--- /dev/null
+/*******************************************************************************
+ * Copyright (c) 2000, 2016 IBM Corporation and others.
+ *
+ * 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:
+ * 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>
+ * <dl>
+ * <dt><b>Feedback:</b></dt>
+ * <dd>FEEDBACK_SELECT, FEEDBACK_SCROLL</dd>
+ * </dl>
+ *
+ * @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;
+ }
+ }
+}
Code Review / simantics / platform.git / blobdiff