Develop Reference

Java OpenCV save video file

I would like to save a file (avi) of some frames (in this case, 600) from my webcam using java opencv, but i have no idea how to do that, the code below gives me the avi file specified but with size 0, no frames inside whatsover, also in the directory i have those 600 frames in jpeg's.
It's important to use java for that, no python.
Mat frame = new Mat();
VideoWriter writer = new VideoWriter("c:/opencv/vid.avi", VideoWriter.fourcc('X','2','6','4'), 30 ,frame.size(), true);
videoCapture = new VideoCapture();
videoCapture.open(0);
videoCapture.set(Videoio.CAP_PROP_FRAME_WIDTH, 1280);
videoCapture.set(Videoio.CAP_PROP_FRAME_HEIGHT, 720);
while (true){
videoCapture.read(frame);
if (!frame.empty())
break;
}
int frameNo = 0;
while (frameNo < 600){
videoCapture.read(frame);
writer.write(frame);
Imgcodecs imageCodecs = new Imgcodecs();
String file = "c:/opencv/i" + frameNo + ".jpg";
Imgcodecs.imwrite(file,frame);
frameNo++;
}
videoCapture.release(); // release device

You didn't mention which openCV version are you using, I use OpenCV-3.4.2
AVI container use DIVX codec reference: https://wiki.videolan.org/DivX/
I modify a bit your code:
Mat frame = new Mat();
VideoWriter writer = new VideoWriter("c:/opencv/vid.avi", VideoWriter.fourcc('D', 'I', 'V', 'X'), 30, new Size(videoCapture.get(Videoio.CAP_PROP_FRAME_WIDTH), videoCapture.get(Videoio.CAP_PROP_FRAME_HEIGHT)));
while(runnable)
{
if(videoCapture.grab())
{
try
{
//Decodes and returns the grabbed video frame.
videoCapture.retrieve(frame);
//encode to .jpg the frame to a MatOfByte
Imgcodecs.imencode(".jpg", frame, mem);
//read into an Image
Image im = ImageIO.read(new ByteArrayInputStream(mem.toArray()));
//Draw image to a Jpanel
BufferedImage buff = (BufferedImage) im;
Graphics g = jPanel1.getGraphics();
g.drawImage(buff, 0, 0, getWidth(), getHeight(), 0, 0, buff.getWidth(), buff.getHeight(), null);
//record the frame
writer.write(frame);
}
catch(Exception ex)
{
System.out.println("Error");
ex.printStackTrace();
}
}
}
videoCapture.release(); // release device

How to compress and resize image from a Rich Text

I am inserting image in using this
var readFileIntoDataUrl = function (fileInfo) {
var loader = $.Deferred(),
fReader = new FileReader();
fReader.onload = function (e) {
loader.resolve(e.target.result);
};
fReader.onerror = loader.reject;
fReader.onprogress = loader.notify;
fReader.readAsDataURL(fileInfo);
return loader.promise();
};
$.when(readFileIntoDataUrl(fileInfo)).done(function (dataUrl) {
execCommand('insertimage', dataUrl);
}).fail(function (e) {
options.fileUploadError("file-reader", e);
});
Let say i added a text Hello World and added a image. Now when i take $("#editor").html() it shows something like below
Here is a sample source of a image+text
Hello World!
img src="data:image/jpeg;base64,/9j/4AAQSkZJRgABAQEAYABgAAD/4QBoRXhpZgAATU0AKgAAAAgA
BAEaAAUAAAABAAAAPgEbAAUAAAABAAAARgEoAAMAAAABAAIAAAExAAIAAAARAAAATgAAAAAAAABgAAAA
AQAAAGAAAAABUGFpbnQuTkVUIHYzLjUuOAAA/9sAQwAHBQUGBQQHBgUGCAcHCAoRCwoJCQoVDxAMERgV
[... more base64 data here....]
Now here i have both text+image So both on server side and client side i want to resize & compress image
So that no one can insert image > 5MP and also keep a rich text with resize image in my db

This is how you can do it on the server side (Java):
String imageData = "Hello World! img src=\"data:image/jpeg;base64,/9j/4AAQSkZJRgABAQEAYABgAAD/4QBoR...";
//Image data starting point
int startIndex = imageData.indexOf(";base64,") + ";base64,".length();
//keep only the image data
imageData = imageData.substring(startIndex, imageData.length());
//convert the image data String to a byte[]
byte[] dta = DatatypeConverter.parseBase64Binary(imageData);
try (InputStream in = new ByteArrayInputStream(dta);) {
BufferedImage fullSize = ImageIO.read(in);
// Create a new image half the size of the original image
BufferedImage resized = new BufferedImage(fullSize.getWidth() / 2, fullSize.getHeight() / 2, BufferedImage.TYPE_4BYTE_ABGR);
Graphics2D g2 = (Graphics2D) resized.getGraphics();
g2.drawImage(fullSize, 0, 0, resized.getWidth(), resized.getHeight(), 0, 0, fullSize.getWidth(), fullSize.getHeight(), null);
g2.dispose();
} catch (IOException e) {
e.printStackTrace();
}
As for the JavaScript part you can use a canvas, size the canvas to the dimension that you want, draw your image on it and use the toDataURL method to convert the image to a String

Automatically capture clip board data and save it into a file

Capture a image from the clipboard whenever Print screen is pressed and save it in a file (.doc) using java
Main aim is to copy the data from the clipboard and automatically save it into local disk without going to the desired program (i.e MS Word)- click new - pressing (Ctrl+V) to paste and save it with a name.
The code should perform all of the above three steps automatically.
My Source Code
public class CaptureScreenShot {
private static String DIR ="C:\\QUIS\\";
private static JTextField txtDocNumber;
public static void main(String[] args) throws Exception{
txtDocNumber = new JTextField();
Robot robot = new Robot();
Dimension d = new Dimension(Toolkit.getDefaultToolkit().getScreenSize());
int width = (int) d.getWidth();
int height = (int) d.getHeight();
robot.delay(5000);
Image image = robot.createScreenCapture(new Rectangle(0, 0, width,
height));
BufferedImage bi = new BufferedImage(width, height,
BufferedImage.TYPE_INT_RGB);
Graphics g = bi.createGraphics();
g.drawImage(image, 0, 0, width, height, null);
String fileNameToSaveTo = "C:/QUIS/screenCapture_" + createTimeStampStr() + ".PNG";
String newFile = "C:/QUIS/x" + ".org";
File newFilee = new File(newFile);
writeImage(bi, fileNameToSaveTo, "PNG");
System.out.println("Screen Captured Successfully and Saved to:\n"+fileNameToSaveTo);
Desktop desktop = Desktop.getDesktop();
writeImage(bi, newFile, "org");
desktop.open(newFilee);
}
public static int writeImage(BufferedImage img, String fileLocation,
String extension) {
try {
BufferedImage bi = img;
File outputfile = new File(fileLocation);
ImageIO.write(bi, extension, outputfile);
} catch (IOException e) {
e.printStackTrace();
}
return 1;
}
public static String createTimeStampStr() throws Exception {
Calendar mycalendar = Calendar.getInstance();
SimpleDateFormat formatter = new SimpleDateFormat("yyyyMMdd_hhmmss");
String timeStamp = formatter.format(mycalendar.getTime());
return timeStamp;
}
}

If you are not particular about a java code, you could use some screen capture tool instead. Snagit is a good tool. You could find it on http://www.techsmith.com/snagit.html

Try this sample code, according to your question it will copy contents from clipboard and will generate image file
Clipboard clipboard = Toolkit.getDefaultToolkit().getSystemClipboard();
try {
//Get data from clipboard and assign it to an image.
//clipboard.getData() returns an object, so we need to cast it to a BufferdImage.
BufferedImage image = (BufferedImage)clipboard.getData(DataFlavor.imageFlavor);
//file that we'll save to disk.
File file = new File("image.jpg");
//class to write image to disk. You specify the image to be saved, its type,
// and then the file in which to write the image data.
ImageIO.write(image, "jpg", file);
}

How to print conent of a JFrame by printer

I would like to print the content of a JFrame/JPanel by printer how to do it? Could sb give me an example of code? I do not understand official tutorial.
EDIT:
I thought it is clear. I do not want to print it to file then print it manually. I want to use java to do this.

BufferedImage image = new BufferedImage(this.getWidth(), this.getHeight(), BufferedImage.TYPE_INT_RGB);
Graphics2D g = image.createGraphics();
this.paint(g);
g.dispose();
// File to save output Image
File imageOut = new File("screenshot.png");
try {
ImageIO.write(image, "png", imageOut);
} catch (IOException ex) {
System.out.println(ex.getMessage());
}
with this as a JFrame

Java file operations after opening image with ImageIO

I am working with Java and combine two images. I save the combined image and want to delete the overlay, but it seems there are still streams open. And i don't know which and how to close them.
f_overlay and f_image are both Files.
// load source images
BufferedImage image = null;
BufferedImage overlay = null;
try {
log.debug(f_image.getAbsolutePath());
log.debug(f_overlay.getAbsolutePath());
image = ImageIO.read(f_image);
overlay = ImageIO.read(f_overlay);
} catch (IOException e) {
log.error(e.getMessage());
}
// create the new image, canvas size is the max. of both image sizes
int w = Math.max(image.getWidth(), overlay.getWidth());
int h = Math.max(image.getHeight(), overlay.getHeight());
BufferedImage combined = new BufferedImage(w, h, BufferedImage.TYPE_INT_ARGB);
// paint both images, preserving the alpha channels
Graphics g = combined.getGraphics();
g.drawImage(image, 0, 0, null);
g.drawImage(overlay, 0, 0, null);
// Save as new image
try {
ImageIO.write(combined, "PNG", f_image);
} catch (IOException e) {
log.error(e.getMessage());
}
// we can delete the overlay now
log.debug("Delete overlay: " + f_overlay.delete());
Are there any suggestions?

I can't see anything wrong in your code.
However, I would only delete the file f_overlay if the reading was successful. Important, after you call delete() on the file object, you must not use the object for anything else, so best is to assign f_overlay=null
boolean state = f_overlay.delete();
f_overlay=null;
log.debug("Delete ... "+state);