Re: grayscale to a JPanel does not work

From:
SamuelXiao <foolsmart2005@gmail.com>
Newsgroups:
comp.lang.java.gui
Date:
Wed, 9 Feb 2011 20:12:10 -0800 (PST)
Message-ID:
<f166bdcd-39c6-4048-816a-caef8129acc0@8g2000prt.googlegroups.com>
On Feb 10, 9:48 am, Knute Johnson <nos...@knutejohnson.com> wrote:

On 02/09/2011 09:17 AM, SamuelXiao wrote:

On Feb 10, 12:37 am, Knute Johnson<nos...@knutejohnson.com> wrote:

On 02/09/2011 07:29 AM, SamuelXiao wrote:

On Feb 9, 10:50 pm, "John B. Matthews"<nos...@nospam.invalid> =

wrote:

In article
<e11dadc9-4a6a-4b16-9845-c99c223cd...@h19g2000prh.googlegroups.com>,

   SamuelXiao<foolsmart2...@gmail.com> wrote:

[...]
I currently paint line chart/bar chart to there (the drawing area
painting line chart/bar chart).
[...]
In addition, I have tried the example in


<http://groups.google.com/group/comp.lang.java.programmer/msg/d4c436=

ab...>

but it does not work as well.


This is the very code I was going to suggest; it works correctly for
me. Are you having trouble converting your chart to a BufferedImage?
I don't know how you create your chart, but org.jfree.chart.JFreeCha=

rt

includes suitable methods.

Any help would be highly appreciated.


--
John B. Matthews
trashgod at gmail dot com
<http://sites.google.com/site/drjohnbmatthews>


Hi, the code converts an imaged to grayscale. but for my situation, I
need to converts Graphics in an applet (lines, rectangels, string) to
grayScale. The paint method in my Applet is like:

public void paint(Graphics g){
    super.paint(g);
    Graphics2D g2d = (Graphics2D) g;

g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING,RenderingHints.V=

ALUE_ANTIALIAS_ON);

//colorSchemeList.getSelectedIndex
    switch(colorSchemeList.getSelectedIndex()){
    case 0:
     showGrayScale(g2d);
             break;
    case 1:
            showHighContrast(g2d);
            break;
    }
}

But it does not work as the example. It just paint another rectangle
with gray color on top of those line/string/so on. Do you have any
idea for it? Thanks.


     public static BufferedImage convertToGray(BufferedImage ima=

ge) {

          BufferedImage gray = new BufferedImage(image.get=

Width(),

           image.getHeight(),BufferedImage.TYPE_BYTE_GRAY)=

;

          ColorConvertOp op = new ColorConvertOp(
           image.getColorModel().getColorSpace(),
           gray.getColorModel().getColorSpace(),null);
          op.filter(image,gray);
          return gray;
      }
--

Knute Johnson
s/nospam/knute2011/


Hi, I tried the code but still the same. I first make the drawing area
in JPanel become a bufferedimage. Then calls the above function and
finally drawImage, but it will return a gray rectangle as well. Below
is the showGrayScale function.

private void showGrayScale(Graphics2D g2d){
   int pre_height = 29;
         // a region in JPanel become a bufferedimage.
   BufferedImage img = new BufferedImage(getWidth(),
                   getHeight()-pre_height, Buffered=

Image.TYPE_INT_RGB);

   g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
   BufferedImage gray = convertToGray(img);

}

and in fact, in the paint function:
public void paint(Graphics g){
   super.paint(g);
   Graphics2D g2d = (Graphics2D) g;

g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING,RenderingHints.VAL=

UE_ANTIALIAS_ON);

showLineChart(g2d);
//colorSchemeList.getSelectedIndex
   switch(colorSchemeList.getSelectedIndex()){
         case 0:
          showGrayScale(g2d);
          break;
         case 1:
                 showHighContrast(g2d);
                 break;
         }

}

it will first paint showLineChart(g2d) which is a function paint line
chart using drawLine and each line has different color. The Rectangle
was at the right position but doesn't grayscale those line chart. Does
I miss something here? Thanks.


You need to send us more than just pieces of code. We really need to
see an SSCCE if you want good help.

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

public class GreyTest extends JPanel implements ActionListener {
     private final BufferedImage color,gray;
     boolean flag = true;

     public GreyTest() {
         setPreferredSize(new Dimension(400,300));
         color = new BufferedImage(400,300,BufferedImage.TYPE=

_INT_ARGB);

         Graphics2D g = color.createGraphics();
         g.setColor(Color.WHITE);
         g.fillRect(0,0,color.getWidth(),color.getHeight());
         g.setColor(Color.RED);
         g.fillRect(50,50,30,250);
         g.setColor(Color.BLUE);
         g.fillRect(90,200,30,100);
         g.setColor(Color.GREEN);
         g.fillRect(140,150,30,150);
         g.setColor(Color.CYAN);
         g.fillRect(180,275,30,25);
         g.setColor(Color.BLACK);
         g.fillRect(220,250,30,50);
         g.setColor(Color.MAGENTA);
         g.fillRect(260,100,30,200);
         gray = convertToGray(color);
     }

     public void actionPerformed(ActionEvent ae) {
         flag = !flag;
         repaint();
     }

     public void paintComponent(Graphics g) {
         if (flag)
             g.drawImage(color,0,0,null);
         else
             g.drawImage(gray,0,0,null);
     }

     static BufferedImage convertToGray(BufferedImage image) {
         BufferedImage gray = new BufferedImage(image.getWidt=

h(),

          image.getHeight(),BufferedImage.TYPE_BYTE_GRAY);
         ColorConvertOp op = new ColorConvertOp(
          image.getColorModel().getColorSpace(),
          gray.getColorModel().getColorSpace(),null);
         op.filter(image,gray);
         return gray;
     }

     public static void main(String[] args) {
         EventQueue.invokeLater(new Runnable() {
             public void run() {
                 JFrame f = new JFrame("Grey Test");
                 f.setDefaultCloseOperation(JFrame.EXIT=

_ON_CLOSE);

                 GreyTest gt = new GreyTest();
                 f.add(gt,BorderLayout.CENTER);
                 JButton b = new JButton("Color/Grey"=

);

                 b.addActionListener(gt);
                 f.add(b,BorderLayout.SOUTH);
                 f.pack();
                 f.setVisible(true);
             }
         });
     }

}

--

Knute Johnson
s/nospam/knute2011/


Thanks all, the grayscale problem was solved. And then I found another
big problem for the color scheme, option 1 use grayscale(solved) but
option 2 high contrast & option 3 winter color. option 2 is ok for me
but for option 3, I found it cannot use the same approach to solve
it. Then now I hard code colorscheme for each option, including
grayscale, high contrast. I set those graphics line/rectanges with
different color instead of the whole area. The problem is also solved
now. But I wonder if there is any approach to set buffered image with
Winter color???

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