Configuring Okular BackendsYou can configure Okular backends by choosing → . Currently, configuration options are provided for EPub, PostScript®, FictionBook, Txt, OpenDocument Text, and PDF backends only.
Using backend configuration pages for EPub, FictionBook, Mobipocket, Markdown, TXT, and OpenDocument Text you can define the font to render documents in the corresponding formats. The button in these pages opens standard KDE font configuration window. Please refer to the KDE Fundamentals documentation for the details.
The description of Markdown, PostScript® and PDF backends configuration pages can be found below.
You can configure Okular Markdown rendering backend based on Discount by choosing Markdown from the list on the left part of the configuration dialog. An additional configurable option is as follows.
- Enable SmartyPants formatting
When checked this option allows Okular to process SmartyPants formatting. Such formatting can be troublesome in the technical texts because of unwanted substitutions (e.g., it replaces
(C)with a copyright symbol). This option is checked by default.
You can configure Okular PostScript® rendering backend based on Ghostscript by choosing Ghostscript from the list on the left part of the configuration dialog. The only configurable option is as follows.
- Use platform fonts
This option determines whether Ghostscript should be allowed to use platform fonts, if unchecked only usage of fonts embedded in the document will be allowed. This option is checked by default.
You can configure Okular PDF rendering backend based on Poppler by choosing PDF from the list on the left part of the configuration dialog. The only configurable option is as follows.
- Enhance thin lines
Drawing lines in Okular is implemented in two steps: generation of the clipping path and filling this clipping path. When the line in the original document is less than one pixel this two step implementation could cause problems. For those lines, the clipping path is filled with the filling color that depends on the thickness of the line part inside the clipping area. If the part of the line inside the clipping area gets very small the contrast between the shape and the background color can become too low for the line to be recognizable. The grids of such lines then looks very unpretty.
Thin line (red), its clipping path (dashed line) and pixel boundaries (black solid lines) Thin line shown at a low contrast To enhance the look of the thin lines Okular implements two options.
The first option is . With this option Okular adjusts clipping path and line position so that clipping path and line are on the same pixel boundary, i.e. Okular enlarges the thin lines to one pixel on the output device. This mode is similar to the Enhance thin lines in Adobe® Reader®. If this option is chosen, the thin lines are always enlarged.
Thin line with enhancement
The second option is . With this option the clipping path and line are adjusted to pixel boundary as well, but the line intensity is corrected according to its width.
Thin line with enhancement
The thin lines are not enhanced by default (option ).
