When I went from a distribution with a GNOME desktop to one based on the KDE desktop, I didn't pay much attention to its application ecosystem and continued using the programs I was used to. It's a shame because I didn't know what I was missing, Okular It is one of the best readers for Linux.
To speak properly, when I refer to one of the best readers, I'm talking about programs that allow us to read and work with the most popular document file formats.
Why Okular is one of the best document readers for Linux
A program can be the best at something or good enough at most things. Caliber's book reader is unbeatable for reading ebooks, Xournal++ for annotating PDF documents, but Okular is good enough at that and many other tasks.
What is Okular?
Okular is a document viewer that works, among others, with formats such as PDF, Epub, PostScript®, Tiff, CHM, DjVU, XPS, Fiction Books, Comic Book and Plucker. Additionally, you can open images and display documents in Markdown notation. Although, as I pointed out, it is part of the KDE application ecosystem, it can also be installed from the repositories in distributions with other desktops or from flat hub
Document navigation
Navigation is no different from other document viewers. It can be done:
- Clicking on the table of contents.
- By clicking on the corresponding page in the sidebar.
- Clicking on an internal link.
- Activating auto scroll mode.
- Using the cursor keys.
Complex documents
A characteristic of the PDF format is that it allows you to insert files within other files and interact by completing forms. In all cases Okular will warn us and ask us what we want to do. It will also allow us to check the signatures and sign them.
Notes
Notes allow us to highlight parts of text that we want to find easily, add information, or remind ourselves of things we need to do. Okular allows us several types of notes:
- Text annotations: By default (although it can be changed in settings) they are black underline and yellow highlight. It works in formats with text.
- Graphic annotations: There are different types of annotations such as Popup Note, Embedded Note, Freehand Drawing, Highlight, Straight, Underline, Polygon, Stamp, Typewriter and Ellipse that can be applied to all supported file formats whether or not they contain text.
It must be clarified that if you want to save the document with its annotations, it can only be done in the native format or in PDF.
Bookmarks
In addition to internal links and notes, An easy way to find a specific part of text is by adding bookmarks. From the bookmarks menu in the sidebar we can see a list of them and by clicking on them we can access the indicated place
Engine configuration
Okular allows us to establish our own characteristics for some file formats. It must be said, however, that except for the PDF format, there is not much that can be done.
- ePub: Font.
- FictionBook: Font.
- Ghoscript: Use or not system font.
- Markdown: Font and whether or not to convert simple punctuation into typographic punctuation.
- mobipocket: Font.
- txt: Font.
- PDF: Configuration of printing characteristics and way of verifying digital signatures.
Accessibility
Something that we visually impaired pay a lot of attention to is the accessibility functions and we cannot complain about Okular since it offers the following alternatives:
- Draw a border around the links: This is ideal for people who are color blind.
- Invert colors: This doesn't need much explanation, the selected light color becomes the selected dark color and vice versa.
- Change colors: We can choose the background and text colors. But, it will only work in two colors, one for light and the other for dark.
- Change background color: Maintains the color of the typography
These are some of the features of Okular. If you want to know the rest, its manual is complete and the menus are easy to understand. Without a doubt, a highly recommended application.
Question: How did you manage to put the dark mode with the green letters in Okular?
Go to Preferences Configure Okular Change dark and light colors. You choose black for light and green for dark.
That "one of the best" thing... It's a real waste to see books in Epub. The format is completely ignored and what in a reader like Caliber appears centered, with wide spacing between paragraphs, the images in their place, in Okular everything appears in a monolithic block that makes clear legibility difficult, the images in a corner or on the next page; and its voice synthesizer is simply unbearable: robotic voices like Stephen Hawking's voice synthesizer in the 90s that give you a headache if you listen to them for more than 10 minutes, and this is the same for epubs and PDFs.
To listen to books while doing something else that does not require reading (reading and listening to text at the same time is almost impossible, the area of the brain that processes language is the same for written and spoken language and you do not realize what you read or what what you hear, xD) Firefox works much better with the Read Aloud plugin and some plugin to view epubs than the supposed "best Linux document viewer." The worst thing is that the main developer, the Spanish Albert Vaca, has known this perfectly well for years and has not the slightest interest in fixing it.
So Okular is very good if you only want to see PDF or CBR, and if you are a fan of reading, forget about it.