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

 /*******************************************************************************
  * Copyright (c) 2000, 2016 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.custom;

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

 /**
  * This adapter class provides a default drag under effect (eg. select and scroll)
  * when a drag occurs over a <code>StyledText</code>.
  *
  * <p>Classes that wish to provide their own drag under effect for a <code>StyledText</code>
  * can extend this class, override the <code>StyledTextDropTargetEffect.dragOver</code>
  * method and override any other applicable methods in <code>StyledTextDropTargetEffect</code> to
  * display their own drag under effect.</p>
  *
  * Subclasses that override any methods of this class should call the corresponding
  * <code>super</code> method to get the default drag under effect implementation.
  *
  * <p>The feedback value is either one of the FEEDBACK constants defined in
  * class <code>DND</code> which is applicable to instances of this class,
  * or it must be built by <em>bitwise OR</em>'ing together
  * (that is, using the <code>int</code> "|" operator) two or more
  * of those <code>DND</code> effect constants.
  * </p>
  * <p>
  * <dl>
  * <dt><b>Feedback:</b></dt>
  * <dd>FEEDBACK_SELECT, FEEDBACK_SCROLL</dd>
  * </dl>
  * </p>
  *
  * @see DropTargetAdapter
  * @see DropTargetEvent
  * @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a>
  *
  * @since 3.3
  */
 public class StyledTextDropTargetEffect extends DropTargetEffect {
 	static final int CARET_WIDTH = 2;
 	static final int SCROLL_HYSTERESIS = 100; // milli seconds
 	static final int SCROLL_TOLERANCE = 20; // pixels

 	int currentOffset = -1;
 	long scrollBeginTime;
 	int scrollX = -1, scrollY = -1;
 	Listener paintListener;

 	/**
 	 * Creates a new <code>StyledTextDropTargetEffect</code> to handle the drag under effect on the specified
 	 * <code>StyledText</code>.
 	 *
 	 * @param styledText the <code>StyledText</code> over which the user positions the cursor to drop the data
 	 */
 	public StyledTextDropTargetEffect(StyledText styledText) {
 		super(styledText);
 		paintListener = event -> {
 			if (currentOffset != -1) {
 				StyledText text = (StyledText) getControl();
 				Point position = text.getLocationAtOffset(currentOffset);
 				int height = text.getLineHeight(currentOffset);
 				event.gc.setBackground(event.display.getSystemColor (SWT.COLOR_BLACK));
 				event.gc.fillRectangle(position.x, position.y, CARET_WIDTH, height);
 			}
 		};
 	}

 	/**
 	 * This implementation of <code>dragEnter</code> provides a default drag under effect
 	 * for the feedback specified in <code>event.feedback</code>.
 	 *
 	 * For additional information see <code>DropTargetAdapter.dragEnter</code>.
 	 *
 	 * Subclasses that override this method should call <code>super.dragEnter(event)</code>
 	 * to get the default drag under effect implementation.
 	 *
 	 * @param event  the information associated with the drag start event
 	 *
 	 * @see DropTargetAdapter
 	 * @see DropTargetEvent
 	 */
 	@Override
 	public void dragEnter(DropTargetEvent event) {
 		currentOffset = -1;
 		scrollBeginTime = 0;
 		scrollX = -1;
 		scrollY = -1;
 		getControl().removeListener(SWT.Paint, paintListener);
 		getControl().addListener (SWT.Paint, paintListener);
 	}

 	/**
 	 * This implementation of <code>dragLeave</code> provides a default drag under effect
 	 * for the feedback specified in <code>event.feedback</code>.
 	 *
 	 * For additional information see <code>DropTargetAdapter.dragLeave</code>.
 	 *
 	 * Subclasses that override this method should call <code>super.dragLeave(event)</code>
 	 * to get the default drag under effect implementation.
 	 *
 	 * @param event  the information associated with the drag leave event
 	 *
 	 * @see DropTargetAdapter
 	 * @see DropTargetEvent
 	 */
 	@Override
 	public void dragLeave(DropTargetEvent event) {
 		StyledText text = (StyledText) getControl();
 		if (currentOffset != -1) {
 			refreshCaret(text, currentOffset, -1);
 		}
 		text.removeListener(SWT.Paint, paintListener);
 		scrollBeginTime = 0;
 		scrollX = -1;
 		scrollY = -1;
 	}

 	/**
 	 * This implementation of <code>dragOver</code> provides a default drag under effect
 	 * for the feedback specified in <code>event.feedback</code>.
 	 *
 	 * For additional information see <code>DropTargetAdapter.dragOver</code>.
 	 *
 	 * Subclasses that override this method should call <code>super.dragOver(event)</code>
 	 * to get the default drag under effect implementation.
 	 *
 	 * @param event  the information associated with the drag over event
 	 *
 	 * @see DropTargetAdapter
 	 * @see DropTargetEvent
 	 * @see DND#FEEDBACK_SELECT
 	 * @see DND#FEEDBACK_SCROLL
 	 */
 	@Override
 	public void dragOver(DropTargetEvent event) {
 		int effect = event.feedback;
 		StyledText text = (StyledText) getControl();

 		Point pt = text.getDisplay().map(null, text, event.x, event.y);
 		if ((effect & DND.FEEDBACK_SCROLL) == 0) {
 			scrollBeginTime = 0;
 			scrollX = scrollY = -1;
 		} else {
 			if (text.getCharCount() == 0) {
 				scrollBeginTime = 0;
 				scrollX = scrollY = -1;
 			} else {
 				if (scrollX != -1 && scrollY != -1 && scrollBeginTime != 0 &&
 					(pt.x >= scrollX && pt.x <= (scrollX + SCROLL_TOLERANCE) ||
 					 pt.y >= scrollY && pt.y <= (scrollY + SCROLL_TOLERANCE))) {
 					if (System.currentTimeMillis() >= scrollBeginTime) {
 						Rectangle area = text.getClientArea();
 						GC gc = new GC(text);
 						FontMetrics fm = gc.getFontMetrics();
 						gc.dispose();
 						double charWidth = fm.getAverageCharacterWidth();
 						int scrollAmount = (int) (10*charWidth);
 						if (pt.x < area.x + 3*charWidth) {
 							int leftPixel = text.getHorizontalPixel();
 							text.setHorizontalPixel(leftPixel - scrollAmount);
 						}
 						if (pt.x > area.width - 3*charWidth) {
 							int leftPixel = text.getHorizontalPixel();
 							text.setHorizontalPixel(leftPixel + scrollAmount);
 						}
 						int lineHeight = text.getLineHeight();
 						if (pt.y < area.y + lineHeight) {
 							int topPixel = text.getTopPixel();
 							text.setTopPixel(topPixel - lineHeight);
 						}
 						if (pt.y > area.height - lineHeight) {
 							int topPixel = text.getTopPixel();
 							text.setTopPixel(topPixel + lineHeight);
 						}
 						scrollBeginTime = 0;
 						scrollX = scrollY = -1;
 					}
 				} else {
 					scrollBeginTime = System.currentTimeMillis() + SCROLL_HYSTERESIS;
 					scrollX = pt.x;
 					scrollY = pt.y;
 				}
 			}
 		}

 		if ((effect & DND.FEEDBACK_SELECT) != 0) {
 			int[] trailing = new int [1];
 			int newOffset = text.getOffsetAtPoint(pt.x, pt.y, trailing, false);
 			newOffset += trailing [0];
 			if (newOffset != currentOffset) {
 				refreshCaret(text, currentOffset, newOffset);
 				currentOffset = newOffset;
 			}
 		}
 	}

 	void refreshCaret(StyledText text, int oldOffset, int newOffset) {
 		if (oldOffset != newOffset) {
 			if (oldOffset != -1) {
 				Point oldPos = text.getLocationAtOffset(oldOffset);
 				int oldHeight = text.getLineHeight(oldOffset);
 				text.redraw (oldPos.x, oldPos.y, CARET_WIDTH, oldHeight, false);
 			}
 			if (newOffset != -1) {
 				Point newPos = text.getLocationAtOffset(newOffset);
 				int newHeight = text.getLineHeight(newOffset);
 				text.redraw (newPos.x, newPos.y, CARET_WIDTH, newHeight, false);
 			}
 		}
 	}

 	/**
 	 * This implementation of <code>dropAccept</code> provides a default drag under effect
 	 * for the feedback specified in <code>event.feedback</code>.
 	 *
 	 * For additional information see <code>DropTargetAdapter.dropAccept</code>.
 	 *
 	 * Subclasses that override this method should call <code>super.dropAccept(event)</code>
 	 * to get the default drag under effect implementation.
 	 *
 	 * @param event  the information associated with the drop accept event
 	 *
 	 * @see DropTargetAdapter
 	 * @see DropTargetEvent
 	 */
 	@Override
 	public void dropAccept(DropTargetEvent event) {
 		if (currentOffset != -1) {
 			StyledText text = (StyledText) getControl();
 			text.setSelection(currentOffset);
 			currentOffset = -1;
 		}
 	}
 }
	/*******************************************************************************
	* Copyright (c) 2000, 2016 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.custom;

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

	/**
	* This adapter class provides a default drag under effect (eg. select and scroll)
	* when a drag occurs over a <code>StyledText</code>.
	*
	* <p>Classes that wish to provide their own drag under effect for a <code>StyledText</code>
	* can extend this class, override the <code>StyledTextDropTargetEffect.dragOver</code>
	* method and override any other applicable methods in <code>StyledTextDropTargetEffect</code> to
	* display their own drag under effect.</p>
	*
	* Subclasses that override any methods of this class should call the corresponding
	* <code>super</code> method to get the default drag under effect implementation.
	*
	* <p>The feedback value is either one of the FEEDBACK constants defined in
	* class <code>DND</code> which is applicable to instances of this class,
	* or it must be built by <em>bitwise OR</em>'ing together
	* (that is, using the <code>int</code> "\|" operator) two or more
	* of those <code>DND</code> effect constants.
	* </p>
	* <p>
	* <dl>
	* <dt><b>Feedback:</b></dt>
	* <dd>FEEDBACK_SELECT, FEEDBACK_SCROLL</dd>
	* </dl>
	* </p>
	*
	* @see DropTargetAdapter
	* @see DropTargetEvent
	* @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a>
	*
	* @since 3.3
	*/
	public class StyledTextDropTargetEffect extends DropTargetEffect {
	static final int CARET_WIDTH = 2;
	static final int SCROLL_HYSTERESIS = 100; // milli seconds
	static final int SCROLL_TOLERANCE = 20; // pixels

	int currentOffset = -1;
	long scrollBeginTime;
	int scrollX = -1, scrollY = -1;
	Listener paintListener;

	/**
	* Creates a new <code>StyledTextDropTargetEffect</code> to handle the drag under effect on the specified
	* <code>StyledText</code>.
	*
	* @param styledText the <code>StyledText</code> over which the user positions the cursor to drop the data
	*/
	public StyledTextDropTargetEffect(StyledText styledText) {
	super(styledText);
	paintListener = event -> {
	if (currentOffset != -1) {
	StyledText text = (StyledText) getControl();
	Point position = text.getLocationAtOffset(currentOffset);
	int height = text.getLineHeight(currentOffset);
	event.gc.setBackground(event.display.getSystemColor (SWT.COLOR_BLACK));
	event.gc.fillRectangle(position.x, position.y, CARET_WIDTH, height);
	}
	};
	}

	/**
	* This implementation of <code>dragEnter</code> provides a default drag under effect
	* for the feedback specified in <code>event.feedback</code>.
	*
	* For additional information see <code>DropTargetAdapter.dragEnter</code>.
	*
	* Subclasses that override this method should call <code>super.dragEnter(event)</code>
	* to get the default drag under effect implementation.
	*
	* @param event the information associated with the drag start event
	*
	* @see DropTargetAdapter
	* @see DropTargetEvent
	*/
	@Override
	public void dragEnter(DropTargetEvent event) {
	currentOffset = -1;
	scrollBeginTime = 0;
	scrollX = -1;
	scrollY = -1;
	getControl().removeListener(SWT.Paint, paintListener);
	getControl().addListener (SWT.Paint, paintListener);
	}

	/**
	* This implementation of <code>dragLeave</code> provides a default drag under effect
	* for the feedback specified in <code>event.feedback</code>.
	*
	* For additional information see <code>DropTargetAdapter.dragLeave</code>.
	*
	* Subclasses that override this method should call <code>super.dragLeave(event)</code>
	* to get the default drag under effect implementation.
	*
	* @param event the information associated with the drag leave event
	*
	* @see DropTargetAdapter
	* @see DropTargetEvent
	*/
	@Override
	public void dragLeave(DropTargetEvent event) {
	StyledText text = (StyledText) getControl();
	if (currentOffset != -1) {
	refreshCaret(text, currentOffset, -1);
	}
	text.removeListener(SWT.Paint, paintListener);
	scrollBeginTime = 0;
	scrollX = -1;
	scrollY = -1;
	}

	/**
	* This implementation of <code>dragOver</code> provides a default drag under effect
	* for the feedback specified in <code>event.feedback</code>.
	*
	* For additional information see <code>DropTargetAdapter.dragOver</code>.
	*
	* Subclasses that override this method should call <code>super.dragOver(event)</code>
	* to get the default drag under effect implementation.
	*
	* @param event the information associated with the drag over event
	*
	* @see DropTargetAdapter
	* @see DropTargetEvent
	* @see DND#FEEDBACK_SELECT
	* @see DND#FEEDBACK_SCROLL
	*/
	@Override
	public void dragOver(DropTargetEvent event) {
	int effect = event.feedback;
	StyledText text = (StyledText) getControl();

	Point pt = text.getDisplay().map(null, text, event.x, event.y);
	if ((effect & DND.FEEDBACK_SCROLL) == 0) {
	scrollBeginTime = 0;
	scrollX = scrollY = -1;
	} else {
	if (text.getCharCount() == 0) {
	scrollBeginTime = 0;
	scrollX = scrollY = -1;
	} else {
	if (scrollX != -1 && scrollY != -1 && scrollBeginTime != 0 &&
	(pt.x >= scrollX && pt.x <= (scrollX + SCROLL_TOLERANCE) \|\|
	pt.y >= scrollY && pt.y <= (scrollY + SCROLL_TOLERANCE))) {
	if (System.currentTimeMillis() >= scrollBeginTime) {
	Rectangle area = text.getClientArea();
	GC gc = new GC(text);
	FontMetrics fm = gc.getFontMetrics();
	gc.dispose();
	double charWidth = fm.getAverageCharacterWidth();
	int scrollAmount = (int) (10*charWidth);
	if (pt.x < area.x + 3*charWidth) {
	int leftPixel = text.getHorizontalPixel();
	text.setHorizontalPixel(leftPixel - scrollAmount);
	}
	if (pt.x > area.width - 3*charWidth) {
	int leftPixel = text.getHorizontalPixel();
	text.setHorizontalPixel(leftPixel + scrollAmount);
	}
	int lineHeight = text.getLineHeight();
	if (pt.y < area.y + lineHeight) {
	int topPixel = text.getTopPixel();
	text.setTopPixel(topPixel - lineHeight);
	}
	if (pt.y > area.height - lineHeight) {
	int topPixel = text.getTopPixel();
	text.setTopPixel(topPixel + lineHeight);
	}
	scrollBeginTime = 0;
	scrollX = scrollY = -1;
	}
	} else {
	scrollBeginTime = System.currentTimeMillis() + SCROLL_HYSTERESIS;
	scrollX = pt.x;
	scrollY = pt.y;
	}
	}
	}

	if ((effect & DND.FEEDBACK_SELECT) != 0) {
	int[] trailing = new int [1];
	int newOffset = text.getOffsetAtPoint(pt.x, pt.y, trailing, false);
	newOffset += trailing [0];
	if (newOffset != currentOffset) {
	refreshCaret(text, currentOffset, newOffset);
	currentOffset = newOffset;
	}
	}
	}

	void refreshCaret(StyledText text, int oldOffset, int newOffset) {
	if (oldOffset != newOffset) {
	if (oldOffset != -1) {
	Point oldPos = text.getLocationAtOffset(oldOffset);
	int oldHeight = text.getLineHeight(oldOffset);
	text.redraw (oldPos.x, oldPos.y, CARET_WIDTH, oldHeight, false);
	}
	if (newOffset != -1) {
	Point newPos = text.getLocationAtOffset(newOffset);
	int newHeight = text.getLineHeight(newOffset);
	text.redraw (newPos.x, newPos.y, CARET_WIDTH, newHeight, false);
	}
	}
	}

	/**
	* This implementation of <code>dropAccept</code> provides a default drag under effect
	* for the feedback specified in <code>event.feedback</code>.
	*
	* For additional information see <code>DropTargetAdapter.dropAccept</code>.
	*
	* Subclasses that override this method should call <code>super.dropAccept(event)</code>
	* to get the default drag under effect implementation.
	*
	* @param event the information associated with the drop accept event
	*
	* @see DropTargetAdapter
	* @see DropTargetEvent
	*/
	@Override
	public void dropAccept(DropTargetEvent event) {
	if (currentOffset != -1) {
	StyledText text = (StyledText) getControl();
	text.setSelection(currentOffset);
	currentOffset = -1;
	}
	}
	}