Viewing PDFs

Lankir provides a high-quality PDF viewing experience powered by the MuPDF rendering engine.

PDF viewer interface overview — *PDF viewer with document, thumbnail sidebar, and navigation controls*

Opening Documents

From the GUI

File menu: File → Open (Ctrl+O)
Drag and drop: Drag PDF files onto the window
Recent files: Select from the sidebar or File → Recent
Command line: lankir /path/to/document.pdf

From the CLI

# Get PDF information
lankir pdf info document.pdf

# Output as JSON
lankir pdf info document.pdf --json

Navigation

Scrolling

Mouse wheel: Scroll up/down
Trackpad: Two-finger scroll
Spacebar: Page down
Shift+Spacebar: Page up

Zoom Controls

Keyboard Shortcuts

Action	Shortcut
Zoom in	`Ctrl++` or `Ctrl+=`
Zoom out	`Ctrl+-`
Actual size (100%)	`Ctrl+0`
Fit width	`Ctrl+1`
Fit page	`Ctrl+2`

Mouse Zoom

Ctrl+Scroll: Zoom in/out at cursor position
Pinch gesture (touchpad): Zoom in/out

Zoom Levels

Available zoom levels: 25%, 50%, 75%, 100%, 125%, 150%, 200%, 300%, 400%

The default zoom level is configurable:

lankir config set defaultZoom 150

View Modes

Scroll Mode (Default)

All pages displayed in a continuous vertical scroll. Best for reading documents.

Single Page Mode

One page at a time, centered in the view. Best for presentations or detailed examination.

Switch modes:

lankir config set defaultViewMode scroll  # or "single"

Document Information

View document metadata:

GUI

File → Properties or Ctrl+I

CLI

lankir pdf info document.pdf

Output includes:

Title, Author, Subject
Creator application
Page count
PDF version
File size
Creation/modification dates

Page Information

Get page dimensions:

lankir pdf pages document.pdf

# Output:
# Page Dimensions:
#   Page 1: 612.00 x 792.00 pts
#   Page 2: 612.00 x 792.00 pts

Standard page sizes in points:

Letter: 612 × 792
A4: 595 × 842
Legal: 612 × 1008

Rendering Pages

Export pages as images:

# Render page 1 at default DPI (150)
lankir pdf render document.pdf --page 1 --output page1.png

# Render at 300 DPI for printing
lankir pdf render document.pdf --page 1 --dpi 300 --output page1_hires.png

# Generate thumbnail (72 DPI)
lankir pdf thumbnail document.pdf --page 1 --size 200 --output thumb.png

Annotations

Lankir displays standard PDF annotations:

Text annotations (sticky notes)
Highlight, underline, strikethrough
Links (clickable)
Form fields (read-only)

Note

Annotation editing is not yet supported. Annotations are rendered as part of the page.

Performance Tips

Large Documents

For PDFs with many pages (100+):

Thumbnails load progressively
Pages render on-demand as you scroll
Memory is managed automatically

Slow Rendering

If rendering is slow:

Reduce zoom level
Disable hardware acceleration:
```
lankir config set hardwareAccel false
```
Close other resource-intensive applications

Keyboard Reference

Action	Shortcut
Open file	`Ctrl+O`
Close file	`Ctrl+W`
Page down	`Space`, `→`, `Page Down`
Page up	`Shift+Space`, `←`, `Page Up`
First page	`Home`
Last page	`End`
Go to page	`Ctrl+G`
Zoom in	`Ctrl++`
Zoom out	`Ctrl+-`
Fit width	`Ctrl+1`
Fit page	`Ctrl+2`
Actual size	`Ctrl+0`
Toggle sidebar	`Ctrl+B`
Properties	`Ctrl+I`
Settings	`Ctrl+,`

Next Steps

Digital Signatures - Sign PDF documents
Signature Verification - Validate signatures

Method	Action
Keyboard	`←`/`→`, `Page Up`/`Page Down`
Sidebar	Click thumbnail
Go to page	`Ctrl+G` → enter page number
First/Last	`Home`/`End`