https://techdoku.nogafam.es/ 2026-05-05T14:07:45+00:00 https://techdoku.nogafam.es/ https://techdoku.nogafam.es/lib/exe/fetch.php?media=wiki:dokuwiki.svg text/html 2021-10-17T01:47:33+00:00 Anonymous (anonymous@undisclosed.example.com) https://techdoku.nogafam.es/doku.php?id=docu:csheet:dtproc:images:convert_png_svg&rev=1634435253&do=diff Convert PNG image to SVG on Linux The following does not work very well on some images apt install potrace convert yourfile.png yourfile.bmp potrace -s yourfile.bmp // result: yourfile.svg Interesting conversion project in node: <https://github.com/jankovicsandras/imagetracerjs#inkscape-extension> text/html 2020-02-07T11:16:24+00:00 Anonymous (anonymous@undisclosed.example.com) https://techdoku.nogafam.es/doku.php?id=docu:csheet:dtproc:images:jpeg_optimize&rev=1581074184&do=diff How to optimize jpeg image sizes Install the package (on Debian-based) apt install jpegoptim We can now remove the metadata # optimize image without lossing quality jpegoptim -f -p AFILE.JPG # lossless # optimize to a fixed bytes size jpegoptim -f -p -S [OPTIMIZE_TO_BYTES] *.JPG # optimize to a percentage threshold jpegoptim -f -p -S '80%' *.JPG text/html 2020-05-21T10:41:27+00:00 Anonymous (anonymous@undisclosed.example.com) https://techdoku.nogafam.es/doku.php?id=docu:csheet:dtproc:images:qr_code_parsing&rev=1590057687&do=diff Encode/Decode QR Code Images to the text value Install the required tools: # to encode text into a qr image apt install qrencode # to decode an image into the text value apt install zbar-tools Usage for the installed tools # generate and display a QR code qrencode "Hi This is my 2d code." -o 2d.png display 2d.png # parse an QR image file to text zbarimg 2d.png >>> QR-Code:Hi This is my 2d code. >>> scanned 1 barcode symbols from 1 images in 0 second