When comparing KDE Okular vs qpdfview, the Slant community recommends KDE Okular for most people. In the question“What are the best PDF viewers for UNIX-like systems?” KDE Okular is ranked 1st while qpdfview is ranked 5th.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Free and open source
Pro Trim margins
Easily trim margins either automatically or manually for easier reading
Pro Featureful
Pro Table selection
Pro Tabbed view option
Pro Supports touch interaction
Pro Low on resources
Pro Reloads on changes instantly
Pro Outline, properties and thumbnail panes
Pro Open multiple pdfs in tabs
qpdfview is a tabbed document viewer.
Pro Allows for some scripting
Opens files in named instances, open files on designated page.
Calling of userscripts on a document is thus far not possible.
Pro Fast search in all opened files
Pro Dark mode
However only inverted colors.
Pro Scale, rotate and fit
Pro Supports TOC-sidebar
Pro Switch tabs with keyboard shortcuts
Pro Continuous and multiple-page layouts
Pro Add highlights and text annotations
Pro DjVu support
Pro Fullscreen and presentation views
Pro PostScript support
Pro Custom background colors
Pro Multiplatform
It is available on any major computer OS.
Pro Deactivation of GUI elements
e.g.:
toggleMenuBar
toggleToolBars
Pro Supports thumbnail preview
Pro Input forms are editable
Cons
Con No XFA Adobe Forms support
Cannot fill PDF Forms created with Adobe.
Con Requires many KDE libraries
Con No middle-mouse auto-scrolling
Instead of scrolling automatically when holding down the mouse wheel and dragging, it instead zooms in or out, in contrast with many other programs.
Con Poor HiDPI support
You may have to tinker with QT__SCALE_FACTOR environment variables to get the desired size and not blurry content (this is a bug; see https://bugs.kde.org/show_bug.cgi?id=362856 and https://bugs.archlinux.org/task/54688)
Con No search results overview
You have to navigate to next/previous hit one by one
Con No "fit to page" option under printing settings
You can only print the content as given so, when you receive a bigger or smaller image thant the default of the printer, you will have to edit it first on other editor.
Con Slow scroll
Its new ultra-slow-scroll for PgUp and PgDn makes it unuseable.
Con Deadly slow on complex pdf files
Con File information missing page size
Con No multiple mapping of commands
For example:
moveDown=Down
moveLeft=Shift+Left
moveRight=Shift+Right
moveUp=Up
Having two key mappings to execute the moveUp command doesn't seem to be possible.
Con Configuration intended via GUI
There is no explicit documentation of configuration parameters used in qpdfview.conf and shortcuts.conf (those are the most important ones). However the files are editable conveniently, which is of value.