Develop Reference

Reading an image as byte array with Android: skImageDecoder::Factory returned null

I have a Spring MVC Web Service that returns an image as a byte array. The output is in json format. The format is png
Here's the code snippet for the image.
BufferedImage img = ImageIO.read(new File(caminho.replace("/", "//")));
imagem = ((DataBufferByte) img.getRaster().getDataBuffer
()).getData();
When I run the server, this is the output:
[{"id":0,"caminhoMDPI":null,"caminhoHDPI":"C:/Users/Marcos/Pictures/postos/drawable-
mdpi/esso_logo.png","caminhoXHDPI":null,"caminhoXXHDPI":null,"imagem":"AAAAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAAAAAAAAAA....]
Eventually, other symbols appear on the "imagem" field. I suppose this is right, but I'm not
sure.
On my Android app, I have a routine to download the image and store it as a blob in the database. I receive the json format and transform it into a class with jackson. I've logged the "imagem" field and it looks the same.
My problem is that I can't transform it into an image. Here's the code snippet:
byte[] img_bandeira = cursor.getBlob(cursor.getColumnIndex("img_bandeira"));
Bitmap bmpBandeira = BitmapFactory.decodeByteArray(img_bandeira, 0, img_bandeira.length);
ImageView ivBandeira = (ImageView) view.findViewById(R.id.ivBandeira);
ivBandeira.setImageBitmap(bmpBandeira);
All I get is a message: skImageDecoder::Factory returned null.
I've looked at other similar posts, tried to change some lines, but nothing happened. I don't know what's going on here. Thanks in advance.

I solved it. In the server, the image should be sent like this:
ByteArrayOutputStream baos = new ByteArrayOutputStream();
BufferedImage img = ImageIO.read(new File(caminho.replace("/", "//")));
ImageIO.write(img, "png", baos);
baos.flush();
String base64String = Base64.encode(baos.toByteArray());
baos.close();
In my app, it should be read like this:
public static Bitmap getImage(byte[] imageArray) {
ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(imageArray);
Bitmap bitmap = BitmapFactory.decodeStream(byteArrayInputStream);
return bitmap;
}
Thank you, everybody ;)

convert all images to PNG

I need a dynamic solution to convert a unknown image format to .png in java.
Will .getType() help me out here, it seems only to return numbers.
The converted image should later be stored in a folder, but I guess that is easly done in the
ImageIO.write().
It's just that with converting an unknown image format that I have no idea how to approach.

This peace of code should do the magic:
File file = new File("unknown.type.pic");
ByteArrayInputStream bais = new ByteArrayInputStream(FileUtils.readFileToByteArray(file);
BufferedImage image = ImageIO.read(bais);
ByteArrayOutputStream baos = new ByteArrayOutputStream();
ImageIO.write(image, "jpg", baos);
OutputStream outputStream = new FileOutputStream ("output.jpg");
baos.writeTo(outputStream);
Add missing try/catch/finally blocks.

Java: BufferedImage to byte array and back

I see that a number of people have had a similar problem, however I'm yet to try find exactly what I'm looking for.
So, I have a method which reads an input image and converts it to a byte array:
File imgPath = new File(ImageName);
BufferedImage bufferedImage = ImageIO.read(imgPath);
WritableRaster raster = bufferedImage .getRaster();
DataBufferByte data = (DataBufferByte) raster.getDataBuffer();
What I now want to do is convert it back into a BufferedImage (I have an application for which I need this functionality). Note that "test" is the byte array.
BufferedImage img = ImageIO.read(new ByteArrayInputStream(test));
File outputfile = new File("src/image.jpg");
ImageIO.write(img,"jpg",outputfile);
However, this returns the following exception:
Exception in thread "main" java.lang.IllegalArgumentException: im == null!
This is because the BufferedImage img is null. I think this has something to do with the fact that in my original conversion from BufferedImage to byte array, information is changed/lost so that the data can no longer be recognised as a jpg.
Does anyone have any suggestions on how to solve this? Would be greatly appreciated.

This is recommended to convert to a byte array
ByteArrayOutputStream baos = new ByteArrayOutputStream();
ImageIO.write(img, "jpg", baos);
byte[] bytes = baos.toByteArray();

Note that calling close or flush will do nothing, you can see this for yourself by looking at their source/doc:
Closing a ByteArrayOutputStream has no effect.
The flush method of OutputStream does nothing.
Thus use something like this:
ByteArrayOutputStream baos = new ByteArrayOutputStream(THINK_ABOUT_SIZE_HINT);
boolean foundWriter = ImageIO.write(bufferedImage, "jpg", baos);
assert foundWriter; // Not sure about this... with jpg it may work but other formats ?
byte[] bytes = baos.toByteArray();
Here are a few links concerning the size hint:
Java: Memory efficient ByteArrayOutputStream
jpg bits per pixel
Of course always read the source code and docs of the version you are using, do not rely blindly on SO answers.

How to get an InputStream from a BufferedImage?

How can I get an InputStream from a BufferedImage object? I tried this but ImageIO.createImageInputStream() always returns NULL
BufferedImage bigImage = GraphicsUtilities.createThumbnail(ImageIO.read(file), 300);
ImageInputStream bigInputStream = ImageIO.createImageInputStream(bigImage);
The image thumbnail is being correctly generated since I can paint bigImage to a JPanel with success.

From http://usna86-techbits.blogspot.com/2010/01/inputstream-from-url-bufferedimage.html
It works very fine!
Here is how you can make an
InputStream for a BufferedImage:
URL url = new URL("http://www.google.com/intl/en_ALL/images/logo.gif");
BufferedImage image = ImageIO.read(url);
ByteArrayOutputStream os = new ByteArrayOutputStream();
ImageIO.write(image, "gif", os);
InputStream is = new ByteArrayInputStream(os.toByteArray());

If you are trying to save the image to a file try:
ImageIO.write(thumb, "jpeg", new File(....));
If you just want at the bytes try doing the write call but pass it a ByteArrayOutputStream which you can then get the byte array out of and do with it what you want.

By overriding the method toByteArray(), returning the buf itself (not copying), you can avoid memory related problems. This will share the same array, not creating another of the correct size. The important thing is to use the size() method in order to control the number of valid bytes into the array.
final ByteArrayOutputStream output = new ByteArrayOutputStream() {
#Override
public synchronized byte[] toByteArray() {
return this.buf;
}
};
ImageIO.write(image, "png", output);
return new ByteArrayInputStream(output.toByteArray(), 0, output.size());

Export ChartFX7 to SVG in Java

Can anybody give an example of exporting a ChartFX7 chart to SVG?
I've tried:
ByteArrayOutputStream baos = new ByteArrayOutputStream();
m_chart.setOutputWriter(new SvgWriter());
m_chart.exportChart(FileFormat.EXTERNAL, baos);
and :
ByteArrayOutputStream baos = new ByteArrayOutputStream();
m_chart.setRenderFormat("SVG");
m_chart.renderToStream();
But both result in a null pointer exception.
The following successfully outputs to XML:
FileOutputStream fos = new FileOutputStream(Debug.getInstance().createExternalFile("chart.xml"));
m_chart.exportChart(FileFormat.XML, fos);

batik is a libary that you can import into your java libary to convert or create svg images. I dont know chartfx7 but that is the standard way to create svg in java.