I want to put an image (visualization of an audio) behind the JSlider which represents the audioplayer, the process of playing.
First I tried to overwrite the paint-method of the Slider
public void paintComponent(Graphics g) {
// Draw the previously loaded image to Component
g.drawImage(img, 0, -100, null);
super.paintComponent(g);
}
this worked, but the image is higher than the slider, so my next try was a JLayeredPane, where I put the JSlider above a JLabel with the image. Looks good for the first moment. But I mentioned that I need the image behind the track of the slider, not the whole slider. There is space to the left and right. Can anybody tell me a way how to calculate this space? Or the width and offset of the track to the border of the slider? This should run under Windows and MacOs, so different LookAndFeels, so I think hard coded values will not work.
Example Slider with background image
Thankyou.
My solution for this Problem is now to overwrite the SliderUI. So this is a very special component, so it's nonrelevant that it looks the same on all LookAndFeels.
It supports also jumping directly to mouse position, which is different to BasicSliderUI.
/**
*
* Custom SliderUI for AudioPlayer with audioimage in background
*/
public class AudioSliderUI extends BasicSliderUI {
private BasicStroke stroke = new BasicStroke(1f, BasicStroke.CAP_ROUND,
BasicStroke.JOIN_ROUND, 0f);
public AudioSliderUI(AudioSlider b) {
super(b);
}
#Override
public void paint(Graphics g, JComponent c) {
Graphics2D g2d = (Graphics2D) g;
g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
super.paint(g, c);
}
#Override
protected Dimension getThumbSize() {
return new Dimension(2, 200);
}
#Override
public void paintTrack(Graphics g) {
Graphics2D g2d = (Graphics2D) g;
Stroke old = g2d.getStroke();
g2d.setStroke(stroke);
g2d.setPaint(Color.WHITE);
if (slider.getOrientation() == SwingConstants.HORIZONTAL) {
g2d.drawLine(trackRect.x, trackRect.y + trackRect.height / 2,
trackRect.x + trackRect.width, trackRect.y + trackRect.height / 2);
} else {
g2d.drawLine(trackRect.x + trackRect.width / 2, trackRect.y,
trackRect.x + trackRect.width / 2, trackRect.y + trackRect.height);
}
g2d.setStroke(old);
Image img = ((AudioSlider)slider).getImage();
g2d.drawImage(img, trackRect.x, trackRect.y, trackRect.width, trackRect.height, slider);
}
#Override
public void paintThumb(Graphics g) {
Rectangle knobBounds = thumbRect;
int w = knobBounds.width;
int h = 100;
int newStarty = knobBounds.height/2- h/2;
g.translate(knobBounds.x, knobBounds.y);
// "plain" version
g.setColor(Color.YELLOW);
g.fillRect(0, newStarty, w, h);
}
#Override
protected TrackListener createTrackListener(JSlider slider) {
return new TrackListener() {
#Override
public void mousePressed(MouseEvent e) {
if (UIManager.getBoolean("Slider.onlyLeftMouseButtonDrag")
&& SwingUtilities.isLeftMouseButton(e)) {
JSlider slider = (JSlider) e.getComponent();
switch (slider.getOrientation()) {
case SwingConstants.VERTICAL:
slider.setValue(valueForYPosition(e.getY()));
break;
case SwingConstants.HORIZONTAL:
slider.setValue(valueForXPosition(e.getX()));
break;
default:
throw new IllegalArgumentException(
"orientation must be one of: VERTICAL, HORIZONTAL");
}
super.mousePressed(e); // isDragging = true;
super.mouseDragged(e);
} else {
super.mousePressed(e);
}
}
#Override
public boolean shouldScroll(int direction) {
return false;
}
};
}
}
Matching Slider:
public class AudioSlider extends JSlider {
private Image img;
public AudioSlider() {
setOpaque(false);
}
/**
* #return the img
*/
public Image getImage() {
return img;
}
public void setImage(Image img) {
this.img = img;
}
}
Works for me, maybe covers not all prospects.
Related
Huy guys, I have a weird problem.
I'm kinda new to swing and java applications.
I'm trying to make a custom UI jslider that changes a jlabel text when you move the thumb.
My problem is: when I use the addChangeListener(), it creates a weird glitch when moving the thumb.
If I don't use it, it works perfectly fine.
How can I update the JLabel without using the change listener or how can I fix this graphic bug?
Most of this code comes from stackoverflow since I don't know much about painting components.
See pictures at the button to better understand the problem
Thanks!
The code in my jpanel
JSlider slider = new JSlider(SwingConstants.HORIZONTAL, 1, 10, 1) {
#Override
public void updateUI() {
setUI(new CustomSliderUI(this));
}
};
// If I comment this line the visual glitch is gone when moving the thumb, but the value doesnt update
slider.addChangeListener((event) -> RAM_LABEL.setText(slider.getValue() + " Gb"));
slider.setMinorTickSpacing(1);
slider.setMajorTickSpacing(10);
slider.setSnapToTicks(true);
slider.setBounds(96, 317, 300, 35);
slider.setCursor(Cursor.getPredefinedCursor(Cursor.HAND_CURSOR));
slider.setOpaque(false);
this.add(slider);
The custom slider ui class
private static class CustomSliderUI extends BasicSliderUI
{
private static final int TRACK_HEIGHT = 8;
private static final int TRACK_ARC = 5;
private static final Dimension THUMB_SIZE = new Dimension(22, 20);
private final RoundRectangle2D.Float trackShape = new RoundRectangle2D.Float();
private final Image knob;
public CustomSliderUI(final JSlider b)
{
super(b);
knob = Swinger.getResource("knob.png");
}
#Override
protected void calculateTrackRect() {
super.calculateTrackRect();
trackRect.y = trackRect.y + (trackRect.height - TRACK_HEIGHT) / 2;
trackRect.height = TRACK_HEIGHT;
trackShape.setRoundRect(trackRect.x, trackRect.y, trackRect.width, trackRect.height, TRACK_ARC, TRACK_ARC);
}
#Override
protected void calculateThumbLocation() {
super.calculateThumbLocation();
thumbRect.y = trackRect.y + (trackRect.height - thumbRect.height) / 2;
}
#Override
protected Dimension getThumbSize() {
return THUMB_SIZE;
}
#Override
public void paint(final Graphics g, final JComponent c) {
((Graphics2D) g).setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
super.paint(g, c);
}
#Override
public void paintTrack(final Graphics g) {
Graphics2D g2 = (Graphics2D) g;
Shape clip = g2.getClip();
boolean inverted = slider.getInverted();
// Paint shadow.
g2.setColor(new Color(170, 170 ,170));
g2.fill(trackShape);
// Paint track background.
g2.setColor(new Color(200, 200 ,200));
g2.setClip(trackShape);
trackShape.y += 1;
g2.fill(trackShape);
trackShape.y = trackRect.y;
g2.setClip(clip);
// Paint selected track.
boolean ltr = slider.getComponentOrientation().isLeftToRight();
if (ltr) inverted = !inverted;
int thumbPos = thumbRect.x + thumbRect.width / 2;
if (inverted) {
g2.clipRect(0, 0, thumbPos, slider.getHeight());
} else {
g2.clipRect(thumbPos, 0, slider.getWidth() - thumbPos, slider.getHeight());
}
g2.setColor(Swinger.getTransparentWhite(0));
g2.fill(trackShape);
g2.setClip(clip);
}
#Override
public void paintThumb(final Graphics g)
{
g.drawImage(knob, thumbRect.x, thumbRect.y, null);
}
#Override
public void paintFocus(final Graphics g) {}
}
Visual glitch when you are moving the cursor, as soon as you stop pressing the mouse it goes back to normal
Regular cursor / when I move it without the change listener
Solved. I went with drawing my own background it was simplier.
private static class CustomSliderUI extends BasicSliderUI
{
private static final Dimension THUMB_SIZE = new Dimension(22, 20);
private final Image thumb, background;
private final JSlider slider;
public CustomSliderUI(final JSlider b)
{
super(b);
slider = b;
thumb = Swinger.getResource("thumb.png");
background = Swinger.getResource("slider.png");
}
#Override
protected Dimension getThumbSize() {
return THUMB_SIZE;
}
#Override
public void paintTrack(final Graphics g) {
g.drawImage(background, 10, 11, 280, 10, null);
}
#Override
public void paintThumb(final Graphics g)
{
g.drawImage(thumb, thumbRect.x, thumbRect.y, null);
slider.repaint();
}
#Override
public void paintFocus(final Graphics g) {}
}
JSlider slider = new JSlider(SwingConstants.HORIZONTAL, 1, 10, 1) {
#Override
public void updateUI() {
setUI(new CustomSliderUI(this));
}
};
slider.addChangeListener((event) -> RAM_LABEL.setText(slider.getValue() + " Gb"));
slider.setBounds(96, 317, 300, 35);
slider.setCursor(Cursor.getPredefinedCursor(Cursor.HAND_CURSOR));
slider.setOpaque(false);
this.add(slider);
I want to write a custom subclass of JLabel that would have two images attached to the border, that can be moved by moving the mouse. Real effects like this:
Here's my subclass, how could I add these attached images?
public class Rect extends JLabel{
private int width,height;
public Rect (int width,int height){
this.width = width;
this.height = height;
setText("b1");
repaint();
}
public void paintComponent(Graphics g){
super.paintComponent(g);
g.setColor(Color.red);
g.drawRect(0, 0, this.width, this.height);
}
public void reDraw(){
this.repaint();
}
public void setWidth(int width) {
this.width = width;
repaint();
}
public void setHeight(int height) {
this.height = height;
repaint();
}
}
To do this there are 4 things you should to do:
Extend an AbstractBorder not a Jlabel, then you can easily add your custom border to any component, not just a jLabel.
Override the paintBorder method so that you can draw your border.
Add an mouse action listeners to keep track of your border images.
And lastly you need a bit of logic to manage your border images.
I found this question interesting so I took a crack at making something as a test. It came out well, and does what you want, but will need a bit of work to get it looking correct. See below for a break down of each point.
Example image before we look at the code:
Extend an AbstractBorder:
public class MyCustomBorder extends AbstractBorder
{
private Color borderColour;
private int borderThickness = 10;
private Point firstSlider = new Point(0, 0);
private Point secondSlider = new Point(0, 0);
private BufferedImage firstSliderImage;
private BufferedImage secondSliderImage;
Boolean draggingFirst = false;
Boolean draggingSecond = false;
//See usage info
public MyCustomBorder(Color colour, int thickness, Point firstSlider, BufferedImage firstSliderImage, Point secondSlider, BufferedImage secondSliderImage)
{
borderColour = colour;
borderThickness = thickness;
this.firstSlider = firstSlider;
this.secondSlider = secondSlider;
this.firstSliderImage = firstSliderImage;
this.secondSliderImage = secondSliderImage;
}
Override the paintBorder method and insets:
#Override
public void paintBorder(Component c, Graphics g, int x, int y, int width, int height)
{
super.paintBorder(c, g, x, y, width, height);
Graphics2D g2d = null;
if (g instanceof Graphics2D)
{
g2d = (Graphics2D) g;
//Draw border fill (currently hard coded to white, but can be changed)
g2d.setColor(Color.white);
//Top
g2d.fill(new Rectangle2D.Double(0, 0, width, borderThickness));
//Left
g2d.fill(new Rectangle2D.Double(0, 0, borderThickness, height));
//Bottom
g2d.fill(new Rectangle2D.Double(0, height-borderThickness, width, borderThickness));
//Right
g2d.fill(new Rectangle2D.Double(width-borderThickness, 0, borderThickness, height));
//draw black seperator
g2d.setColor(borderColour);
//Top
g2d.fill(new Rectangle2D.Double(borderThickness, borderThickness, width-(borderThickness*2), 1));
//Left
g2d.fill(new Rectangle2D.Double(borderThickness, borderThickness, 1, height-(borderThickness*2)));
//Bottom
g2d.fill(new Rectangle2D.Double(borderThickness, height-borderThickness-1, width-(borderThickness*2), 1));
//Right
g2d.fill(new Rectangle2D.Double(width-borderThickness-1, borderThickness, 1, height-(borderThickness*2)));
//draw sliders an custom position
g2d.drawImage(scale(secondSliderImage), null, secondSlider.x, secondSlider.y);
g2d.drawImage(scale(firstSliderImage), null, firstSlider.x, firstSlider.y);
}
}
#Override
public Insets getBorderInsets(Component c)
{
return (getBorderInsets(c, new Insets(borderThickness, borderThickness, borderThickness, borderThickness)));
}
#Override
public Insets getBorderInsets(Component c, Insets insets)
{
insets.left = insets.top = insets.right = insets.bottom = borderThickness;
return insets;
}
#Override
public boolean isBorderOpaque()
{
return false;
}
}
Add mouse action listeners:
//listeners for dragging
void addListeners(Component button)
{
button.addMouseMotionListener(new java.awt.event.MouseMotionAdapter()
{
public void mouseDragged(java.awt.event.MouseEvent evt)
{
//Only drag if a slider was selected
if (draggingFirst)
{
//update position of silder
firstSlider = snapToEdge(evt.getPoint(), evt.getComponent());
evt.getComponent().repaint();
}
else if (draggingSecond)
{
//update position of silder
secondSlider = snapToEdge(evt.getPoint(), evt.getComponent());
evt.getComponent().repaint();
}
}
});
button.addMouseListener(new java.awt.event.MouseAdapter()
{
//check if a slider was selected
public void mousePressed(java.awt.event.MouseEvent evt)
{
if (isInside(evt.getPoint(), firstSlider))
{
draggingFirst = true;
}
else if (isInside(evt.getPoint(), secondSlider))
{
draggingSecond = true;
}
}
public void mouseReleased(java.awt.event.MouseEvent evt)
{
//cancel selected slider
draggingFirst = false;
draggingSecond = false;
}
});
}
Logic:
//check if a slider was selected
private Boolean isInside(Point clicked, Point toCheck)
{
if (clicked.x > toCheck.x && clicked.x < toCheck.x + borderThickness)
{
if (clicked.y > toCheck.y && clicked.y < toCheck.y + borderThickness)
{
return true;
}
}
return false;
}
//snap a sliders co-ords to as edge
private Point snapToEdge(Point dragged, Component label)
{
//work out how close to each edge
int topEdge = dragged.y;
int leftEdge = dragged.x;
int rightEdge = label.getWidth()- dragged.x;
int bottomEdge = label.getHeight() - dragged.y;
//snap to slider co-ords to closest edge
if (topEdge < leftEdge && topEdge < rightEdge && topEdge < bottomEdge)
{
dragged.y = 0;
}
else if (leftEdge < rightEdge && leftEdge < bottomEdge)
{
dragged.x = 0;
}
else if (rightEdge < bottomEdge)
{
dragged.x = label.getWidth()-borderThickness;
}
else
{
dragged.y = label.getHeight()-borderThickness;
}
return dragged;
}
//scale slider images to fit border size
public BufferedImage scale(BufferedImage image)
{
BufferedImage resizedImage = null;
if (image != null)
{
double border = borderThickness;
resizedImage = new BufferedImage(borderThickness, borderThickness, TYPE_INT_ARGB);
Graphics2D g = resizedImage.createGraphics();
AffineTransform at = AffineTransform.getScaleInstance(border / (double)image.getWidth(), border / (double)image.getHeight());
g.drawRenderedImage(image, at);
}
return resizedImage;
}
The full code to copy and paste can be found here:
https://github.com/sorifiend/customBorder/blob/master/MyCustomBorder.java
Usage Example:
You can put this code in your form class to add a border to most swing components. In this example I added it to a jLabel called my_jLabel:
//Create border
MyCustomBorder border = new MyCustomBorder(Color.BLACK, 10, new Point(0, 0), img1, new Point(0, 0), img2);
//Add border to component called my_jLabel
my_jLabel.setBorder(border);
//Add action listeners for dragging sliders (very important)
border.addListeners(my_jLabel);
I have tried quite a few tutorials and I can't seem to get double buffering to work. Here is my main (the update() method is the code i tried, but I still see flickering):
public class Main extends JApplet implements Runnable {
private static final long serialVersionUID = 1L;
private static int width = 900;
private static int height = 600;
public static int fps = 60;
public Thread thread = new Thread(this);
private Image dbImage;
private Graphics dbg;
public static Ailoid ailoid = new Ailoid();
// Initialize
public void init() {
setSize(width, height);
setBackground(Color.white);
ailoid.setLocation(new Location(100, 100));
AlienManager.registerAlien(ailoid);
}
// Paint graphics
public void paint(Graphics g) {
super.paint(g);
g.setColor(Color.green);
for (Alien alien : AlienManager.getAliens()) {
Location loc = alien.getLocation();
int x = loc.getX();
int y = loc.getY();
g.fillRect(x, y, 10, 20);
}
}
// Update graphics for double buffering
public void update(Graphics g) {
if (dbImage == null) {
dbImage = createImage (width, height);
dbg = dbImage.getGraphics();
}
dbg.setColor (getBackground ());
dbg.fillRect (0, 0, width, height);
dbg.setColor (getForeground());
paint (dbg);
g.drawImage (dbImage, 0, 0, this);
}
// Thread start
#Override
public void start() {
thread.start();
}
// Thread stop
#Override
public void destroy() {
thread = null;
}
// Thread run
#Override
public void run() {
while (thread != null) {
Updater.run();
repaint();
try {
// 1000 divided by fps to get frames per millisecond
Thread.sleep(1000 / fps);
}
catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
If someone could help it would be greatly appreciated!
Instead of drawing your objects one by one, draw them on an image and then tell the renderer to draw that entire image. This eliminates the flickering.
Here's an example of how you might accomplish it.
class DoubleBufferedCanvas extends Canvas {
public void update(Graphics g) {
Graphics offgc;
Image offscreen = null;
Dimension d = size();
// create the offscreen buffer and associated Graphics
offscreen = createImage(d.width, d.height);
offgc = offscreen.getGraphics();
// clear the exposed area
offgc.setColor(getBackground());
offgc.fillRect(0, 0, d.width, d.height);
offgc.setColor(getForeground());
// do normal redraw
paint(offgc);
// transfer offscreen to window
g.drawImage(offscreen, 0, 0, this);
}
}
I need to make my background in a game move up all the time..
I know that I need to use some thread that added variable to 'y' coordinate of the image
I tried to do something but when it started moving all the background get streaking in some reason, cant understand why...
picture : streaking background
public class Background {
private BufferedImage image;
.....
....
public Background(int x, int y) {
this.x = x;
this.y = y;
// Try to open the image file background.png
try {
BufferedImageLoader loader = new BufferedImageLoader();
image = loader.loadImage("/backSpace.png");
}
catch (Exception e) { System.out.println(e); }
}
/**
* Method that draws the image onto the Graphics object passed
* #param window
*/
public void draw(Graphics window) {
// Draw the image onto the Graphics reference
window.drawImage(image, getX(), getY(), image.getWidth(), image.getHeight(), null);
// Move the x position left for next time
this.y +=1 ;
}
public class ScrollingBackground extends Canvas implements Runnable {
// Two copies of the background image to scroll
private Background backOne;
private Background backTwo;
private BufferedImage back;
public ScrollingBackground() {
backOne = new Background();
backTwo = new Background(backOne.getImageWidth(), 0);
new Thread(this).start();
setVisible(true);
}
#Override
public void run() {
try {
while (true) {
Thread.currentThread().sleep(5);
repaint();
}
}
catch (Exception e) {}
}
#Override
public void update(Graphics window) {
paint(window);
}
public void paint(Graphics window) {
Graphics2D twoD = (Graphics2D)window;
if (back == null)
back = (BufferedImage)(createImage(getWidth(), getHeight()));
Graphics buffer = back.createGraphics();
backOne.draw(buffer);
backTwo.draw(buffer);
twoD.drawImage(back, null, 0, 0);
}
You dont need a new thread for it, that just overcomplicates things in this case.
You just need to add a factor to the Y coordinate of the background continuesly.
For example:
float scrollFactor = 0.5f; //Moves the background 0.5 pixels up per call of the draw method
public void draw(Graphics window) {
window.drawImage(image, getX(), getY(), image.getWidth(), image.getHeight(), null);
this.y += scrollFactor;
}
I have some code to draw rectangles. It's used to draw rectangles on a JPanel, to mark boundaries of widgets. Here the code first, after that I'll explain my problem cq. question.
First off, I have a class (WidgetDrawingPanel) which extends JPanel.
public WidgetDrawingPanel(int width, int height) {
/*To make things visible at least*/
widgets.add(new Widget(10,10,100,100, WidgetType.TextField));
widgets.add(new Widget(50,50,100,200, WidgetType.TextField));
this.width = width;
this.height = height;
this.setBackground(Color.BLUE);
addListener(); //adds both MouseMotionListener and MouseListener
}
Below you'll see me reference ch a lot. This is a CoordinateHolder, which holds start and current coordinates of my mouse movement.
private void addListener() {
this.addMouseMotionListener(new MouseMotionListener() {
#Override
public void mouseDragged(MouseEvent arg0) {
ch.currentX = arg0.getX();
ch.currentY = arg0.getY();
System.out.println("dragging " + ch.currentX + ","+ch.currentY);
WidgetDrawingPanel.this.repaint();
}
});
this.addMouseListener(new MouseListener() {
#Override
public void mouseReleased(MouseEvent event) {
ch.endX = event.getX();
ch.endY = event.getY();
try {
checkCoords();
} catch (OutsidePanelException e) {
e.printStackTrace();
JOptionPane.showMessageDialog(null, "drawn Outside Panel");
}
}
#Override
public void mousePressed(MouseEvent event) {
ch = new CoordinateHolder(event.getX(), event.getY());
}
});
}
and, finally, the paintComponent(Grapics) method. There's loop through Widgets, which are actually just already drawn Rects (x, y, w, h attributes), but which a little more information, which is not useful in the drawing part of the application. Everytime you release the mouse, the CoordinateHolder is converted into a Widget, and added to widgets.
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
System.out.println("Paint");
g.setColor(Color.BLUE);
g.fillRect(0, 0, width, height); //making the whole panel blue
g.setColor(Color.RED);
Graphics2D g2 = (Graphics2D)g;
g2.setStroke(new BasicStroke(3));
for (Widget w : widgets) {
g.drawRect(w.getX(), w.getY(), w.getW(), w.getH());
}
if (ch != null)
g.drawRect(ch.startX, ch.startY, ch.currentX - ch.startX, ch.currentY - ch.startY);
}
This code is working, but I suspect this is highly inefficient and inperformant, as above code continually refreshes the JPanel on mouse drag, which is, say, once every 10ms? I suppose it'll get slow really soon, especially when the user creates a heck of a lot rectangles (which are also continally redrawn, as seen in painComponent(Graphics)).
Question cq. Problem
Is there a better, less resource consuming method, where the user can drag rectangles smoothly?
I read an answer to this Drag rectangle on JFrame in Java, but the author of that answer seems to do it the same as me. But again, that's way inperformant, right? Or should computers be easily able to redraw the component continually, and is this actually a valid approach?
To show lots of non-changing background shapes, draw them to a BufferedImage and then show that BufferedImage in the paintComponent(...) method. So while a shape is being drawn, draw it in paintComponent(...) but once the shape is done being drawn, perhaps on mouseRelease, then draw it in the background BufferedImage.
Note that what will slow your current drawing code the most may be your debugging SOP statements, but I assume that these will be removed from the finished code.
For example:
import java.awt.*;
import java.awt.event.*;
import java.awt.image.BufferedImage;
import javax.swing.*;
#SuppressWarnings("serial")
public class DrawingPanel extends JPanel {
private static final int PREF_W = 600;
private static final int PREF_H = 400;
private static final Color DRAWING_COLOR = new Color(255, 100, 200);
private static final Color FINAL_DRAWING_COLOR = Color.red;
private BufferedImage backgroundImg;
private Point startPt = null;
private Point endPt = null;
private Point currentPt = null;
public DrawingPanel() {
backgroundImg = new BufferedImage(PREF_W, PREF_H,
BufferedImage.TYPE_INT_ARGB);
Graphics g = backgroundImg.getGraphics();
g.setColor(Color.blue);
g.fillRect(0, 0, PREF_W, PREF_H);
g.dispose();
MyMouseAdapter myMouseAdapter = new MyMouseAdapter();
addMouseMotionListener(myMouseAdapter);
addMouseListener(myMouseAdapter);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
if (backgroundImg != null) {
g.drawImage(backgroundImg, 0, 0, this);
}
if (startPt != null && currentPt != null) {
g.setColor(DRAWING_COLOR);
int x = Math.min(startPt.x, currentPt.x);
int y = Math.min(startPt.y, currentPt.y);
int width = Math.abs(startPt.x - currentPt.x);
int height = Math.abs(startPt.y - currentPt.y);
g.drawRect(x, y, width, height);
}
}
#Override
public Dimension getPreferredSize() {
return new Dimension(PREF_W, PREF_H);
}
public void drawToBackground() {
Graphics g = backgroundImg.getGraphics();
g.setColor(FINAL_DRAWING_COLOR);
int x = Math.min(startPt.x, endPt.x);
int y = Math.min(startPt.y, endPt.y);
int width = Math.abs(startPt.x - endPt.x);
int height = Math.abs(startPt.y - endPt.y);
g.drawRect(x, y, width, height);
g.dispose();
startPt = null;
repaint();
}
private class MyMouseAdapter extends MouseAdapter {
#Override
public void mouseDragged(MouseEvent mEvt) {
currentPt = mEvt.getPoint();
DrawingPanel.this.repaint();
}
#Override
public void mouseReleased(MouseEvent mEvt) {
endPt = mEvt.getPoint();
currentPt = null;
drawToBackground();
}
#Override
public void mousePressed(MouseEvent mEvt) {
startPt = mEvt.getPoint();
}
}
private static void createAndShowGui() {
DrawingPanel mainPanel = new DrawingPanel();
JFrame frame = new JFrame("Drawing Panel");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}