bundles/org.eclipse.swt/Eclipse SWT Custom Widgets/common/org/eclipse/swt/custom/MouseNavigator.java - platform/eclipse.platform.swt - Git at Google

 /**
  * Copyright (c) 2019 Laurent CARON.
  *
  * 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:
  * Laurent CARON (laurent.caron at gmail dot com) - initial API and implementation (bug 542777)
  */
 package org.eclipse.swt.custom;

 import org.eclipse.swt.*;
 import org.eclipse.swt.graphics.*;
 import org.eclipse.swt.widgets.*;

 /**
  * This class add the following behaviour to <code>StyledText</code> widgets:
  * <p>
  * When the user clicks on the wheel, a circle with arrows appears. When the user moves the mouse,
  * the StyledText content is scrolled (on the right or on the left for horizontal movements, up or down for vertical movements).
  * </p>
  *
  * @since 3.110
  */
 class MouseNavigator {
 	private final StyledText parent;
 	boolean navigationActivated = false;
 	private GC gc;
 	private static final int CIRCLE_RADIUS = 15;
 	private static final int CENTRAL_POINT_RADIUS = 2;
 	private Point originalMouseLocation;
 	private final Listener mouseDownListener, mouseUpListener, paintListener, mouseMoveListener, focusOutListener;
 	private boolean hasHBar, hasVBar;
 	private Cursor previousCursor;

 	MouseNavigator(final StyledText styledText) {
 		if (styledText == null) {
 			SWT.error(SWT.ERROR_NULL_ARGUMENT);
 		}
 		if (styledText.isDisposed()) {
 			SWT.error(SWT.ERROR_WIDGET_DISPOSED);
 		}
 		parent = styledText;

 		mouseDownListener = (event) -> {
 			onMouseDown(event);
 		};
 		parent.addListener(SWT.MouseDown, mouseDownListener);

 		mouseUpListener = (event) -> {
 			onMouseUp(event);
 		};
 		parent.addListener(SWT.MouseUp, mouseUpListener);

 		paintListener = (event) -> {
 			onPaint(event);
 		};
 		parent.addListener(SWT.Paint, paintListener);

 		mouseMoveListener = (event) -> {
 			onMouseMove(event);
 		};
 		parent.addListener(SWT.MouseMove, mouseMoveListener);

 		focusOutListener = (event) -> {
 			onFocusOut(event);
 		};
 		parent.addListener(SWT.FocusOut, focusOutListener);
 	}

 	void onMouseDown(Event e) {
 		if ((e.button != 2) || navigationActivated) {
 			return;
 		}

 		if (!parent.isVisible() || !parent.getEnabled() || parent.middleClickPressed) {
 			return;
 		}

 		// Widget has no bar or bars are not enabled
 		initBarState();

 		if (!hasHBar && !hasVBar) {
 			return;
 		}

 		navigationActivated = true;
 		previousCursor = parent.getCursor();
 		parent.setCursor(parent.getDisplay().getSystemCursor(SWT.CURSOR_ARROW));
 		originalMouseLocation = getMouseLocation();
 		parent.redraw();
 	}

 	private void initBarState() {
 		hasHBar = computeHasHorizontalBar();
 		hasVBar = computeHasVerticalBar();
 	}

 	private boolean computeHasHorizontalBar() {
 		final ScrollBar horizontalBar = parent.getHorizontalBar();
 		final boolean hasHorizontalBar = horizontalBar != null && horizontalBar.isVisible();
 		final boolean exceedHorizontalSpace = parent.computeSize(SWT.DEFAULT, SWT.DEFAULT).x > parent.getSize().x;
 		return hasHorizontalBar && exceedHorizontalSpace;
 	}

 	private boolean computeHasVerticalBar() {
 		final ScrollBar verticalBar = parent.getVerticalBar();
 		final boolean hasVerticalBar = verticalBar != null && verticalBar.isEnabled();
 		final boolean exceedVerticalSpace = parent.computeSize(SWT.DEFAULT, SWT.DEFAULT).y > parent.getSize().y;
 		return hasVerticalBar && exceedVerticalSpace;
 	}

 	private void onMouseUp(Event e) {
 		if ((computeDist() < CIRCLE_RADIUS) && (computeDist() >= 0)) {
 			return;
 		}
 		deactivate();
 	}

 	public int computeDist() {
 		if (originalMouseLocation == null) {
 			return -1;
 		}
 		final Point mouseLocation = getMouseLocation();
 		final int deltaX = originalMouseLocation.x - mouseLocation.x;
 		final int deltaY = originalMouseLocation.y - mouseLocation.y;
 		final int dist = (int) Math.sqrt(deltaX * deltaX + deltaY * deltaY);
 		return dist;
 	}

 	private void deactivate() {
 		parent.setCursor(previousCursor);
 		navigationActivated = false;
 		originalMouseLocation = null;
 		parent.redraw();
 	}

 	private void onFocusOut(Event e) {
 		deactivate();
 	}

 	private void onMouseMove(Event e) {
 		if (!navigationActivated) {
 			return;
 		}

 		final Point mouseLocation = getMouseLocation();
 		final int deltaX = originalMouseLocation.x - mouseLocation.x;
 		final int deltaY = originalMouseLocation.y - mouseLocation.y;
 		final int dist = (int) Math.sqrt(deltaX * deltaX + deltaY * deltaY);
 		if (dist < CIRCLE_RADIUS) {
 			return;
 		}

 		parent.setRedraw(false);
 		if (hasHBar) {
 			final ScrollBar bar = parent.getHorizontalBar();
 			bar.setSelection((int) (bar.getSelection() - deltaX * .1));
 			fireSelectionEvent(e, bar);
 		}

 		if (hasVBar) {
 			final ScrollBar bar = parent.getVerticalBar();
 			bar.setSelection((int) (bar.getSelection() - deltaY * .1));
 			fireSelectionEvent(e, bar);
 		}
 		parent.setRedraw(true);
 		parent.redraw();
 	}

 	private void fireSelectionEvent(final Event e, final ScrollBar bar) {
 		final Event event = new Event();
 		event.widget = bar;
 		event.display = parent.getDisplay();
 		event.type = SWT.Selection;
 		event.time = e.time;

 		for (final Listener selectionListener : bar.getListeners(SWT.Selection)) {
 			selectionListener.handleEvent(event);
 		}
 	}

 	private Point getMouseLocation() {
 		final Point cursorLocation = Display.getCurrent().getCursorLocation();
 		final Point relativeCursorLocation = parent.toControl(cursorLocation);
 		return relativeCursorLocation;
 	}

 	private void onPaint(final Event e) {
 		if (!navigationActivated) {
 			return;
 		}

 		final Rectangle rect = parent.getClientArea();
 		if (rect.width == 0 || rect.height == 0) {
 			return;
 		}
 		gc = e.gc;
 		gc.setAntialias(SWT.ON);
 		gc.setAdvanced(true);

 		final Color oldForegroundColor = gc.getForeground();
 		final Color oldBackgroundColor = gc.getBackground();
 		gc.setBackground(parent.getForeground());

 		drawCircle();
 		drawCentralPoint();

 		drawArrows();

 		gc.setForeground(oldForegroundColor);
 		gc.setBackground(oldBackgroundColor);
 	}

 	private void drawCircle() {
 		gc.setBackground(parent.getBackground());
 		gc.setForeground(parent.getForeground());
 		gc.setAlpha(200);
 		gc.fillOval(originalMouseLocation.x - CIRCLE_RADIUS, originalMouseLocation.y - CIRCLE_RADIUS, CIRCLE_RADIUS * 2, CIRCLE_RADIUS * 2);
 		gc.setBackground(parent.getForeground());
 		gc.setAlpha(255);
 		gc.drawOval(originalMouseLocation.x - CIRCLE_RADIUS, originalMouseLocation.y - CIRCLE_RADIUS, CIRCLE_RADIUS * 2, CIRCLE_RADIUS * 2);
 	}

 	private void drawCentralPoint() {
 		gc.fillOval(originalMouseLocation.x - CENTRAL_POINT_RADIUS, originalMouseLocation.y - CENTRAL_POINT_RADIUS, CENTRAL_POINT_RADIUS * 2, CENTRAL_POINT_RADIUS * 2);
 	}

 	private void drawArrows() {
 		gc.setLineWidth(2);
 		if (hasHBar) {
 			drawHorizontalArrows();
 		}
 		if (hasVBar) {
 			drawVerticalArrows();
 		}
 	}

 	private void drawHorizontalArrows() {
 		final int[] points = new int[6];
 		// Left
 		points[0] = originalMouseLocation.x - 6;
 		points[1] = originalMouseLocation.y + 3;
 		points[2] = originalMouseLocation.x - 9;
 		points[3] = originalMouseLocation.y;
 		points[4] = originalMouseLocation.x - 6;
 		points[5] = originalMouseLocation.y - 3;
 		gc.drawPolyline(points);

 		// Right
 		points[0] = originalMouseLocation.x + 7;
 		points[1] = originalMouseLocation.y + 3;
 		points[2] = originalMouseLocation.x + 10;
 		points[3] = originalMouseLocation.y;
 		points[4] = originalMouseLocation.x + 7;
 		points[5] = originalMouseLocation.y - 3;
 		gc.drawPolyline(points);
 	}

 	private void drawVerticalArrows() {
 		final int[] points = new int[6];
 		// Upper
 		points[0] = originalMouseLocation.x - 3;
 		points[1] = originalMouseLocation.y - 6;
 		points[2] = originalMouseLocation.x;
 		points[3] = originalMouseLocation.y - 10;
 		points[4] = originalMouseLocation.x + 3;
 		points[5] = originalMouseLocation.y - 6;
 		gc.drawPolyline(points);

 		// Lower
 		points[0] = originalMouseLocation.x - 3;
 		points[1] = originalMouseLocation.y + 7;
 		points[2] = originalMouseLocation.x;
 		points[3] = originalMouseLocation.y + 11;
 		points[4] = originalMouseLocation.x + 3;
 		points[5] = originalMouseLocation.y + 7;
 		gc.drawPolyline(points);

 	}

 	void dispose() {
 		if (parent.isDisposed()) {
 			return;
 		}
 		parent.removeListener(SWT.MouseDown, mouseDownListener);
 		parent.removeListener(SWT.MouseUp, mouseUpListener);
 		parent.removeListener(SWT.Paint, paintListener);
 		parent.removeListener(SWT.MouseMove, mouseMoveListener);
 		parent.removeListener(SWT.MouseExit, focusOutListener);
 	}
 }
	/**
	* Copyright (c) 2019 Laurent CARON.
	*
	* 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:
	* Laurent CARON (laurent.caron at gmail dot com) - initial API and implementation (bug 542777)
	*/
	package org.eclipse.swt.custom;

	import org.eclipse.swt.*;
	import org.eclipse.swt.graphics.*;
	import org.eclipse.swt.widgets.*;

	/**
	* This class add the following behaviour to <code>StyledText</code> widgets:
	* <p>
	* When the user clicks on the wheel, a circle with arrows appears. When the user moves the mouse,
	* the StyledText content is scrolled (on the right or on the left for horizontal movements, up or down for vertical movements).
	* </p>
	*
	* @since 3.110
	*/
	class MouseNavigator {
	private final StyledText parent;
	boolean navigationActivated = false;
	private GC gc;
	private static final int CIRCLE_RADIUS = 15;
	private static final int CENTRAL_POINT_RADIUS = 2;
	private Point originalMouseLocation;
	private final Listener mouseDownListener, mouseUpListener, paintListener, mouseMoveListener, focusOutListener;
	private boolean hasHBar, hasVBar;
	private Cursor previousCursor;

	MouseNavigator(final StyledText styledText) {
	if (styledText == null) {
	SWT.error(SWT.ERROR_NULL_ARGUMENT);
	}
	if (styledText.isDisposed()) {
	SWT.error(SWT.ERROR_WIDGET_DISPOSED);
	}
	parent = styledText;

	mouseDownListener = (event) -> {
	onMouseDown(event);
	};
	parent.addListener(SWT.MouseDown, mouseDownListener);

	mouseUpListener = (event) -> {
	onMouseUp(event);
	};
	parent.addListener(SWT.MouseUp, mouseUpListener);

	paintListener = (event) -> {
	onPaint(event);
	};
	parent.addListener(SWT.Paint, paintListener);

	mouseMoveListener = (event) -> {
	onMouseMove(event);
	};
	parent.addListener(SWT.MouseMove, mouseMoveListener);

	focusOutListener = (event) -> {
	onFocusOut(event);
	};
	parent.addListener(SWT.FocusOut, focusOutListener);
	}

	void onMouseDown(Event e) {
	if ((e.button != 2) \|\| navigationActivated) {
	return;
	}

	if (!parent.isVisible() \|\| !parent.getEnabled() \|\| parent.middleClickPressed) {
	return;
	}

	// Widget has no bar or bars are not enabled
	initBarState();

	if (!hasHBar && !hasVBar) {
	return;
	}

	navigationActivated = true;
	previousCursor = parent.getCursor();
	parent.setCursor(parent.getDisplay().getSystemCursor(SWT.CURSOR_ARROW));
	originalMouseLocation = getMouseLocation();
	parent.redraw();
	}

	private void initBarState() {
	hasHBar = computeHasHorizontalBar();
	hasVBar = computeHasVerticalBar();
	}

	private boolean computeHasHorizontalBar() {
	final ScrollBar horizontalBar = parent.getHorizontalBar();
	final boolean hasHorizontalBar = horizontalBar != null && horizontalBar.isVisible();
	final boolean exceedHorizontalSpace = parent.computeSize(SWT.DEFAULT, SWT.DEFAULT).x > parent.getSize().x;
	return hasHorizontalBar && exceedHorizontalSpace;
	}

	private boolean computeHasVerticalBar() {
	final ScrollBar verticalBar = parent.getVerticalBar();
	final boolean hasVerticalBar = verticalBar != null && verticalBar.isEnabled();
	final boolean exceedVerticalSpace = parent.computeSize(SWT.DEFAULT, SWT.DEFAULT).y > parent.getSize().y;
	return hasVerticalBar && exceedVerticalSpace;
	}

	private void onMouseUp(Event e) {
	if ((computeDist() < CIRCLE_RADIUS) && (computeDist() >= 0)) {
	return;
	}
	deactivate();
	}

	public int computeDist() {
	if (originalMouseLocation == null) {
	return -1;
	}
	final Point mouseLocation = getMouseLocation();
	final int deltaX = originalMouseLocation.x - mouseLocation.x;
	final int deltaY = originalMouseLocation.y - mouseLocation.y;
	final int dist = (int) Math.sqrt(deltaX * deltaX + deltaY * deltaY);
	return dist;
	}

	private void deactivate() {
	parent.setCursor(previousCursor);
	navigationActivated = false;
	originalMouseLocation = null;
	parent.redraw();
	}

	private void onFocusOut(Event e) {
	deactivate();
	}

	private void onMouseMove(Event e) {
	if (!navigationActivated) {
	return;
	}

	final Point mouseLocation = getMouseLocation();
	final int deltaX = originalMouseLocation.x - mouseLocation.x;
	final int deltaY = originalMouseLocation.y - mouseLocation.y;
	final int dist = (int) Math.sqrt(deltaX * deltaX + deltaY * deltaY);
	if (dist < CIRCLE_RADIUS) {
	return;
	}

	parent.setRedraw(false);
	if (hasHBar) {
	final ScrollBar bar = parent.getHorizontalBar();
	bar.setSelection((int) (bar.getSelection() - deltaX * .1));
	fireSelectionEvent(e, bar);
	}

	if (hasVBar) {
	final ScrollBar bar = parent.getVerticalBar();
	bar.setSelection((int) (bar.getSelection() - deltaY * .1));
	fireSelectionEvent(e, bar);
	}
	parent.setRedraw(true);
	parent.redraw();
	}

	private void fireSelectionEvent(final Event e, final ScrollBar bar) {
	final Event event = new Event();
	event.widget = bar;
	event.display = parent.getDisplay();
	event.type = SWT.Selection;
	event.time = e.time;

	for (final Listener selectionListener : bar.getListeners(SWT.Selection)) {
	selectionListener.handleEvent(event);
	}
	}

	private Point getMouseLocation() {
	final Point cursorLocation = Display.getCurrent().getCursorLocation();
	final Point relativeCursorLocation = parent.toControl(cursorLocation);
	return relativeCursorLocation;
	}

	private void onPaint(final Event e) {
	if (!navigationActivated) {
	return;
	}

	final Rectangle rect = parent.getClientArea();
	if (rect.width == 0 \|\| rect.height == 0) {
	return;
	}
	gc = e.gc;
	gc.setAntialias(SWT.ON);
	gc.setAdvanced(true);

	final Color oldForegroundColor = gc.getForeground();
	final Color oldBackgroundColor = gc.getBackground();
	gc.setBackground(parent.getForeground());

	drawCircle();
	drawCentralPoint();

	drawArrows();

	gc.setForeground(oldForegroundColor);
	gc.setBackground(oldBackgroundColor);
	}

	private void drawCircle() {
	gc.setBackground(parent.getBackground());
	gc.setForeground(parent.getForeground());
	gc.setAlpha(200);
	gc.fillOval(originalMouseLocation.x - CIRCLE_RADIUS, originalMouseLocation.y - CIRCLE_RADIUS, CIRCLE_RADIUS * 2, CIRCLE_RADIUS * 2);
	gc.setBackground(parent.getForeground());
	gc.setAlpha(255);
	gc.drawOval(originalMouseLocation.x - CIRCLE_RADIUS, originalMouseLocation.y - CIRCLE_RADIUS, CIRCLE_RADIUS * 2, CIRCLE_RADIUS * 2);
	}

	private void drawCentralPoint() {
	gc.fillOval(originalMouseLocation.x - CENTRAL_POINT_RADIUS, originalMouseLocation.y - CENTRAL_POINT_RADIUS, CENTRAL_POINT_RADIUS * 2, CENTRAL_POINT_RADIUS * 2);
	}

	private void drawArrows() {
	gc.setLineWidth(2);
	if (hasHBar) {
	drawHorizontalArrows();
	}
	if (hasVBar) {
	drawVerticalArrows();
	}
	}

	private void drawHorizontalArrows() {
	final int[] points = new int[6];
	// Left
	points[0] = originalMouseLocation.x - 6;
	points[1] = originalMouseLocation.y + 3;
	points[2] = originalMouseLocation.x - 9;
	points[3] = originalMouseLocation.y;
	points[4] = originalMouseLocation.x - 6;
	points[5] = originalMouseLocation.y - 3;
	gc.drawPolyline(points);

	// Right
	points[0] = originalMouseLocation.x + 7;
	points[1] = originalMouseLocation.y + 3;
	points[2] = originalMouseLocation.x + 10;
	points[3] = originalMouseLocation.y;
	points[4] = originalMouseLocation.x + 7;
	points[5] = originalMouseLocation.y - 3;
	gc.drawPolyline(points);
	}

	private void drawVerticalArrows() {
	final int[] points = new int[6];
	// Upper
	points[0] = originalMouseLocation.x - 3;
	points[1] = originalMouseLocation.y - 6;
	points[2] = originalMouseLocation.x;
	points[3] = originalMouseLocation.y - 10;
	points[4] = originalMouseLocation.x + 3;
	points[5] = originalMouseLocation.y - 6;
	gc.drawPolyline(points);

	// Lower
	points[0] = originalMouseLocation.x - 3;
	points[1] = originalMouseLocation.y + 7;
	points[2] = originalMouseLocation.x;
	points[3] = originalMouseLocation.y + 11;
	points[4] = originalMouseLocation.x + 3;
	points[5] = originalMouseLocation.y + 7;
	gc.drawPolyline(points);

	}

	void dispose() {
	if (parent.isDisposed()) {
	return;
	}
	parent.removeListener(SWT.MouseDown, mouseDownListener);
	parent.removeListener(SWT.MouseUp, mouseUpListener);
	parent.removeListener(SWT.Paint, paintListener);
	parent.removeListener(SWT.MouseMove, mouseMoveListener);
	parent.removeListener(SWT.MouseExit, focusOutListener);
	}
	}