how to convert a gif image to jpg?

Question

it has transparent background,

when i using ImageIO.write(image,"jpg", file) to save,it's be broken

the broken result is here

how to fix it problem? thank you

my code:

import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.net.URL;
import javax.imageio.ImageIO;
import junit.framework.TestCase;

public class ImageResize1  extends TestCase{

    public void testT1() throws IOException{
        URL url=new URL("http://ec.europa.eu/culture/media/programme/images/logos/01_tr_media_col/01_tr_media_col_gif.gif");
        BufferedImage image=ImageIO.read(url);
        File file=new File("C:/temp/java/t7.jpg");
        ImageIO.write(image,"jpg", file);
    }
}

i used:

for(int x = 0; x < scaled.getWidth(); x++) {
    for(int y = 0; y < scaled.getHeight(); y++) {
        int rgb = scaled.getRGB(x, y);
        int alpha = (rgb >> 24) & 0xff;
        if(alpha != 255) {
            scaled.setRGB(x, y,-1); //set white
        }
    }
}

check it from here

it's not right,result is here

Related: http://stackoverflow.com/questions/464825/converting-transparent-gif-png-to-jpeg-using-java — JoseK, Sep 15 '10 at 11:17
JPEG is a lossy format designed for photographs, and is bad for an image with sharp edges, like a diagram or the provided logo. It will look fuzzy and ugly. I recommend PNG instead. — Christoffer Hammarström, Sep 15 '10 at 11:32

score 2 · Answer 1 · answered Sep 15 '10 at 11:16

2

JPG doesn't support transparency, so you can't.

Try using PNG, TIFF or GIF instead.

answered Sep 15 '10 at 11:16

Vivien Barousse

20,555
2
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i don't need transparency, i want a white(#FFFFFF) background – Koerr Sep 15 '10 at 11:18
Hum, sorry, that wasn't specified in your question. What do you mean by "it's broken"? – Vivien Barousse Sep 15 '10 at 11:21

score 2 · Accepted Answer · edited May 23 '17 at 12:09

AreaAveragingScaleFilter scaleFilter =
    new AreaAveragingScaleFilter(
                Math.round(originalWidth / factorX),
                Math.round(originalHeight / factorY));
ImageProducer producer = new FilteredImageSource(original.getSource(), scaleFilter);
ImageGenerator generator = new ImageGenerator();
producer.startProduction(generator);
BufferedImage scaled = generator.getImage();

for(int x = 0; x < scaled.getWidth(); x++) {
    for(int y = 0; y < scaled.getHeight(); y++) {
        int rgb = scaled.getRGB(x, y);
        int alpha = (rgb >> 24) & 0xff;
        if(alpha != 255) {
            scaled.setRGB(x, y,-1); //set white
        }
    }
}


JPEGImageWriteParam param = new JPEGImageWriteParam(null);
param.setCompressionMode(JPEGImageWriteParam.MODE_EXPLICIT);
param.setCompressionQuality((float) 0.85);
java.util.Iterator<ImageWriter> it = ImageIO.getImageWritersBySuffix("jpg");
ImageWriter writer = it.next();
dest.getParentFile().mkdirs();
writer.setOutput(new FileImageOutputStream(dest));
writer.write(null, new IIOImage(scaled, null, null), param);
writer.dispose();

Check it from here

score 0 · Answer 3 · answered Sep 15 '10 at 11:17

I can't comment on the code as I'm not a Java guru, but...

The JPEG format doesn't support transparent backgrounds, so if you're expecting that to be retained, it won't happen.

(not sure why you're doing the conversion, but if you need a high-colour format that does support transparency, use PNG instead)

score 0 · Answer 4 · answered Sep 15 '10 at 11:24

Converting from one format to another is just the beginning :) if it was me I'll use ImageMagik by passing the command to OS and let the ImageMagick take care of the rest

ImageMagick homepage

Beside converting you can resize, add text and almost do all the photoshop tricks on your newly created image and it is easy.

how to convert a gif image to jpg?

4 Answers4

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