/*
* Copyright (c) 1997, 2011, Oracle and/or its affiliates. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* - Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* - Neither the name of Oracle nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
* IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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*/
/*
* This source code is provided to illustrate the usage of a given feature
* or technique and has been deliberately simplified. Additional steps
* required for a production-quality application, such as security checks,
* input validation and proper error handling, might not be present in
* this sample code.
*/
import java.applet.Applet;
import java.awt.AWTEvent;
import java.awt.BorderLayout;
import java.awt.Button;
import java.awt.Canvas;
import java.awt.Choice;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.FontMetrics;
import java.awt.Frame;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.Label;
import java.awt.LayoutManager;
import java.awt.Panel;
import java.awt.TextField;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.event.TextEvent;
import java.awt.image.ColorModel;
import java.awt.image.MemoryImageSource;
enum DitherMethod {
NOOP, RED, GREEN, BLUE, ALPHA, SATURATION
};
@SuppressWarnings("serial")
public class DitherTest extends Applet implements Runnable {
private Thread runner;
private DitherControls XControls;
private DitherControls YControls;
private DitherCanvas canvas;
public static void main(String args[]) {
Frame f = new Frame("DitherTest");
DitherTest ditherTest = new DitherTest();
ditherTest.init();
f.add("Center", ditherTest);
f.pack();
f.setVisible(true);
ditherTest.start();
}
@Override
public void init() {
String xspec = null, yspec = null;
int xvals[] = new int[2];
int yvals[] = new int[2];
try {
xspec = getParameter("xaxis");
yspec = getParameter("yaxis");
} catch (NullPointerException ignored) {
//only occurs if run as application
}
if (xspec == null) {
xspec = "red";
}
if (yspec == null) {
yspec = "blue";
}
DitherMethod xmethod = colorMethod(xspec, xvals);
DitherMethod ymethod = colorMethod(yspec, yvals);
setLayout(new BorderLayout());
XControls = new DitherControls(this, xvals[0], xvals[1],
xmethod, false);
YControls = new DitherControls(this, yvals[0], yvals[1],
ymethod, true);
YControls.addRenderButton();
add("North", XControls);
add("South", YControls);
add("Center", canvas = new DitherCanvas());
}
private DitherMethod colorMethod(String s, int vals[]) {
DitherMethod method = DitherMethod.NOOP;
if (s == null) {
s = "";
}
String lower = s.toLowerCase();
for (DitherMethod m : DitherMethod.values()) {
if (lower.startsWith(m.toString().toLowerCase())) {
method = m;
lower = lower.substring(m.toString().length());
}
}
if (method == DitherMethod.NOOP) {
vals[0] = 0;
vals[1] = 0;
return method;
}
int begval = 0;
int endval = 255;
try {
int dash = lower.indexOf('-');
if (dash < 0) {
endval = Integer.parseInt(lower);
} else {
begval = Integer.parseInt(lower.substring(0, dash));
endval = Integer.parseInt(lower.substring(dash + 1));
}
} catch (NumberFormatException ignored) {
}
if (begval < 0) {
begval = 0;
} else if (begval > 255) {
begval = 255;
}
if (endval < 0) {
endval = 0;
} else if (endval > 255) {
endval = 255;
}
vals[0] = begval;
vals[1] = endval;
return method;
}
/**
* Calculates and returns the image. Halts the calculation and returns
* null if the Applet is stopped during the calculation.
*/
private Image calculateImage() {
Thread me = Thread.currentThread();
int width = canvas.getSize().width;
int height = canvas.getSize().height;
int xvals[] = new int[2];
int yvals[] = new int[2];
int xmethod = XControls.getParams(xvals);
int ymethod = YControls.getParams(yvals);
int pixels[] = new int[width * height];
int c[] = new int[4]; //temporarily holds R,G,B,A information
int index = 0;
for (int j = 0; j < height; j++) {
for (int i = 0; i < width; i++) {
c[0] = c[1] = c[2] = 0;
c[3] = 255;
if (xmethod < ymethod) {
applyMethod(c, xmethod, i, width, xvals);
applyMethod(c, ymethod, j, height, yvals);
} else {
applyMethod(c, ymethod, j, height, yvals);
applyMethod(c, xmethod, i, width, xvals);
}
pixels[index++] = ((c[3] << 24) | (c[0] << 16) | (c[1] << 8)
| c[2]);
}
// Poll once per row to see if we've been told to stop.
if (runner != me) {
return null;
}
}
return createImage(new MemoryImageSource(width, height,
ColorModel.getRGBdefault(), pixels, 0, width));
}
private void applyMethod(int c[], int methodIndex, int step,
int total, int vals[]) {
DitherMethod method = DitherMethod.values()[methodIndex];
if (method == DitherMethod.NOOP) {
return;
}
int val = ((total < 2)
? vals[0]
: vals[0] + ((vals[1] - vals[0]) * step / (total - 1)));
switch (method) {
case RED:
c[0] = val;
break;
case GREEN:
c[1] = val;
break;
case BLUE:
c[2] = val;
break;
case ALPHA:
c[3] = val;
break;
case SATURATION:
int max = Math.max(Math.max(c[0], c[1]), c[2]);
int min = max * (255 - val) / 255;
if (c[0] == 0) {
c[0] = min;
}
if (c[1] == 0) {
c[1] = min;
}
if (c[2] == 0) {
c[2] = min;
}
break;
}
}
@Override
public void start() {
runner = new Thread(this);
runner.start();
}
@Override
public void run() {
canvas.setImage(null); // Wipe previous image
Image img = calculateImage();
if (img != null && runner == Thread.currentThread()) {
canvas.setImage(img);
}
}
@Override
public void stop() {
runner = null;
}
@Override
public void destroy() {
remove(XControls);
remove(YControls);
remove(canvas);
}
@Override
public String getAppletInfo() {
return "An interactive demonstration of dithering.";
}
@Override
public String[][] getParameterInfo() {
String[][] info = {
{ "xaxis", "{RED, GREEN, BLUE, ALPHA, SATURATION}",
"The color of the Y axis. Default is RED." },
{ "yaxis", "{RED, GREEN, BLUE, ALPHA, SATURATION}",
"The color of the X axis. Default is BLUE." }
};
return info;
}
}
@SuppressWarnings("serial")
class DitherCanvas extends Canvas {
private Image img;
private static String calcString = "Calculating...";
@Override
public void paint(Graphics g) {
int w = getSize().width;
int h = getSize().height;
if (img == null) {
super.paint(g);
g.setColor(Color.black);
FontMetrics fm = g.getFontMetrics();
int x = (w - fm.stringWidth(calcString)) / 2;
int y = h / 2;
g.drawString(calcString, x, y);
} else {
g.drawImage(img, 0, 0, w, h, this);
}
}
@Override
public void update(Graphics g) {
paint(g);
}
@Override
public Dimension getMinimumSize() {
return new Dimension(20, 20);
}
@Override
public Dimension getPreferredSize() {
return new Dimension(200, 200);
}
public Image getImage() {
return img;
}
public void setImage(Image img) {
this.img = img;
repaint();
}
}
@SuppressWarnings("serial")
class DitherControls extends Panel implements ActionListener {
private CardinalTextField start;
private CardinalTextField end;
private Button button;
private Choice choice;
private DitherTest applet;
private static LayoutManager dcLayout = new FlowLayout(FlowLayout.CENTER,
10, 5);
public DitherControls(DitherTest app, int s, int e, DitherMethod type,
boolean vertical) {
applet = app;
setLayout(dcLayout);
add(new Label(vertical ? "Vertical" : "Horizontal"));
add(choice = new Choice());
for (DitherMethod m : DitherMethod.values()) {
choice.addItem(m.toString().substring(0, 1)
+ m.toString().substring(1).toLowerCase());
}
choice.select(type.ordinal());
add(start = new CardinalTextField(Integer.toString(s), 4));
add(end = new CardinalTextField(Integer.toString(e), 4));
}
/* puts on the button */
public void addRenderButton() {
add(button = new Button("New Image"));
button.addActionListener(this);
}
/* retrieves data from the user input fields */
public int getParams(int vals[]) {
try {
vals[0] = scale(Integer.parseInt(start.getText()));
} catch (NumberFormatException nfe) {
vals[0] = 0;
}
try {
vals[1] = scale(Integer.parseInt(end.getText()));
} catch (NumberFormatException nfe) {
vals[1] = 255;
}
return choice.getSelectedIndex();
}
/* fits the number between 0 and 255 inclusive */
private int scale(int number) {
if (number < 0) {
number = 0;
} else if (number > 255) {
number = 255;
}
return number;
}
/* called when user clicks the button */
@Override
public void actionPerformed(ActionEvent e) {
if (e.getSource() == button) {
applet.start();
}
}
}
@SuppressWarnings("serial")
class CardinalTextField extends TextField {
String oldText = null;
public CardinalTextField(String text, int columns) {
super(text, columns);
enableEvents(AWTEvent.KEY_EVENT_MASK | AWTEvent.TEXT_EVENT_MASK);
oldText = getText();
}
// Consume non-digit KeyTyped events
// Note that processTextEvent kind of eliminates the need for this
// function, but this is neater, since ideally, it would prevent
// the text from appearing at all. Sigh. See bugid 4100317/4114565.
//
@Override
protected void processEvent(AWTEvent evt) {
int id = evt.getID();
if (id != KeyEvent.KEY_TYPED) {
super.processEvent(evt);
return;
}
KeyEvent kevt = (KeyEvent) evt;
char c = kevt.getKeyChar();
// Digits, backspace, and delete are okay
// Note that the minus sign is not allowed (neither is decimal)
if (Character.isDigit(c) || (c == '\b') || (c == '\u007f')) {
super.processEvent(evt);
return;
}
Toolkit.getDefaultToolkit().beep();
kevt.consume();
}
// Should consume TextEvents for non-integer Strings
// Store away the text in the tf for every TextEvent
// so we can revert to it on a TextEvent (paste, or
// legal key in the wrong location) with bad text
//
// Note: it would be easy to extend this to an eight-bit
// TextField (range 0-255), but I'll leave it as-is.
//
@Override
protected void processTextEvent(TextEvent te) {
// The empty string is okay, too
String newText = getText();
if (newText.equals("") || textIsCardinal(newText)) {
oldText = newText;
super.processTextEvent(te);
return;
}
Toolkit.getDefaultToolkit().beep();
setText(oldText);
}
// Returns true for Cardinal (non-negative) numbers
// Note that the empty string is not allowed
private boolean textIsCardinal(String textToCheck) {
try {
return Integer.parseInt(textToCheck, 10) >= 0;
} catch (NumberFormatException nfe) {
return false;
}
}
}