Java get image from BufferedImage Zxing QR Code

[mike salazar]

Hi my question is the next, im doing a qr code in java with zxing jar.

I create the qr code and save in my computer, but i dont want write the qr code in the computer, i want get the image for use inside my code and add in a pdf file.


My code is the next

public void generateQR(String text) throws NSJPNegocioException {

	String filePath = "D:/ImageQR.png";
		int size = 200;
		String fileType = "png";
		File myFile = new File(filePath);
		BitMatrix byteMatrix = null;
		int CrunchifyWidth = 0;
		
			
			Map<EncodeHintType, Object> hintMap = new EnumMap<EncodeHintType, Object>(EncodeHintType.class);
			hintMap.put(EncodeHintType.CHARACTER_SET, "UTF-8");
			
			hintMap.put(EncodeHintType.MARGIN, 1); 
			hintMap.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.L);
 
			QRCodeWriter qrCodeWriter = new QRCodeWriter();
			try {
				byteMatrix = qrCodeWriter.encode(text, BarcodeFormat.QR_CODE, size,
					size, hintMap);
				CrunchifyWidth = byteMatrix.getWidth();
			} catch (WriterException e) {
				e.printStackTrace(); 
			}
			
			BufferedImage image = new BufferedImage(CrunchifyWidth, CrunchifyWidth,
					BufferedImage.TYPE_INT_RGB);
			image.createGraphics();
 
			Graphics2D graphics = (Graphics2D) image.getGraphics();
			graphics.setColor(Color.WHITE);
			graphics.fillRect(0, 0, CrunchifyWidth, CrunchifyWidth);
			graphics.setColor(Color.BLACK);
 
			for (int i = 0; i < CrunchifyWidth; i++) {
				for (int j = 0; j < CrunchifyWidth; j++) {
					if (byteMatrix.get(i, j)) {
						graphics.fillRect(i, j, 1, 1);
					}
				}
			}
			
			try{
				ImageIO.write(image, fileType, myFile);
				} catch (IOException e) {
					e.printStackTrace();
				}

}

In this code im writing the image in the computer, i was thinking in return the BitMatrix object and make the conversion to image, and save in a image variable. But i dont know how to get the image.

[Campbell Ritchie]

What's Zxing? Is it a kind of exclusive or, or an app for picture manipulation?

Discussion added to our GUIs forum.

[mike salazar]

Campbell Ritchie wrote:What's Zxing? Is it a kind of exclusive or, or an app for picture manipulation?

Discussion added to our GUIs forum.

Is a library for make barcode or qr code

[Norm Radder]

how to get the image.

Are you asking about the variable named image declared on line 26?

[mike salazar]

Norm Radder wrote:

how to get the image.

Are you asking about the variable named image declared on line 26?

no sorry, my question is about this

ImageIO.write(image, fileType, myFile);

in this line is writting the image to the path in the computer, i want return the image instead of write the image to the path

[Norm Radder]

i want return the image

To return an object from a method, declare the method to return the class of the object and use a return statement to return the object.
Look at the java tutorial:  https://docs.oracle.com/javase/tutorial/java/javaOO/returnvalue.html

[Rob Spoor]

Use MatrixToImageWriter to write a BitMatrix to a file or an output stream, or convert it into a BufferedImage. How that can be embedded in a PDF file depends on the PDF library you use.

[Tim Holloway]

This might be of service: https://stackoverflow.com/questions/10354858/qr-code-generation-into-scalable-eps-with-java

Since QR codes are images there are several ways to put them in a PDF. The two primary ways are as a bitmapped image or as PostScript. Bitmapped images originally were in TIFF form, but as far as I know, modern PDFs can handle things like PNG directly.

PostScript (and SVG) are the better option, since they're actual graphic commands and render cleanly regardless of how you zoom in or out or print. Bitmapped images can become blurred or distorted when scaled. PostScript, incidentally, is the "machine language" of PDFs and EPS.

PostScript is a programming language, so if desired you could actually generate a rendering program PS function for QR output and feed it a string of bit values. Or, take the easy way out and just render a matrix of black and white rectangles.