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Java - Saving byte[] into an image file

This post is a follow up to :
ImageIO.read can't read ByteArrayInputStream (image processing)
Similar to the OP, I am getting a null pointer whenever I try to read from my ByteArrayInputStream (as it should, as explained by the top answer). Noticing this, I have implemented the code from the #haraldK 's answer from the post above in order to correct this issue, but I have run into another problem. I have the following code:
byte[] imageInByteArr = ...
// convert byte array back to BufferedImage
int width = 1085;
int height = 696;
BufferedImage convertedGrayScale = new BufferedImage(width, height, BufferedImage.TYPE_BYTE_GRAY);
convertedGrayScale.getRaster().setDataElements(0, 0, width, height, imageInByteArr );
try {
ImageIO.write(convertedGrayScale, "jpg", new File("C:\\test.jpg"));
}
catch (IOException e) {
System.err.println("IOException: " + e);
}
Upon execution, I run into a java.lang.ArrayIndexOutOfBoundsException: null error on the line right before the try/catch block. My first thought was that this null pointer was arising for not having a file in my C drive called test.jpg. I adjusted to fix that worry, yet I am still getting the same null pointer issue at convertedGrayScale.getRaster().setDataElements(0, 0, width, height, imageInByteArr );. Why is this happening?
On another note, aside from writing the file uining ImageIO, is there ANY other way for me to convert the byte[] into a visual representation of an image? I have tried to just print the array onto a file and saving it as a '.jpg', but the file will not open. Any suggestions will help. To summarize, I am looking to convert a byte[] into an image and save it OR render it onto a browser. Whichever is easier/doable.

it appears that your imageInByteArr is too short. I was able to get the same error you get from this
public static void main(String[] args) {
int width = 1085;
int height = 696;
byte[] imageInByteArr = new byte[width ];
BufferedImage convertedGrayScale = new BufferedImage(width, height, BufferedImage.TYPE_BYTE_GRAY);
convertedGrayScale.getRaster().setDataElements(0, 0, width, height, imageInByteArr);
}
when using width*height for size of imageInByteArr or anything bigger i get no error, but when it's smaller than the data you are trying to update it throws the exception.

Java ImageIO.read(URL) returning null when it shouldn't

Okay so I have spent about 15 hours trying to figure this out. I am working on this program that gets exported to a non-runnable jar file. The issue is I am trying to load an image in the jar and set it to a variable.
I HAVE looked at other posts and I think I have tried everything I could find but nothing seems to work.
I am not asking how to FIND the image as I can get the URL of the image, but then ImageIO.read(URL) is not throwing any exception, but returning null. The image is a .png which I have heard is compatible with ImageIO.read(). I am using an API so that is what the log() lines are.
Any help is appreciated. Thank you!
My Project:
Project
->src
-->package
--->Main.java
--->paint.png
My Code:
In my main method:
(mainPaint is a private Image)
mainPaint = getImage("paint.png");
The method:
private Image getImage(String fileName) {
URL url = getClass().getResource(fileName);
BufferedImage image = null;
log(url.toString()); // To make sure I have the correct file
// returning jar:file:/C:/Users/Me/MyJar.jar!/package/paint.png
try {
image = ImageIO.read(url);
} catch (IOException e1) {
log("Error converting url to image.");
// This is not happening
}
if (image == null) {
log("Image is null.");
// This is happening
}
return image;
}
Is the URL invalid? Am I just missing something? I'm just trying to save the local image in the jar as an Image object, I feel like this is way too difficult for what I am trying to do.
EDIT:
I also just tried making mainPaint a BufferedImage and using:
Image image = Toolkit.getDefaultToolkit().getImage(getClass().getResource(fileName));
if(image == null) {
log("Image is null");
}
log("Height: " + image.getHeight(null));
log("Width: " + image.getWidth(null));
BufferedImage bimage = new BufferedImage(image.getWidth(null), image.getHeight(null), BufferedImage.TYPE_INT_ARGB);
// Draw the image on to the buffered image
Graphics2D bGr = bimage.createGraphics();
bGr.drawImage(image, 0, 0, null);
bGr.dispose();
// Return the buffered image
return bimage;
The height and width of the image are returning -1?

ImageIO.read() will not load SVG files, so if your images are in SVG formate you will need to add plugins to it to support SVG
Here is another SO post that explain where you can do that.

ImageIO.read() will load only GIF, PNG, JPEG, BMP, and WBMP image types.
Any other image type will return null without error.
It could answer to your question .

Cropping BufferedImage For Use in Xuggle encodeVideo

I have an application to capture video of the screen and save to a file. I give the user the ability to pick between 480, 720, and "Full Screen" video sizes. A 480 will record in a small box on the screen, 720 will record in a larger box, and of course, "Full Screen" will record in an even larger box. However, this full screen box is NOT the actual screen resolution. It is the app window size, which happens to be around 1700x800. The Video Tool works perfectly for the 480 and 720 options, and will also work if "Full Screen" is overwridden to be the entire screen of 1920x1080.
My question: Are only certain sizes allowed? Does it have to fit a certain aspect ratio, or be an "acceptable" resolution? My code, below, is modified from the xuggle CaptureScreenToFile.java file (the location of the problem is noted by comments):
public void run() {
try {
String parent = "Videos";
String outFile = parent + "example" + ".mp4";
file = new File(outFile);
// This is the robot for taking a snapshot of the screen. It's part of Java AWT
final Robot robot = new Robot();
final Rectangle customResolution = where; //defined resolution (custom record size - in this case, 1696x813)
final Toolkit toolkit = Toolkit.getDefaultToolkit();
final Rectangle fullResolution = new Rectangle(toolkit.getScreenSize()); //full resolution (1920x1080)
// First, let's make a IMediaWriter to write the file.
final IMediaWriter writer = ToolFactory.makeWriter(outFile);
writer.setForceInterleave(false);
// We tell it we're going to add one video stream, with id 0,
// at position 0, and that it will have a fixed frame rate of
// FRAME_RATE.
writer.addVideoStream(0, 0, FRAME_RATE, customResolution.width, customResolution.height); //if I use fullResolution, it works just fine - but captures more of the screen than I want.
// Now, we're going to loop
long startTime = System.nanoTime();
while (recording) {
// take the screen shot
BufferedImage screen = robot.createScreenCapture(fullResolution); //tried capturing using customResolution, but did not work. Instead, this captures full screen, then tries to trim it below (also does not work).
// convert to the right image type
BufferedImage bgrScreen = convertToType(screen, BufferedImage.TYPE_3BYTE_BGR); //Do I need to convert after trimming?
BufferedImage trimmedScreen = bgrScreen.getSubimage((int)customResolution.getX(), (int)customResolution.getY(), (int)customResolution.getWidth(), (int)customResolution.getHeight());
// encode the image
try{
//~~~~Problem is this line of code!~~~~ Error noted below.
writer.encodeVideo(0, trimmedScreen, System.nanoTime() - startTime, TimeUnit.NANOSECONDS); //tried using trimmedScreen and bgrScreen
} catch (Exception e) {
e.printStackTrace();
}
// sleep for framerate milliseconds
Thread.sleep((long) (1000 / FRAME_RATE.getDouble()));
}
// Finally we tell the writer to close and write the trailer if
// needed
writer.close();
} catch (Throwable e) {
System.err.println("an error occurred: " + e.getMessage());
}
}
public static BufferedImage convertToType(BufferedImage sourceImage, int targetType) {
BufferedImage image;
// if the source image is already the target type, return the source image
if (sourceImage.getType() == targetType)
image = sourceImage;
// otherwise create a new image of the target type and draw the new image
else {
image = new BufferedImage(sourceImage.getWidth(), sourceImage.getHeight(), targetType);
image.getGraphics().drawImage(sourceImage, 0, 0, null);
}
return image;
}
Error:
java.lang.RuntimeException: could not open stream com.xuggle.xuggler.IStream#2834912[index:0;id:0;streamcoder:com.xuggle.xuggler.IStreamCoder#2992432[codec=com.xuggle.xuggler.ICodec#2930320[type=CODEC_TYPE_VIDEO;id=CODEC_ID_H264;name=libx264;];time base=1/50;frame rate=0/0;pixel type=YUV420P;width=1696;height=813;];framerate:0/0;timebase:1/90000;direction:OUTBOUND;]: Operation not permitted
Note: The file is successfully created, but has size of zero, and cannot be opened by Windows Media Player, with the following error text:
Windows Media Player cannot play the file. The Player might not support the file type or might not support the codec that was used to compress the file.
Sorry for the wordy question. I'm interested in learning WHAT and WHY, not just a solution. So if anyone can explain why it isn't working, or point me towards material to help, I'd appreciate it. Thanks!

Try to have the dimension even numbers 1696x812

Loading image from file as given "type" into an OpenCV Mat?

I recently started working with the Java bindings for OpenCV to make a quick and dirty project to do template matching. Basically I am trying to read a set of jpg images (saved in MS Paint) into Mats and then use template matching to find their locations from a screen shot taken with Java.Robot.
When it comes time to do the template matching this error is thrown
OpenCV Error: Assertion failed ((depth == CV_8U || depth == CV_32F)
&& type == _templ.type() && _img.dims() <= 2) in cv::matchTemplate
After searching it looks like the issue is that the two Mats I am trying to use do not have the same "type". What I am not sure of is what this refers to. I assume it is the Mats CvType, if I print out the CvType of the image and template I get a type() of 4 == CvType.CV_32SC1 for my template I get a type() of 20 == CvType.CV_32SC3.
But I feel like this is not the correct type() I am trying to compare, I have feeling it refers to the data type of how the data is stored in the Mat? But I have no good links to back this up just remembrances from many SO searches.
Here is my code for loading in my jpg images into a Mat
Mat pic_ = Imgcodecs.imread("MyPath\\image.jpg");
pic_.convertTo(pic_, CvType.CV_32SC1);
Here the second line turns my type() from 20 to 16, though as per my last comment I don't think this is the proper way to alter the Mat to match the image?... Because convertTo'ing this Mat to match the type of the screen shot `(below) does not fix the error?
Here is how I am creating the image Mat
Rectangle screenRect = new Rectangle(Toolkit.getDefaultToolkit().getScreenSize());
BufferedImage screenShot = rob.createScreenCapture(screenRect);
Mat screenImage = bufferedImageToMat(screenShot);
So I first take a screenshot with Java.Robot.createScreenCapture I then convert it to a Mat with
private Mat bufferedImageToMat(BufferedImage inBuffImg)
{
BufferedImage image = new BufferedImage(inBuffImg.getWidth(), inBuffImg.getHeight(), BufferedImage.TYPE_INT_RGB);
Graphics2D g2d= image.createGraphics();
g2d.drawImage(inBuffImg, 0, 0, null);
g2d.dispose();
Mat mat = new Mat(image.getHeight(), image.getWidth(), CvType.CV_32SC1);
int[] data = ((DataBufferInt) image.getRaster().getDataBuffer()).getData();
mat.put(0, 0, data);
return mat;
}
From what I could tell the BufferedImage created by Robot is of type BufferedImage.TYPE_3BYTE_BGR which gives me an error "DataBufferInt cannot be cast to DataBufferByte" when trying to get the pixel data. So per the linked question I redraw the BufferedImage as type BufferedImage.TYPE_INT_RGB and pull out the data as a DataBufferInt.
So in all, should I be trying to match the Mat.type() or does my problem lie elsewhere? If not elsewhere how can I alter either of the Mats so that they can be used with Imgproc.matchTemplate properly?
I feel like the easiest solution would be to convert the image loaded from file to match the screenshot Mat?
EDIT: The exact section of code that gives the error is below
// Mat imageTemplate is a function argument; the loaded jpg image
// Take a picture of the screen
Rectangle screenRect = new Rectangle(Toolkit.getDefaultToolkit().getScreenSize());
BufferedImage screenShot = rob.createScreenCapture(screenRect);
Mat screenImage = bufferedImageToMat(screenShot);
// Create the result matrix
int result_cols = screenImage.cols() - imageTemplate.cols() + 1;
int result_rows = screenImage.rows() - imageTemplate.rows() + 1;
Mat result = new Mat(result_rows, result_cols, CvType.CV_32SC1);
newStatus("ScreenType: " + screenImage.type());
newStatus("TemplaType: " + imageTemplate.type());
// Choose a matching method
int matchMethod = Imgproc.TM_SQDIFF_NORMED;
// Do the Matching and Normalize
Imgproc.matchTemplate(screenImage, imageTemplate, result, matchMethod);
// Error occurs on previous line

As #Miki pointed out in the comments the answer was getting the channe type to match for the image and template. I ended up changing my bufferedImageToMat function.
private Mat bufferedImageToMat(BufferedImage inBuffImg)
{
BufferedImage image = new BufferedImage(inBuffImg.getWidth(), inBuffImg.getHeight(), BufferedImage.TYPE_4BYTE_ABGR);
Graphics2D g2d= image.createGraphics();
g2d.drawImage(inBuffImg, 0, 0, null);
g2d.dispose();
Mat mat = new Mat(image.getHeight(), image.getWidth(), CvType.CV_8UC3);
byte[] data = ((DataBufferByte) image.getRaster().getDataBuffer()).getData();
mat.put(0, 0, data);
return mat;
}
My templates are read in as CvType.CV_8UC3, so it was just a matter of creating a Mat from the screen image with this type!

Java BufferedImage alternatives

I am trying to implement a simple class that will allow a user to crop an image to be used for their profile picture. This is a java web application.
I have done some searching and found that java.awt has a BufferedImage class, and this appears (at first glance) to be perfect for what I need. However, it seems that there is a bug in this (or perhaps java, as I have seen suggested) that means that the cropping does not always work correctly.
Here is the code I am using to try to crop my image:
BufferedImage profileImage = getProfileImage(form, modelMap);
if (profileImage != null) {
BufferedImage croppedImage = profileImage
.getSubimage(form.getStartX(), form.getStartY(), form.getWidth(), form.getHeight());
System.err.println(form.getStartX());
System.err.println(form.getStartY());
File finalProfileImage = new File(form.getProfileImage());
try {
String imageType = getImageType(form.getProfileImage());
ImageIO.write(croppedImage, imageType, finalProfileImage);
}
catch (Exception e) {
logger.error("Unable to write cropped image", e);
}
}
return modelAndView;
}
protected BufferedImage getProfileImage(CropImageForm form, Map<String, Object> modelMap) {
String profileImageFileName = form.getProfileImage();
if (validImage(profileImageFileName) && imageExists(profileImageFileName)) {
BufferedImage image = null;
try {
image = getCroppableImage(form, ImageIO.read(new File(profileImageFileName)), modelMap);
}
catch (IOException e) {
logger.error("Unable to crop image, could not read profile image: [" + profileImageFileName + "]");
modelMap.put("errorMessage", "Unable to crop image. Please try again");
return null;
}
return image;
}
modelMap.put("errorMessage", "Unable to crop image. Please try again.");
return null;
}
private boolean imageExists(String profileImageFileName) {
return new File(profileImageFileName).exists();
}
private BufferedImage getCroppableImage(CropImageForm form, BufferedImage image, Map<String, Object> modelMap) {
int cropHeight = form.getHeight();
int cropWidth = form.getWidth();
if (cropHeight <= image.getHeight() && cropWidth <= image.getWidth()) {
return image;
}
modelMap.put("errorMessage", "Unable to crop image. Crop size larger than image.");
return null;
}
private boolean validImage(String profileImageFileName) {
String extension = getImageType(profileImageFileName);
return (extension.equals("jpg") || extension.equals("gif") || extension.equals("png"));
}
private String getImageType(String profileImageFileName) {
int indexOfSeparator = profileImageFileName.lastIndexOf(".");
return profileImageFileName.substring(indexOfSeparator + 1);
}
The form referred to in this code snippet is a simple POJO which contains integer values of the upper left corner to start cropping (startX and startY) and the width and height to make the new image.
What I end up with, however, is a cropped image that always starts at 0,0 rather than the startX and startY position. I have inspected the code to make sure the proper values are being passed in to the getSubimage method, and they appear to be.
Are there simple alternatives to using BufferedImage for cropping an image. I have taken a brief look at JAI. I would rather add a jar to my application than update the jdk installed on all of the production boxes, as well as any development/testing servers and local workstations.
My criteria for selecting an alternative are:
1) simple to use to crop an image as this is all I will be using it for
2) if not built into java or spring, the jar should be small and easily deployable in a web-app
Any suggestions?
Note: The comment above that there is an issue with bufferedImage or Java was something I saw in this posting: Guidance on the BufferedImage.getSubimage(int x, int y, int w, int h) method?

I have used getSubimage() numerous times before without any problems. Have you added a System.out.println(form.getStartX() + " " + form.getStartY()) before that call to make sure they're not both 0?
Also, are you at least getting an image that is form.getWidth() x form.getHeight()?
Do make sure you are not modifying/disposing profileImage in any way since the returned BufferedImage shares the same data array as the parent.
The best way is to just simply draw it across if you want a completely new and independent BufferedImage:
BufferedImage croppedImage = new BufferedImage(form.getWidth(),form.getHeight(),BufferedImage.TYPE_INT_ARGB);
Graphics g = croppedImage.getGraphics();
g.drawImage(profileImage,0,0,form.getWidth(),form.getHeight(),form.getStartX(),form.getStartY(),form.getWidth(),form.getHeight(),null);
g.dispose();

You can do it in this manner as well (code is not 100% tested as I adopted for example from an existing app i did):
import javax.imageio.*;
import java.awt.image.*;
import java.awt.geom.*;
...
BufferedImage img = ImageIO.read(imageStream);
...
/*
* w = image width, h = image height, l = crop left, t = crop top
*/
ColorModel dstCM = img.getColorModel();
BufferedImage dst = new BufferedImage(dstCM, dstCM.createCompatibleWritableRaster(w, h), dstCM.isAlphaPremultiplied(), null);
Graphics2D g = dst.createGraphics();
g.drawRenderedImage(img, AffineTransform.getTranslateInstance(-l,-t));
g.dispose();
java.io.File outputfile = new java.io.File(sessionScope.get('absolutePath') + java.io.File.separator + sessionScope.get('lastUpload'));
ImageIO.write(dst, 'png', outputfile);

Thanks for all who replied. It turns out that the problem was not in the cropping code at all.
When I displayed the image to be cropped, I resized it to fit into my layout nicely, then used a javascript cropping tool to figure out the coordinates to crop.
Since I had resized my image, but didn't take the resizing into account when I was determining the cropping coordinates, I ended up with coordinates that appeared to coincide with the top left corner.
I have changed the display to no longer resize the image, and now cropping is working beautifully.