Principles

Seven rules that every Tacit app follows. Each is short enough to check against a screen.

One signal for each state

A state has one sign. Selection is a wash. Hover is a lighter wash. Pressed is a darker one. When a row is selected, it does not also get a bar, heavier words and a colour: three signs for one state read as three states, and the accent bar already means "you are here" in the rail.

A short list whose selected row is shown by its wash alone.
DoA selected row, shown by its wash alone. See List row.

Content first

A file shows itself. A picture is a small picture, not a symbol of a picture in a box. A song shows its name. The window's own furniture, its rail and header, stays quiet so that what the person came for is the loudest thing on the page.

The path is the title

One level for each page. The title of a page is where you are: Files, then Downloads. The parents are in the secondary ink and press to go back. There is no subtitle under it; a count appears where it matters, as in "3 files, 2.9 GB" when you select three.

A page header reading Files, Photos, then two rows.
DoThe path is the title.
A page header reading Photos with a line under it: Folder, 3 files, 2.9 GB.
Don'tPut a description under the title. It says again what the rows say.

Nothing grows open under a passing pointer

The pointer points; it does not decide. A rail does not widen, a panel does not open and a list does not rearrange because the pointer went across it. Hover is a wash and nothing else. Things open when a person presses, or presses a key. A page also never opens, expands or rearranges itself because of playback or anything in the background: the accent only marks where the playing thing lives.

Large things land and stop

A big surface moves once, to its place. A panel arrives on a curve that decelerates hard and ends still; it leaves faster than it came. Bounce is for small, direct feedback, such as a switch knob, and never for a panel or a list. The keyboard is never behind: a selection that follows a held arrow key jumps, it does not glide. See Motion.

Words, not symbols, for actions

An action is a word. Symbols are for kinds of things (a song, a PDF) and for places (Home, Downloads). "Open with…" and "Move to the trash" are words, 40 pixels high, and the destructive one goes last with the warning symbol, so a risk is never said by colour alone. The few icon buttons (back, forward, close) have names for screen readers, and a tip where the symbol is not plain.

Three actions as words in a list, the last, Move to the trash, with the warning symbol in the risk ink.
DoActions as words, the risk last.
A row of five icon buttons: open with, park, archive, rename, trash.
Don'tA row of symbols for actions. Each has to be learnt, and the trash sits among them.

Each fact said once

Say it where it belongs and nowhere else. The day is the heading, so the rows say only the time. The kind of file is the symbol, so there is no badge saying "PDF". A reason for a failure is said once, in the place a person is looking, and the row keeps only its symbol.

A list headed Today with two rows that give a size and a time.
DoThe heading says the day; the rows say the time.
The same list where each row says Today again before its time.
Don'tSay Today in the heading and in every row.

Experimental, in Tacit.Kit 0.1.

Text and figures: CC BY 4.0. Tacit.Kit: LGPL-3.0 code, OFL fonts. The Tacit name.