) {
		checkFill();
		gc.fillRoundRectangle(r.x + translateX, r.y + translateY, r.width, r.height, arcWidth, arcHeight);
	}

	/**
	 * @see Graphics#fillString(String, int, int)
	 */
	@Override
	public void fillString(String s, int x, int y) {
		checkText();
		gc.drawString(s, x + translateX, y + translateY, false);
	}

	/**
	 * @see Graphics#fillText(String, int, int)
	 */
	@Override
	public void fillText(String s, int x, int y) {
		checkText();
		gc.drawText(s, x + translateX, y + translateY, false);
	}

	/**
	 * @see Graphics#getAlpha()
	 */
	@Override
	public int getAlpha() {
		return currentState.alpha;
	}

	/**
	 * @see Graphics#getAntialias()
	 */
	@Override
	public int getAntialias() {
		return ((currentState.graphicHints & AA_MASK) >> AA_SHIFT) - AA_WHOLE_NUMBER;
	}

	@Override
	public boolean getAdvanced() {
		return (currentState.graphicHints & ADVANCED_GRAPHICS_MASK) != 0;
	}

	/**
	 * @see Graphics#getBackgroundColor()
	 */
	@Override
	public Color getBackgroundColor() {
		return currentState.bgColor;
	}

	/**
	 * @see Graphics#getClip(Rectangle)
	 */
	@Override
	public Rectangle getClip(Rectangle rect) {
		if (currentState.relativeClip != null) {
			currentState.relativeClip.getBoundingBox(rect);
			return rect;
		}
		throw new IllegalStateException("Clipping can no longer be queried due to transformations"); //$NON-NLS-1$
	}

	/**
	 * @see Graphics#getFillRule()
	 */
	@Override
	public int getFillRule() {
		return ((currentState.graphicHints & FILL_RULE_MASK) >> FILL_RULE_SHIFT) - FILL_RULE_WHOLE_NUMBER;
	}

	/**
	 * @see Graphics#getFont()
	 */
	@Override
	public Font getFont() {
		return currentState.font;
	}

	/**
	 * @see Graphics#getFontMetrics()
	 */
	@Override
	public FontMetrics getFontMetrics() {
		checkText();
		return gc.getFontMetrics();
	}

	/**
	 * @see Graphics#getForegroundColor()
	 */
	@Override
	public Color getForegroundColor() {
		return currentState.fgColor;
	}

	/**
	 * @see Graphics#getInterpolation()
	 */
	@Override
	public int getInterpolation() {
		return ((currentState.graphicHints & INTERPOLATION_MASK) >> INTERPOLATION_SHIFT) - INTERPOLATION_WHOLE_NUMBER;
	}

	/**
	 * @since 3.5
	 */
	public void getLineAttributes(LineAttributes lineAttributes) {
		copyLineAttributes(lineAttributes, currentState.lineAttributes);
	}

	/**
	 * @see Graphics#getLineCap()
	 */
	@Override
	public int getLineCap() {
		return currentState.lineAttributes.cap;
	}

	/**
	 * @see Graphics#getLineJoin()
	 */
	@Override
	public int getLineJoin() {
		return currentState.lineAttributes.join;
	}

	/**
	 * @see Graphics#getLineStyle()
	 */
	@Override
	public int getLineStyle() {
		return currentState.lineAttributes.style;
	}

	/**
	 * @see Graphics#getLineWidth()
	 */
	@Override
	public int getLineWidth() {
		return (int) currentState.lineAttributes.width;
	}

	@Override
	public float getLineWidthFloat() {
		return currentState.lineAttributes.width;
	}

	@Override
	public float getLineMiterLimit() {
		return currentState.lineAttributes.miterLimit;
	}

	/**
	 * @since 3.5
	 */
	public float[] getLineDash() {
		return currentState.lineAttributes.dash.clone();
	}

	/**
	 * @since 3.5
	 */
	public float getLineDashOffset() {
		return currentState.lineAttributes.dashOffset;
	}

	/**
	 * @see Graphics#getTextAntialias()
	 */
	@Override
	public int getTextAntialias() {
		return ((currentState.graphicHints & TEXT_AA_MASK) >> TEXT_AA_SHIFT) - AA_WHOLE_NUMBER;
	}

	/**
	 * @see Graphics#getXORMode()
	 */
	@Override
	public boolean getXORMode() {
		return (currentState.graphicHints & XOR_MASK) != 0;
	}

	/**
	 * Called by constructor, initializes all State information for currentState
	 */
	protected void init() {
		currentState.bgColor = appliedState.bgColor = gc.getBackground();
		currentState.fgColor = appliedState.fgColor = gc.getForeground();
		currentState.font = appliedState.font = gc.getFont();
		currentState.lineAttributes = gc.getLineAttributes();
		appliedState.lineAttributes = clone(currentState.lineAttributes);
		currentState.graphicHints |= gc.getLineStyle();
		currentState.graphicHints |= gc.getAdvanced() ? ADVANCED_GRAPHICS_MASK : 0;
		currentState.graphicHints |= gc.getXORMode() ? XOR_MASK : 0;

		appliedState.graphicHints = currentState.graphicHints;

		currentState.relativeClip = new RectangleClipping(gc.getClipping());
		currentState.alpha = gc.getAlpha();
	}

	private void initTransform(boolean force) {
		if (!force && translateX == 0 && translateY == 0) {
			return;
		}

		if (transform == null) {
			transform = new Transform(Display.getCurrent());
			elementsNeedUpdate = true;
			transform.translate(translateX, translateY);
			translateX = 0;
			translateY = 0;
			gc.setTransform(transform);
			currentState.graphicHints |= ADVANCED_GRAPHICS_MASK;
		}
	}

	/**
	 * @see Graphics#popState()
	 */
	@Override
	public void popState() {
		stackPointer--;
		restoreState(stack.get(stackPointer));
	}

	/**
	 * @see Graphics#pushState()
	 */
	@Override
	public void pushState() {
		if (currentState.relativeClip == null) {
			throw new IllegalStateException("The clipping has been modified in" + //$NON-NLS-1$
					"a way that cannot be saved and restored."); //$NON-NLS-1$
		}

		try {
			State s;
			currentState.dx = translateX;
			currentState.dy = translateY;

			if (elementsNeedUpdate) {
				elementsNeedUpdate = false;
				currentState.affineMatrix = new float[6];
				transform.getElements(currentState.affineMatrix);
			}
			if (stack.size() > stackPointer) {
				s = stack.get(stackPointer);
				s.copyFrom(currentState);
			} else {
				stack.add(currentState.clone());
			}
			sharedClipping = true;
			stackPointer++;
		} catch (CloneNotSupportedException e) {
			throw new RuntimeException(e);
		}
	}

	private static void reconcileHints(GC gc, int applied, int hints) {
		int changes = hints ^ applied;

		if ((changes & XOR_MASK) != 0) {
			gc.setXORMode((hints & XOR_MASK) != 0);
		}

		// Check to see if there is anything remaining
		changes &= ~XOR_MASK;
		if (changes != 0) {
			if ((changes & INTERPOLATION_MASK) != 0) {
				gc.setInterpolation(((hints & INTERPOLATION_MASK) >> INTERPOLATION_SHIFT) - INTERPOLATION_WHOLE_NUMBER);
			}

			if ((changes & FILL_RULE_MASK) != 0) {
				gc.setFillRule(((hints & FILL_RULE_MASK) >> FILL_RULE_SHIFT) - FILL_RULE_WHOLE_NUMBER);
			}

			if ((changes & AA_MASK) != 0) {
				gc.setAntialias(((hints & AA_MASK) >> AA_SHIFT) - AA_WHOLE_NUMBER);
			}

			if ((changes & TEXT_AA_MASK) != 0) {
				gc.setTextAntialias(((hints & TEXT_AA_MASK) >> TEXT_AA_SHIFT) - AA_WHOLE_NUMBER);
			}

			// If advanced was flagged, but none of the conditions which trigger
			// advanced
			// actually got applied, force advanced graphics on.
			if ((changes & ADVANCED_GRAPHICS_MASK) != 0) {
				if ((hints & ADVANCED_GRAPHICS_MASK) != 0 && !gc.getAdvanced()) {
					gc.setAdvanced(true);
				}
			}
		}
	}

	/**
	 * @see Graphics#restoreState()
	 */
	@Override
	public void restoreState() {
		restoreState(stack.get(stackPointer - 1));
	}

	/**
	 * Sets all State information to that of the given State, called by
	 * restoreState()
	 *
	 * @param s the State
	 */
	protected void restoreState(State s) {
		/*
		 * We must set the transformation matrix first since it affects things like
		 * clipping regions and patterns.
		 */
		setAffineMatrix(s.affineMatrix);
		currentState.relativeClip = s.relativeClip;
		sharedClipping = true;

		// If the GC is currently advanced, but it was not when pushed, revert
		if (gc.getAdvanced() && (s.graphicHints & ADVANCED_GRAPHICS_MASK) == 0) {
			// Set applied clip to null to force a re-setting of the clipping.
			appliedState.relativeClip = null;
			gc.setAdvanced(false);
			appliedState.graphicHints &= ~ADVANCED_HINTS_MASK;
			appliedState.graphicHints |= ADVANCED_HINTS_DEFAULTS;
		}

		setBackgroundColor(s.bgColor);
		setBackgroundPattern(s.bgPattern);

		setForegroundColor(s.fgColor);
		setForegroundPattern(s.fgPattern);

		setAlpha(s.alpha);
		setLineAttributes(s.lineAttributes);
		setFont(s.font);

		// This method must come last because above methods will incorrectly set
		// advanced state
		setGraphicHints(s.graphicHints);

		translateX = currentState.dx = s.dx;
		translateY = currentState.dy = s.dy;
	}

	/**
	 * This method requires advanced graphics support. A check should be made to
	 * ensure advanced graphics is supported in the user's environment before
	 * calling this method. See {@link GC#getAdvanced()}.
	 *
	 * @see Graphics#rotate(float)
	 */
	@Override
	public void rotate(float degrees) {
		// Flush clipping, patter, etc., before applying transform
		checkGC();
		initTransform(true);
		transform.rotate(degrees);
		gc.setTransform(transform);
		elementsNeedUpdate = true;

		// Can no longer operate or maintain clipping
		appliedState.relativeClip = currentState.relativeClip = null;
	}

	/**
	 * @see Graphics#scale(double)
	 */
	@Override
	public void scale(double factor) {
		scale((float) factor, (float) factor);
	}

	/**
	 * This method requires advanced graphics support. A check should be made to
	 * ensure advanced graphics is supported in the user's environment before
	 * calling this method. See {@link GC#getAdvanced()}.
	 *
	 * @see org.eclipse.draw2d.Graphics#scale(float, float)
	 */
	@Override
	public void scale(float horizontal, float vertical) {
		// Flush any clipping before scaling
		checkGC();

		initTransform(true);
		transform.scale(horizontal, vertical);
		gc.setTransform(transform);
		elementsNeedUpdate = true;

		checkSharedClipping();
		if (currentState.relativeClip != null) {
			currentState.relativeClip.scale(horizontal, vertical);
		}
	}

	private void setAffineMatrix(float[] m) {
		if (!elementsNeedUpdate && currentState.affineMatrix == m) {
			return;
		}
		currentState.affineMatrix = m;
		if (m != null) {
			transform.setElements(m[0], m[1], m[2], m[3], m[4], m[5]);
		} else if (transform != null) {
			transform.dispose();
			transform = null;
			elementsNeedUpdate = false;
		}
		gc.setTransform(transform);
	}

	/**
	 * This method requires advanced graphics support. A check should be made to
	 * ensure advanced graphics is supported in the user's environment before
	 * calling this method. See {@link GC#getAdvanced()}.
	 *
	 * @see Graphics#setAlpha(int)
	 */
	@Override
	public void setAlpha(int alpha) {
		currentState.graphicHints |= ADVANCED_GRAPHICS_MASK;
		if (currentState.alpha != alpha) {
			currentState.alpha = alpha;
			gc.setAlpha(currentState.alpha);
		}
	}

	/**
	 * This method requires advanced graphics support. A check should be made to
	 * ensure advanced graphics is supported in the user's environment before
	 * calling this method. See {@link GC#getAdvanced()}.
	 *
	 * @see Graphics#setAntialias(int)
	 */
	@Override
	public void setAntialias(int value) {
		currentState.graphicHints &= ~AA_MASK;
		currentState.graphicHints |= ADVANCED_GRAPHICS_MASK | (value + AA_WHOLE_NUMBER) << AA_SHIFT;
	}

	@Override
	public void setAdvanced(boolean value) {
		if (value) {
			currentState.graphicHints |= ADVANCED_GRAPHICS_MASK;
		} else {
			currentState.graphicHints &= ~ADVANCED_GRAPHICS_MASK;
		}
	}

	/**
	 * @see Graphics#setBackgroundColor(Color)
	 */
	@Override
	public void setBackgroundColor(Color color) {
		currentState.bgColor = color;
		if (currentState.bgPattern != null) {
			currentState.bgPattern = null;
			// Force the BG color to be stale
			appliedState.bgColor = null;
		}
	}

	/**
	 * @see Graphics#setBackgroundPattern(Pattern)
	 */
	@Override
	public void setBackgroundPattern(Pattern pattern) {
		currentState.graphicHints |= ADVANCED_GRAPHICS_MASK;
		if (currentState.bgPattern == pattern) {
			return;
		}
		currentState.bgPattern = pattern;

		if (pattern != null) {
			initTransform(true);
		}
		gc.setBackgroundPattern(pattern);
	}

	/**
	 * This method requires advanced graphics support. A check should be made to
	 * ensure advanced graphics is supported in the user's environment before
	 * calling this method. See {@link GC#getAdvanced()}.
	 *
	 * @see Graphics#setClip(Path)
	 */
	@Override
	public void setClip(Path path) {
		initTransform(false);
		if (((appliedState.graphicHints ^ currentState.graphicHints) & FILL_RULE_MASK) != 0) {
			// If there is a pending change to the fill rule, apply it first.
			gc.setFillRule(((currentState.graphicHints & FILL_RULE_MASK) >> FILL_RULE_SHIFT) - FILL_RULE_WHOLE_NUMBER);
			// As long as the FILL_RULE is stored in a single bit, just toggling
			// it works.
			appliedState.graphicHints ^= FILL_RULE_MASK;
		}
		gc.setClipping(path);
		appliedState.relativeClip = currentState.relativeClip = null;
	}

	/**
	 * Simple implementation of clipping a Path within the context of current
	 * clipping rectangle for now (not region)
	 * <li>Note that this method wipes out the clipping rectangle area, hence if
	 * clients need to reset it call {@link #restoreState()}
	 *
	 * @see org.eclipse.draw2d.Graphics#clipPath(org.eclipse.swt.graphics.Path)
	 */
	@Override
	public void clipPath(Path path) {
		initTransform(false);
		if (((appliedState.graphicHints ^ currentState.graphicHints) & FILL_RULE_MASK) != 0) {
			// If there is a pending change to the fill rule, apply it first.
			gc.setFillRule(((currentState.graphicHints & FILL_RULE_MASK) >> FILL_RULE_SHIFT) - FILL_RULE_WHOLE_NUMBER);
			// As long as the FILL_RULE is stored in a single bit, just toggling
			// it works.
			appliedState.graphicHints ^= FILL_RULE_MASK;
		}
		Rectangle clipping = currentState.relativeClip != null ? getClip(new Rectangle()) : new Rectangle();
		if (!clipping.isEmpty()) {
			Path flatPath = new Path(path.getDevice(), path, 0.01f);
			PathData pathData = flatPath.getPathData();
			flatPath.dispose();
			Region region = new Region(path.getDevice());
			loadPath(region, pathData.points, pathData.types);
			region.intersect(
					new org.eclipse.swt.graphics.Rectangle(clipping.x, clipping.y, clipping.width, clipping.height));
			gc.setClipping(region);
			appliedState.relativeClip = currentState.relativeClip = null;
			region.dispose();
		}
	}

	/**
	 * @see Graphics#setClip(Rectangle)
	 */
	@Override
	public void setClip(Rectangle rect) {
		currentState.relativeClip = new RectangleClipping(rect);
	}

	/**
	 * @see Graphics#setFillRule(int)
	 */
	@Override
	public void setFillRule(int rule) {
		currentState.graphicHints &= ~FILL_RULE_MASK;
		currentState.graphicHints |= (rule + FILL_RULE_WHOLE_NUMBER) << FILL_RULE_SHIFT;
	}

	/**
	 * @see Graphics#setFont(Font)
	 */
	@Override
	public void setFont(Font f) {
		currentState.font = f;
	}

	/**
	 * @see Graphics#setForegroundColor(Color)
	 */
	@Override
	public void setForegroundColor(Color color) {
		currentState.fgColor = color;
		if (currentState.fgPattern != null) {
			currentState.fgPattern = null;
			// Force fgColor to be stale
			appliedState.fgColor = null;
		}
	}

	/**
	 * @see Graphics#setForegroundPattern(Pattern)
	 */
	@Override
	public void setForegroundPattern(Pattern pattern) {
		currentState.graphicHints |= ADVANCED_GRAPHICS_MASK;
		if (currentState.fgPattern == pattern) {
			return;
		}
		currentState.fgPattern = pattern;

		if (pattern != null) {
			initTransform(true);
		}
		gc.setForegroundPattern(pattern);
	}

	private void setGraphicHints(int hints) {
		currentState.graphicHints = hints;
	}

	/**
	 * This method requires advanced graphics support. A check should be made to
	 * ensure advanced graphics is supported in the user's environment before
	 * calling this method. See {@link GC#getAdvanced()}.
	 *
	 * @see Graphics#setInterpolation(int)
	 */
	@Override
	public void setInterpolation(int interpolation) {
		// values range [-1, 3]
		currentState.graphicHints &= ~INTERPOLATION_MASK;
		currentState.graphicHints |= ADVANCED_GRAPHICS_MASK
				| (interpolation + INTERPOLATION_WHOLE_NUMBER) << INTERPOLATION_SHIFT;
	}

	@Override
	public void setLineAttributes(LineAttributes lineAttributes) {
		copyLineAttributes(currentState.lineAttributes, lineAttributes);
	}

	/**
	 * @see Graphics#setLineCap(int)
	 */
	@Override
	public void setLineCap(int value) {
		currentState.lineAttributes.cap = value;
	}

	/**
	 * @see Graphics#setLineDash(int[])
	 */
	@Override
	public void setLineDash(int[] dashes) {
		float[] fArray = null;
		if (dashes != null) {
			fArray = new float[dashes.length];
			for (int i = 0; i < dashes.length; i++) {
				fArray[i] = dashes[i];
			}
		}
		setLineDash(fArray);
	}

	/**
	 * @param value
	 * @since 3.5
	 */
	@Override
	public void setLineDash(float[] value) {
		if (value != null) {
			// validate dash values
			for (float element : value) {
				if (element <= 0) {
					SWT.error(SWT.ERROR_INVALID_ARGUMENT);
				}
			}

			currentState.lineAttributes.dash = value.clone();
			currentState.lineAttributes.style = SWT.LINE_CUSTOM;
		} else {
			currentState.lineAttributes.dash = null;
			currentState.lineAttributes.style = SWT.LINE_SOLID;
		}
	}

	/**
	 * @since 3.5
	 */
	@Override
	public void setLineDashOffset(float value) {
		currentState.lineAttributes.dashOffset = value;
	}

	/**
	 * @see Graphics#setLineJoin(int)
	 */
	@Override
	public void setLineJoin(int value) {
		currentState.lineAttributes.join = value;
	}

	/**
	 * @see Graphics#setLineStyle(int)
	 */
	@Override
	public void setLineStyle(int value) {
		currentState.lineAttributes.style = value;
	}

	/**
	 * @see Graphics#setLineWidth(int)
	 */
	@Override
	public void setLineWidth(int width) {
		currentState.lineAttributes.width = width;
	}

	@Override
	public void setLineWidthFloat(float value) {
		currentState.lineAttributes.width = value;
	}

	@Override
	public void setLineMiterLimit(float value) {
		currentState.lineAttributes.miterLimit = value;
	}

	/**
	 * This method requires advanced graphics support. A check should be made to
	 * ensure advanced graphics is supported in the user's environment before
	 * calling this method. See {@link GC#getAdvanced()}.
	 *
	 * @see Graphics#setTextAntialias(int)
	 */
	@Override
	public void setTextAntialias(int value) {
		currentState.graphicHints &= ~TEXT_AA_MASK;
		currentState.graphicHints |= ADVANCED_GRAPHICS_MASK | (value + AA_WHOLE_NUMBER) << TEXT_AA_SHIFT;
	}

	/**
	 * @see Graphics#setXORMode(boolean)
	 */
	@Override
	public void setXORMode(boolean xor) {
		currentState.graphicHints &= ~XOR_MASK;
		if (xor) {
			currentState.graphicHints |= XOR_MASK;
		}
	}

	/**
	 * This method requires advanced graphics support. A check should be made to
	 * ensure advanced graphics is supported in the user's environment before
	 * calling this method. See {@link GC#getAdvanced()}.
	 *
	 * @see Graphics#shear(float, float)
	 */
	@Override
	public void shear(float horz, float vert) {
		// Flush any clipping changes before shearing
		checkGC();
		initTransform(true);
		float[] matrix = new float[6];
		transform.getElements(matrix);
		transform.setElements(matrix[0] + matrix[2] * vert, matrix[1] + matrix[3] * vert, matrix[0] * horz + matrix[2],
				matrix[1] * horz + matrix[3], matrix[4], matrix[5]);

		gc.setTransform(transform);
		elementsNeedUpdate = true;
		// Can no longer track clipping changes
		appliedState.relativeClip = currentState.relativeClip = null;
	}

	/**
	 * This method may require advanced graphics support if using a transform, in
	 * this case, a check should be made to ensure advanced graphics is supported in
	 * the user's environment before calling this method. See
	 * {@link GC#getAdvanced()}.
	 *
	 * @see Graphics#translate(int, int)
	 */
	@Override
	public void translate(int dx, int dy) {
		if (dx == 0 && dy == 0) {
			return;
		}
		if (transform != null) {
			// Flush clipping, pattern, etc. before applying transform
			checkGC();
			transform.translate(dx, dy);
			elementsNeedUpdate = true;
			gc.setTransform(transform);
		} else {
			translateX += dx;
			translateY += dy;
		}
		checkSharedClipping();
		if (currentState.relativeClip != null) {
			currentState.relativeClip.translate(-dx, -dy);
		}
	}

	/**
	 * This method requires advanced graphics support. A check should be made to
	 * ensure advanced graphics is supported in the user's environment before
	 * calling this method. See {@link GC#getAdvanced()}.
	 *
	 * @see Graphics#translate(float, float)
	 */
	@Override
	public void translate(float dx, float dy) {
		initTransform(true);
		checkGC();
		transform.translate(dx, dy);
		elementsNeedUpdate = true;
		gc.setTransform(transform);
		checkSharedClipping();
		if (currentState.relativeClip != null) {
			currentState.relativeClip.translate(-dx, -dy);
		}
	}

	private static void translatePointArray(int[] points, int translateX, int translateY) {
		if (translateX == 0 && translateY == 0) {
			return;
		}
		for (int i = 0; (i + 1) < points.length; i += 2) {
			points[i] += translateX;
			points[i + 1] += translateY;
		}
	}

	/**
	 * Countermeasure against LineAttributes class not having its own clone()
	 * method.
	 *
	 * @since 3.6
	 */
	public static LineAttributes clone(LineAttributes src) {
		float[] dashClone = null;
		if (src.dash != null) {
			dashClone = new float[src.dash.length];
			System.arraycopy(src.dash, 0, dashClone, 0, dashClone.length);
		}
		return new LineAttributes(src.width, src.cap, src.join, src.style, dashClone, src.dashOffset, src.miterLimit);
	}

	/**
	 * Countermeasure against LineAttributes class not having a copy by value
	 * function.
	 *
	 * @since 3.6
	 */
	public static void copyLineAttributes(LineAttributes dest, LineAttributes src) {
		if (dest != src) {
			dest.cap = src.cap;
			dest.join = src.join;
			dest.miterLimit = src.miterLimit;
			dest.style = src.style;
			dest.width = src.width;
			dest.dashOffset = src.dashOffset;

			if (src.dash == null) {
				dest.dash = null;
			} else {
				if ((dest.dash == null) || (dest.dash.length != src.dash.length)) {
					dest.dash = new float[src.dash.length];
				}
				System.arraycopy(src.dash, 0, dest.dash, 0, src.dash.length);
			}
		}
	}

	/**
	 * Utility method for use with countermeasure against passing line attributes to
	 * SWT forcing advanced graphics.
	 *
	 * @return
	 * @since 3.2
	 */
	private static int[] convertFloatArrayToInt(float[] fArray) {
		int[] iArray = null;
		if (fArray != null) {
			int arrayLen = fArray.length;
			iArray = new int[arrayLen];
			for (int i = 0; i < arrayLen; i++) {
				iArray[i] = (int) fArray[i];
			}
		}
		return iArray;
	}

	static void loadPath(Region region, float[] points, byte[] types) {
		int start = 0, end = 0;
		for (byte type : types) {
			switch (type) {
			case SWT.PATH_MOVE_TO: {
				if (start != end) {
					int n = 0;
					int[] temp = new int[end - start];
					for (int k = start; k < end; k++) {
						temp[n] = Math.round(points[k]);
						n++;
					}
					region.add(temp);
				}
				start = end;
				end += 2;
				break;
			}
			case SWT.PATH_LINE_TO: {
				end += 2;
				break;
			}
			case SWT.PATH_CLOSE: {
				if (start != end) {
					int n = 0;
					int[] temp = new int[end - start];
					for (int k = start; k < end; k++) {
						temp[n] = Math.round(points[k]);
						n++;
					}
					region.add(temp);
				}
				start = end;
				break;
			}
			}
		}
		if (start != end) {
			int n = 0;
			int[] temp = new int[end - start];
			for (int k = start; k < end; k++) {
				temp[n] = Math.round(points[k]);
				n++;
			}
			region.add(temp);
		}
	}
}