| /******************************************************************************* |
| * 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(); |
| int charWidth = fm.getAverageCharWidth(); |
| int scrollAmount = 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; |
| } |
| } |
| } |