We get to see lots of ‘interesting‘ PDF files in developing a Java PDF library to handle PDF files…
Today’s example comes from a PDF creation tool called Solid PDF Creator Plus (188.8.131.52) according to the PRODUCER entry (which may not be 100% correct as it can be set manually to anything).
In a PDF you can declare a list of fonts used and assign a name to them. In this file we had
F3 1108 0 R /F4 1112 0 R >> >>
So F3 is the font defined by the object 1108 0 R and F4 is in 1112 0 R. F1 and F2 are actually null objects so not used. This in itself is allowed in the PDF spec (let’s face it anything is allowed in the PDF specification unless it is explicitly banned!). So it is not technically a bug. But it is pretty pointless because it makes the file bigger and more confusing than it needs to be. It is just sloppy programming in the PDF creation tool.
Do you have any favourite PDF bugs?
This post is part of our “Fonts Articles Index” in these articles we explore Fonts.
This post is part of our “Understanding the PDF File Format” series. In each article, we discuss a PDF feature, bug, gotcha or tip. If you wish to learn more about PDF, we have 13 years worth of PDF knowledge and tips, so click here to visit our series index!
IDRsolutions develop a Java PDF library, a PDF forms to HTML5 converter, a PDF to HTML5 or SVG converter and a Java Image Library that doubles as an ImageIO replacement. On the blog our team post about anything interesting they learn about.