examples/org.eclipse.swt.examples/src/org/eclipse/swt/examples/graphics/InterpolationTab.java

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

import org.eclipse.swt.*;
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.layout.*;
import org.eclipse.swt.widgets.*;

/**
 * This tab shows the effects of applying various interpolation algorithms to
 * images that have been stretched or shrunk.
 */
public class InterpolationTab extends GraphicsTab {
	
	Combo imageCb;	// combo for selecting images

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

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

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

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

public void createControlPanel(Composite parent) {
	
	Composite comp;
	GridLayout gridLayout = new GridLayout(2, false);
	
	// create drop down combo 
	comp = new Composite(parent, SWT.NONE);
	comp.setLayout(gridLayout);
	new Label(comp, SWT.CENTER).setText(GraphicsExample
				.getResourceString("Image")); //$NON-NLS-1$
	imageCb = new Combo(comp, SWT.DROP_DOWN);
	imageCb.add(GraphicsExample.getResourceString("House")); //$NON-NLS-1$
	imageCb.add(GraphicsExample.getResourceString("Question")); //$NON-NLS-1$
	imageCb.add(GraphicsExample.getResourceString("Task")); //$NON-NLS-1$
	imageCb.add(GraphicsExample.getResourceString("Font")); //$NON-NLS-1$
	imageCb.add(GraphicsExample.getResourceString("Cube")); //$NON-NLS-1$
	imageCb.add(GraphicsExample.getResourceString("SWT")); //$NON-NLS-1$
	imageCb.add(GraphicsExample.getResourceString("Ovals")); //$NON-NLS-1$
	imageCb.select(0);
	imageCb.addListener(SWT.Selection, new Listener() {
		public void handleEvent(Event event) {
				example.redraw();
		}
	});
}

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

	float scaleX = 10f;
	float scaleY = 10f;
	Image image = null;
	switch (imageCb.getSelectionIndex()) {
	
	case 0:
		image = GraphicsExample.loadImage(device, GraphicsExample.class, "home_nav.gif");
		break;
	case 1:
		image = GraphicsExample.loadImage(device, GraphicsExample.class, "help.gif");
		break;
	case 2:
		image = GraphicsExample.loadImage(device, GraphicsExample.class, "task.gif");
		break;
	case 3:
		image = GraphicsExample.loadImage(device, GraphicsExample.class, "font.gif");
		break;
	case 4:
		image = GraphicsExample.loadImage(device, GraphicsExample.class, "cube.png");
		scaleX = 0.75f;
		scaleY = 0.5f;
		break;
	case 5:
		image = GraphicsExample.loadImage(device, GraphicsExample.class, "swt.png");
		scaleX = 0.4f;
		scaleY = 0.8f;
		break;
	case 6:
		image = GraphicsExample.loadImage(device, GraphicsExample.class, "ovals.png");
		scaleX = 1.1f;
		scaleY = 0.5f;
		break;
	}
	
	Rectangle bounds = image.getBounds();
	
	// draw the original image
	gc.drawImage(image, (width-bounds.width)/2, 20);	
	
	Font font = new Font(device, getPlatformFont(), 20, SWT.NORMAL);
	gc.setFont(font);
	
	// write some text below the original image
	String text = GraphicsExample.getResourceString("OriginalImg"); //$NON-NLS-1$
	Point size = gc.stringExtent(text);	
	gc.drawString(text, (width-size.x)/2, 25 + bounds.height, true);
	
	Transform transform = new Transform(device);
	transform.translate((width - (bounds.width * scaleX + 10) * 4) / 2, 25 + bounds.height + size.y +
				(height - (25 + bounds.height + size.y + bounds.height*scaleY)) / 2);
	transform.scale(scaleX, scaleY);

	// --- draw strings ---
	float[] point = new float[2];
	text = GraphicsExample.getResourceString("None"); //$NON-NLS-1$
	size = gc.stringExtent(text);	
	point[0] = (scaleX*bounds.width + 5 - size.x)/(2*scaleX);
	point[1] = bounds.height;
	transform.transform(point);
	gc.drawString(text, (int)point[0], (int)point[1], true);
	
	text = GraphicsExample.getResourceString("Low"); //$NON-NLS-1$
	size = gc.stringExtent(text);
	point[0] = (scaleX*bounds.width + 5 - size.x)/(2*scaleX) + bounds.width;
	point[1] = bounds.height;
	transform.transform(point);
	gc.drawString(text, (int)point[0], (int)point[1], true);
	
	text = GraphicsExample.getResourceString("Default"); //$NON-NLS-1$
	size = gc.stringExtent(text);
	point[0] = (scaleX*bounds.width + 5 - size.x)/(2*scaleX) + 2*bounds.width;
	point[1] = bounds.height;
	transform.transform(point);
	gc.drawString(text, (int)point[0], (int)point[1], true);
	
	text = GraphicsExample.getResourceString("High"); //$NON-NLS-1$
	size = gc.stringExtent(text);
	point[0] = (scaleX*bounds.width + 5 - size.x)/(2*scaleX) + 3*bounds.width;
	point[1] = bounds.height;
	transform.transform(point);
	gc.drawString(text, (int)point[0], (int)point[1], true);

	gc.setTransform(transform);
	transform.dispose();

	// --- draw images ---
	
	// no interpolation
	gc.setInterpolation(SWT.NONE);
	gc.drawImage(image, 0, 0);
	
	// low interpolation
	gc.setInterpolation(SWT.LOW);
	gc.drawImage(image, bounds.width, 0);

	// default interpolation
	gc.setInterpolation(SWT.DEFAULT);
	gc.drawImage(image, 2*bounds.width, 0);
	
	// high interpolation
	gc.setInterpolation(SWT.HIGH);
	gc.drawImage(image, 3*bounds.width, 0);

	font.dispose();
	if (image != null) image.dispose();
}

/**
 * Returns the name of a valid font for the host platform.
 */
static String getPlatformFont() {
	if(SWT.getPlatform() == "win32") {
		return "Arial";	
	} else if (SWT.getPlatform() == "motif") {
		return "Helvetica";		
	} else if (SWT.getPlatform() == "gtk") {
		return "Baekmuk Batang";		
	} else if (SWT.getPlatform() == "carbon") {
		return "Arial";
	} else { // photon, etc ...
		return "Verdana";
	}
}
}