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/*******************************************************************************
* 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
* Lars Vogel <Lars.Vogel@vogella.com> - Bug 507339
*******************************************************************************/
package org.eclipse.swt.snippets;
/*
* SWT accessibility snippet: respond to text-based questions from an AT
*
* For a list of all SWT example snippets see
* http://www.eclipse.org/swt/snippets/
*
* @since 3.6
*/
import static org.eclipse.swt.events.KeyListener.*;
import org.eclipse.swt.*;
import org.eclipse.swt.accessibility.*;
import org.eclipse.swt.events.*;
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.layout.*;
import org.eclipse.swt.widgets.*;
public class Snippet334 {
final static String text = "line one\nline two\nline three";
static Display display;
static Shell shell;
static Canvas canvas;
public static void main(String[] arg) {
display = new Display();
shell = new Shell(display);
shell.setLayout(new GridLayout(2, false));
Label label = new Label(shell, SWT.NONE);
label.setText("Test:");
canvas = new Canvas(shell, SWT.MULTI | SWT.BORDER);
final Caret caret = new Caret (canvas, SWT.NONE);
canvas.addPaintListener(e -> {
GC gc = e.gc;
gc.drawText(text, 10, 10);
caret.setBounds (10, 10, 2, gc.getFontMetrics().getHeight());
Rectangle rect = canvas.getClientArea();
if (canvas.isFocusControl()) {
gc.drawFocus(rect.x, rect.y, rect.width, rect.height);
}
});
canvas.addTraverseListener(e -> {
switch (e.detail) {
case SWT.TRAVERSE_TAB_NEXT:
case SWT.TRAVERSE_TAB_PREVIOUS:
e.doit = true; // enable traversal
break;
}
});
// key listener enables traversal out)
canvas.addKeyListener(keyPressedAdapter(e-> {}));
canvas.addFocusListener(new FocusAdapter() {
@Override
public void focusGained(FocusEvent e) {
canvas.redraw();
}
@Override
public void focusLost(FocusEvent e) {
canvas.redraw();
}
});
canvas.addMouseListener(new MouseAdapter() {
@Override
public void mouseDown(MouseEvent e) {
canvas.setFocus();
}
});
Accessible acc = canvas.getAccessible();
acc.addRelation(ACC.RELATION_LABELLED_BY, label.getAccessible());
acc.addAccessibleControlListener(new AccessibleControlAdapter() {
@Override
public void getRole(AccessibleControlEvent e) {
e.detail = ACC.ROLE_TEXT;
}
@Override
public void getLocation(AccessibleControlEvent e) {
Rectangle rect = canvas.getBounds();
Point pt = shell.toDisplay(rect.x, rect.y);
e.x = pt.x;
e.y = pt.y;
e.width = rect.width;
e.height = rect.height;
}
@Override
public void getValue(AccessibleControlEvent e) {
e.result = text;
}
@Override
public void getFocus(AccessibleControlEvent e) {
e.childID = ACC.CHILDID_SELF;
}
@Override
public void getChildCount (AccessibleControlEvent e) {
e.detail = 0;
}
@Override
public void getState (AccessibleControlEvent e) {
e.detail = ACC.STATE_NORMAL | ACC.STATE_FOCUSABLE;
if (canvas.isFocusControl()) e.detail |= ACC.STATE_FOCUSED | ACC.STATE_SELECTABLE;
}
});
acc.addAccessibleTextListener(new AccessibleTextExtendedAdapter() {
@Override
public void getSelectionRange(AccessibleTextEvent e) {
// select the first 4 characters for testing
e.offset = 0;
e.length = 4;
}
@Override
public void getCaretOffset(AccessibleTextEvent e) {
e.offset = 0;
}
@Override
public void getTextBounds(AccessibleTextEvent e) {
// for now, assume that start = 0 and end = text.length
GC gc = new GC(canvas);
Point extent = gc.textExtent(text);
gc.dispose();
Rectangle rect = display.map(canvas, null, 10, 10, extent.x, extent.y);
e.x = rect.x;
e.y = rect.y;
e.width = rect.width;
e.height = rect.height;
}
@Override
public void getText(AccessibleTextEvent e) {
int start = 0, end = text.length();
switch (e.type) {
case ACC.TEXT_BOUNDARY_ALL:
start = e.start;
end = e.end;
break;
case ACC.TEXT_BOUNDARY_CHAR:
start = e.count >= 0 ? e.start + e.count : e.start - e.count;
start = Math.max(0, Math.min(end, start));
end = start;
e.count = start - e.start;
e.start = start;
e.end = start;
break;
case ACC.TEXT_BOUNDARY_LINE:
int offset = e.count <= 0 ? e.start : e.end;
offset = Math.min(offset, text.length());
int lineCount = 0;
int index = 0;
while(index != -1) {
lineCount ++;
index = text.indexOf("\n", index);
if (index != -1) index++;
}
e.count = e.count < 0 ? Math.max(e.count, -lineCount) : Math.min(e.count, lineCount);
index = 0;
int lastIndex = 0;
String[] lines = new String[lineCount];
for (int i = 0; i < lines.length; i++) {
index = text.indexOf("\n", index);
lines[i] = index != -1 ?
text.substring(lastIndex, index) :
text.substring(lastIndex);
lastIndex = index;
index++;
}
int len = 0;
int lineAtOffset = 0;
for (int i = 0; i < lines.length; i++) {
len += lines[i].length();
if (len >= e.offset) {
lineAtOffset = i;
break;
}
}
int result = Math.max(0, Math.min(lineCount-1, lineAtOffset + e.count));
e.count = result -lineAtOffset;
e.result = lines[result];
break;
}
e.result = text.substring(start, end);
}
@Override
public void getSelectionCount(AccessibleTextEvent e) {
e.count = 1;
}
@Override
public void getSelection(AccessibleTextEvent e) {
// there is only 1 selection, so index = 0
getSelectionRange(e);
e.start = e.offset;
e.end = e.offset + e.length;
}
@Override
public void getRanges(AccessibleTextEvent e) {
// for now, ignore bounding box
e.start = 0;
e.end = text.length() - 1;
}
@Override
public void getCharacterCount(AccessibleTextEvent e) {
e.count = text.length();
}
@Override
public void getVisibleRanges(AccessibleTextEvent e) {
e.start = 0;
e.end = text.length() - 1;
}
});
Button button = new Button(shell, SWT.PUSH);
button.setText("Button");
button.setLayoutData(new GridData(SWT.FILL, SWT.CENTER, false, false, 2, 1));
shell.pack();
shell.open();
while (!shell.isDisposed()) {
if (!display.readAndDispatch())
display.sleep();
}
display.dispose();
}
}
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