/*******************************************************************************
* Copyright (c) 2008 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.examples.accessibility;
import java.text.MessageFormat;
import java.util.ResourceBundle;
import java.util.Vector;
import org.eclipse.swt.*;
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.widgets.*;
import org.eclipse.swt.events.*;
import org.eclipse.swt.accessibility.*;
/**
* Instances of this class represent a very simple accessible bar chart.
* From an accessibility point of view, they present the data as a "list" with "list items".
*/
public class BarChart extends Canvas {
static ResourceBundle bundle = ResourceBundle.getBundle("examples_accessibility");
Vector<Object[]> data = new Vector<Object[]>();
String title;
int color = SWT.COLOR_RED;
int selectedItem = -1;
int valueMin = 0;
int valueMax = 10;
int valueIncrement = 1;
static final int GAP = 4;
static final int AXIS_WIDTH = 2;
/**
* Constructs a new instance of this class given its parent
* and a style value describing its behavior and appearance.
*
* @param parent a composite control which will be the parent of the new instance (cannot be null)
* @param style the style of control to construct
*/
public BarChart(Composite parent, int style) {
super (parent, style);
addListeners();
}
void addListeners() {
addPaintListener(new PaintListener() {
public void paintControl(PaintEvent e) {
GC gc = e.gc;
Rectangle rect = getClientArea();
Display display = getDisplay();
int count = data.size();
Point valueSize = gc.stringExtent (new Integer(valueMax).toString());
int leftX = rect.x + 2 * GAP + valueSize.x;
int bottomY = rect.y + rect.height - 2 * GAP - valueSize.y;
int unitWidth = (rect.width - 4 * GAP - valueSize.x - AXIS_WIDTH) / count - GAP;
int unitHeight = (rect.height - 3 * GAP - AXIS_WIDTH - 2 * valueSize.y) / ((valueMax - valueMin) / valueIncrement);
// draw the title
int titleWidth = gc.stringExtent (title).x;
int center = (Math.max(titleWidth, count * (unitWidth + GAP) + GAP) - titleWidth) / 2;
gc.setForeground(display.getSystemColor(SWT.COLOR_BLACK));
gc.drawString(title, leftX + AXIS_WIDTH + center, rect.y + GAP);
// draw the y axis and value labels
gc.setLineWidth(AXIS_WIDTH);
gc.drawLine(leftX, rect.y + GAP + valueSize.y, leftX, bottomY);
for (int i = valueMin; i <= valueMax; i+=valueIncrement) {
int y = bottomY - i * unitHeight;
gc.drawLine(leftX, y, leftX - GAP, y);
gc.drawString(new Integer(i).toString(), rect.x + GAP, y - valueSize.y);
}
// draw the x axis and item labels
gc.drawLine(leftX, bottomY, rect.x + rect.width - GAP, bottomY);
for (int i = 0; i < count; i++) {
Object [] dataItem = data.elementAt(i);
String itemLabel = (String)dataItem[0];
int x = leftX + AXIS_WIDTH + GAP + i * (unitWidth + GAP);
gc.drawString(itemLabel, x, bottomY + GAP);
}
// draw the bars
gc.setBackground(display.getSystemColor(color));
for (int i = 0; i < count; i++) {
Object [] dataItem = data.elementAt(i);
int itemValue = ((Integer)dataItem[1]).intValue();
int x = leftX + AXIS_WIDTH + GAP + i * (unitWidth + GAP);
gc.fillRectangle(x, bottomY - AXIS_WIDTH - itemValue * unitHeight, unitWidth, itemValue * unitHeight);
}
if (isFocusControl()) {
if (selectedItem == -1) {
// draw the focus rectangle around the whole bar chart
gc.drawFocus(rect.x, rect.y, rect.width, rect.height);
} else {
// draw the focus rectangle around the selected item
Object [] dataItem = data.elementAt(selectedItem);
int itemValue = ((Integer)dataItem[1]).intValue();
int x = leftX + AXIS_WIDTH + GAP + selectedItem * (unitWidth + GAP);
gc.drawFocus(x, bottomY - itemValue * unitHeight - AXIS_WIDTH, unitWidth, itemValue * unitHeight + AXIS_WIDTH + GAP + valueSize.y);
}
}
}
});
addFocusListener(new FocusAdapter() {
@Override
public void focusGained(FocusEvent e) {
redraw();
}
@Override
public void focusLost(FocusEvent e) {
redraw();
}
});
addMouseListener(new MouseAdapter() {
@Override
public void mouseDown(MouseEvent e) {
if (getClientArea().contains(e.x, e.y)) {
setFocus();
int item = -1;
int count = data.size();
for (int i = 0; i < count; i++) {
if (itemBounds(i).contains(e.x, e.y)) {
item = i;
break;
}
}
if (item != selectedItem) {
selectedItem = item;
redraw();
getAccessible().setFocus(item);
getAccessible().selectionChanged();
}
}
}
});
addKeyListener(new KeyAdapter() {
@Override
public void keyPressed(KeyEvent e) {
boolean change = false;
switch (e.keyCode) {
case SWT.ARROW_DOWN:
case SWT.ARROW_RIGHT:
selectedItem++;
if (selectedItem >= data.size()) selectedItem = 0;
change = true;
break;
case SWT.ARROW_UP:
case SWT.ARROW_LEFT:
selectedItem--;
if (selectedItem <= -1) selectedItem = data.size() - 1;
change = true;
break;
case SWT.HOME:
selectedItem = 0;
change = true;
break;
case SWT.END:
selectedItem = data.size() - 1;
change = true;
break;
}
if (change) {
redraw();
getAccessible().setFocus(selectedItem);
getAccessible().selectionChanged();
}
}
});
addTraverseListener(new TraverseListener() {
public void keyTraversed(TraverseEvent e) {
switch (e.detail) {
case SWT.TRAVERSE_TAB_NEXT:
case SWT.TRAVERSE_TAB_PREVIOUS:
e.doit = true;
break;
}
}
});
getAccessible().addAccessibleListener(new AccessibleAdapter() {
@Override
public void getName(AccessibleEvent e) {
MessageFormat formatter = new MessageFormat(""); //$NON_NLS$
formatter.applyPattern(bundle.getString("name")); //$NON_NLS$
int childID = e.childID;
if (childID == ACC.CHILDID_SELF) {
e.result = title;
} else {
Object [] item = data.elementAt(childID);
e.result = formatter.format(item);
}
}
@Override
public void getDescription(AccessibleEvent e) {
int childID = e.childID;
if (childID != ACC.CHILDID_SELF) {
Object [] item = data.elementAt(childID);
String value = item[1].toString();
String colorName = bundle.getString("color" + color); //$NON_NLS$
MessageFormat formatter = new MessageFormat(""); //$NON_NLS$
formatter.applyPattern(bundle.getString("color_value")); //$NON_NLS$
e.result = formatter.format(new String [] {colorName, value});
}
}
});
getAccessible().addAccessibleControlListener(new AccessibleControlAdapter() {
@Override
public void getRole(AccessibleControlEvent e) {
if (e.childID == ACC.CHILDID_SELF) {
e.detail = ACC.ROLE_LIST;
} else {
e.detail = ACC.ROLE_LISTITEM;
}
}
@Override
public void getChildCount(AccessibleControlEvent e) {
e.detail = data.size();
}
@Override
public void getChildren(AccessibleControlEvent e) {
int count = data.size();
Object[] children = new Object[count];
for (int i = 0; i < count; i++) {
children[i] = new Integer(i);
}
e.children = children;
}
@Override
public void getChildAtPoint(AccessibleControlEvent e) {
Point testPoint = toControl(e.x, e.y);
int childID = ACC.CHILDID_NONE;
if (getClientArea().contains(testPoint)) {
childID = ACC.CHILDID_SELF;
int count = data.size();
for (int i = 0; i < count; i++) {
if (itemBounds(i).contains(testPoint)) {
childID = i;
break;
}
}
}
e.childID = childID;
}
@Override
public void getLocation(AccessibleControlEvent e) {
Rectangle location = null;
Point pt = null;
int childID = e.childID;
if (childID == ACC.CHILDID_SELF) {
location = getClientArea();
pt = getParent().toDisplay(location.x, location.y);
} else {
location = itemBounds(childID);
pt = toDisplay(location.x, location.y);
}
e.x = pt.x;
e.y = pt.y;
e.width = location.width;
e.height = location.height;
}
@Override
public void getFocus(AccessibleControlEvent e) {
int childID = ACC.CHILDID_NONE;
if (isFocusControl()) {
if (selectedItem == -1) {
childID = ACC.CHILDID_SELF;
} else {
childID = selectedItem;
}
}
e.childID = childID;
}
@Override
public void getSelection(AccessibleControlEvent e) {
e.childID = (selectedItem == -1) ? ACC.CHILDID_NONE : selectedItem;
}
@Override
public void getValue(AccessibleControlEvent e) {
int childID = e.childID;
if (childID != ACC.CHILDID_SELF) {
Object [] dataItem = data.elementAt(childID);
e.result = ((Integer)dataItem[1]).toString();
}
}
@Override
public void getState(AccessibleControlEvent e) {
int childID = e.childID;
e.detail = ACC.STATE_FOCUSABLE;
if (isFocusControl()) e.detail |= ACC.STATE_FOCUSED;
if (childID != ACC.CHILDID_SELF) {
e.detail |= ACC.STATE_SELECTABLE;
if (childID == selectedItem) e.detail |= ACC.STATE_SELECTED;
}
}
});
}
@Override
public Point computeSize (int wHint, int hHint, boolean changed) {
checkWidget ();
int count = data.size();
GC gc = new GC (this);
int titleWidth = gc.stringExtent (title).x;
Point valueSize = gc.stringExtent (new Integer(valueMax).toString());
int itemWidth = 0;
for (int i = 0; i < count; i++) {
Object [] dataItem = data.elementAt(i);
String itemLabel = (String)dataItem[0];
itemWidth = Math.max(itemWidth, gc.stringExtent (itemLabel).x);
}
gc.dispose();
int width = Math.max(titleWidth, count * (itemWidth + GAP) + GAP) + 3 * GAP + AXIS_WIDTH + valueSize.x;
int height = 3 * GAP + AXIS_WIDTH + valueSize.y * ((valueMax - valueMin) / valueIncrement + 3);
if (wHint != SWT.DEFAULT) width = wHint;
if (hHint != SWT.DEFAULT) height = hHint;
int border = getBorderWidth ();
Rectangle trim = computeTrim (0, 0, width + border*2, height + border*2);
return new Point (trim.width, trim.height);
}
/**
* Add a labeled data value to the bar chart.
*
* @param label a string describing the value
* @param value the data value
*/
public void addData (String label, int value) {
checkWidget ();
data.add(new Object[] {label, new Integer(value)});
}
/**
* Set the title of the bar chart.
*
* @param title a string to display as the bar chart's title.
*/
public void setTitle (String title) {
checkWidget ();
this.title = title;
}
/**
* Set the bar color to the specified color.
* The default color is SWT.COLOR_RED.
*
* @param color any of the SWT.COLOR_* constants
*/
public void setColor (int color) {
checkWidget ();
this.color = color;
}
/**
* Set the minimum value for the y axis.
* The default minimum is 0.
*
* @param min the minimum value
*/
public void setValueMin (int min) {
checkWidget ();
valueMin = min;
}
/**
* Set the maximum value for the y axis.
* The default maximum is 10.
*
* @param max the maximum value
*/
public void setValueMax (int max) {
checkWidget ();
valueMax = max;
}
/**
* Set the increment value for the y axis.
* The default increment is 1.
*
* @param increment the increment value
*/
public void setValueIncrement (int increment) {
checkWidget ();
valueIncrement = increment;
}
/* The bounds of the specified item in the coordinate system of the BarChart. */
Rectangle itemBounds(int index) {
Rectangle rect = getClientArea();
GC gc = new GC (BarChart.this);
Point valueSize = gc.stringExtent (new Integer(valueMax).toString());
gc.dispose();
int leftX = rect.x + 2 * GAP + valueSize.x;
int bottomY = rect.y + rect.height - 2 * GAP - valueSize.y;
int unitWidth = (rect.width - 4 * GAP - valueSize.x - AXIS_WIDTH) / data.size() - GAP;
int unitHeight = (rect.height - 3 * GAP - AXIS_WIDTH - 2 * valueSize.y) / ((valueMax - valueMin) / valueIncrement);
Object [] dataItem = data.elementAt(index);
int itemValue = ((Integer)dataItem[1]).intValue();
int x = leftX + AXIS_WIDTH + GAP + index * (unitWidth + GAP);
return new Rectangle(x, bottomY - itemValue * unitHeight - AXIS_WIDTH, unitWidth, itemValue * unitHeight + AXIS_WIDTH + GAP + valueSize.y);
}
}