pardes.git/src/animation.zig, branch release-0.24

The focused cursor rides with a moving pane, and a focus change glides to the new one

2026-10-01T03:12:16Z

G3's springs now keep the cursor's place in its pane: a pane that moves in the layout carries them, and the quad is drawn through the pane's presented box (its transition track), so through a slide, zoom or drag the cursor rides with the text, and with no transition it lands with it. A focus change, to another pane or into a column's or the workspace's tag, glides from where the cursor was drawn to the new place instead of snapping, unclamped while it crosses. While panes move the cursor is drawn as the overlay quad instead of vanishing (golden 18-mid-transition re-recorded for that: the only change is the quad, gliding into the new column's tag). Lapis: a tag plaque starts flush against its grip's button, the scroll gap between them part of the plaque, so grip and plaque read as one piece, on pane and column rows alike; below the button's row the grip keeps its band. Themes without plaques are unchanged (their grip band and tag band are one colour, no sliver).

T3: PanelCurtain wipes behind a soft edge two cells wide

2026-10-01T03:12:16Z

The curtain's glyph slide becomes a wipe: the new grid behind a head that crosses the pane, the old ahead, and between them two columns whose colours step from the old ground to the new in OKLab (CharSource.edge). Only the head's columns change from frame to frame.

T4: the terminal's dissolve swaps cells in ordered (Bayer) order

2026-10-01T03:12:16Z

animation.dissolveRevealed (the tty compositor's dissolve and the pointer mapping that follows it) swaps each changed cell once at its place in a 4x4 Bayer matrix, shifted by the pane's serial so two panes differ, instead of at a hashed noise threshold: the new content comes in as an even patterned screen (§9.2 T4). Endpoints stay exact. Tests: a 4x4 block reveals exactly t x 16 cells at t = 1/4, 1/2, 3/4. Snapshots unchanged. Feel review: .scratch/render/tty/dissolve/ (the matrix over two real frames; the recorded session's pane did not animate, noted in docs/effects.md).

G10: the theme's chrome fades through OKLab, easing in and out

2026-10-01T03:12:16Z

ChromeTheme.interpolate mixes each colour in OKLab (colors.mixOklab), so a fade between hues keeps its lightness instead of going dark and muddy mid way; animation.Fade eases it in and out (smooth), and one retargeted mid fade eases out from where it shows, so it never stalls. Still 10 frames (160 ms). The page, text and syntax colours change at once as before. Tests: OKLab round-trips its ends exactly and keeps a red-to-green mid-way brighter than the sRGB mix. Gates as G9 (no golden moved). Feel review: .scratch/render/crossfade/.

G7: a moving pane casts a shadow, a retargeted move keeps its speed, a dissolve crossfades

2026-10-01T03:12:16Z

- Track.launch: a move retargeted mid-way (Presentation.sync) starts at the old move's speed along the new one's longest side (carriedLaunch, Motion.easeFrom/speedFrom), so a second change during a slide bends the motion instead of stopping it dead. The macOS track ABI grows the float (pardes.h, 48 bytes; its reserved byte is named motion, as in Zig). - A pane that slides, zooms or rises casts Lift's soft shadow at sin(pi x progress) of its strength, on the other panes' bodies and rails alone, under the same contrast ceiling, carried by its track. - The GUI's PanelDissolve is a crossfade: the new cell drawn first, the old one over it at 1 - progress, premultiplied, on the blending cell pipeline for such groups (new cells now emitted before old ones, as the old layers already came after the new). sRGB blend, not linear light (documented). The tty keeps its per-cell swap. Presentation.zig's and animation.zig's tests were not in any test root; pardes.zig's test block now takes them in. Tests: a retargeted move carries its speed and still lands exactly; a moving pane's shadow is clipped off every tag, grip and its own body, none at the start or the landing, most mid-way. GUI golden 18 changes by the shadow (frame 6 of a slide). Gates as G6. Feel review: .scratch/render/transitions/.

G6: a wheel's notch scrolls the core at once and the picture glides after it

2026-10-01T03:12:16Z

A mouse wheel's notch (SDL's whole-number step, notchOf) scrolls the core by its lines at once, so keys and clicks act where the text is, and the picture follows on the Motion flavour's spring at half again its pace, critically damped whatever the flavour (text never passes its mark), carried from its current speed (animation.Spring.carry), so notches in a row flow on. How far the rows moved is measured on the next frame against the last (Glide.measure: a wrapped line's rows, a terminal's output, with a couple of rows' slack for the cursor's line and its number); the rows that left are kept, nearest first, and drawn in the gap the lag opens; the lag is never more than the body's height. A touchpad's fractions move the picture under the finger as before; `Motion off` lands a notch at once; a PDF page scrolls as before. The glide runs on the core's continuous path: Pardes.shell_continuous keeps frames coming every loop while it moves and carries a virtual clock with it; idle, nothing. The test feed takes wheel events (ESC]777;mouse;wheel;;;BEL). Tests: notch vs fraction; a carried spring keeps its speed and never passes its mark; a notch over two-row lines lags two rows, keeps the rows that left, settles frame by frame and leaves the continuous path, and lands at once with Motion off. Gates as G5. Feel review: .scratch/render/scroll/glide-{smooth,crisp,bouncy,off}{,-quarter}.mp4 and strips (a notch down, three, then two up).

G3: the focused cursor glides a jump on the Motion flavour's springs, and blinks

2026-10-01T03:12:15Z

The core owns the motion, as Lift: animation.CursorGlide keeps the focused cursor's four corners on springs (leading corners at the flavour's pace x2.4, trailing ones x follow, so a jump smears and collapses; a long jump bows by the flavour's arc), sampled at each frame's own time. A step of a cell or less, insert mode, a focus change and any scroll (a file's view, a terminal's output) land at once; a snap lands a glide under way too. The quad is clamped to the focused pane when drawn (never its springs). Chrome carries it on the wire (cursor_glide: bit 1 a cursor, bit 0 gliding; cursor_alpha; cursor_quad, grid cells; cursor_idle_ms): the GUI draws the quad as an overlay in the cursor's colour, at 85% (70% on the long flavours) rising to solid as it lands, and hides the cells' cursors while it does: one or the other every frame. Only the focused cursor glides. Blink (CursorBlink, on by default in pixel shells) is the shell's: from cursor_idle_ms and when the frame arrived, solid while typing and 500 ms after, 530 ms halves with 80 ms eased edges, solid after 10 s idle, and never while the window is unfocused or minimized or on a virtual clock. An edge redraws the last frame with no core render (level B, blink_redraws); an attached GUI blinks from the same field without a frame per edge. Tests: snaps a cell, glides a jump with smear and bow, arrives under a pixel by 150 ms on smooth and lands exactly, shifts with a scroll; blink holds, eases, stops; the core glides a jump (ge) frame by frame (gliding exactly while it moves, alpha rising, exact at rest), snaps a step (j) and a switch to insert mid-glide; a terminal's scrolling output lands its cursor; wire round-trip of the cursor record. Shared files: src/animation.zig, src/pardes.zig, src/config.zig (toggle CursorBlink), src/surface.zig, src/detached/wire.zig.

Motion flavours differ by design, and drive notice drops and pane moves

2026-10-01T03:12:15Z

The flavours looked alike because Lift, the only motion that read them, moves a shadow a few pixels: overshoot and wind-up were sub-pixel. By design now: crisp leaves at full speed and never passes its mark; smooth (the default) eases in and out in twice crisp's time, a slide arriving in 208 ms (inside §8.1's 220); bouncy passes its mark by ~30% and settles twice; playful winds up, passes by ~40%, and stretches and squashes, text included (the user's choice). Small motions are exaggerated by the flavour's gain. Motion gains launch, gain, span and norm, and ease(u)/speed(u) for moves of fixed length. The notice drop follows ease() over its fall (alpha never behind its position) and stays inside its pane's body past its row. Panel tracks carry the flavour in Track.motion (the old padding byte; macOS header name follows); opening and moving slides, zooms and rises follow it over span x their frames; landed, a pane is exactly its target; closing keeps its own exit. A pane past its mark never takes a neighbour's click; a rising one stays in its box. Tests: each flavour's lift trajectory distinct; flavour character; exact landing bit for bit; a stretched pane's drawn cells map back; the overshoot hit rule; the vertical clip at peak; legacy tests pinned to crisp. GUI golden 18-mid-transition changes (the retuned smooth slide at frame 6). Shared files: src/animation.zig, src/Presentation.zig, src/Messages.zig, src/macos.zig, src/config.zig, src/pardes.zig tests, src/ninep/screen.zig test, docs/effects.md, docs/config.md.

Motion flavours, and Lift is shadow, rim or auto: auto on a dark page recedes the other panes (InactiveDim)

2026-10-01T03:12:15Z

Motion off|crisp|smooth|bouncy|playful is one parameter set (animation.Motion) every fx animation reads. One focus spring per pane drives both the lift and the dim, at the flavour's pace; a grid snaps. Lift drops glow and surface. A shadow falls on pane bodies and rails only, capped so text and the selection keep min(contrast, 4.5); rim is a hairline along the focused tag's top. auto is a shadow on a light page; on a dark page the core recedes the unfocused panes' text (InactiveDim, ported from 2e4d97f, default 30 under auto) with the same floor. Tests: focused text contrast is never below unfocused in any style, dim or theme; the focused pane's cells and tag are untouched by a dim. Shared files: src/config.zig, src/builtins.zig, src/ninep/ctl.zig, src/surface.zig, src/detached/wire.zig, docs/config.md, test/snapshots/builtins.snap (one more wheel for the longer help).

G1: Lift, soft elevation shadows (off by default)

2026-10-01T03:12:15Z

`Lift` (a GUI toggle, capability lift) lifts the focused pane on a critically damped spring (animation.Spring: closed form, about 240 ms to settle, velocity kept across retargets, settled = no frames) and floats notices. The core puts the lift on the regions (Region.lift, on the wire); the GUI casts from it: a soft shadow is decor, an erf rectangle on one quad grown by 3 sigma (decor.frag, flag 0x10000000), in the quad's own space so a track's transform carries it; darken-only, the caster's rect left alone, alpha pre-warped for linear light and IGN-dithered. Cast last in its group, so a neighbour's rails and rules darken with its text; a notice's before its rule. Strength is capped per theme so text over the darkest shadow keeps min(its contrast, 4.5) (test over the native themes). Opt-in until the focus lift/dim default is decided. Feel review material: docs/effects.md. Test-mode PARDES_TEST_SERIES keeps every captured frame. Shared files touched: pardes.zig (two fields, one nextWake line), detached/wire.zig (lift on the region), config.zig, builtins.zig (capability), gui.zig. Not touched: Messages.zig, mouse.zig, tty, host_io.