Previews in depth

Select a file, press Enter, and konoma picks the right renderer from its rule table (see Configuration). q always goes back. ? shows the keys for the current preview type.

Markdown

Rendered with headings, full-width rules, tables (with column alignment and inline styles), task lists, code fences (syntax-highlighted), Mermaid fences (rendered as real diagram images), and inline images (local and remote, drawn as real pixels).

• Links: Tab / Shift-Tab walk every link and checkbox in the document; Enter opens the focused link — local paths open inside konoma, URLs open in the browser.
• Task checkboxes: focus with Tab, toggle with Space. The state character is written back to the file — verified against the file on disk first, so it never clobbers a concurrent edit (e.g. by an AI agent). The states cycle through ui.md_task_states (default [ ] ⇄ [x]; add a custom in-progress state like [/] if you like).
• Mermaid diagrams: ```mermaid fences render inline as real images — laid out and rasterized fully in-process (no browser or Node), dark-themed with a transparent background so they blend into the terminal. A diagram is drawn at its natural size (its own text matching the size of the surrounding body text) and is never enlarged; a small diagram stays small, while a genuinely busy one is wide and uses the pane. ui.mermaid_rows sets an upper limit on the height, not a target — the diagram only shrinks below that (aspect preserved) if its natural size exceeds it or the pane’s width. Tab focuses a diagram; + / - zoom it in place (h j k l pan, 0 fits), and Enter opens it full screen (q returns to the same spot). Standalone .mmd files open full screen directly. ui.mermaid = "text" keeps the legacy Unicode rendering; unsupported diagrams fall back to it automatically.
• Edge routing: ui.mermaid_routing (default "splines") picks how a flowchart’s or state diagram’s (stateDiagram-v2) edges are laid out; the default reproduces mermaid’s own layout exactly, so nothing changes unless you set this. "konoma-orthogonal" is konoma’s own router: every edge bends only at right angles with sharp corners, decision diamonds become chamfered rectangles so edges land on a flat face, and a straight-through edge across ranks aligns into a single unbent lane — a clean schematic look, for those two diagram kinds only. This mode also switches the diagram to konoma’s own designed palette and style — dark node fill with rounded corners, dashed subgraph frames, neutral edges, and classDef/ style colors applied consistently to a node’s border, its edges, and its label — so ui.mermaid_theme has no effect here. Set it with ui.mermaid_routing = "konoma-orthogonal".
• LaTeX math: $…$ and $$…$$ (or \(…\) / \[…\]) are typeset in pure Rust and drawn as images — no browser, no Node, no TeX installation. An inline formula is always drawn in the running text, like ordinary Markdown; one too wide for the line shrinks to fit instead of being lifted onto a line of its own. A display formula is centered. $5 and anything inside code stays literal. Set ui.math = "text" to keep the raw LaTeX instead, and ui.math_color to match your terminal’s foreground.
• Block alignment: ui.md_table_align (default "left") and ui.md_image_align (default "center") place a table’s box and a block image — a standalone ![alt](url), a row of badges, a Mermaid diagram — at the left, the center, or the right of the preview. The table setting moves the whole grid, including any picture inside a cell; it does not touch alignment within a cell, which a column’s :---: still decides.
• Raw source: R toggles the decorated view against the raw Markdown source, where precise line/column selection works.

Code and text

Syntax highlighting resolves the grammar by extension, then file name (.bashrc, Makefile, Dockerfile, …), then first line. Large files stream through a windowed reader, so multi-hundred-MB logs open instantly.

• / searches; n / N jump between matches.
• A 2D caret moves with h j k l; v selects by character, V by line; y copies the selection. 0 / $ jump within the line, g / G to the ends.
• Y copies an @path#L12-34 reference for the caret or selection.
• Files with uncommitted changes get an editor-style git gutter (green added / blue modified / red deleted).
• Wrap is configurable (ui.wrap); with wrap off, long lines scroll horizontally.

CSV / TSV tables

Comma- and tab-separated files render as an aligned grid with rainbow column colors and a cell cursor:

• h j k l move by cell; g/G first/last row; 0/$ first/last column.
• y opens a copy menu: cell, row, column, or full path.
• Enter opens the cursor cell in a popup — the full, untruncated value, wrapped and scrollable (Enter / q / Esc closes it).
• Quoted fields, CJK widths, ragged rows and non-UTF-8 input are all handled; parsing failures fall back to plain text.

Archives

.zip, .tar and .tar.gz open in the same grid: one row per entry with its name, size and modified date. Nothing is extracted — konoma only reads the archive’s index — so cell search (/), the cell cursor and the y copy menu all work exactly as they do for CSV, on a listing that never touches your disk.

Images, SVG, GIF, video, PDF

Drawn as real pixels in any terminal that speaks a graphics protocol — kitty graphics (Ghostty, kitty, WezTerm, Konsole), iTerm2, or sixel. konoma has its own compressed transfer for the kitty protocol, so those terminals are the fastest; anywhere else the picture degrades to a coarse but visible half-block approximation.

• + / - zoom, 0/= reset to fit, h j k l pan.
• GIFs animate automatically. SVGs rasterize in-process (no external tools).
• Videos show a representative frame. H.264 and HEVC inside .mp4/.m4v/.mov and .mkv/.webm are decoded natively in Rust — nothing to install, which covers an iPhone’s default recording format as well as the container most ripped or re-encoded files arrive in. VP9, AV1, the older codecs (Xvid, MPEG-2, WMV, …), the .avi container, and the uncommon profiles (H.264 in 10-bit / 4:2:2 / 4:4:4 / monochrome, HEVC outside Main / Main 10 4:2:0) use ffmpegthumbnailer/ffmpeg if installed, and show a hint if not. Want playback? Delegate to mpv with one config rule.
• PDFs render page by page, natively in Rust (hayro, no external tool needed) — J / K (or PageDown/PageUp) turn any page. On macOS only, the rare PDF hayro can’t render (encrypted, corrupt, or otherwise unsupported) falls back to the system’s own qlmanage/sips — already installed — though those can only produce the first page.

Everything else

Files matching no rule that look like text open as text; anything else shows a safe [can not preview] screen. konoma never crashes on unknown input — add a rule in the config to teach it new formats, including delegation to any external command.