The Okular Handbook

# The Okular Handbook

Albert Astals Cid `<aacid@kde.org>`

Pino Toscano `<pino@kde.org>`

Revision 0.19 (KDE 4.13) (2014-02-25)

Legal Notice

Okular is a KDE universal document viewer based on KPDF code.

Chapter 1. Introduction
Introduction

# Chapter 1. Introduction

Okular is a KDE universal document viewer based on the code of the KPDF application. Although being based on KPDF code, Okular has some unique features such as overview mode, improved presentation support and annotation support.

Okular supports a lot of different formats like PDF, PostScript®, Tiff, CHM, DjVU, Images (png, jpg, etc.) XPS, Open Document (ODT), Fiction Books, Comic Book, Plucker, EPub and Fax. For all supported formats and their features see Okular Document Format Handlers.

Chapter 2. Basic Usage
Basic Usage

# Chapter 2. Basic Usage

## Opening Files

To view any supported file in Okular, select File → Open..., choose a supported file in the dialog and click Open. Your file should now be displayed in the main window.

### Important

The new document will be opened in a new tab should the Open new files in tabs option on the General configuration page is checked.

If you have already opened files in Okular before, you can quickly access them by selecting them in the File → Open Recent menu.

Okular is the default KDE application for PDF and PostScript® files, launched when you click with the left mouse button on such a file type in the filemanager. If you want to open any file whose format is supported by Okular use Open with... → Okular from context menu in the filemanager.

After having a file opened you probably want to read it and therefore navigate through it. Go to the next section to learn more about this.

Navigating
Navigating

## Navigating

This section describes how you can navigate through a document in Okular.

There are multiple ways of scrolling the viewing area. One is to use the Up Arrow and Down Arrow keys. You may also use the scrollbar, your mousewheel or the Page Up and Page Down keys.

You can also use vim-like navigation keys, namely H to move to the top of the previous page, L to move to the top of the next page, J to move one line down, and K to move one line up.

Another way is to hold the left mouse button down at any place on the document while dragging the mouse in the opposite direction of where you want to move. This procedure only works if the Browse Tool is enabled, which you can select by choosing Tools → Browse Tool.

### Note

When viewing a document in the Presentation mode use Up Arrow and Down Arrow keys to switch between pages or slides. The number and the position of the current slide will be shown in the overlay at the right upper corner of screen.

If you want to read a document with several pages use the automatic scrolling feature of Okular. Start automatic scrolling with Shift+Down Arrow or Shift+Up Arrow. Then use these keys to increase and decrease the scrolling speed. You can start or stop automatic scrolling temporarily by pressing the Shift key; pressing any other key deactivates this feature.

Another way to navigate through a document with several pages is to use the mouse pointer. Drag the page up or down, continue to drag even while reaching the bottom or top of the screen and behold. Once you cross the border of a page, the mouse cursor appears on top or bottom of the screen again and you can just continue to drag.

The navigation panel on the left side of the screen enables two more ways of navigating through a document:

- If you click on a page thumbnail the viewing area will be brought to that page.

- If the document has a table of contents, clicking on a table of contents item will bring the document to the page linked to that item.

- If the document has bookmarks, enable the Bookmarks view and click them to go to the associated page. If bookmarks are not only shown for the current document, you can quickly switch to bookmarks in all recently opened files.

- If the document has annotations, enable the Reviews view and click the annotations or select them with the Up Arrow and Down Arrow keys and press Return to go to the associated page.

Some documents have links. In this case you can click on them and the view will change to the page it links to. If the link is to a web page or some other document the default KDE handler for that format will be invoked. For example, clicking on a link pointing to “http://www.kde.org” will open the web page in the default KDE's web browser.

### Important

The document internal links work only when Browse Tool is used.

Additionally, you may use the following functionality to quickly move to specific places in the document:

- You can go to the beginning of the document using Ctrl+Home or using Go → Beginning of the document.

- You can go to the end of the document using Ctrl+End or using Go → End of the document.

- You can go forward in the document using Space or Page Down. To go to the next page of the document use the Next Page Toolbar button or Go → Next Page in the menubar.

- You can go back in the document using Backspace or Page Up. To go to the previous page of the document use Previous Page Toolbar button or Go → Previous Page in the menubar.

- You can go back to the positions in the document where you came from in a chronological order. Consider e.g. reading the phrase “As shown in [15], …”, and you want to know quickly lookup reference [15]. So you click on it, and Okular will jump to the list of references. Using Alt+Shift+Left or Go → Back in the menubar will bring you back to exactly the position where you came from.

- You can go forward in the document after the jumping back as described above using Alt+Shift+Right or Go → Forward in the menubar.

- You can go to the next match when searching using F3 or Enter (when the focus is on Find text field) keys or Edit → Find Next menu item or move back to the previous match using Shift+F3 or Shift+Enter (when the focus is on Find text field) keys or Edit → Find Previous menu item.

Presentation Mode
Presentation Mode

## Presentation Mode

The Presentation mode represents another way to view documents in Okular. It can be enabled in View → Presentation. It shows the document on a page per page basis. The pages are shown with zoom to page, that means all the page is visible.

### Note

PDF documents can even specify that they are always opened in presentation mode.

When in presentation mode, you have an helper bar located on the top of the screen. Just move the mouse cursor to the top of the screen to make it appear.

To navigate between pages you may use the left mouse button (next page) and the right mouse button (previous page), the mouse wheel, the arrow icons or the line edit in the top bar, or the keys specified in the Navigating section.

Use Play/Pause button in the top bar to start playing presentation or pause it, correspondingly.

You can exit presentation mode at any time by pressing the Esc key or clicking the Quit icon in the top bar.

You can also draw on the current page with a pencil. Click on the Toggle Drawing Mode icon in the top bar to enable or disable the possibility to draw in the presentation mode. The drawings are cleared automatically when leaving the presentation mode. You can also click on the Erase Drawings icon to remove the drawings in the current page.

The presentation mode has support for more than one screen in a multi-monitor configuration. With more than one screen a new button will appear in the top bar, with the icon of a screen: this is a drop down box that allows you to move the presentation to any of the other available screens.

Presentation mode has some configuration options, you can find their description in the chapter Configuring Okular.

Inverse Search between LATEX Editors and Okular
Inverse Search between LATEX Editors and Okular

## Inverse Search between LATEX Editors and Okular

Inverse search is a very useful feature when you are writing a LATEX document yourself. If everything is set up properly, you can click into Okular's window with the left mouse button while pressing Shift. After that editor loads the LATEX source file and jumps to the proper paragraph.

Inverse search cannot work unless:

- The source file has been compiled successfully.

- Okular knows which editor you would like to use.

- The Browse Tool has to be enabled, which you can select by choosing Tools → Browse Tool .

With this feature of Okular, a left mouse click while pressing Shift in the DVI or PDF document will result in editor opening the corresponding LATEX document and attempt to go to the corresponding line. Remember to tell Okular to use proper editor, in Okular's menu item Settings → Configure Okular... (on the page Editor).

For more details on editor configuration please refer to the corresponding section of this manual.

Configuring editor in Okular

Chapter 3. Okular Advanced Features
Okular Advanced Features

# Chapter 3. Okular Advanced Features

## Embedded Files

If the current document has some files embedded in it, when you open it a yellow bar will appear above the page view to notify you about the embedded files.

In this case, you can either click on the link in the text of the bar or choose File → Embedded Files to open the embedded files dialog. The dialog allows you to view the embedded files and to extract them.

Forms
Forms

## Forms

If the current document has forms, when you open it a bar will appear above the page view where you can enable the forms.

In this case, you can either click on Show Forms in the bar or choose View → Show Forms to enter data into the form fields.

Annotations
Annotations

## Annotations

Okular allows you to review and annotate your documents. Annotations created in Okular are automatically saved in the internal local data folder for each user. Okular does not implicitly change any document it opens.

Okular has two different kind of annotations:

Text annotations like Yellow Highlighter and Black Underlining for files with text like e.g. PDF.

Graphic annotations like Pop-up Note, Inline Note, Freehand Line, Highlighter, Straight Line, Polygon, Stamp, Underline, and Ellipse for all formats supported by Okular.

Using the context menu either in the Reviews view of the navigation panel or in the main window you can open a Pop up Note for any kind of annotation and add or edit comments.

Annotations are not only limited to PDF files, they can be used for any format Okular supports.

Since KDE 4.2, Okular has the "document archiving" feature. This is an Okular-specific format for carrying the document plus various metadata related to it (currently only annotations). You can save a "document archive" from the open document by choosing File → Export As → Document Archive. To open an Okular document archive, just open it with Okular as it would be e.g. a PDF document.

Since Okular 0.15 you can also save annotations directly into PDF files. This feature is only available if Okular has been built with version 0.20 or later of Poppler rendering library. You can use File → Save As... to save the copy of PDF file with annotations.

### Note

It is not possible to save annotations into PDF file if original file was encrypted and Okular uses Poppler libraries of version which is lower than 0.22.

### Note

If you open a PDF with existing annotations, your annotation changes are not automatically saved in the internal local data folder, and you need to save the modified document (using File → Save As...) before closing it. Should you forget to do this Okular will show confirmation window that allows you to save the document.

### Note

Due to DRM limitations (typically with PDF documents), adding, editing some properties or removing annotations could not be possible.

### Note

Any action on annotations (creation and removal of annotations, editing arbitrary annotation properties, relocating annotations with Ctrl+drag, and editing the text contents of an annotation) can be undone or redone using the corresponding item from the Edit menu. It is also possible to undo the action by pressing Ctrl+Z and redo the undone action by pressing Ctrl+Shift+Z.

Since Okular 0.17 you can configure the default properties and appearance of each annotating tool. Please refer to the corresponding section in this documentation.

### Adding annotations

To add some annotations to the document, you have to activate the annotating toolbar. This is done by either selecting Tools → Review or pressing F6. Once the annotating toolbar is shown, just press one of its buttons or use keyboard shortcuts (keys from 1 to 9) to start constructing that annotation.

The annotating toolbar helps you to make annotations with drawings, shapes, and text messages. You can use the annotating toolbar to mark up a document (e.g. add lines, ellipses, polygons, stamps, highlights, underlines etc.). The table below describes exactly what the default set of annotating toolbar buttons does.

Button | Tool Name | Description
--- | --- | ---
| Pop-up Note | To draw multiline note. The note will can be viewed by double clicking on an icon in the document. Click on the tool button, then click on the place in the document where the pop-up note should be added. Enter the text of pop-up note then click on the Close this note button in the top right corner of the pop-up window.
| Inline Note | To draw inline note. The note will be shown inline as is. Click on the tool button, then click with the left mouse button and hold to place the top-left corner of the note, then drag to place the bottom-right one. Enter the text of the note then click on the OK to save the note, Cancel to cancel note entering or Clear to clear the note.
| Freehand Line | To draw free-form lines. Click on the tool button, then click with the left mouse button and hold to place the start of the line, then drag to draw the line.
| Highlighter | To highlight text in the document with some given background color. Click on the tool button, then click with the left mouse button and hold to place the beginning of the highlighted text snippet, then drag to highlight it.
| Straight Line | To mark with a line. Click on the tool button, then click with the left mouse button to place the starting point of the line, then drag to place of the ending point of the line should be and click once more.

Polygon

To draw a closed plane figure from three or more segments. The corresponding note can be viewed by double clicking inside the polygon.

Click on the tool button, then click with the left mouse button to place the first vertex of the polygon, then drag to place of the second vertex. Proceed until you draw the whole polygon up to the first vertex. Click twice if you want to add some note to the polygon. Enter the text of the note then click on the OK to save the note, Cancel to cancel note entering or Clear to clear the note.

| Stamp | To mark the text or image with some predefined shape. Click on the tool button then click with the left mouse button to place the stamp. A single click just places a square stamp (useful for icons). To add a rectangular stamp you can click with the left mouse button and hold to place the top-left point, then drag to place the bottom-right one.
| Underline | To underline some text. Click on the tool button, then click with the left mouse button and hold to place the beginning of the underlined text snippet, then drag to underline it.
| Ellipse | To draw an ellipse around some chosen area. Click on the tool button, then click with the left mouse button and hold to place the top-left corner of the circumscribed rectangular for the ellipse, then drag to place the bottom-right one.

The contents of the annotating toolbar can be configured using the Annotations page of Okular configuration dialog. This page can be opened with right mouse button clicking on the annotating toolbar then choosing Configure Annotations... from the context menu.

With a single left mouse button click on an annotation tool button you can use a tool once. If you e.g. want to highlight all important parts of a text, activate that tool permanently by double clicking on the tool button. Press the Esc key or click the tool button again to leave the permanent mode.

### Note

The annotating toolbar can be docked in any side of the viewing area: just drag it to move it to another place.

### Note

Activating the annotating toolbar will make you switch to the Browse Tool Mode.

You can stop the construction any time by pressing again on the button of the annotation you are constructing, or by pressing the Esc key.

The newly constructed annotation will have as author the author you set in the Annotations page in Okulars configuration dialog. The Annotations page can also be used to configure the content of the annotating toolbar.

### Removing annotations

To remove an annotation, just click on it with the right mouse button, and select Delete.

When removing the annotation, its window will be closed if open.

### Note

This option could not be enabled because the document does not allow removing annotations.

### Editing annotations

To edit an annotation, click on it with the right mouse button and select Properties. A dialog will appear with the general annotation settings (like color and opacity, author, etc.) and the settings specific to that annotation type.

To move an annotation, hold down the Ctrl key, move the mouse pointer on it and then start dragging with the left mouse button.

### Note

Depending on the document permissions (typically with PDF documents), some options can be disabled.

Bookmark Management
Bookmark Management

## Bookmark Management

Okular has a very flexible bookmark system. Okular saves the position on the page in bookmark and allows you to define more than one bookmark per page.

To manage bookmarks in Okular you can use Bookmarks view from Navigation Panel, Bookmarks menu or context menu of document view (click with right mouse button to open it).

### Bookmarks view

To open Bookmarks view click on Bookmarks item on the Navigation Panel. If the Navigation Panel is not shown, use Settings → Show Navigation Panel (F7) main menu item to make it visible.

The filter bar at the top of Bookmarks view can be used to filter the content of bookmark list pane according to the text in the box.

The list pane permits to view the bookmark list in a tree-like fashion: each document in the list can be “expanded” or “collapsed” by clicking on the < or v icon next to it.

Click on icon below the list to show only the bookmarks from the current document.

Right-click menu of document item can be used to open document, rename its item or remove it from the list. Remember that the removal of a document item leads to the removal of all bookmarks in the corresponding document.

Right-click menus of individual bookmark items allow you to go to the bookmark, rename or remove it.

Command Line Options
Command Line Options

## Command Line Options

Though Okular may most often be started from the KDE program menu, or a desktop icon, it can also be opened at the command line prompt of a terminal window. There are a few useful options that are available when doing this.

### Specify a File

By specifying the path and name of a particular file the user can have Okular open that file immediately upon startup. This option might look something like the following:

    % okular /home/myhome/docs/mydoc.pdf

### Note

For PDF documents, the name can be given as `document_name`#`named_destination` where `named_destination` is a particular named destination embedded in the document.

### Other Command Line Options

The following command line help options are available

`okular `--help``

  This lists the most basic options available at the command line.

`okular `--help-qt``

  This lists the options available for changing the way Okular interacts with Qt™.

`okular `--help-kde``

  This lists the options available for changing the way Okular interacts with KDE.

`okular `--help-all``

  This lists all of the command line options.

`okular `--author``

  Lists Okular's authors in the terminal window

`okular `-v, --version``

  Lists version information for Qt™, KDE, and Okular. Also available through `okular `-v``

`okular `--license``

  Shows license information.

`okular `--page `number```

  Open a page with a given number in the document. Also available through `okular `-p `number```

`okular `--presentation``

  Start the document in presentation mode.

`okular `--print``

  Start with print dialog.

`okular `--unique``

  Unique instance control.

`okular `--noraise``

  Allows to prevent Okular window raising after the start.

`okular `--``

  End of options.

Chapter 4. The Menubar
The Menubar

# Chapter 4. The Menubar

## The File Menu

File → Open... (Ctrl+O)

  Open a supported file or Okular archive. If there is already an opened file it will be closed. For more information, see the section about Opening Files.

File → Open Recent

  Open a file which was used previously from a submenu. If a file is currently being displayed it will be closed. For more information, see the section about Opening Files.

File → Import PostScript as PDF...

  Open a PostScript® file and convert it to PDF.

File → Save As...

  Save the currently open file under a different name using the document backend. With the PDF backend (Poppler >= 0.8 required) it is possible to save the document with the changed values of the form fields. It can be possible (provided that the data were not secured using DRM) to save annotations with PDF files (Poppler >= 0.22 required).

File → Save Copy As...

  Save a copy of the currently open file under a different name without using the current document backend.

File → Reload (F5)

  Reload the currently open file.

File → Print... (Ctrl+P)

  Print the currently displayed document.

File → Print Preview...

  Show a preview of how the currently displayed document would be printed with the default options.

File → Properties

  Display some basic information about the document, such as title, author, creation date, and details about the fonts used. The available information depends on the type of document.

File → Embedded Files...

  Show the files embedded in the document, if the document has any. For more information, see the section about the Embedded Files.

File → Export As

  This item contains the export formats the current document can be exported to. The first entry for all kind of documents is always Plain Text...

  The second entry is Document Archive, which allows you to save the document with your annotations into an Okular-specific archive format. Thus it is easily possible to share the original document and your annotations with other Okular users or work with them collaboratively.

File → Quit (Ctrl+Q)

  Close Okular.

The Edit Menu
The Edit Menu

## The Edit Menu

Edit → Undo (Ctrl+Z)

  Undo the last annotation editing command (creation and removal of annotations, editing arbitrary annotation properties, relocating annotations with Ctrl+drag, and editing the text contents of an annotation).

Edit → Redo (Ctrl+Shift+Z)

  Redo the last undo step when editing annotations.

Edit → Copy (Ctrl+C)

  Copy the currently selected text in Text Selection mode to the clipboard.

Edit → Select All (Ctrl+A)

  Selects all the text (if the document provides it). This works only in Text Selection mode.

Edit → Find... (Ctrl+F)

  Show the find bar on the bottom of the viewing area that allows you to search for a string in the document.

Edit → Find Next (F3)

  Try to find the previous searched string again in the document.

Edit → Find Previous (Shift+F3)

  Goes to the previous occurrence of the search string in the document.

The View Menu
The View Menu

## The View Menu

View → Presentation (Ctrl+Shift+P)

  Activates the Presentation Mode. For more information, see the section about Presentation Mode.

View → Zoom In (Ctrl++)

  Increase the magnification of the document view.

View → Zoom Out (Ctrl+-)

  Decrease the magnification of the document view.

View → Fit Width

  Change the magnification of the document view to a value that makes the pages' width equal to the document view's width.

View → Fit Page

  Change the magnification of the document view to a value that makes at least one whole page visible.

View → Auto Fit

  Change the magnification of the document view to a value that, depending on the size relation between the page and the view area, automatically either makes the pages' width equal to the document view's width (like fit-width), the pages' height equal to the document view's height (like fit-height), or the whole page visible (like fit-page).

View → Continuous

  Enable the continuous page mode. In continuous mode, all pages of the document are shown, and you can scroll through them without having to use the Go → Previous Page and Go → Next Page options.

View → View Mode

  This submenu makes you choose the view mode for the pages. The possible options are: Single Page (only one page per row), Facing Pages (two pages per row, in a book style), Facing Pages (Center First Page) and Overview (the number of columns is the one specified in the Okular settings).

View → Orientation

  This submenu allows you to changes the orientation of the pages of the document.

  ### Note

  The rotation is applied to the orientation of every page.

  You can select Original Orientation to restore the orientation of the document, discarding all the rotations applied manually.

View → Page Size

  Changes the size of the pages of the document.

  ### Note

  This submenu is active only if the current type of document supports different page sizes.

View → Trim Margins

  Remove the white border of pages when viewing pages.

View → Show/Hide Forms

  Show or hides the display of the form fields of the document.

  ### Note

  This menu item is active only if the current document has form fields.

The Go Menu
The Go Menu

## The Go Menu

Go → Previous Page

  View the previous page of the document.

Go → Next Page

  View the next page of the document.

Go → Beginning of the document (Ctrl+Home)

  Go to the beginning of the document.

Go → End of the document (Ctrl+End)

  Go to the end of the document.

Go → Back (Alt+Shift+Left)

  Go back to the previous view of the document.

Go → Forward (Alt+Shift+Right)

  Move forward to the next view of the document. This only works if you have already moved back before.

Go → Go to Page... (Ctrl+G)

  Open a dialog which allows you to go to any page of the document.

The Bookmarks Menu
The Bookmarks Menu

## The Bookmarks Menu

Bookmarks → Add/Remove Bookmark (Ctrl+B)

  Add or remove a bookmark for the current position.

Bookmarks → Rename Bookmark

  Rename a bookmark for the current position.

Bookmarks → Previous Bookmark

  Go to the previous bookmark, or do nothing if there are no bookmarks prior to the current one.

Bookmarks → Next Bookmark

  Go to the next bookmark, or do nothing if there are no bookmarks after the current one.

Bookmarks → No Bookmarks

  This is an always disabled action that appears in this menu only if the current document has no bookmarks. Otherwise a list of all bookmarks is displayed here. Clicking on these bookmarks allows you to go directly to the associated position.

The Tools Menu
The Tools Menu

## The Tools Menu

Tools → Browse Tool (Ctrl+1)

  The mouse will have its normal behavior, left mouse button for dragging the document and following links and right mouse button for adding bookmarks and fit to width.

Tools → Zoom Tool (Ctrl+2)

  The mouse will work as a zoom tool. Clicking left mouse button and dragging will zoom the view to the selected area, clicking right mouse button will bring the document back to the previous zoom.

Tools → Selection Tool (Ctrl+3)

  The mouse will work as a select tool. In that mode clicking left mouse button and dragging will give the option of copying the text/image of current selected area to the clipboard, speak a text or to save an image to a file.

Tools → Text Selection Tool (Ctrl+4)

  The mouse will work as a text selection tool. In that mode clicking left mouse button and dragging will give the option of selecting the text of the document. Then, just click with the right mouse button to copy to the clipboard or speak the current selection.

Tools → Table Selection Tool (Ctrl+5)

  Draw a rectangle around the text for the table, then use the click with the left mouse button to divide the text block into rows and columns. A left mouse button click on a existing line removes it and merges the adjacent rows or columns.

Tools → Magnifier (Ctrl+6)

  Activates the magnifier mode for the mouse pointer. Press and hold the left mouse button to activate magnifier widget, move the pointer for panning through the document. The magnifier scales each pixel in the document into 10 pixels in the magnifier widget.

Tools → Review (F6)

  Open the review toolbar. The review toolbar allows you to add annotations on the document you are reading. For more information, please see the section about Annotations.

Tools → Speak Whole Document , Tools → Speak Current Page , Tools → Stop Speaking

  These items allow you to speak the whole document or just the current page and stop speaking using the KDE Text-to-Speech system Jovie.

  The Speak ... actions are enabled only if Jovie is available in the system.

The Settings Menu
The Settings Menu

## The Settings Menu

Settings → Show Menubar (Ctrl+M)

  Toggle the Menubar display on and off. Once hidden it can be made visible using the shortcut Ctrl+M again. If the menubar is hidden, the context menu opened with a right mouse button click anywhere in the view area has an extra entry Show Menubar.

Settings → Show Toolbar

  Toggle the Toolbar display on and off.

Settings → Show Navigation Panel (F7)

  Toggle the navigation panel on and off.

Settings → Show Page Bar

  Toggle the page bar at the bottom of document area on and off to save vertical place in Okular window.

Settings → Full Screen Mode (Ctrl+Shift+F)

  Enables the full screen mode. Note that full screen mode is different from presentation mode insofar as the only peculiarity of full screen mode is that it hides the window decorations, the menubar and the toolbar.

Settings → Configure Shortcuts...

  Opens a window that lets you configure the keyboard shortcuts for many menu commands.

Settings → Configure Toolbars...

  Opens a window that lets you choose which icons are visible in the toolbar.

Settings → Configure Backends...

  Opens the Backend Configuration window.

Settings → Configure Okular...

  Opens the Configure window.

The Help Menu
The Help Menu

## The Help Menu

Help → Okular Handbook (F1)

  Invokes the KDE Help system starting at the Okular help pages. (this document).

Help → What's This? (Shift+F1)

  Changes the mouse cursor to a combination arrow and question mark. Clicking on items within Okular will open a help window (if one exists for the particular item) explaining the item's function.

Help → Report Bug...

  Opens the Bug report dialog where you can report a bug or request a “wishlist” feature.

Help → Switch Application Language...

  Opens a dialog where you can edit the Primary language and Fallback language for this application.

Help → About Okular

  This will display version and author information.

Help → About KDE

  This displays the KDE version and other basic information.

Chapter 5. Configuring Okular Backends
Configuring Okular Backends

# Chapter 5. Configuring Okular Backends

You can configure Okular backends by choosing Settings → Configure Backends.... Currently, configuration options are provided for EPub, PostScript®, FictionBook, Txt, OpenDocument Text, and PDF backends only.

Using backend configuration pages for EPub, FictionBook, Txt and OpenDocument Text you can define the font to render documents in the corresponding formats. The Choose... button in these pages opens standard KDE font configuration window. Please refer to the KDE Fundamentals documentation for the details.

The description of PostScript® and PDF backends configuration pages can be found below.

## PostScript® backend configuration

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.

PDF backend configuration
PDF backend configuration

## PDF backend configuration

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 Solid. 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 Solid enhancement

  The second option is Shape. 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 Shape enhancement

  The thin lines are not enhanced by default (option No).

Chapter 6. Configuring Okular
Configuring Okular

# Chapter 6. Configuring Okular

## General configuration

You can configure Okular by choosing Settings → Configure Okular.... The configuration dialog is split into six sections. This chapter describes the available options in detail.

- General

- Accessibility

- Performance

- Presentation

- Annotations

- Editor

Depending on the currently installed backends, the Settings → Configure Backends... menu item could be enabled. This particular configuration dialog holds the configurations of the backends that can actually be configured.

General
General

## General

Show scrollbars

  Whether to show scrollbars for the document view.

Link the thumbnails with the page

  Whether the thumbnails view should always display the current page or not.

Show hints and info messages

  Whether to show some informative messages on startup, file load, etc.

Display document title in titlebar if available

  Whether to show the current document title in the titlebar of Okular window. If no metadata for title found in the document or this item is unchecked Okular shows filename of the document.

When not displaying document title

  You can choose any of two options, Display file name only or Display full file path.

Obey DRM limitations

  Whether Okular should obey DRM (Digital Rights Management) restrictions. DRM limitations are used to make it impossible to perform certain actions with PDF documents, such as copying content to the clipboard. Note that in some configurations of Okular, this option is not available.

Open new files in tabs

  Whether to open new documents in tabs. The tabs are disabled by default.

  The default shortcuts to switch between tabs are Ctrl+. (Next tab) and Ctrl+, (Previous tab).

Reload document on file change

  Whether opened files should be automatically checked for changes and updated, if necessary.

Show backend selection dialog

  Whether Okular should ask the user which backend to use in case of more than one backend able to open the current file. If unchecked, Okular will use the backend with the highest priority.

Overview columns

  This option represents the number of columns to use in the overview mode.

Page Up/Down overlap

  Here you can define the percentage of the current viewing area that should be visible after pressing Page Up/Page Down keys.

Default Zoom

  This options specifies the default zoom mode for file which were never opened before. For those files which were opened before the previous zoom mode is applied.

Accessibility
Accessibility

## Accessibility

Draw border around links

  Whether to draw a border around links.

Change colors

  Enables the color changing options.

Invert Colors

  Inverts colors on the view, i.e. black objects will be shown white.

Change Paper Color

  Changes the paper's color, i.e. the document's background.

Change Dark & Light Colors

  Changes the dark and light color to your preference, that means black will not be rendered as black but as the selected dark color and white will not be rendered as white but as the selected light color.

Convert to Black & White

  Converts the document to black and white. You can set the threshold and the contrast. Setting the threshold to a higher value by moving it to the right will result in lighter grays used.

Performance
Performance

## Performance

Enable transparency effects

  Draw selections and other special graphics using transparency effects. Disable the option to draw them using outline or opaque fill styles and increase speed on selections.

Memory Usage

  Okular can achieve best performance by tuning the memory usage, based on your system and your tastes. The more memory you let it to use, the faster the program will behave. The Default profile is good for every system, but you can prevent Okular from using more memory than necessary by selecting the Low profile, or let it get the most out of your system using Aggressive. Use Greedy profile to preload all pages without risk of system memory overfull (only 50% of total memory or free memory will be used).

Rendering

  Using this group of options you can improve text and image rendering in Okular. The result depends on the device to display the document. Enable Text Antialias and Enable Graphics Antialias items can be used to switch on and off spatial anti-aliasing of text and images in document, correspondingly. Enable Text Hinting item is meant to be a switcher for font hinting. Antialiasing and hinting change how the documents are displayed, you may want to tweak them to your preference.

Presentation
Presentation

## Presentation

Advance every

  Enables automatic advancing of pages given a time period.

Loop after last page

  When navigating on presentation mode and going past the last page the first page will appear.

Background color

  The color that will fill the part of the screen not covered by the page when on presentation mode.

Pencil color

  The color of the pencil used when drawing on the pages during the presentation mode.

Mouse cursor

  Whether the mouse should be always hidden, always shown or hidden after a small time of inactivity.

Show progress indicator

  Whether to show a progress circle that shows the current page and the total number of pages on the upper right corner of the presentation screen every time you change the page.

Show summary page

  Whether to show a summary page at the beginning of the presentation with the title, author and number of pages of the document.

Enable transitions

  Use this check box to enable or disable transition effects between pages.

Default transition

  The transition effect between page and page if the document does not specify one. Set this to Random Transition to make Okular randomly choose one of the available effects.

Placement

  In this section you can select the Screen used to display the presentation.

  Current Screen is same screen of the Okular window that starts the presentation mode.

  Default Screen is the screen marked as default in the xinerama configuration.

  Screen 0, Screen 1 etc. are the available screens.

Annotations
Annotations

## Annotations

Author

  The author of the contents added on a document. Default is the name from the Password & User Account page of the System Settings module Account Details.

Annotation tools

  This pane is used to configure your annotating toolbar.

  There are five buttons (Add, Edit, Remove, Move Up, Move Down) and a list box (which lists the contents of the current annotating toolbar) which are used to configure the toolbar.

  If you need to add some tool button on the toolbar click on the Add button. You can choose the Name, the Type and the Appearance of the created tool.

  ### Note

  Please remember that annotation tools in Okular are highly configurable. For example, you can have two buttons of the same tool but with different color. Do not hesitate to experiment in choosing the button set that is exactly tailored to your workflow.

  Click on some item in the list box then click on the corresponding button at the right part of the page to edit, remove, move up or move down the item. The keyboard shortcut of the tool (keys from 1 to 9) depends on its position in the list of annotating toolbar.

Editor
Editor

## Editor

Editor

  Choose the editor you want to launch when Okular wants to open a source file. This is the case when the document has references to the various points (usually row and column number) of sources it was generated from. The DVI format supports natively the addition of the information about the sources the LaTeX document was generated from. A similar system exists for PDF documents, called pdfsync, which stores these extra information in an external file named after the PDF file itself (for example `mydocument.pdfsync` for `mydocument.pdf`).

  Okular ships with preconfigured settings for the following editors: Kate, Kile, SciTE, Emacs client, and LyX client.

  ### Note

  To use inverse search in Kile, you have to compile your LATEX file with the Modern configuration.

Command

  This is the command and its parameters to invoke the selected editor with the source file of the actual document.

  This field will be filled automatically if you use one of the preconfigured editors. Otherwise, please choose Custom Text Editor in Editor drop down box and refer to the documentation on your favorite editor to find the proper command.

  You can use the following placeholders:

  - %f - the file name

  - %l - the line of the file to be reached

  - %c - the column of the file to be reached

  If %f is not specified, then the document name is appended to the specified command.

Chapter 7. Credits and License
Credits and License

# Chapter 7. Credits and License

Program Copyright:

- Albert Astals `(aacid AT kde.org)` Current maintainer

- Pino Toscano `(pino AT kde.org)`

- Enrico Ros `(eros.kde AT email.it)` KPDF developer

Documentation Copyright:

- Albert Astals `(aacid AT kde.org)` Author

- Titus Laska `(titus.laska AT gmx.de)` Some updates and additions

- Pino Toscano `(pino AT kde.org)`

This documentation is licensed under the terms of the GNU Free Documentation License.

This program is licensed under the terms of the GNU General Public License.

Appendix A. Installation
Installation

# Appendix A. Installation

## How to obtain Okular

Okular is part of the KDE project http://www.kde.org/.

Okular can be found in the kdegraphics package on ftp://ftp.kde.org/pub/kde/, the main FTP site of the KDE project.

Compilation and Installation
Compilation and Installation

## Compilation and Installation

### Note

If you are reading this help in the KHelpCenter, Okular has already been installed on this system and you do not need install it anymore.

For detailed information on how to compile and install KDE applications see Building and Running KDE Software From Source

Since KDE uses cmake you should have no trouble compiling it. Should you run into problems please report them to the KDE mailing lists.