/*******************************************************************************
 * Copyright (c) 2006, 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.examples.graphics;

import org.eclipse.swt.SWT;
import org.eclipse.swt.graphics.Device;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.Path;
import org.eclipse.swt.graphics.Pattern;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.graphics.Transform;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Label;
import org.eclipse.swt.widgets.Menu;
import org.eclipse.swt.widgets.Spinner;

/**
 * This tab demonstrates the use of alpha blending. It allows a user to specify
 * a custom alpha value.
 */
public class CustomAlphaTab extends AnimatedGraphicsTab {

	private Spinner alphaSpinner;
	private Button colorButton;
	private GraphicsBackground background;
	private Menu menu;
	private int angle;

public CustomAlphaTab(GraphicsExample example) {
	super(example);
}

@Override
public String getCategory() {
	return GraphicsExample.getResourceString("Alpha"); //$NON-NLS-1$
}

@Override
public String getText() {
	return GraphicsExample.getResourceString("CustomAlpha"); //$NON-NLS-1$
}

@Override
public String getDescription() {
	return GraphicsExample.getResourceString("CustomAlphaDescription"); //$NON-NLS-1$
}

@Override
public void dispose() {
	if (menu != null) {
		menu.dispose();
		menu = null;
	}
}

/**
 * Creates the widgets used to control the drawing.
 */
@Override
public void createControlPanel(Composite parent) {
	super.createControlPanel(parent);

	// create drop down combo for choosing clipping
	Composite comp;

	// create spinner for line width
	comp = new Composite(parent, SWT.NONE);
	comp.setLayout(new GridLayout(2, false));
	new Label(comp, SWT.CENTER).setText(GraphicsExample
				.getResourceString("Alpha")); //$NON-NLS-1$
	alphaSpinner = new Spinner(comp, SWT.BORDER | SWT.WRAP);
	alphaSpinner.setMinimum(0);
	alphaSpinner.setMaximum(255);
	alphaSpinner.setSelection(127);
	alphaSpinner.addListener(SWT.Selection, event -> example.redraw());

	// color menu
	ColorMenu cm = new ColorMenu();
	cm.setPatternItems(example.checkAdvancedGraphics());
	menu = cm.createMenu(parent.getParent(), gb -> {
		background = gb;
		colorButton.setImage(gb.getThumbNail());
		example.redraw();
	});

	// initialize the background to the 5th item in the menu (blue)
	background = (GraphicsBackground)menu.getItem(4).getData();

	// color button
	comp = new Composite(parent, SWT.NONE);
	comp.setLayout(new GridLayout(2, false));

	colorButton = new Button(comp, SWT.PUSH);
	colorButton.setText(GraphicsExample
			.getResourceString("Color")); //$NON-NLS-1$
	colorButton.setImage(background.getThumbNail());
	colorButton.addListener(SWT.Selection, event -> {
		final Button button = (Button) event.widget;
		final Composite parent1 = button.getParent();
		Rectangle bounds = button.getBounds();
		Point point = parent1.toDisplay(new Point(bounds.x, bounds.y));
		menu.setLocation(point.x, point.y + bounds.height);
		menu.setVisible(true);
	});
}

@Override
public void next(int width, int height) {

	angle = (angle+1)%360;
}

@Override
public void paint(GC gc, int width, int height) {
	if (!example.checkAdvancedGraphics()) return;
	Device device = gc.getDevice();

	Pattern pattern = null;
	if (background.getBgColor1() != null) {
		gc.setBackground(background.getBgColor1());
	} else if (background.getBgImage() != null) {
		pattern = new Pattern(device, background.getBgImage());
		gc.setBackgroundPattern(pattern);
	}

	gc.setAntialias(SWT.ON);
	gc.setAlpha(alphaSpinner.getSelection());

	// rotate on center
	Transform transform = new Transform(device);
	transform.translate(width/2, height/2);
	transform.rotate(-angle);
	transform.translate(-width/2, -height/2);
	gc.setTransform(transform);
	transform.dispose();

	// choose the smallest between height and width
	int diameter = (height < width) ? height : width;

	Path path = new Path(device);
	path.addArc((width-diameter/5)/2, (height-diameter/5)/2, diameter/5, diameter/5, 0, 360);
	path.addArc(5*(width-diameter/8)/12, 4*(height-diameter/8)/12, diameter/8, diameter/8, 0, 360);
	path.addArc(7*(width-diameter/8)/12, 8*(height-diameter/8)/12, diameter/8, diameter/8, 0, 360);
	path.addArc(6*(width-diameter/12)/12, 3*(height-diameter/12)/12, diameter/12, diameter/12, 0, 360);
	path.addArc(6*(width-diameter/12)/12, 9*(height-diameter/12)/12, diameter/12, diameter/12, 0, 360);
	path.addArc(11.5f*(width-diameter/18)/20, 5*(height-diameter/18)/18, diameter/18, diameter/18, 0, 360);
	path.addArc(8.5f*(width-diameter/18)/20, 13*(height-diameter/18)/18, diameter/18, diameter/18, 0, 360);
	path.addArc(62f*(width-diameter/25)/100, 32*(height-diameter/25)/100, diameter/25, diameter/25, 0, 360);
	path.addArc(39f*(width-diameter/25)/100, 67*(height-diameter/25)/100, diameter/25, diameter/25, 0, 360);

	gc.fillPath(path);
	path.dispose();

    if (pattern != null) pattern.dispose();
}
}
