I have the image of a circle of size 256 x 256. The circle can be created by using a function B(i,j). By using a Java producer and consumer model, how can I create a java program to draw the circle?
The code in this image is using the octave code.
Here's the Java Swing GUI I created.
I created (or produced) the image in the CreateImage class. I used the code in your problem image, except I didn't take the square root. Comparing the squares of the numbers was faster.
I drew (or consumed) the image on a JPanel. I'm not going to explain the Swing code in great detail. I wrote what I needed to write to display the image.
Here's the code:
package com.ggl.testing;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.image.BufferedImage;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class DrawImage implements Runnable {
public static void main(String[] args) {
SwingUtilities.invokeLater(new DrawImage());
}
#Override
public void run() {
Image image = new CreateImage(256, 256, 80).createImage();
JFrame frame = new JFrame("Image of a circle");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new DrawingPanel(256, 256, image));
frame.pack();
frame.setVisible(true);
}
public class DrawingPanel extends JPanel {
private static final long serialVersionUID = 1584647402715684757L;
private Image image;
public DrawingPanel(int width, int height, Image image) {
this.image = image;
this.setPreferredSize(new Dimension(width, height));
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawImage(image, 0, 0, this);
}
}
public class CreateImage {
private int width;
private int height;
private int radius;
public CreateImage(int width, int height, int radius) {
this.width = width;
this.height = height;
this.radius = radius;
}
public Image createImage() {
int circleRadiusSquared = radius * radius;
BufferedImage image = new BufferedImage(width, height,
BufferedImage.TYPE_INT_RGB);
Graphics g = image.getGraphics();
for (int i = 0; i < width; i++) {
int idist = i - width / 2;
for (int j = 0; j < height; j++) {
int jdist = j - height / 2;
int distSquared = idist * idist + jdist * jdist;
if (distSquared < circleRadiusSquared) {
g.setColor(Color.WHITE);
} else {
g.setColor(Color.BLACK);
}
g.drawLine(i, j, i, j);
}
}
g.dispose();
return image;
}
}
}
Related
The code creates a JFrame with a JPanel onto which it draws an image loaded from a file. The objective is to make a rectangular area of the picture, such as for example the red square, appear darker than the rest. I'm assuming this may involve taking a subimage of the image, looping through an array of pixels, scaling them, and then painting that subimage onto the JPanel, but I don't know how to do this using the Java API.
package SpriteEditor_Tests;
import java.awt.*;
import java.awt.event.*;
import java.awt.image.*;
import java.io.*;
import javax.imageio.*;
import javax.swing.*;
public class ImageTestApp extends JFrame
{
public BufferedImage image;
int x1 = 50;
int x2 = 100;
int y1 = 50;
int y2 = 100;
public static void main (String [] args)
{
new ImageTestApp();
}
public ImageTestApp()
{
setTitle("Image Test App");
try
{
image = ImageIO.read(new File("C:/Users/Paul/Desktop/derp.png"));
}
catch (IOException io)
{
System.out.println("IO caught"); System.exit(0);
}
setSize(500,500);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setVisible(true);
add(new ImageDisplay());
}
class ImageDisplay extends JPanel
{
public void paintComponent(Graphics g)
{
g.drawImage(image, -100, -100, getWidth(), getHeight(), Color.RED, null);
g.setColor(Color.RED);
g.drawRect(x1, y1, Math.abs(x2 - x1), Math.abs(y2 - y1));
}
}
}
A "simple" solution would be to just create a new instance of Color with the desired alpha applied to it and fill the area you want darkened.
This is great if you have a color you want to use, but when I want to use a predefined color, it's not as simple. Instead, I prefer to use an AlphaComposite as it gives me some advantages.
import java.awt.AlphaComposite;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.awt.image.BufferedImage;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class Test {
public static void main(String[] args) {
new Test();
}
public Test() {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
JFrame frame = new JFrame();
frame.add(new TestPane());
frame.pack();
frame.setVisible(true);
}
});
}
public class TestPane extends JPanel {
private BufferedImage background;
public TestPane() {
try {
background = ImageIO.read(getClass().getResource("/images/background.jpg"));
} catch (IOException ex) {
ex.printStackTrace();
}
}
#Override
public Dimension getPreferredSize() {
if (background == null) {
return new Dimension(200, 200);
}
return new Dimension(background.getWidth(), background.getHeight());
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
if (background == null) {
return;
}
Graphics2D g2d = (Graphics2D) g.create();
g2d.drawImage(background, 0, 0, this);
int x = (getWidth() - 100) / 2;
int y = (getHeight() - 100) / 2;
Rectangle rect = new Rectangle(x, y, 200, 200);
g2d.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER, 0.5f));
g2d.fill(rect);
g2d.dispose();
g2d = (Graphics2D) g.create();
g2d.setColor(Color.RED);
g2d.drawRect(x, y, 200, 200);
g2d.dispose();
}
}
}
Now, if want to generate a new image with the are darkened, you can follow the same basic concept, but instead of painting to the components Graphics context, you'd paint directly to the BufferedImages Graphics content. This is the wonderful power of the abstract nature of the Graphics API.
Don't forget, when you override a method, you are obliged to either over take ALL of its responsibilities or call its super implementation.
paintComponent does some basic, but important work and you should make sure to call super.paintComponent before you start performing your custom painting, this will just reduce any possibility of issues.
Darken each pixel individually
Okay, if, instead, you want to darken each pixel in the rectangle individually, this becomes a "little" more complicated, but not hard.
After a lot of time and testing, I settled on using the follow algorithm to darken a given color. This will push the color towards "black" the more you darken it, which some algorithms don't do.
public static Color darken(Color color, double fraction) {
int red = (int) Math.round(Math.max(0, color.getRed() - 255 * fraction));
int green = (int) Math.round(Math.max(0, color.getGreen() - 255 * fraction));
int blue = (int) Math.round(Math.max(0, color.getBlue() - 255 * fraction));
int alpha = color.getAlpha();
return new Color(red, green, blue, alpha);
}
Then, all you have to do is get the the color of the pixel, darken it and reapply.
For this example, I actually use a separate sub image, but you can do it directly to the parent image
BufferedImage subImage = background.getSubimage(x, y, 200, 200);
for (int row = 0; row < subImage.getHeight(); row++) {
for (int col = 0; col < subImage.getWidth(); col++) {
int packedPixel = subImage.getRGB(col, row);
Color color = new Color(packedPixel, true);
color = darken(color, 0.5);
subImage.setRGB(col, row, color.getRGB());
}
}
Now, before someone jumps down my throat, no, this is not the most performant approach, but it gets over messing about with "packed" pixel values (because I can never remember how to unpack those :P) and most of my API code is based around the use of Color anyway
Runnable example...
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class Test {
public static void main(String[] args) {
new Test();
}
public Test() {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
JFrame frame = new JFrame();
frame.add(new TestPane());
frame.pack();
frame.setVisible(true);
}
});
}
public static Color darken(Color color, double fraction) {
int red = (int) Math.round(Math.max(0, color.getRed() - 255 * fraction));
int green = (int) Math.round(Math.max(0, color.getGreen() - 255 * fraction));
int blue = (int) Math.round(Math.max(0, color.getBlue() - 255 * fraction));
int alpha = color.getAlpha();
return new Color(red, green, blue, alpha);
}
public class TestPane extends JPanel {
private BufferedImage background;
private BufferedImage darkended;
public TestPane() {
try {
background = ImageIO.read(getClass().getResource("/images/background.jpg"));
int x = (background.getWidth() - 100) / 2;
int y = (background.getHeight() - 100) / 2;
BufferedImage subImage = background.getSubimage(x, y, 200, 200);
for (int row = 0; row < subImage.getHeight(); row++) {
for (int col = 0; col < subImage.getWidth(); col++) {
int packedPixel = subImage.getRGB(col, row);
Color color = new Color(packedPixel, true);
color = darken(color, 0.5);
subImage.setRGB(col, row, color.getRGB());
}
}
darkended = subImage;
} catch (IOException ex) {
ex.printStackTrace();
}
}
#Override
public Dimension getPreferredSize() {
if (background == null) {
return new Dimension(200, 200);
}
return new Dimension(background.getWidth(), background.getHeight());
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
if (background == null) {
return;
}
Graphics2D g2d = (Graphics2D) g.create();
g2d.drawImage(background, 0, 0, this);
int x = (getWidth() - 100) / 2;
int y = (getHeight() - 100) / 2;
g2d.drawImage(darkended, x, y, this);
g2d.setColor(Color.RED);
g2d.drawRect(x, y, 200, 200);
g2d.dispose();
}
}
}
I really need some help with that.
I'm trying to crop an image into a circle and it's fine but the pixels outside the circle stay white. How can I put them transparent?
My code it's:
static ColorImage Circulo(ColorImage img, int radius) {
for (int x=0; x < img.getWidth(); x++ ) {
for(int y=0; y < img.getHeight(); y++) {
if((x - (img.getWidth()/2)) * (x - (img.getWidth()/2)) + (y - (img.getHeight()/2) )* (y - (img.getHeight()/2)) <= (radius*radius)) {
img.setColor(x, y, img.getColor(x, y));
}else {
Color c = new Color (255, 255, 255);
img.setColor(x, y, c );
}
}
}
return img;
}
Try this. This will paint the image on the screen inside a circle. If you want to create a new image, get the Graphics context from a BufferedImage and write the image to that instead of the graphics context in paintComponent. Any image format will work as this does not rely on any transparency mode of the graphics image.
The main idea behind this is setting the clip region to that of a circle. Then whatever you paint will only appear in that region.
In this example, I made the diameter of the circle the minimum of the width and height of the image. This way, the entire circle will fit in a rectangle.
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.RenderingHints;
import java.awt.geom.Ellipse2D;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class ImageInCircle extends JPanel {
JFrame f = new JFrame();
Image img;
int width;
int height;
static String imgFile =
"location/of/image/img.gif";
public static void main(String[] args) {
SwingUtilities.invokeLater(()->new ImageInCircle().start());
}
#Override
public Dimension getPreferredSize() {
return new Dimension(width, height);
}
public ImageInCircle () {
f.add(this);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
public void start() {
try {
img = ImageIO.read(new File(imgFile));
} catch (IOException fne) {
fne.printStackTrace();
}
width = img.getWidth(null);
height = img.getHeight(null);
revalidate();
f.setVisible(true);
f.pack();
f.setLocationRelativeTo(null);
repaint();
}
public void paintComponent(Graphics g) {
super.paintComponent(g);
setBackground(Color.white);
Graphics2D g2 = (Graphics2D) g;
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
int circleDiameter = Math.min(width,height);
Ellipse2D.Double circle = new Ellipse2D.Double(0,0,circleDiameter,circleDiameter);
g2.setClip(circle);
g2.drawImage(img,0,0,this);
}
}
I hope my first post isn't too basic for y'all.
I'm trying to do some per-pixel drawing on a JCanvas using a BufferedImage (using setRGB()). I thought I would test all was working with a single diagonal line from the origin to the width/height of the JCanvas. The trouble is that I get a strange offset in the x axis that I can't seem to fix!
Here's a link to the problem:
http://i811.photobucket.com/albums/zz31/bohngy/problemMandel_zpsae20713a.jpeg
Here's the code:
public class Mandelbrot extends JFrame {
private BufferedImage I;
public Mandelbrot() {
super("Mandelbrot Set");
setSize(600, 600);
setResizable(false);
setDefaultCloseOperation(EXIT_ON_CLOSE);
I = new BufferedImage(getWidth(), getHeight(), BufferedImage.TYPE_INT_RGB);
for (int x = 0; x < getHeight(); x++) {
for (int y = 0; y < getWidth(); y++) {
I.setRGB(x, x, Color.GREEN.getRGB());
}
}
}
#Override
public void paint(Graphics g) {
g.drawImage(I, 0, 0, this);
}
public static void main(String[] args) {
new Mandelbrot().setVisible(true);
}
}
General issues
Don't extend JFrame (particularly, don't override the paint method of JFrame). Instead, do the painting in the paintComponent method a class that extends JPanel
Create the GUI from the Event Dispatch Thread
The main reason for the unexpected result is that you are creating an image that has the size of the frame - but the frame also has a title bar and a border, and these are "covering" parts of the image. The size of the area that is actually available for painting is smaller than the total frame size. Additionally, the getWidth() and getHeight() methods may return garbage as long as the frame is not yet visible on the screen.
One approach considering all this could look like in this snippet:
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.GridLayout;
import java.awt.image.BufferedImage;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class Mandelbrot
{
public static void main(String[] args)
{
SwingUtilities.invokeLater(new Runnable()
{
#Override
public void run()
{
createAndShowGUI();
}
});
}
private static void createAndShowGUI()
{
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().setLayout(new GridLayout(1, 1));
BufferedImage image = createImage(500, 500);
ImagePanel imagePanel = new ImagePanel(image);
frame.getContentPane().add(imagePanel);
frame.pack();
frame.setVisible(true);
}
private static BufferedImage createImage(int w, int h)
{
BufferedImage image = new BufferedImage(w, h,
BufferedImage.TYPE_INT_RGB);
for (int x = 0; x < w; x++)
{
image.setRGB(x, x, Color.GREEN.getRGB());
}
return image;
}
static class ImagePanel extends JPanel
{
private final BufferedImage image;
ImagePanel(BufferedImage image)
{
this.image = image;
}
#Override
public Dimension getPreferredSize()
{
if (super.isPreferredSizeSet())
{
return super.getPreferredSize();
}
return new Dimension(image.getWidth(), image.getHeight());
}
#Override
protected void paintComponent(Graphics g)
{
super.paintComponent(g);
g.drawImage(image, 0, 0, null);
}
}
}
All BufferedImage objects have an upper left corner coordinate of (0, 0). Any Raster used to construct a BufferedImage must therefore have minX=0 and minY=0.
Therein lies your problem.
JavaDoc for BufferedImage
Edit:
Also remove this from your loop:
for (int y = 0; y < getWidth(); y++) {
I.setRGB(x, x, Color.GREEN.getRGB());
}
I created a background using a relatively bland texture (it repeats well, so that's a bonus). However, on top of that, I am trying to add two images in random positions, each five times. So I tried that out with this -
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.Insets;
import java.io.File;
import java.io.IOException;
import java.util.Random;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class RepeatDiagonals {
public static Image whiteOverlayStreak;
public static Image blackOverlayStreak;
public static JFrame framePanel;
public static DiagonalImages diagTest;
public static void createAndInitGUI() {
diagTest = new DiagonalImages();
framePanel = new JFrame("Diagonal Testing");
framePanel.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
framePanel.setPreferredSize(new Dimension(1020, 720));
framePanel.add(diagTest);
framePanel.pack();
framePanel.setVisible(true);
}
public static void main(String[] args) {
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndInitGUI();
} // public void run() Closing
}); // SwingUtilities Closing
}
}
// TODO Add in constructor for better image import
class DiagonalImages extends JPanel {
public static final String IMAGE_PATH_WHITESTREAK = "imageFolder/whiteBackgroundStreakOverlay.png";
public static final String IMAGE_PATH_BLACKSTREAK = "imageFolder/blackBackgroundStreakOverlay.png";
public static Image whiteOverlayStreak;
public static Image blackOverlayStreak;
public static Image overlayStreak;
DiagonalImages() {
loadImages();
setVisible(true);
setOpaque(false);
};
public void loadImages() {
try {
whiteOverlayStreak = ImageIO.read(new File(IMAGE_PATH_WHITESTREAK));
blackOverlayStreak = ImageIO.read(new File(IMAGE_PATH_BLACKSTREAK));
} catch (IOException e) {
e.printStackTrace();
}
}
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g;
Dimension size = this.getSize();
Insets insets = this.getInsets();
int w = size.width - insets.left - insets.right;
int h = size.height - insets.top - insets.bottom;
Random randomInteger = new Random();
randomInteger.nextInt(900);
for (int i = 0; i < 3; i++) {
int x = randomInteger.nextInt() % w;
int y = randomInteger.nextInt() % h;
g2d.drawImage(blackOverlayStreak, x, y, null);
}
for (int i2 = 0; i2 < 5; i2++){
int x2 = randomInteger.nextInt() % w;
int y2 = randomInteger.nextInt() % h;
g2d.drawImage(whiteOverlayStreak, x2, y2, null);
}
}
}
The relevant part of the main code:
// Makes the Initial BorderLayout
allContent = new ImagePanel(image);
allContent.setLayout(new BorderLayout());
allContent.add(new DiagonalImages());
allContent.add(tabbedPane, BorderLayout.CENTER);
allContent.add(logoImage, BorderLayout.NORTH);
allContent.setVisible(true);
allContent.setOpaque(false);
// Add ScrollPane
scrollPane = new JScrollPane(allContent);
scrollPane.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED);
scrollPane.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
scrollPane.getVerticalScrollBar().setUnitIncrement(10);
scrollPane.setOpaque(false);
scrollPane.getViewport().setOpaque(false);
scrollPane.setBorder(new EmptyBorder(0, 0, 0, 0));
scrollPane.setWheelScrollingEnabled(true);
// JFrame programFrame Constructors
programFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
programFrame.setLayout(new BorderLayout());
programFrame.add(scrollPane);
programFrame.pack();
programFrame.setVisible(true);
programFrame.setResizable(true);
programFrame.setSize(1280, 720);
programFrame.setLocationRelativeTo(null);
And here's the ImagePanel I have:
import java.awt.Graphics;
import java.awt.Image;
import javax.swing.JPanel;
class ImagePanel extends JPanel {
private Image image;
private boolean tile;
ImagePanel(Image image) {
this.image = image;
this.tile = false;
};
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
int iw = image.getWidth(this);
int ih = image.getHeight(this);
if (iw > 0 && ih > 0) {
for (int x = 0; x < getWidth(); x += iw) {
for (int y = 0; y < getHeight(); y += ih) {
g.drawImage(image, x, y, iw, ih, this);
}
}
}
}
}
Thanks for the (future) help!
EDIT: Made a small change based on the answer given, and it's still not working.
Okay, so the problem is that the image that's supposed to be repeated isn't actually even showing up.
EDIT2: Rewrote my entire code for this, and it's still not working. Even setting the background color isn't working, which leads me to believe it's a problem with my paintComponent.
EDIT3: paintComponent is working thanks to help. My final problem is getting it to work correctly in my main method.
First JFrame.setVisible(true); should be done last, after pack() which does layouting.
framePanel.pack();
framePanel.setVisible(true);
The images maybe better reside in the application (jar) itself, then you can use getClass().getResource("...").
They should be loaded outside paint, say in the constructor. I guess, it was test code.
public static Image whiteOverlayStreak;
public static Image blackOverlayStreak;
DiagonalImages() {
loadImages();
}
private void loadImages() {
whiteOverlayStreak = new ImageIcon(
getClass().getResource("/white.jpg")).getImage();
blackOverlayStreak = new ImageIcon(
getClass().getResource("/black.jpg")).getImage();
}
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g;
int x = r.nextInt(w);
int y = r.nextInt(h);
Your failure was not using #Override because then you would have seen, that you miswrote Graphics2D g instead of Graphics g. The function paintComponent never got called! LoL
Additional question: adding a second panel
framePanel.setLayout(new BorderLayout());
framePanel.add(diagTest, BorderLayout.CENTER);
framePanel.add(otherPanel, BorderLayout.SOUTH);
It wasn't really an SSCCE.
I haven't tested this fully, mainly because I didn't want to have to set up an entire Eclipse project just to point out the obvious mistake.
Separate the image process from the JPanel.
Only extend Swing components when you're modifying a component method.
Here's my version of your code. I had to modify your code to read an image to get it to work. You're going to have to figure out that part of the code yourself.
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.Insets;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.Random;
import javax.imageio.ImageIO;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
class GUIImages {
private Image whiteDiagonal;
// private Image blackDiagonal;
public GUIImages() {
loadImages();
}
private void loadImages() {
try {
whiteDiagonal = ImageIO.read(new File(
"C:/Documents and Settings/BOP00082/" +
"My Documents/My Pictures/Places-icon.png"));
} catch (IOException e) {
e.printStackTrace();
}
// whiteDiagonal = new ImageIcon(this.getClass().getResource(
// "imageFolder/whiteBackgroundStreakOverlay.png")).getImage();
// blackDiagonal = new ImageIcon(this.getClass().getResource(
// "imageFolder/blackBackgroundStreakOverlay.png")).getImage();
}
public void doDrawing(JPanel panel, Graphics g) {
Graphics2D g2d = (Graphics2D) g;
g2d.drawImage(createDiagonalImage(panel), 0, 0, null);
}
private Image createDiagonalImage(JPanel panel) {
BufferedImage buffImg = new BufferedImage(677, 856,
BufferedImage.TYPE_INT_ARGB);
Graphics2D gbi = buffImg.createGraphics();
Dimension size = panel.getSize();
Insets insets = panel.getInsets();
int w = size.width - insets.left - insets.right;
int h = size.height - insets.top - insets.bottom;
Random r = new Random();
for (int i = 0; i < 5; i++) {
int x = Math.abs(r.nextInt()) % w;
int y = Math.abs(r.nextInt()) % h;
gbi.drawImage(whiteDiagonal, x, y, null);
}
gbi.dispose();
return buffImg;
}
}
class Surface extends JPanel {
GUIImages images;
public Surface(GUIImages images) {
this.images = images;
}
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
images.doDrawing(this, g);
}
}
public class RepeatDiagonals implements Runnable {
JFrame frame;
#Override
public void run() {
frame = new JFrame();
frame.setTitle("Repeat Diagonals");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new Surface(new GUIImages()));
frame.setSize(350, 250);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new RepeatDiagonals());
}
}
I want to draw a PARTIALLY transparent image on top of another (Making shadows over things). I am currently using java's Graphics2D class to render, I've been told to set the composite to AlphaComposite, but that only sets it completely transparent.
Can I do this with my current setup? What do I have to do to fix this?
This is the code I was told that would make it partially transparent:
AlphaComposite ac = java.awt.AlphaComposite.getInstance(AlphaComposite.CLEAR, 0.5F);
g.setComposite(ac);
(I am using png images by the way)
Heres your sscce (these are all in different classes but i put them together for simplicity) (I use an image called "Test" in the local folder "Images", you can use whatever for this as long as it is a png Image named the same
import java.awt.AlphaComposite;
import java.awt.Color;
import java.awt.DisplayMode;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.Window;
import javax.swing.ImageIcon;
import com.blazingkin.atrox.ScreenManager;
public class AtroxAdventrum{
public static void main(String[] args) {
new AtroxAdventrum().run();
}
private static DisplayMode modes[] = {
//new DisplayMode(1080,720,32,0),
//new DisplayMode(1080,720,24,0),
//new DisplayMode(1080,720,16,0),
//new DisplayMode(1440,900,32,0),
//new DisplayMode(1440,900,24,0),
//new DisplayMode(1440,900,16,0),
};
private boolean running = true;
public ScreenManager s;
public void stop(){
running = false;
}
public void run(){
try{
init();
gameLoop();
}finally{
s.restoreScreen();
}
}
public void init(){
s = new ScreenManager();
DisplayMode dm = s.findFirstCompatibleMode(modes);
s.setFullScreen(dm);
Window w = s.getFullScreenWindow();
w.setFont(new Font("Arial", Font.PLAIN, 20));
w.setBackground(Color.black);
w.setForeground(Color.white);
}
public void gameLoop(){
long startTime = System.currentTimeMillis();
long cumTime = startTime;
while (running)
{
long timePassed = System.currentTimeMillis() - cumTime;
cumTime += timePassed;
if (limitfps){
try{
Thread.sleep(15);
}catch(Exception e){}
}
update(timePassed);
Graphics2D g = s.getGraphics();
draw(g);
g.dispose();
s.update();
}
}
public void update(long timePassed){
}
public boolean limitfps = false;
public void draw(Graphics2D g){
g.clearRect(0, 0, s.getWidth(), s.getHeight());
AlphaComposite ac = java.awt.AlphaComposite.getInstance(AlphaComposite.CLEAR,0.5F);
g.setComposite(ac);
g.drawImage(new ImageIcon("Images/Test.png").getImage(), 30, 30, 30, 30, null);
}
}
If you run this you will have to alt + tab out and end the process (as it doesnt have anything in this portion of code to do such)
You're using the wrong rule -- don't use AlphaComposite.CLEAR.
The AlphaComposite API states this about CLEAR:
Both the color and the alpha of the destination are cleared (Porter-Duff Clear rule). Neither the source nor the destination is used as input.
So this will make the image disappear. Experiment with other rules. While you were creating your SSCCE, I created mine. See what happens when you comment out the one rule line for the other. For example change this
// int rule = AlphaComposite.CLEAR;
int rule = AlphaComposite.SRC_OVER;
to this:
int rule = AlphaComposite.CLEAR;
// int rule = AlphaComposite.SRC_OVER;
The whole SSCCE:
import java.awt.AlphaComposite;
import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Composite;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.Stroke;
import java.awt.image.BufferedImage;
import javax.swing.*;
public class TestAlphaComposite extends JPanel {
private static final int PREF_W = 400;
private static final int PREF_H = PREF_W;
private static final Stroke BASIC_STROKE = new BasicStroke(6f);
BufferedImage backgroundImage;
BufferedImage overlayImage;
public TestAlphaComposite() {
backgroundImage = createBackGroundImage();
overlayImage = createOverlayImage();
}
private BufferedImage createBackGroundImage() {
BufferedImage img = new BufferedImage(PREF_W, PREF_H,
BufferedImage.TYPE_INT_ARGB);
Graphics2D g2 = img.createGraphics();
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
g2.setStroke(BASIC_STROKE);
g2.setColor(Color.blue);
int circleCount = 10;
for (int i = 0; i < circleCount ; i++) {
int x = (i * PREF_W) / (2 * circleCount);
int y = x;
int w = PREF_W - 2 * x;
int h = w;
g2.drawOval(x, y, w, h);
}
g2.dispose();
return img;
}
private BufferedImage createOverlayImage() {
BufferedImage img = new BufferedImage(PREF_W, PREF_H,
BufferedImage.TYPE_INT_ARGB);
Graphics2D g2 = img.createGraphics();
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
g2.setStroke(BASIC_STROKE);
g2.setColor(Color.red);
int circleCount = 10;
for (int i = 0; i < circleCount + 1; i++) {
int x1 = (i * PREF_W) / (circleCount);
int y1 = 0;
int x2 = PREF_W - x1;
int y2 = PREF_H;
float alpha = (float)i / circleCount;
if (alpha > 1f) {
alpha = 1f;
}
// int rule = AlphaComposite.CLEAR;
int rule = AlphaComposite.SRC_OVER;
Composite comp = AlphaComposite.getInstance(rule , alpha );
g2.setComposite(comp );
g2.drawLine(x1, y1, x2, y2);
}
g2.dispose();
return img;
}
#Override
public Dimension getPreferredSize() {
return new Dimension(PREF_W, PREF_H);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
if (backgroundImage != null) {
g.drawImage(backgroundImage, 0, 0, null);
}
if (overlayImage != null) {
g.drawImage(overlayImage, 0, 0, null);
}
}
private static void createAndShowGui() {
JFrame frame = new JFrame("TestAlphaComposite");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(new TestAlphaComposite());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
By the way, your SSCCE isn't a true SSCCE. There's no way that any of us can compile or run that code as it has dependencies that we don't have access to, namely "com.blazingkin.atrox.ScreenManager". If you need our help in the future, you'll want to write better complying sscce's.