drawTapeStrip — simplified: tape crease pattern + a single red pin.

evalCurve returns (x,y) at parametric t for a linear interp between (fx,fy) and (fx+dx,fy+dy) plus a downward sag = 4*sagAmt*t*(1-t).

resolveEndpoint returns an endpoint's screen position, honoring the optional pin override (used by the zoom transition).

shadowChar picks a character for a shadow cell — dithered base + slash sprinkles in the mid-density band for texture.

shadowRect paints an ASCII-dithered drop shadow under a rect.

snapPullToNote walks the notes list and snaps the pull's target to the next (or previous, if dir=-1) note's pin position, skipping the source.

--- ANSI-aware string splicing ------------------------------------- splitAtVisual cuts `s` at visible cell column `col`. CSI escape sequences (`\x1b[

styleRune — Unicode block offsets: sans-serif bold: A..Z=0x1D5D4 a..z=0x1D5EE 0..9=0x1D7EC sans-serif italic: A..Z=0x1D608 a..z=0x

zoomStep clamps within the full [ZoomMin, ZoomMax] range.

AddBoard appends a fresh board with a unique grain seed and makes it active. Returns the new board.

BgSGR emits the background-color SGR for this color. The renderer is otherwise foreground-only; this is used for the optional solid board background.

DeleteBoard removes the board at index i. Refuses to delete the last remaining board.

DitherShade returns a halftone char for a given (x,y) and density 0..1.

Hit tests a screen-cell (cx, cy) against the note's current screen rect.

Label returns a human-readable summary for the toast.

NewNote places a note at screen-centre converted to world coords, so it appears centred at whatever zoom level the user is on.

Pos returns an endpoint's SCREEN position (for drawing).

Progress: 0 = at source, 1 = at target. In runs 0→1; Out runs 1→0.

Run is the package's main entry point. cmd/redthread/main.go calls it.

StyleViewText applies styleRune to a pre-rendered string while passing through ANSI CSI escape sequences untouched. Useful when post-processing the ou

captureDeleteSnapshot records `n` and the strings that touch it so a subsequent `u` can put everything back. Overwrites any prior snapshot — undo only

colorIndex returns the BackgroundColors index for the cursor, or -1.

commitPullAt finalizes the pull: connects to a note if the target lands on one, otherwise drops a wall-pin at the world coords beneath.

composeEditorValue builds the textarea seed text. Empty notes seed as an empty string so the cursor lands on row 1, not row 3.

drawHelpPanel renders the bordered slide-up panel. anim ∈ [0,1] controls its height. Columns are rendered at fixed x-offsets so all keys/descriptions

drawNoteAt renders the full note (border, tape, title, body, decor) at an arbitrary rect. Used by both normal rendering and the zoom transition.

drawNoteAtWithBorder is drawNoteAt with an explicit border-color override (used during the zoom transition to avoid the highlight flashing mid-anim).

drawNoteFrame draws only the frame (tape, borders, title row, separator, inner flourish, fold glyph) — NOT the body. Used in edit mode where a live te

drawTabBar draws row 0: " redthread • work │ personal │ ideas ". The active board has a "•" prefix and brighter color. While renaming, the active b

drawTransitionView — clean 3D zoom with an animated backdrop fade. The cork + background notes fade from full brightness (at transition start) down to

effectiveStyleAt returns the SGR sequence active at visual column `col` within string `s` — i.e., the last CSI seen before that column. An empty retur

handleBgMenuKey drives the background picker. Up/down move between the cork toggle, the color rows, and the custom-hex row, live-previewing as they go

--- key handlers ------------------------------------------------------

--- mouse handlers ---------------------------------------------------

handlePullKey lets the keyboard drive the in-progress string pull — arrows nudge the virtual endpoint, tab/S-tab snap to other notes, enter commits at

handleRenameKey intercepts every keystroke while the user is editing a board's name in the tab bar. Enter commits, esc cancels.

lerpRect eases rect a toward b by t with easeInOutCubic — gives a nicer "glide" than a linear or ease-out-only curve.

newCanvas builds a canvas pre-set with the workspace's solid background (nil for cork/transparent, which keeps cells transparent).

pickStringChar maps a local (dx, dy) direction to a line character, accounting for terminal cell aspect ratio (~2:1 tall:wide). Without this correctio

restoreDeletedNote re-inserts the most recently deleted note at its original z-position on its original board, along with any strings it was connected

riseOffset returns the Y-offset (negative = up) applied during the morph to sell the 3D lift. Peaks at the middle of the transition with amplitude ~3

--- seed ---------------------------------------------------------

shadowGrowth returns how many extra cells of shadow thickness to add during the morph. Peaks mid-transition.

splitClipboardText parses pasted text into (title, body) the same way the editor's Split does: first line is the title, the rest is the body, with at

syncColor live-previews the fill as the cursor lands on a color/custom row; on the cork row the fill is left unchanged.

visibleWidth returns the visible-cell width of a string, ignoring CSI.

Brightness — Rec 601 luma, used by the monochrome dither pass.

FillRect writes a single rune + style across a rectangular area, overwriting whatever was there (useful for drop shadows, clears, etc).

GenStars returns a stable cork-texture for (w,h) using the default seed. For per-board grain, use GenStarsForBoard.

HalftoneChar is a simple level lookup (0..4).

IsEmpty returns true if the cell is the fully-transparent default.