/*******************************************************************************
* Copyright (c) 2014 EclipseSource 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:
* EclipseSource - initial API and implementation
******************************************************************************/
package com.eclipsesource.tabris.widgets;
import static com.eclipsesource.tabris.internal.Clauses.when;
import static com.eclipsesource.tabris.internal.Clauses.whenNull;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.PaintEvent;
import org.eclipse.swt.events.PaintListener;
import org.eclipse.swt.graphics.Color;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Canvas;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Widget;
import com.eclipsesource.tabris.ui.TabrisUI;
import com.eclipsesource.tabris.widgets.swipe.Swipe;
/**
* <p>
* When you build your app with a paging concept using {@link Swipe}, {@link TabrisUI} or any homebrew solution it’s
* sometimes required that you need to indicate the paging progress. This is often done using colored bullets. With the
* {@link PagingIndicator} you can create such bullets. It allows you to define the number of bullets, the active one
* and the look and feel.
* </p>
* <p>
* The {@link PagingIndicator} is a stand alone {@link Widget}. It needs to be part of your layout.
* </p>
*
* @since 1.3
*/
public class PagingIndicator extends Composite {
private Canvas indicatorCanvas;
private Color inactiveColor;
private Color activeColor;
private int count;
private int activeIndex;
private int spacing;
private int diameter;
/**
* <p>
* Creates a new {@link PagingIndicator} with the provided parent. Default values are:
* <ul>
* <li>bullet count = 1</li>
* <li>active bullet index = 0</li>
* <li>spacing between bullets = 9px</li>
* <li>bullet diameter = 7px</li>
* <li>active color = blue</li>
* <li>inactive color = gray</li>
* </ul>
* </p>
*
* @param parent the parent to use. Must not be <code>null</code>.
*/
public PagingIndicator( Composite parent ) {
super( parent, SWT.NONE );
initializeIndicator( parent );
createCanvas();
}
private void initializeIndicator( Composite parent ) {
setInternalLayout();
count = 1;
activeIndex = 0;
spacing = 9;
diameter = 7;
inactiveColor = parent.getDisplay().getSystemColor( SWT.COLOR_GRAY );
activeColor = new Color( parent.getDisplay(), 0, 122, 255 );
}
private void setInternalLayout() {
GridLayout gridLayout = new GridLayout();
gridLayout.marginHeight = 0;
gridLayout.marginWidth = 0;
gridLayout.verticalSpacing = 0;
gridLayout.horizontalSpacing = 0;
setLayout( gridLayout );
}
private void createCanvas() {
indicatorCanvas = new Canvas( this, SWT.NONE );
indicatorCanvas.setLayoutData( new GridData( SWT.CENTER, SWT.CENTER, true, true ) );
addPaintListener();
}
private void addPaintListener() {
indicatorCanvas.addPaintListener( new PaintListener() {
@Override
public void paintControl( PaintEvent event ) {
drawIndicators( event.gc );
getParent().layout( true, true );
}
} );
}
/**
* <p>
* Sets the number of the bullets to show.
* </p>
*
* @param count the number of bullets. Must be >= 0.
*/
public void setCount( int count ) {
when( count < 0 ).throwIllegalArgument( "Count must be positive but was " + count );
this.count = count;
update();
}
/**
* <p>
* Returns the number of bullets to show.
* </p>
*/
public int getCount() {
return count;
}
/**
* <p>
* Marks the bullet with the defined index as active.
* </p>
*
* @param index the index of the bullet to become active. Must be >= 0.
*
* @throws IllegalStateException when the defined index does not exist.
*/
public void setActive( int index ) {
when( index < 0 ).throwIllegalArgument( "Index must be positive but was " + index );
when( index > ( count - 1 ) ).throwIllegalState( "Index " + index + " does not exist. Count is " + count + "." );
this.activeIndex = index;
update();
}
/**
* <p>
* Returns the index of the active bullet.
* </p>
*/
public int getActive() {
return activeIndex;
}
/**
* <p>
* Sets the color of the active bullet.
* </p>
*
* @param activeColor the color to use for active bullets. Must not be <code>null</code>.
*/
public void setActiveColor( Color activeColor ) {
whenNull( activeColor ).throwIllegalArgument( "Active color must not be null" );
this.activeColor = activeColor;
update();
}
/**
* <p>
* Returns the active color.
* </p>
*/
public Color getActiveColor() {
return activeColor;
}
/**
* <p>
* Sets the color of the inactive bullets.
* </p>
*
* @param inactiveColor the color to use for inactive bullets. Must not be <code>null</code>.
*/
public void setInactiveColor( Color inactiveColor ) {
whenNull( inactiveColor ).throwIllegalArgument( "Inactive color must not be null" );
this.inactiveColor = inactiveColor;
update();
}
/**
* <p>
* Returns the inactive color.
* </p>
*/
public Color getInactiveColor() {
return inactiveColor;
}
/**
* <p>
* Sets the spacing used between bullets.
* </p>
*
* @param spacing the spacing to use in pixel. Must be >= 0.
*/
public void setSpacing( int spacing ) {
when( spacing < 0 ).throwIllegalArgument( "Spacing must be positive but was " + spacing );
this.spacing = spacing;
update();
}
/**
* <p>
* Returns the spacing used between bullets.
* </p>
*/
public int getSpacing() {
return spacing;
}
/**
* <p>
* Sets the diameter of the bullets.
* </p>
*
* @param diameter the diameter to use for the bullets. Must be >= 0.
*/
public void setDiameter( int diameter ) {
when( diameter < 0 ).throwIllegalArgument( "Diameter must be positive but was " + diameter );
this.diameter = diameter;
update();
}
public int getDiameter() {
return diameter;
}
@Override
public void update() {
super.update();
updateSize();
drawIndicators();
getParent().layout( true, true );
}
private void updateSize() {
int width = ( getCount() * diameter ) + ( Math.max( 0, getCount() - 1 ) * spacing );
indicatorCanvas.setSize( width, diameter );
GridData gd = ( GridData )indicatorCanvas.getLayoutData();
gd.heightHint = diameter;
gd.widthHint = width;
}
private void drawIndicators() {
drawIndicators( new GC( indicatorCanvas ) );
}
private void drawIndicators( GC gc ) {
for( int i = 0; i < getCount(); i++ ) {
if( i == getActive() ) {
gc.setBackground( getActiveColor() );
} else {
gc.setBackground( getInactiveColor() );
}
int x = ( getDiameter() + getSpacing() ) * i;
gc.fillOval( x, 0, getDiameter(), getDiameter() );
}
gc.dispose();
}
Canvas getCanvas() {
return indicatorCanvas;
}
}