4 replies to this topic

[dunnkers]

Hello, i come here with yet another problem i can't figure out.

I'm trying to fade a text from 250 alpha to 0, And it starts counting the alpha off when the user clicks.
I have the time since the user clicked in miliseconds.
Here what i have now:

final Point mouseLocation = new Point(mouse.getMousePressX(), mouse.getMousePressY());

long sincePressed = System.currentTimeMillis() - mouse.getMousePressTime();


if (sinceT <= 1000) { //when user clicks, and time after click is less then 1 sec.. this gets executed

    int alpha = ?help here?;

    g.setColor(new Color(255, 0, 0, alpha));

    g.fillOval(mouseLocation.x - 10, mouseLocation.y - 10, 20, 20);

}

Please help, i really can't figure it out myself..

[dunnkers]

Anyone - please?
I'm highly appreciating all posts

[wim DC]

Define alpha as a class variable. Set it to 255 in the constructor of the class.
Then do alpha--; to lower it by 1.

public class MyClass{
  private in alpha;
  
  public MyClass(){
    alpha = 255;
  }


//your code here somewhere, with alpha--; instead of int alpha = ?help here?;

}

[dunnkers]

Thanks! will try this

[ZekeDragon]

I had not attempted to make a GUI component in Swing fade out and in before, and this post made me want to find out how to do it. I knew that since fading inherently takes time, whatever method I'd use would have to utilize a separate thread that would add Runnable's to the Event Dispatch Thread. Fortunately I didn't have to do something complicated thanks to javax.swing.Timer, since that object runs the passed in ActionListener's actionPerformed() method on the Event Dispatch Thread.

It still seems a bit messy to me, but here's the full source code of my FadeLabel object and a simple window to run it. This should just build without issues by creating a new file called "Simple.java", pasting the below code into it and compiling using "javac Simple.java". There's a couple warnings about serialVersionUID but other than that nothing will pop up.

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

class FadeLabel extends JLabel
{
    public static final int FADE_IN = 0;
    public static final int FADE_OUT = 1;

    public FadeLabel(String value)
    {
        super(value);
        fps = 30;
        fadeValue = 255;
        isFading = false;
        fadeState = FADE_IN;
        timer = null;
    }

    public synchronized void startFadeOut()
    {
        if (fadeState == FADE_OUT) return;

        timer = new Timer(1000 / fps, new FadeListener(this, FADE_OUT, 5));
        timer.start();

        fadeState = FADE_OUT;
    }

    public synchronized void startFadeIn()
    {
        if (fadeState == FADE_IN) return;

        timer = new Timer(1000 / fps, new FadeListener(this, FADE_IN, 5));
        timer.start();

        fadeState = FADE_IN;
    }

    public void toggleFade()
    {
        if (fadeState == FADE_OUT)
        {
            startFadeIn();  
        }
        else
        {
            startFadeOut();
        }
    }

    public boolean isCurrentlyFading()
    {
        return isFading;
    }

    public ActionListener getFadeToggleListener()
    {
        return new FadeToggleListener(this);
    }

// PRIVATE IMPLEMENTATION:

    private int fadeValue;
    private boolean isFading;
    private int fadeState;
    private int fps;
    private javax.swing.Timer timer;

    private boolean fade(int value, int type)
    {
        boolean retVal = false;

        if (type == FADE_IN)
        {
            retVal = modifyFadeValue(value);
        }
        else
        {
            retVal = modifyFadeValue(-value);
        }

        if (retVal)
        {
            // In order to determine the color and clear out the Alpha
            // value from the Color class' getRGB() method, we binary
            // AND with 0x00ffffff to clear it, then bit-shift fadeValue
            // by 24 and binary OR the result of the bit-shift with
            // the cleared RGB values.
            int colorType = this.getForeground().getRGB();
            colorType = colorType & 0x00ffffff; 

            this.setForeground(new Color(colorType | (fadeValue << 24), true));

            Dimension dim = this.getSize();
            this.repaint(10, 0, 0, dim.height, dim.width);
        }

        return retVal;
    }

    private boolean modifyFadeValue(int amount)
    {
        if ((fadeValue == 255 && amount > 0) ||
            (fadeValue == 0   && amount < 0) ||
             amount == 0                       ) return false;

        fadeValue += amount;

        if (fadeValue > 255) fadeValue = 255;
        if (fadeValue < 0) fadeValue = 0;

        return true;
    }

    private class FadeListener implements ActionListener
    {
        private int fadeType;
        private int intensity;
        private FadeLabel currentLabel;

        public FadeListener(FadeLabel curLab, int fType, int intense)
        {
            currentLabel = curLab;
            fadeType = fType;
            setIntensity(intense);
        }

        public void setIntensity(int value)
        {
            if (value < 0) return;

            intensity = value;
        }

        public void actionPerformed(ActionEvent e)
        {
            currentLabel.isFading = true;

            if (currentLabel.fade(intensity, fadeType) == false)
            {
                currentLabel.isFading = false;
                Timer t = (javax.swing.Timer) e.getSource();
                t.stop();
            }
        }
    }

    private class FadeToggleListener implements ActionListener
    {
        private FadeLabel label;

        public FadeToggleListener(FadeLabel l)
        {
            label = l;
        }

        public void actionPerformed(ActionEvent e)
        {
            if (label.isCurrentlyFading()) return;

            if (label.fadeState == FADE_OUT)
            {
                startFadeIn();
            }
            else
            {
                startFadeOut();
            }
        }
    }
}

public class Simple extends JPanel
{
    private FadeLabel fader;

    public Simple()
    {
        JButton but = new JButton("Toggle Fade");
        fader = new FadeLabel("I can fade!");
        but.addActionListener(fader.getFadeToggleListener());
        setLayout(new BoxLayout(this, BoxLayout.PAGE_AXIS));
        add(fader);
        add(but);
    }

    public static void main(String[] args)
    {
        Simple s = new Simple();
        JFrame f = new JFrame();

        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.setContentPane(s);
        f.setSize(300, 200);
        f.setVisible(true);
    }
}