Develop Reference

Writing image into pdf file in java without saving it

I am generating QR image, and then I save it in PDF file. I am using the following code:
BarcodeQRCode qrcode = new BarcodeQRCode("This is a test QR code!", 1, 1, null);
Image image = qrcode.createAwtImage(Color.BLACK, Color.WHITE);
BufferedImage buffImg = new BufferedImage(image.getWidth(null), image.getWidth(null), BufferedImage.TYPE_4BYTE_ABGR);
File qrImageFile = new File(qrImageFilePath);
ImageIO.write(buffImg, "png", qrImageFile);
Because my PDF file is based on HTML string, so I put the QR image file path in the string (besides other texts and images), and then write the whole string in the PDF.
My question: Can I do the same process without saving the Image on my computer? And if yes, how I can include it in the string?
Thank you.

Write animated-gif stored in BufferedImage to java.io.File Object

I am reading a gif image from internet url.
// URL of a sample animated gif, needs to be wrapped in try-catch block
URL imageUrl = new Url("http://4.bp.blogspot.com/-CTUfMbxRZWg/URi_3Sp-vKI/AAAAAAAAAa4/a2n_9dUd2Hg/s1600/Kei_Run.gif");
// reads the image from url and stores in BufferedImage object.
BufferedImage bImage = ImageIO.read(imageUrl);
// creates a new `java.io.File` object with image name
File imageFile = new File("download.gif");
// ImageIO writes BufferedImage into File Object
ImageIO.write(bImage, "gif", imageFile);
The code executes successfully. But, the saved image is not animated as the source image is.
I have looked at many of the stack-overflow questions/answers, but i am not able to get through this. Most of them do it by BufferedImage frame by frame which alters frame-rate. I don't want changes to the source image. I want to download it as it is with same size, same resolution and same frame-rate.
Please keep in mind that i want to avoid using streams and unofficial-libraries as much as i can(if it can't be done without them, i will use them).
If there is an alternative to ImageIO or the way i read image from url and it gets the thing done, please point me in that direction.

There is no need to decode the image and then re-encode it.
Just read the bytes of the image, and write the bytes, as is, to the file:
try (InputStream in = imageUrl.openStream()) {
Files.copy(in, new File("download.gif").toPath());
}

Encoding image file

I have an int array of color r,g and b values. And I would like to encode them in a image file. Is there an easy method in android to write this data to an image? Also which image format should I use for this, png?

Create a bitmap using your int array like this using Bitmap.createBitmap:
int[] array; // array of int RGB values e.g. 0x00ff0000 = red
Bitmap bitmap = Bitmap.createBitmap(array, width, height, Bitmap.Config.ARGB_8888);
Then write it out using Bitmap.compress:
outStream = new FileOutputStream(filepath);
bitmap.compress(Bitmap.CompressFormat.PNG, 100, outStream);
You can call Environment.getExternalStorageDirectory() to get a folder on external storage where you can save the file, if that's where you want to save it. You can get the path with get File.getAbsolutePath(), e.g:
String filepath = Environment.getExternalStorageDirectory().getAbsolutePath() + "/image.png";
You need the WRITE_EXTERNAL_STORAGE permission defined in your AndroidManifest.xml to be able to write to files on external storage.

There are pure java implementations for reading and writting images:
Image processing library for Android and Java
Probably some will work in android out of the box

I believe ImageIO is available in Android. The ImageIO API provides methods to read the source image and to write the image in the new file format.
To read the image, simply provide the ImageIO.read() method a File object for the source image. This will return a BufferedImage.
//Create file for the source
File input = new File("c:/temp/image.bmp");
//Read the file to a BufferedImage
BufferedImage image = ImageIO.read(input);
Once you have the BufferedImage, you can write the image as a PNG. You will need to create a File object for the destination image. When calling the write() method, specify the type string as "png".
//Create a file for the output
File output = new File("c:/temp/image.png");
//Write the image to the destination as a PNG
ImageIO.write(image, "png", output);

ImageIO.read closes inputs stream

I write images and other data to binary file. When I read image via ImageIO.read(InputStream) from that file, it reads image, it is ok, but method closes given input stream and I cant proceed to read other data.
Why so it is made?
Then how read image without closing stream?
EDIT: It is simple code that writes image and string after into file:
File f = new File("test.bin");
if(f.exists())
f.delete();
f.createNewFile();
DataOutputStream os = new DataOutputStream(new FileOutputStream(f));
BufferedImage img = ImageIO.read(new File("test.jpg"));
ImageIO.write(img, "jpg", os);
os.writeUTF("test string after image");
os.close();
And code that reads all:
DataInputStream is = new DataInputStream(new FileInputStream(f));
BufferedImage img = ImageIO.read(is);
String s = is.readUTF(); // on this line EOFException occurs
System.out.println(s);
NetBeans output:
Exception in thread "main" java.io.EOFException
at java.io.DataInputStream.readUnsignedShort(DataInputStream.java:340)
at java.io.DataInputStream.readUTF(DataInputStream.java:589)
at java.io.DataInputStream.readUTF(DataInputStream.java:564)
at mediamanager.Main.test(Main.java:105)
at mediamanager.Main.main(Main.java:44)
May be I'm doing something wrong?

Quote from the documentation of ImageIO.read(InputStream)
This method does not close the provided InputStream after the read operation has completed; it is the responsibility of the caller to close the stream, if desired.
Emphasis not mine.
The problem is elsewhere. Probably in your code.

I can see two possible causes of such behaviour:
Image reader use buffer to read data from the stream to improve performance. So it reads more data from the stream.
Also image reader could try to read EXIF for already parsed image. Such information usually appended at the end of file to avoid full file rewriting when you are just adding a couple of piece of information about the image.
Try ImageIO.setUseCash(false) it could help.

Image resizing using imgscalr API in java

How to convert Buffered image into a file object.
My function actually needs to return a file object . The imgscalr resizing function returns a BufferedImage after resizing.so How to convert it into a file object.

Here is an example of writing to a PNG file:
ImageIO.write(yourImage, "PNG", "yourfile.png");
You must import ImageIO (javax.imageio) first, however.
Then you can get the File object for the image with new File("yourfile.png");.
You could put this in a function for ease of use; here is an example:
public File imageToFile(BufferedImage img, String fileName) {
if (!(fileName.endsWith(".png"))) fileName += ".png";
ImageIO.write(img, "PNG", filename);
return new File(fileName);
}
Here is a link to the docs.
You cannot make a file object without saving... well, a file. You could put it in a temporary directory and delete it when you are done using it, though.