Re: grayscale to a JPanel does not work

Knute Johnson <>
Wed, 09 Feb 2011 08:37:46 -0800
On 02/09/2011 07:29 AM, SamuelXiao wrote:

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

In article

  SamuelXiao<> 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


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.JFreeChart
includes suitable methods.

Any help would be highly appreciated.

John B. Matthews
trashgod at gmail dot com

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){
   Graphics2D g2d = (Graphics2D) g;


    case 0:
    case 1:

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 image) {
         BufferedImage gray = new BufferedImage(image.getWidth(),
         ColorConvertOp op = new ColorConvertOp(
         return gray;

Knute Johnson

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