Develop Reference

GridView only create Images when they would be visible

Hei there
So I have the following problem. I have around 1500 images of playing cards. I want to display them in a "Gallery" where you could scroll through them. I was able to create a GridView with the ImageCell object and I was also able to add images to it. Now my problem is that if I add all Image's at once logically Java crashes because of a heap error. I have the image url's (local files) in a list. How could I implement that it only load lets say 15 images. If I then scroll it loads the next 15 and unloads the old ones. So it would only load the images of the actual visible images and not all 1500. How would I do this? I am completely out of ideas.
The Platform.runLater() is needed because some sort of issue with ControlsFX
Here my code:
public void initialize() {
GridView<Image> gridView = new GridView<>();
gridView.setCellFactory(gridView1 -> new ImageGridCell(true));
Image image = new Image("C:\\Users\\nijog\\Downloads\\cardpictures\\01DE001.png");
gridView.setCellWidth(340);
gridView.setCellHeight(512);
//Platform.runLater(()-> {
// for (int i = 0; i < 5000; i++){
// gridView.getItems().add(image);
// }
//});
Platform.runLater(() -> gridView.getItems().addAll(createImageListFromCardFiles()));
borderPane.setCenter(gridView);
}
protected List<Image> createImageListFromCardFiles(){
List<Image> imageViewList = new ArrayList<>();
App.getCardService().getCardArray().stream()
//.filter(Card::isCollectible)
.sorted(Comparator.comparingInt(Card::getCost))
.sorted(Comparator.comparing(Card::isChampion).reversed())
.skip(0)
//.limit(100)
.forEach(card -> {
try {
String url = String.format(App.pictureFolderPath +"%s.png", card.getCardCode());
imageViewList.add(new Image(url));
} catch (Exception e) {
System.out.println("Picture file not found [CardCode = " + card.getCardCode() + "]");
App.logger.writeLog(Logger.Operation.EXCEPTION, "Picture file not found [CardCode = " + card.getCardCode() + "]");
}
});
return imageViewList;
}

You might not need to use the strategy you describe. You're displaying the images in cells of size 340x512, which is 174,080 pixels. Image storage is 4 bytes per pixel, so this is 696,320 bytes per image; 1500 of them will consume about 1GB. You just need to make sure you load the image at the size you are displaying it (instead of its native size):
// imageViewList.add(new Image(url));
imageViewList.add(new Image(url, 340, 512, true, true, true));
If you need an image at full size later (e.g. if you want the user to select an image from your grid view and display it in a bigger pane), you'd just need to reload it from the url.
If you do need to implement the strategy you describe, GridView supports that out of the box. Just keep a list of the URLs, instead of the Images, and use a custom GridCell to load the image as needed. This will consume significantly less memory, at the cost of a lot more I/O (loading the images) and CPU (parsing the image format).
Make the items for the GridView the image urls, stored as Strings.
Then you can do something like:
GridView<String> gridView = new GridView<>();
gridView.getItems().addAll(getAllImageURLs());
gridView.setCellFactory(gv -> new GridCell<>() {
private final ImageView imageView = new ImageView();
{
imageView.fitWidthProperty().bind(widthProperty());
imageView.fitHeightProperty().bind(heightProperty());
imageView.setPreserveRatio(true);
}
#Override
protected void updateItem(String url, boolean empty) {
super.updateItem(url, empty);
if (empty || url == null) {
setGraphic(null);
} else {
double w = getGridView().getCellWidth();
double h = getGridView().getCellHeight();
imageView.setImage(new Image(url, w, h, true, true, true));
setGraphic(imageView);
}
}
});
protected List<String> getAllImageURLs(){
return App.getCardService().getCardArray().stream()
// isn't the first sort redundant here?
.sorted(Comparator.comparingInt(Card::getCost))
.sorted(Comparator.comparing(Card::isChampion).reversed())
.map(card -> String.format(App.pictureFolderPath +"%s.png", card.getCardCode()))
.collect(Collectors.toList());
}

Image comparaison performance java

i have this code below, but it is not efficient at all, it is very very slow and more pictures i have to compare more long time it takes.
For example i have 500 pictures, each process lasts 2 minutes, 500 x 2 min =1000 min !
the specificity is as soon as there is picture same as compared, move it to another folder. then retrieve the rest files to compare i++
any idea ?
public static void main(String[] args) throws IOException {
String PicturesFolderPath=null;
String removedFolderPath=null;
String pictureExtension=null;
if(args.length>0) {
PicturesFolderPath=args[0];
removedFolderPath=args[1];
pictureExtension=args[2];
}
if(StringUtils.isBlank(pictureExtension)) {
pictureExtension="jpg";
}
if(StringUtils.isBlank(removedFolderPath)) {
removedFolderPath=Paths.get(".").toAbsolutePath().normalize().toString()+"/removed";
}
if(StringUtils.isBlank(PicturesFolderPath)) {
PicturesFolderPath=Paths.get(".").toAbsolutePath().normalize().toString();
}
System.out.println("path to find pictures folder "+PicturesFolderPath);
System.out.println("path to find removed pictures folder "+removedFolderPath);
Collection<File> fileList = FileUtils.listFiles(new File(PicturesFolderPath), new String[] { pictureExtension }, false);
System.out.println("there is "+fileList.size()+" files founded with extention "+pictureExtension);
Iterator<File> fileIterator=fileList.iterator();
//Iterator<File> loopFileIterator=fileList.iterator();
File dest=new File(removedFolderPath);
while(fileIterator.hasNext()) {
File file=fileIterator.next();
System.out.println("process image :"+file.getName());
//each new iteration we retrieve the files staying
Collection<File> list = FileUtils.listFiles(new File(PicturesFolderPath), new String[] { pictureExtension }, false);
for(File f:list) {
if(compareImage(file,f) && !file.getName().equals(f.getName()) ) {
String filename=file.getName();
System.out.println("file :"+file.getName() +" equal to "+f.getName()+" and will be moved on removed folder");
File existFile=new File(removedFolderPath+"/"+file.getName());
if(existFile.exists()) {
existFile.delete();
}
FileUtils.moveFileToDirectory(file, dest, false);
fileIterator.remove();
System.out.println("file :"+filename+" removed");
break;
}
}
}
}
// This API will compare two image file //
// return true if both image files are equal else return false//**
public static boolean compareImage(File fileA, File fileB) {
try {
// take buffer data from botm image files //
BufferedImage biA = ImageIO.read(fileA);
DataBuffer dbA = biA.getData().getDataBuffer();
int sizeA = dbA.getSize();
BufferedImage biB = ImageIO.read(fileB);
DataBuffer dbB = biB.getData().getDataBuffer();
int sizeB = dbB.getSize();
// compare data-buffer objects //
if(sizeA == sizeB) {
for(int i=0; i<sizeA; i++) {
if(dbA.getElem(i) != dbB.getElem(i)) {
return false;
}
}
return true;
}
else {
return false;
}
}
catch (Exception e) {
e.printStackTrace();
return false;
}
}

The already mentioned answer should help you a bit, as considering the width and height of a picture should exclude more candidate pairs quickly.
However, you still have a big problem: For every new file, you read all old files. The number of comparisons grows quadratically and with doing ImageIO.read for every step, it simply must be slow.
You need some fingerprints, which can be compared very fast. You can't use fingerprinting over the whole file content as its infested by the metadata, but you can fingerprint the image data alone.
Just iterate over the image data of a file (like you do), and compute e.g., MD5 hash of it. Store it e.g., as a String in HashSet and you'll get a very fast lookup.
Some untested code
For every image file you want to compare, you compute (using Guava's hashing)
HashCode imageFingerprint(File file) {
Hasher hasher = Hashing.md5().newHasher();
BufferedImage image = ImageIO.read(file);
DataBuffer buffer = image.getData().getDataBuffer();
int size = buffer.getSize();
for(int i=0; i<size; i++) {
hasher.putInt(buffer.getElem(i));
}
return hasher.hash();
}
The computation works with the image data only, just like compareImage in the question, so the metadata get ignored.
Instead of searching for a duplicate in a directory, you compute the fingerprints of all its files and store them in a HashSet<HashCode>. For a new file, you compute its fingerprint and look it up in the set.

How to edit a microsoft window spacing from a java application?

i'm trying to implement steganography's word shifting coding protocol on a microsoft word report using java application. Basicly, it uses an existing report and edit it's spacing to put some secret data. If it's wider, then its 1 bit data. And if it's narrower, then it's 0 bit data. So i wonder what kind of library should i have to start constructing this java app or if java doesn't support this kind of comunication with ms-word what kind language of programming should i use, thank you for your time.

I would recommend using C# and the Microsoft.Office.Interop.Word. You can use the free Visual Studio Community version (https://www.visualstudio.com/products/visual-studio-community-vs), create a console application and add a reference for the interop namespace (in project explorer, right click on references, add reference: COM->Microsoft Word 16.0 Object Library).
Simple example:
namespace WordShiftingExample
{
class Program
{
private static int[] getSpaces(string text)
{
System.Collections.ArrayList list = new System.Collections.ArrayList();
int index = 0;
while (index != text.LastIndexOf(" "))
{
index = text.IndexOf(" ", index + 1);
list.Add(index);
}
return list.ToArray(typeof(int)) as int[];
}
static void Main(string[] args)
{
try
{
Microsoft.Office.Interop.Word.Application winword = new Microsoft.Office.Interop.Word.Application();
winword.ShowAnimation = false;
winword.Visible = false;
object missing = System.Reflection.Missing.Value;
Microsoft.Office.Interop.Word.Document document = winword.Documents.Add(ref missing, ref missing, ref missing, ref missing);
float zero = 0.1F;
float one = 0.15F;
document.Content.Text = "This is a test document.";
//set word-spacing for first two spaces
int[] spaces = getSpaces(document.Content.Text);
document.Range(spaces[0], spaces[0]+1).Font.Spacing=zero;
document.Range(spaces[1], spaces[1]+1).Font.Spacing = one;
//read word-spacing for first two spaces
System.Diagnostics.Debug.WriteLine(document.Range(spaces[0], spaces[0]+1).Font.Spacing); // prints 0.1
System.Diagnostics.Debug.WriteLine(document.Range(spaces[1], spaces[1]+1).Font.Spacing); // prints 0.15
//Save the document
object filename = System.Environment.GetEnvironmentVariable("USERPROFILE")+"\\temp1.docx";
document.SaveAs2(ref filename);
document.Close(ref missing, ref missing, ref missing);
document = null;
winword.Quit(ref missing, ref missing, ref missing);
winword = null;
}
catch (Exception ex)
{
System.Diagnostics.Debug.WriteLine(ex.StackTrace);
}
}
}
}

I cant get any output from the Sample Code of Face Detection and recognition code using JavaCV on Eclipse(Juno).

I was practicing on some face recognition and detection codes using Java on JavaCv on Eclpise Juno. The Thing is i was trying to run the sample code below but i cant get the expected result or output. The sample code is as follows
import com.googlecode.javacpp.Loader;
import com.googlecode.javacv.*;
import com.googlecode.javacv.cpp.*;
import static com.googlecode.javacv.cpp.opencv_core.*;
import static com.googlecode.javacv.cpp.opencv_imgproc.*;
import static com.googlecode.javacv.cpp.opencv_calib3d.*;
import static com.googlecode.javacv.cpp.opencv_objdetect.*;
public class Demo {
public static void main(String[] args) throws Exception {
String classifierName = null;
if (args.length > 0) {
classifierName = args[0];
} else {
System.err.println("C://opencv/data/haarcascades\"haarcascade_frontalface_alt.xml\".");
System.exit(1);
}
// Preload the opencv_objdetect module to work around a known bug.
Loader.load(opencv_objdetect.class);
// We can "cast" Pointer objects by instantiating a new object of the desired class.
CvHaarClassifierCascade classifier = new CvHaarClassifierCascade(cvLoad(classifierName));
if (classifier.isNull()) {
System.err.println("Error loading classifier file \"" + classifierName + "\".");
System.exit(1);
}
// CanvasFrame is a JFrame containing a Canvas component, which is hardware accelerated.
// It can also switch into full-screen mode when called with a screenNumber.
CanvasFrame frame = new CanvasFrame("Some Title");
// OpenCVFrameGrabber uses opencv_highgui, but other more versatile FrameGrabbers
// include DC1394FrameGrabber, FlyCaptureFrameGrabber, OpenKinectFrameGrabber,
// PS3EyeFrameGrabber, VideoInputFrameGrabber, and FFmpegFrameGrabber.
FrameGrabber grabber = new OpenCVFrameGrabber(0);
grabber.start();
// FAQ about IplImage:
// - For custom raw processing of data, getByteBuffer() returns an NIO direct
// buffer wrapped around the memory pointed by imageData.
// - To get a BufferedImage from an IplImage, you may call getBufferedImage().
// - The createFrom() factory method can construct an IplImage from a BufferedImage.
// - There are also a few copy*() methods for BufferedImage<->IplImage data transfers.
IplImage grabbedImage = grabber.grab();
int width = grabbedImage.width();
int height = grabbedImage.height();
IplImage grayImage = IplImage.create(width, height, IPL_DEPTH_8U, 1);
IplImage rotatedImage = grabbedImage.clone();
// Let's create some random 3D rotation...
CvMat randomR = CvMat.create(3, 3), randomAxis = CvMat.create(3, 1);
// We can easily and efficiently access the elements of CvMat objects
// with the set of get() and put() methods.
randomAxis.put((Math.random()-0.5)/4, (Math.random()-0.5)/4, (Math.random()-0.5)/4);
cvRodrigues2(randomAxis, randomR, null);
double f = (width + height)/2.0; randomR.put(0, 2, randomR.get(0, 2)*f);
randomR.put(1, 2, randomR.get(1, 2)*f);
randomR.put(2, 0, randomR.get(2, 0)/f); randomR.put(2, 1, randomR.get(2, 1)/f);
System.out.println(randomR);
// Objects allocated with a create*() or clone() factory method are automatically released
// by the garbage collector, but may still be explicitly released by calling release().
// You shall NOT call cvReleaseImage(), cvReleaseMemStorage(), etc.
//on objects allocated this way.
CvMemStorage storage = CvMemStorage.create();
// We can allocate native arrays using constructors taking an integer as argument.
CvPoint hatPoints = new CvPoint(3);
// Again, FFmpegFrameRecorder also exists as a more versatile alternative.
FrameRecorder recorder = new OpenCVFrameRecorder("output.avi", width, height);
recorder.start();
while (frame.isVisible() && (grabbedImage = grabber.grab()) != null) {
cvClearMemStorage(storage);
// Let's try to detect some faces! but we need a grayscale image...
cvCvtColor(grabbedImage, grayImage, CV_BGR2GRAY);
CvSeq faces = cvHaarDetectObjects(grayImage, classifier, storage,
1.1, 3, CV_HAAR_DO_CANNY_PRUNING);
int total = faces.total();
for (int i = 0; i < total; i++) {
CvRect r = new CvRect(cvGetSeqElem(faces, i));
int x = r.x(), y = r.y(), w = r.width(), h = r.height();
cvRectangle(grabbedImage, cvPoint(x, y), cvPoint(x+w, y+h), CvScalar.RED, 1, CV_AA, 0);
// To access the elements of a native array, use the position() method.
hatPoints.position(0).x(x-w/10) .y(y-h/10);
hatPoints.position(1).x(x+w*11/10).y(y-h/10);
hatPoints.position(2).x(x+w/2) .y(y-h/2);
cvFillConvexPoly(grabbedImage, hatPoints.position(0), 3, CvScalar.GREEN, CV_AA, 0);
}
// Let's find some contours! but first some thresholding...
cvThreshold(grayImage, grayImage, 64, 255, CV_THRESH_BINARY);
// To check if an output argument is null we may call either isNull() or equals(null).
CvSeq contour = new CvSeq(null);
cvFindContours(grayImage, storage, contour, Loader.sizeof(CvContour.class),
CV_RETR_LIST, CV_CHAIN_APPROX_SIMPLE);
while (contour != null && !contour.isNull()) {
if (contour.elem_size() > 0) {
CvSeq points = cvApproxPoly(contour, Loader.sizeof(CvContour.class),
storage, CV_POLY_APPROX_DP, cvContourPerimeter(contour)*0.02, 0);
cvDrawContours(grabbedImage, points, CvScalar.BLUE, CvScalar.BLUE, -1, 1, CV_AA);
}
contour = contour.h_next();
}
cvWarpPerspective(grabbedImage, rotatedImage, randomR);
frame.showImage(rotatedImage);
recorder.record(rotatedImage);
}
recorder.stop();
grabber.stop();
frame.dispose();
}
}
The Output i am getting is a line printed in red and its like.
C://opencv/data/haarcascades"haarcascade_frontalface_alt.xml".
Can anybody show what i missed?
I am new to image processing and so please can anyone indicate me where i could get good tutorials and sample source codes that could teach me how to master all the in-built functions in JavaCv and their functionalities? I was working on my final year project and really need your hand on this one.
With lots of respect
Sisay

haarcascade_frontalface_alt.xml is trained classifier for detecting frontal face. It is usually present in opencv_installation_folder/opencv/data/haarcascade folder. you can give the direct path of your classifier instead of taking it from command line as
classifierName = opencv_installation_folder/opencv/data/harcascade/haarcascade_frontalface_alt.xml

that demo expects you to give it the cascade-file as an argument. it just stops, if it does not get one.
maybe you want to change the beginning like this:
public class Demo {
public static void main(String[] args) throws Exception {
String classifierName = "C:/opencv/data/haarcascades/haarcascade_frontalface_alt.xml";
if (args.length > 0) {
classifierName = args[0];
}
like that, it takes an arg from cmdline if present, else it takes the default-value

Get GPS data from an image Java code

I would like to get the metadata from an image file in my local system using Java code
In the attached image you can see the desired data which i would like to pull from java code.
I wrote the below code and do not seem pull the data mentioned in the "Details" tab. The below code's output is and this is not what I look for.
Started ..
Format name: javax_imageio_jpeg_image_1.0
Format name: javax_imageio_1.0
Please give me your ideas. Thanks
try {
ImageInputStream inStream = ImageIO.createImageInputStream(new File("D:\\codeTest\\arun.jpg"));
Iterator<ImageReader> imgItr = ImageIO.getImageReaders(inStream);
while (imgItr.hasNext()) {
ImageReader reader = imgItr.next();
reader.setInput(inStream, true);
IIOMetadata metadata = reader.getImageMetadata(0);
String[] names = metadata.getMetadataFormatNames();
int length = names.length;
for (int i = 0; i < length; i++) {
System.out.println( "Format name: " + names[ i ] );
}
}
} catch (IOException e) {
e.printStackTrace();
}

There's no easy way to do it with the Java Core API. You'd have to parse the image's metadata tree, and interpret the proper EXIF tags. Instead, you can pick up the required code from an existing library with EXIF-parsing capabilities, and use it in yours. For example, I have used the Image class of javaxt, which provides a very useful method to extract GPS metadata from an image. It is as simple as:
javaxt.io.Image image = new javaxt.io.Image("D:\\codeTest\\arun.jpg");
double[] gps = image.getGPSCoordinate();
Plus, javaxt.io.Image has no external dependencies, so you can just use that particular class if you don't want to add a dependency on the entire library.

I suggest you read the EXIF header of the image and then parse the tags for finding the GPS information. In Java there is a great library (called metadata-extractor) for extracting and parsing the EXIF header. Please see the getting started for this library here.
Once you do the first 2 steps in the tutorial, look for the tags starting with [GPS] ([GPS] GPS Longitude, [GPS] GPS Latitude, ...).

Based on #dan-d answer, here is my code (kotlin)
private fun readGps(file: String): Optional<GeoLocation> {
// Read all metadata from the image
// Read all metadata from the image
val metadata: Metadata = ImageMetadataReader.readMetadata(File(file))
// See whether it has GPS data
val gpsDirectories = metadata.getDirectoriesOfType(
GpsDirectory::class.java)
for (gpsDirectory in gpsDirectories) {
// Try to read out the location, making sure it's non-zero
val geoLocation = gpsDirectory.geoLocation
if (geoLocation != null && !geoLocation.isZero) {
return Optional.of(geoLocation)
}
}
return Optional.empty()
}