Develop Reference

How do I know whether the image is rotated or inverted while extracting from pdf using PDFBox

Task: My task is to extract all images from pdf and save it to a local file.
Problem: When I am trying to extract images from pdf, I have seen that all images are not loading in properly.
Consider my pdf as 3 images. When I am trying to extract images I have seen that few images are saving in rotated, inverted or with some other rotation angles.
I am not sure what properties does that image consists of in pdf.
Question:
1. I want to know whether an image is rotated or not?
2. If Yes, then I want to know in which angle is that rotated. So that I can change that rotation and save it to my local.
Is there any method or property by which we can know the above properties?
Below is the code I have used:
#Override
protected void processOperator(Operator operator, List<COSBase> operands) throws IOException {
String operation = operator.getName();
if ("Do".equals(operation)) {
COSName objectName = (COSName) operands.get(0);
PDXObject xobject = getResources().getXObject(objectName);
if (xobject instanceof PDImageXObject) {
PDImageXObject image = (PDImageXObject) xobject;
int imageWidth = image.getWidth();
int imageHeight = image.getHeight();
System.out.println(image.getMetadata());//output null
// same image to local
BufferedImage bImage = new BufferedImage(imageWidth, imageHeight, BufferedImage.TYPE_INT_ARGB);
bImage = image.getImage();
System.out.println(bImage.getPropertyNames());//output null
ImageIO.write(bImage, "PNG", new File("C:/PdfBox_Examples/" + "image_" + imageNumber + ".png"));
System.out.println("Image saved.");
imageNumber++;
} else if (xobject instanceof PDFormXObject) {
PDFormXObject form = (PDFormXObject) xobject;
showForm(form);
}
} else {
super.processOperator(operator, operands);
}
}

How to make pdf image fit the whole screen android

I'm using this depo git application that allows you to capture or choose images and save them in a pdf document. It's working great except the image saved does not fit the whole screen.
So I tried changing theses numbers Document document = new Document(PageSize.A4, 38, 38, 50, 38); or image.setBorderWidth(15);
(documentRect.getWidth() - image.getScaledWidth()) / 2,
(documentRect.getHeight() - image.getScaledHeight()) / 2);
but no luck...
Furthermore the author didn't not use any imageview on layout so I have to edit problematically. Any ideas ?
Update : apparently changing image.scaleAbsolute(bmp.getWidth(), bmp.getHeight()); to
image.scaleAbsolute(500f, 500f); or image.scalePercent(500f); does the trick (I have to play with the numbers to fit the page).
Downside the quality image is horrible...
PdfUtils
public static final String LOG_ACTIVITY = "PdfUtils";
public static String ImgPdf(Activity activity, ArrayList<String> listPathImg,String folder, String pdfName) {
String result ="";
Image image;
String path = FileUtils.createFolderApp(folder);
path = path + pdfName + ".pdf";
Document document = new Document(PageSize.A4, 38, 38, 50, 38);
Log.v(LOG_ACTIVITY, "Document Created");
Rectangle documentRect = document.getPageSize();
try {
PdfWriter writer = PdfWriter.getInstance(document, new FileOutputStream(path));
document.open();
for (int i = 0; i < listPathImg.size(); i++) {
Bitmap bmp = MediaStore
.Images
.Media
.getBitmap(
activity.getContentResolver(),
Uri.fromFile(new File(listPathImg.get(i))));
ByteArrayOutputStream stream = new ByteArrayOutputStream();
bmp.compress(Bitmap.CompressFormat.PNG, 70, stream);
image = Image.getInstance(listPathImg.get(i));
if (bmp.getWidth() > documentRect.getWidth() || bmp.getHeight() > documentRect.getHeight()) {
//bitmap is larger than page,so set bitmap's size similar to the whole page
image.scaleAbsolute(documentRect.getWidth(), documentRect.getHeight());
} else {
//bitmap is smaller than page, so add bitmap simply.
//[note: if you want to fill page by stretching image,
// you may set size similar to page as above]
image.scaleAbsolute(bmp.getWidth(), bmp.getHeight());
}
image.setAbsolutePosition(
(documentRect.getWidth() - image.getScaledWidth()) / 2,
(documentRect.getHeight() - image.getScaledHeight()) / 2);
image.setBorder(Image.BOX);
image.setBorderWidth(15);
document.add(image);
document.newPage();
}
result=path;
} catch (Exception err) {
err.printStackTrace();
result="";
} finally {
document.close();
}
return result;
}

Instead of image.scaleAbsolute(width,height) try image.scaleToFit(width,height)

I think what you want to do is change the size of
Rectangle documentRect = document.getPageSize();
Rectangle has 4 parameters that you can set on construction (x , y, width, height).
Changing those might solve your problem.

I use PDF24 Creator if I understand the question correctly.

Solution from this answer.
I changed image.scaleAbsolute(bmp.getWidth(), bmp.getHeight()); to
image.scalePercent(scaler); ofc you have to include
float scaler = ((document.getPageSize().getWidth() - document.leftMargin()
- document.rightMargin() - indentation) / image.getWidth()) * 100;
Now it fit. Though the image quality is not perfect.

OpenCV on Android: net.forward yields "215 Assertion failed"

Following this tutorial from openCV, and it should be straight forward. However, it crashes with an assertion fail on the net.forward, that I cannot resolve/find anywhere else.
Thought this problem seemed similar and tried to go through the fix/problem finding. However, restarting the discussion and trials showed it is likely not the same. I used initially 3.4.3, which did not support the same Mat type somehow. Updated to 3.4.7 now, and can confirm the blob size is okay (generated from image). Tried also various other prototxt and caffemodels, but doubt by now that the problem lies there (works if the files are okay, otherwise the net loading fails). The key code should be this:
// Load a network.
public void onCameraViewStarted(int width, int height) {
String proto = getPath("deploy.prototxt", this);
String weights = getPath("MobileNetSSD_deploy.caffemodel", this);
net = Dnn.readNetFromCaffe(proto, weights);
Log.i(TAG, "Network loaded successfully");
}
public Mat onCameraFrame(CvCameraViewFrame inputFrame) {
// Get a new frame
Mat frame = inputFrame.rgba();
Imgproc.cvtColor(frame, frame, Imgproc.COLOR_RGBA2RGB);
// Forward image through network.
Mat blob = Dnn.blobFromImage(frame, 0.007843,
new Size(300, 300),
new Scalar(127.5, 127.5, 127.5));
net.setInput(blob);
Mat detections = net.forward(); //***215 ASSERTION FAILED occurs***
int cols = frame.cols();
int rows = frame.rows();
detections = detections.reshape(1, (int)detections.total() / 7);
for (int i = 0; i < detections.rows(); ++i) {
double confidence = detections.get(i, 2)[0];
if (confidence > 0.2) {
int classId = (int)detections.get(i, 1)[0];
int left = (int)(detections.get(i, 3)[0] * cols);
int top = (int)(detections.get(i, 4)[0] * rows);
int right = (int)(detections.get(i, 5)[0] * cols);
int bottom = (int)(detections.get(i, 6)[0] * rows);
// Draw rectangle around detected object.
Imgproc.rectangle(frame, new Point(left, top), new Point(right, bottom),
new Scalar(0, 255, 0));
String label = classNames[classId] + ": " + confidence;
int[] baseLine = new int[1];
Size labelSize = Imgproc.getTextSize(label, Core.FONT_HERSHEY_SIMPLEX, 0.5, 1, baseLine);
// Draw background for label.
Imgproc.rectangle(frame, new Point(left, top - labelSize.height),
new Point(left + labelSize.width, top + baseLine[0]),
new Scalar(255, 255, 255), Core.FILLED);
// Write class name and confidence.
Imgproc.putText(frame, label, new Point(left, top),
Core.FONT_HERSHEY_SIMPLEX, 0.5, new Scalar(0, 0, 0));
}
}
return frame;
}
public void onCameraViewStopped() {}
// Upload file to storage and return a path.
private static String getPath(String file, Context context) {
AssetManager assetManager = context.getAssets();
BufferedInputStream inputStream = null;
try {
// Read data from assets.
inputStream = new BufferedInputStream(assetManager.open(file));
byte[] data = new byte[inputStream.available()];
inputStream.read(data);
inputStream.close();
// Create copy file in storage.
File outFile = new File(context.getFilesDir(), file);
FileOutputStream os = new FileOutputStream(outFile);
os.write(data);
os.close();
// Return a path to file which may be read in common way.
return outFile.getAbsolutePath();
} catch (IOException ex) {
Log.i(TAG, "Failed to upload a file");
}
return "";
}
The full error message is
cv::Exception: OpenCV(3.4.7) /build/3_4_pack-android/opencv/modules/dnn/src/layers/batch_norm_layer.cpp:39: error: (-215:Assertion failed) blobs.size() >= 2 in function 'cv::dnn::BatchNormLayerImpl::BatchNormLayerImpl(const cv::dnn::experimental_dnn_34_v13::LayerParams&)'
I expect it to not crash. The frame should be okay (image loaded), the net is not empty, and the layers in the net seem fine too (checked since there are some differences using caffe in java). Any help is appreciated!

After some days of research in different directions, I found the problem: the frame format should be BGR, not RGB! That means
Imgproc.cvtColor(frame, frame, Imgproc.COLOR_RGBA2BGR);

Writing javafx.scene.image.Image to file?

How would I go about writing a javafx.scene.image.Image image to a file. I know you can use ImageIO on BufferedImages but is there any way to do it with a javafx Image?

Just convert it to a BufferedImage first, using javafx.embed.swing.SwingFXUtils:
Image image = ... ; // javafx.scene.image.Image
String format = ... ;
File file = ... ;
ImageIO.write(SwingFXUtils.fromFXImage(image, null), format, file);

Almost 3 years later and I now have the knowledge to do and answer this. Yes the original answer was also valid but it involved first converting the image to a BufferedImage and I ideally wanted to avoid swing entirely. While this does output the raw RGBA version of the image that's good enough for what I needed to do. I actually could just use raw BGRA since I was writing the software to open the result but since gimp can't open that I figure I'd convert it to RGBA.
Image img = new Image("file:test.png");
int width = (int) img.getWidth();
int height = (int) img.getHeight();
PixelReader reader = img.getPixelReader();
byte[] buffer = new byte[width * height * 4];
WritablePixelFormat<ByteBuffer> format = PixelFormat.getByteBgraInstance();
reader.getPixels(0, 0, width, height, format, buffer, 0, width * 4);
try {
BufferedOutputStream out = new BufferedOutputStream(new FileOutputStream("test.data"));
for(int count = 0; count < buffer.length; count += 4) {
out.write(buffer[count + 2]);
out.write(buffer[count + 1]);
out.write(buffer[count]);
out.write(buffer[count + 3]);
}
out.flush();
out.close();
} catch(IOException e) {
e.printStackTrace();
}

JavaFX has no built-in method to do this.
To solve this problem, I implemented a very small (< 20KiB) library for writing PNG files: https://github.com/Glavo/SimplePNG
Usage:
Image img = new Image("path-to-image.jpg");
try (PNGWriter writer = new PNGWriter(Files.newOutputStream(Path.of("output.png")))) {
writer.write(PNGJavaFXUtils.asArgbImage(img));
}
// Or you can use the shortcut:
// PNGJavaFXUtils.writeImage(img, Path.of("output.png"));
It has no dependencies and can work on the JRE that only have java.base.
I avoid the dependence on Java AWT (java.desktop) through it.

My batch jpg resizer works with color images, but grayscale ones become washed out

I've been having a problem with my Java program. It's for resizing images. You drop it into a folder and run it, and it creates a new folder with the resized images. It works great on color, but it has a problem with grayscale. The images are converted, but they become lighter and more washed out, as if someone has messed with the curves or levels. All the input files and output files are sRGB color space jpegs, saved in RGB color mode. I have thousands of 50 megapixel film scans I'm trying to convert down to 15 megapixels or less. Any help or ideas anyone could offer would be most appreciated. The programs full code is below, it's about 130 lines. I have a feeling the problem may be in the toBufferedImage function but I'm lost as to what it could be.
package jpegresize;
import java.awt.*;
import java.awt.image.*;
import java.util.*;
import java.io.*;
import javax.imageio.*;
import javax.imageio.stream.*;
import javax.swing.*;
public class Main {
public static void main(String[] args) {
System.out.println("JPEGResize running . . .");
int max_side = 4096;
float quality = 0.9f;
if(args.length == 0) System.out.println("No maximum side resolution or compression quality arguments given, using default values.\nUsage: java -jar JPEGResize.jar <maximum side resolution in pixels> <quality 0 to 100 percent>");
if(args.length >= 1) max_side = Integer.parseInt(args[0]);
if(args.length >= 2) quality = Float.parseFloat(args[1]) / 100.0f;
System.out.println("Maximum side resolution: " + max_side);
System.out.println("Compression quality: " + (quality * 100) + "%");
File folder = new File(".");
File[] listOfFiles = folder.listFiles(new JPEGFilter());
for(int i = 0; i < listOfFiles.length; i++) {
System.out.println("Processing " + listOfFiles[i].getName() + " . . .");
resizeFile(listOfFiles[i].getName(), max_side, quality);
System.out.println("Saved /resized/" + listOfFiles[i].getName());
}
System.out.println("Operations complete.");
}
public static void resizeFile(String filename, int max_side, float quality) {
try
{
BufferedImage input_img = ImageIO.read(new File(filename));
double aspect_ratio = ((double)input_img.getWidth()) / ((double)input_img.getHeight());
int width, height;
if(input_img.getWidth() >= input_img.getHeight()) {
width = max_side;
height = (int)(((double)max_side) / aspect_ratio);
}
else {
width = (int)(((double)max_side) * aspect_ratio);
height = max_side;
}
Image scaled_img = input_img.getScaledInstance(width, height, Image.SCALE_SMOOTH);
BufferedImage output_img = toBufferedImage(scaled_img);
Iterator iter = ImageIO.getImageWritersByFormatName("jpeg");
ImageWriter writer = (ImageWriter)iter.next();
ImageWriteParam iwp = writer.getDefaultWriteParam();
iwp.setCompressionMode(ImageWriteParam.MODE_EXPLICIT);
iwp.setCompressionQuality(quality);
File doesDirExist = new File("resized/");
if(!doesDirExist.exists())
new File("resized").mkdir();
File file = new File("resized/" + filename);
FileImageOutputStream output = new FileImageOutputStream(file);
writer.setOutput(output);
IIOImage image = new IIOImage(output_img, null, null);
writer.write(null, image, iwp);
writer.dispose();
}
catch (IOException e)
{
e.printStackTrace();
}
}
// This method returns a buffered image with the contents of an image
public static BufferedImage toBufferedImage(Image image) {
if (image instanceof BufferedImage) {
return (BufferedImage)image;
}
// This code ensures that all the pixels in the image are loaded
image = new ImageIcon(image).getImage();
// Create a buffered image with a format that's compatible with the screen
BufferedImage bimage = null;
GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();
try {
// Determine the type of transparency of the new buffered image
int transparency = Transparency.OPAQUE;
// Create the buffered image
GraphicsDevice gs = ge.getDefaultScreenDevice();
GraphicsConfiguration gc = gs.getDefaultConfiguration();
bimage = gc.createCompatibleImage(
image.getWidth(null), image.getHeight(null), transparency);
} catch (HeadlessException e) {
// The system does not have a screen
}
if (bimage == null) {
// Create a buffered image using the default color model
int type = BufferedImage.TYPE_INT_RGB;
bimage = new BufferedImage(image.getWidth(null), image.getHeight(null), type);
}
// Copy image to buffered image
Graphics g = bimage.createGraphics();
// Paint the image onto the buffered image
g.drawImage(image, 0, 0, null);
g.dispose();
return bimage;
}
}
class JPEGFilter implements FilenameFilter {
public boolean accept(File dir, String name) {
return (name.toLowerCase().endsWith(".jpg")) || (name.toLowerCase().endsWith(".jpeg"));
}
}

If jdk's classes and methods are buggy, report the bug to oracle (oh! I wish I could go on saying to SUN..).
And, while the next release will correct the bug ;), try some work arounds, scaling image by yourself like proposed here.
Regards,
Stéphane

In your code, you assume jpeg are encoded in RGB, but that's not always the case. It's also possible to encode 8 bit gray scaled jpeg. So I suggest that you try this when building your BufferedImage, replace :
BufferedImage.TYPE_INT_RGB;
by
BufferedImage.TYPE_BYTE_GRAY;
and see if it works for those images.
If so, then you still have to find out a way to determine the encoding type to automatically change the type of BufferedImage color encoding to use, but you will be one stop closer.
Regards,
Stéphane