I'm trying to get information about scanned images that are saved into PDF files through iText (using Java). I can get width and height (either through
Matrix, or through
BufferedImage). The idea was to use the answer here to calculate the DPI, but I am a bit lost. Are these values (width and height) in pixels or points? Is there any other way to achieve this? There are a lot of answers on how to scale and save an image to a PDF file, but I didn't find any on how to read the width/height/scale of an image and be confident about the result.
Now you don’t need to calculate the DPI values yourself. There is an
ImageData class in iText 7 with built-in methods to solve your problem:
ImageData image = ImageDataFactory.create(IMG);
int x = image.getDpiX();
int y = image.getDpiY();
Click How to get the image DPI in PDF? if you want to see how to answer this question in iText 5.