Visualizations

SpaceKnife can draw a scan three ways. All three show the same data and share the view’s state: the same zoom, selection, filter and history. Size becomes area in the treemap, length in the flame graph and angle in the polar flame graph. Pick the one that answers your question best, and switch at any time with V.

The three visualizations

Treemap

The treemap fills the whole view with the zoom root’s contents. Every block’s area is proportional to the space it takes on disk.

An open folder is a frame with a title bar (name and size). Its contents are laid out inside it, and so on down.
Files are solid blocks in their file class color (see Coloring).
By default larger blocks go to the top left of their folder. Turn off Sort by size in Settings › Visualization to order by name instead; positions then stay steadier while a scan runs.
Deeper frames get a slightly lighter background so you can tell the levels apart. Level contrast and Border contrast in Settings › Appearance make the difference stronger or softer.
A folder on the last detail level, or one too small to hold its contents, is drawn as a solid collapsed block that keeps its name and size. Zoom in to open it.
Blocks big enough for text show their name, larger ones also their size. Long names end in “…”. Hover a block that is too small for text to see what it is.

Block proportions (Settings › Visualization) makes treemap blocks taller or wider; 0 keeps them as square as possible. It only affects the treemap.

Flame graph

The flame graph stacks one band per level. The zoom root is the root bar, which spans the full width. Its children sit in the next band, each one inside its parent’s span, with a length proportional to its size.

By default the root bar is at the bottom and the levels grow upward. To flip it, set Settings › Visualization › Flame graph direction to Root at top. Open flame graphs change at once.
The root bar shows the zoom root’s name in bold, followed by its size.
Bars are 20 to 48 px tall, scaled with Font size. The number of bands is the detail level or what fits in the view’s height, whichever is smaller.
Folders, open or collapsed, are solid bars, so you can read a deep path from the root bar outward in one line.

The flame graph is good for deep, narrow trees: a long chain of nested folders stays readable, and widths in one band are easy to compare.

Polar flame graph

The polar flame graph is the flame graph wrapped into a circle. The zoom root is the center disc and level k is the k-th ring outward.

Items start at 12 o’clock and run clockwise, largest first (with Sort by size on). Each sector’s angle is proportional to its size, and a child sector stays inside its parent’s angle.
The center disc shows the zoom root’s name and size. While you hover a sector, the disc shows that sector’s name, its size and its share of the zoom root (“{pct} of total”).
Rings are at least 14 px wide, scaled with Font size. The number of rings is the detail level or what fits in the radius, whichever is smaller.
Outer rings are longer, so they have room for smaller items: small folders deep down show up as thin spikes on the outside.
Labels follow the sector’s shape. A thick, narrow sector writes its name along the radius; the others write along the arc, with the size as a second line when it fits. Text is always upright.
The hover card follows the pointer here, because a large sector can cover most of the disc.

The root bar and the center disc

In both flame graphs the zoom root is drawn too, as the root bar or the center disc. It answers the mouse like this:

Action	Result
Click	Clears the selection; the details panel shows the zoom root
Double-click	Goes up one level
Right-click	Opens the zoom root’s context menu (without Show only this (zoom in))
Hover	Shows the zoom root’s hover card
`Shift`+`F10` with nothing selected	Opens the zoom root’s context menu

The treemap has no such element: its zoom root is the whole view.

Switching

How	What it does
Toolbar, Visualization group (icons, left of the level control)	Click a visualization
`V`	Next visualization, wrapping around
`Shift`+`V`	Previous visualization
Command palette, Cycle visualization	Same as `V`; its status line says which one is current
Command palette, type `visualization`	Visualization: treemap, Visualization: flame graph, Visualization: polar flame graph pick one directly

What switching keeps and what it doesn’t:

Kept: the zoom root (also a zoom into a “small items” block), back and forward history, the selection, the filter and its dim or hide mode, the detail level and the free and unknown space switches.
Changed: the coloring becomes the one the target visualization last used (see Coloring).
Closed: the hover card and the context menu.
Not recorded in history: Backspace never takes you back to the previous visualization.

The two pictures cross-fade for 200 ms; with Reduce motion on they swap at once. You can switch while a scan runs, while it is paused, on an opened snapshot and in a comparison. The scan itself is not affected.

A visualization this window can’t show stays on the toolbar, disabled, and its tooltip says why. V skips it.

Every tab and every split pane has its own visualization. New views start with Settings › Appearance › Visualization › Default visualization for new views.

Coloring

The toolbar’s Coloring group has four modes. C steps through them in this order: Classes → Flat → Time → Branch → Classes. Coloring changes colors only; the layout stays where it is.

Mode	Toolbar	Command palette	Color shows
File classes	Classes	Coloring: file classes	The file class, found by the extension: Video, Pictures, Audio, Archives, Programs, Documents, Games, Code, Data, and Other for the rest; the files in games, projects and other recognised folders take the folder’s class. Edit the classes in Settings › File classes.
Flat	Flat	Coloring: flat	Nothing: every file has the same neutral color, so only size and structure remain
Date modified	Time	Coloring: date modified	How recently a file changed, in five bands: under a day, a week, a month, a year, and older
Top-level branch	Branch	Coloring: top-level branch	Which top-level item a block belongs to

The four Coloring: … commands only appear when you type in the palette; Cycle coloring (C) is always there.

More about the modes:

Branch: each item directly under the zoom root gets its own hue (there are eight), and everything below it keeps that hue, shading darker with depth. Merged blocks on the top level and the free and unknown space stay neutral gray. A new branch gets the hue used least on screen that also differs from its neighbors, and a branch keeps its hue while a scan reorders the blocks. The hues are handed out again when the zoom root changes.
Time and Classes on merged blocks: a “small items” block takes the time band that holds most of its bytes, and the file class that holds at least half of its bytes (otherwise Other).
Folders: in the treemap, open folder frames always use their level colors, and collapsed folders and “+N more” blocks use a neutral collapsed color (in Branch they take the branch hue). In the flame graphs, folder bars use four gray tones by depth, again except in Branch.

Each visualization remembers its own coloring in each view. The treemap starts with Classes, the flame graph and the polar flame graph with Branch. Switch a treemap to Time, move to the flame graph and back, and the treemap is still on Time. The defaults for new views are in Settings › Appearance: Default treemap coloring and Default coloring for flame graphs and polar flame graphs.

Detail levels

The detail level says how many levels below the zoom root are drawn. At level N the folders of levels 1 to N − 1 are open and the folders on level N are collapsed; nothing deeper is drawn.

Keys	Toolbar	Command palette
`Ctrl`+`=` (or `Ctrl`+`+`)	+ on the Level control	Raise detail level
`Ctrl`+`-`	− on the Level control	Lower detail level

The range is 1 to 15. New views start at Settings › Visualization › Initial detail level (5 by default).
Changing the level only redraws: the zoom root and the selection stay.
Each view has its own level.
The flame graphs can only draw as many bands or rings as fit. When that is fewer than you asked for, the level control adds “Levels that fit: n”. Make the window taller, or zoom in, to see more.

Small items and “+N more”

A block smaller than Settings › Visualization › Minimum block size (3 to 20 px, 10 by default) is not drawn on its own. In the treemap “smaller” means area; in the flame graph it means length along the band, and in the polar flame graph the arc length in the middle of the ring.

What is too small is merged:

“N small items”: two or more files of one folder that are each too small. The block has a dotted texture and takes the color of the file class that holds at least half of its bytes (otherwise Other).
“+N more”: whatever is still too small at that level (small folders, a single small file, or a “small items” block that is itself too small), merged into one block in a neutral color, placed last.

Working with merged blocks:

Double-click one, or select it and press Enter, to lay out its members one by one, largest first. What still doesn’t fit becomes a new “+N more”. The breadcrumb ends in “N small items” or “+N more”, and Backspace takes you back.
Select one and the details panel explains what it is.
In its context menu, Open, Show in Explorer, the terminal and Copy path are unavailable (a merged block is not one place on disk), and it can’t be tagged. Add to delete basket adds the whole block with its members. The Delete key does not add merged blocks; use the menu.

Raise Minimum block size for a calmer picture with fewer, larger blocks; lower it to see more individual files.

Free and unknown space

When the zoom root is a whole volume you scanned (for example C:\ or /), two more blocks appear on the first level and are sorted with the rest:

Free space: the volume’s free space as the system reports it. Green stripes with a solid outline.
Unknown space: the used space the system reports minus everything the scan counted. That is usually places the scan could not read and space the system reserves. Gray stripes with a dashed outline. It is not drawn when the difference is zero or less. While the scan runs it is called Unknown space · not scanned yet and shrinks as the scan goes on.

Keys	Toolbar	Command palette
`F`	Free space chip	Show/hide free space
`U`	Unknown space chip	Show/hide unknown space

Turning a block off redraws the rest to fill the view, so you see the scanned files at a larger scale.
New views follow Show free space in new views and Show unknown space in new views in Settings › Visualization.
They disappear once you zoom into a folder, and are not drawn in comparisons or while a filter hides non-matches. You can’t zoom into them or tag them.
In the flame graphs they are segments of the first band.

A large unknown space is worth a look: scanning with more rights usually makes it smaller. See Troubleshooting.

The Recycle Bin

What you deleted into the Recycle Bin (the Trash on macOS) still takes up space until the bin is emptied. SpaceKnife marks it so you don’t mistake it for files you use:

Everything in the bin is shaded and cross-hatched inside a coral dashed outline.
The bin itself carries a badge: Recycle Bin · emptying frees 12.3 GB (Trash · … on macOS). It also shows as the root bar or center disc when you zoom into the bin in a flame graph.
The hover card says In the Recycle Bin: the space comes back when the bin is emptied.
With Moving (the default), the dashes march and a band of light sweeps across the bin now and then. Reduce motion holds them still.

The bins it knows: $Recycle.Bin at the top of each Windows drive; ~/.Trash and .Trashes at the top of a volume on macOS; ~/.local/share/Trash and .Trash-<user id> at the top of a drive on Linux (the freedesktop.org Trash, used by GNOME, KDE and most file managers; rm deletes without one). A scan of the whole drive includes the bin; a scan of one folder does only when the bin is inside it.

While SpaceKnife monitors the scan, moving files to the bin moves their blocks into it, and emptying the bin turns that space into free space.

Choose Moving, Still or Off in Settings › Appearance › Treemap visuals › Recycle Bin effect.

To leave the bin out of the picture, press R or click the Recycle Bin chip next to Unknown space (Trash on macOS). The chip is there only when the scan holds a bin, and not in comparisons. With it off, the bin takes no room and the rest grows to fill the view. Its bytes are not counted as unknown space, and a view zoomed into the bin keeps showing it. New views follow Settings › Visualization › Geometry › Show the Recycle Bin in new views.

While a scan runs: the breathing outline

The picture fills in while the scan runs, several times a second. You can select, hover, zoom, go back, change the level and switch the visualization the whole time.

A folder that has been found but not read yet is a striped block that says Waiting to scan…. It opens once its contents are read.
Folders still being read, up to three levels below the zoom root (and the zoom root itself), breathe: an accent-colored outline glows and fades slowly. Inner levels breathe a little later than outer ones, so the glow ripples inward.
With Reduce motion on, the outline stays still.

The breathing outline and the change flashes share one switch: Settings › Visualization › Flash changed blocks.

Change flashes

After the scan, live monitoring keeps the picture up to date (see Live monitoring). When a file is added, deleted or changes size, its block flashes: a yellow outline with a glow, two pulses, then it fades.

When the changed item is not drawn on its own (too small, merged, or inside a collapsed folder), the block that holds it flashes. In the flame graphs, a change inside the zoom root that falls on no bar or sector flashes the root bar or the center disc.
With Reduce motion on, there is no flashing. The changed block shows a static badge with the change, for example “+212 MB”, for about ten seconds, where it fits.
Turn flashing off with Settings › Visualization › Flash changed blocks.

In a comparison

When you compare a scan with a snapshot (see Snapshots and comparison), all three visualizations show changes instead of sizes:

Area, length or angle is the amount of change. A folder’s size line shows its net change, such as “+14.8 GB” or “−5.7 GB”.
Orange means growth, in four tiers, and blue means decrease, in three. The tiers are 1, 3 and 8 GB, and step down to smaller units when all changes are small; the side panel’s legend shows the current bounds.
Items that are new since the base get a New badge when the block is big enough. Deleted items appear as decrease, sized by what they were in the base.
The Coloring group becomes Changes shown with All, Growth and Decrease; C steps through these instead of the colorings.
There are no free or unknown space blocks, so F and U do nothing. Split view is not available.
Esc first clears the selection; pressed again with nothing selected, it leaves the comparison.

Settings that shape the picture

The defaults, the initial detail level and the two “in new views” switches only affect views opened afterwards; everything else applies at once to the open views. See the Settings reference for the full list.

Setting	Where	Effect
Default visualization for new views	Appearance › Visualization	Treemap, flame graph or polar flame graph
Default treemap coloring	Appearance › Coloring	Classes by default
Default coloring for flame graphs and polar flame graphs	Appearance › Visualization	Branch by default
Reduce motion	Appearance › Animation	Instant zoom and switching, badges instead of flashes, still outlines
Level contrast, Border contrast	Appearance › Treemap visuals	How much folder levels and block edges stand out
Highlight halo levels	Appearance › Treemap visuals	How many ancestors light up on hover or selection (0 to 10)
Hover highlight, Selection shadow, Mouse trail	Appearance › Treemap visuals	Outline under the pointer, shadow under the selection, fading trail
Font size	Visualization › Geometry	80 to 140 %; also scales bar and ring sizes
Minimum block size	Visualization › Geometry	When small items are merged
Block proportions	Visualization › Geometry	Treemap only: taller or wider blocks
Initial detail level	Visualization › Geometry	Level of new views
Show free space / unknown space in new views	Visualization › Geometry	Start values of `F` and `U`
Show the Recycle Bin in new views	Visualization › Geometry	Start value of `R`
Sort by size	Visualization › Geometry	Largest first, or by name
Flame graph direction	Visualization › Flame graph	Root at bottom or at top
Zoom animation duration	Visualization › Animation	0 to 600 ms, 250 by default; 0 turns it off
Flash changed blocks	Visualization › Change highlights	Change flashes and the breathing outline

Keys on this page

Keys	Action
`V` / `Shift`+`V`	Next / previous visualization
`C`	Next coloring (in a comparison: next Changes shown option)
`Ctrl`+`=` / `Ctrl`+`-`	Raise / lower the detail level
`F`	Show or hide free space
`U`	Show or hide unknown space
`R`	Show or hide the Recycle Bin (when the scan holds one)
Double-click, `Enter`	Zoom in, also into merged blocks

Single-letter keys don’t work while you type in a text field, and a focused drop-down list keeps C and V for itself. On macOS you can press ⌘ wherever this page says Ctrl. All keys are listed in Keyboard shortcuts; zooming and the rest of the navigation are in Navigating the picture.