Give a mis-drag a way back

Develop edits now save themselves to a sidecar the moment you leave the
image, so until this there was no way to undo one — the mistake was
persisted and the only recourse was to remember the old number.

The history is a stack of snapshots, because the edit graph is already
plain data: `Preset::capture` reduces it to what differs from default and
`Preset::apply` puts it back, so undo is those two calls and nothing else.
A command object per action, with an inverse beside it, would have been a
second thing every operation had to register — and operations are declared
in YAML precisely so that a new one needs no code written for it. A
snapshot cannot fall behind them.

The interesting part is coalescing. A slider drag emits an event per frame
and must be one step, not forty. Nothing in the interface reports a gesture
boundary — the same wall the render coalescing hit, and it is answered the
same way rather than by threading a "finger is down" out of every slider,
curve point and crop handle. What stands in for the boundary is the control
plus recency: changes to the same control within 700 ms amend one step.
Which control is "the same" is asked of the graph, not listed: an operation
whose declared presentation claims a parameter is one where a single
gesture moves several — a curve point carries an x and a y — so those
coalesce as one widget. Nothing in the history names the tone curve.

The compromise, and it is a real one: a control let go of and picked up
again within the window is one step rather than two. Buying the other
answer costs a gesture-boundary signal on every control, which is more
surface than the difference is worth.

The stack is bounded at 64 states for NFR-RES-1 — a develop session stays
open for hours. Sixty-four rather than a byte cap: what is being bounded is
steps a photographer would want back, and a byte cap would give the
elaborate edit the shallowest history, which is exactly backwards.

The session owns its history and every mutator records into it, so the
callbacks in `lib.rs` cannot change the edit and forget to — with a dozen
generic callbacks that would have been one press of undo away from wrong
every time a control was added. Opening a photograph makes its stored edit
the floor rather than a step: it is not work done in this sitting, and an
undo reaching behind it would discard a previous session's edit and then
save that on the way out.

Not yet done, from FR-DEV-5: history is per-session and in memory, and
there are no named snapshots. What mattered was that a saved mis-drag had
no way back at all.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
This commit is contained in:
2026-08-17 09:03:34 +02:00
co-authored by Claude Opus 5
parent 2330ed25e9
commit 7f524d2fd0
5 changed files with 779 additions and 2 deletions
+65 -2
View File
@@ -13,8 +13,8 @@ use dr_decode::RawImage;
use dr_gpu::{AdjustPass, DemosaicedImage, Demosaicer, GpuContext};
use dr_pipeline::ops::curve;
use dr_pipeline::{
CropRect, EditGraph, OpCapability, OpId, ParamId, ParamKind, Presentation, Preset, Scope, Unit,
WidgetKind,
CropRect, Edit, EditGraph, History, OpCapability, OpId, ParamId, ParamKind, Presentation,
Preset, Scope, Unit, WidgetKind,
};
use crate::labels;
@@ -23,6 +23,15 @@ use crate::ParamRow;
/// A loaded image plus its edit state.
pub struct DevelopSession {
graph: EditGraph,
/// TRACES: FR-DEV-5
/// Undo, kept beside the graph rather than in the window.
///
/// Every mutator below records into it, so a caller cannot change the edit
/// and forget to. That is the whole reason it lives here: the callbacks in
/// `lib.rs` are generic by construction and there are a dozen of them, and
/// a history the *call sites* had to remember would be one press of undo
/// away from wrong every time a control is added.
history: History,
demosaiced: DemosaicedImage,
adjust: AdjustPass,
}
@@ -73,8 +82,10 @@ impl DevelopSession {
) -> Self {
let mut graph = EditGraph::default_chain();
graph.set_orientation(orientation);
let history = History::new(&graph);
Self {
graph,
history,
demosaiced,
adjust: AdjustPass::new(ctx),
}
@@ -450,6 +461,9 @@ impl DevelopSession {
for p in &cap.params {
self.graph.set_param(cap.id, p.id, p.default);
}
// One step, though it moved every parameter the operation has: the
// user pressed one button.
self.history.record(&self.graph, Edit::Discrete);
}
/// Reset a curve, which is to reset its operation.
@@ -471,6 +485,8 @@ impl DevelopSession {
return;
};
self.graph.set_param(op, param, value);
let edit = Edit::for_param(&self.graph, op, param);
self.history.record(&self.graph, edit);
}
/// Return one parameter to its default.
@@ -487,10 +503,12 @@ impl DevelopSession {
.map(|p| p.default)
.unwrap_or(0.0);
self.graph.set_param(op, param, default);
self.history.record(&self.graph, Edit::Discrete);
}
pub fn reset_all(&mut self) {
self.graph.reset();
self.history.record(&self.graph, Edit::Discrete);
}
fn lookup(&self, op_index: i32, param_index: i32) -> Option<(OpId, ParamId)> {
@@ -654,6 +672,10 @@ impl DevelopSession {
/// Set the crop rectangle, in fractions of the source.
pub fn set_crop(&mut self, rect: CropRect) {
self.graph.set_crop(rect);
// Keyed on the operation, not on a parameter: one drag of one handle
// moves the origin and the extent together.
self.history
.record(&self.graph, Edit::Op(dr_pipeline::framing::ID));
}
pub fn crop(&self) -> CropRect {
@@ -673,6 +695,7 @@ impl DevelopSession {
self.graph.set_crop(rotate_crop(crop, turns));
}
self.graph.rotate_quarters(turns);
self.history.record(&self.graph, Edit::Discrete);
}
/// Straightening, in degrees. Positive turns the image clockwise.
@@ -697,6 +720,7 @@ impl DevelopSession {
dr_pipeline::framing::FLIP_H,
f32::from(u8::from(!h)),
);
self.history.record(&self.graph, Edit::Discrete);
}
pub fn toggle_flip_v(&mut self) {
@@ -706,6 +730,7 @@ impl DevelopSession {
dr_pipeline::framing::FLIP_V,
f32::from(u8::from(!v)),
);
self.history.record(&self.graph, Edit::Discrete);
}
/// Set the straightening angle, in degrees.
@@ -715,6 +740,10 @@ impl DevelopSession {
dr_pipeline::framing::ANGLE,
degrees,
);
self.history.record(
&self.graph,
Edit::Param(dr_pipeline::framing::ID, dr_pipeline::framing::ANGLE),
);
}
/// Whether the framing currently changes the image — what lights the
@@ -737,6 +766,7 @@ impl DevelopSession {
let view = self.graph.framing().view();
self.graph.framing_mut().reset();
self.graph.framing_mut().set_view(view);
self.history.record(&self.graph, Edit::Discrete);
}
/// How far the viewport is zoomed in: 1.0 fits the frame, 4.0 is 4×.
@@ -859,6 +889,10 @@ impl DevelopSession {
/// values the sliders are showing, and nothing here pushes them.
pub fn apply_settings(&mut self, preset: &Preset, scope: Scope) {
preset.apply(&mut self.graph, scope);
// A paste is undoable, and is the action most in need of it: it
// replaces everything in scope at once, so getting it wrong costs more
// than any single control can.
self.history.record(&self.graph, Edit::Discrete);
}
/// TRACES: FR-CAT-8
@@ -870,6 +904,35 @@ impl DevelopSession {
/// orientation survives it, since that was never an edit.
pub fn apply_version(&mut self, version: &dr_pipeline::Version) {
version.apply(&mut self.graph);
// The stored edit becomes the floor rather than a step. It is not
// something the user did in this sitting, and an undo that reached
// behind it would discard a previous session's work in one press —
// then persist that on the way out, since saving is automatic.
self.history.reset(&self.graph);
}
/// TRACES: FR-DEV-5
/// Step the edit back one, returning whether anything moved.
///
/// The panel must be rebuilt from [`Self::rows`] afterwards, for the same
/// reason a paste must: this moves values the controls are showing and
/// nothing here pushes them.
pub fn undo(&mut self) -> bool {
self.history.undo(&mut self.graph)
}
/// TRACES: FR-DEV-5
/// Step the edit forward one, returning whether anything moved.
pub fn redo(&mut self) -> bool {
self.history.redo(&mut self.graph)
}
pub fn can_undo(&self) -> bool {
self.history.can_undo()
}
pub fn can_redo(&self) -> bool {
self.history.can_redo()
}
}
+52
View File
@@ -256,6 +256,11 @@ fn reset_view_state(window: &AppWindow) {
window.set_flip_h(false);
window.set_flip_v(false);
window.set_framing_modified(false);
// A photograph that failed to decode has no session, so nothing below
// will speak for it — and the buttons would otherwise keep offering the
// previous image's history.
window.set_can_undo(false);
window.set_can_redo(false);
}
/// Push the framing back to the geometry panel.
@@ -961,6 +966,15 @@ pub fn run(paths: Vec<PathBuf>) -> Result<()> {
Rc::new(move |window: &AppWindow, draft: bool| {
let mut slot = session.borrow_mut();
let Some(s) = slot.as_mut() else { return };
// TRACES: FR-DEV-5
// Whether undo has anywhere to go, pushed from here because every
// edit ends in a redraw and nothing else is on all of their paths:
// the parameter callbacks sync rows, the framing ones sync the
// geometry panel, and a paste arrives through neither.
window.set_can_undo(s.can_undo());
window.set_can_redo(s.can_redo());
let (mut w, mut h) = *viewport.borrow();
// **Half resolution while the gesture is still moving.**
@@ -1505,6 +1519,44 @@ pub fn run(paths: Vec<PathBuf>) -> Result<()> {
});
}
// ---- undo and redo (FR-DEV-5) ---------------------------------------
//
// Thin, because the history lives in the session and every mutator there
// records into it — see `DevelopSession::history`. What is left for the
// interface is the refresh a paste also needs: the controls are showing
// values that have just moved underneath them.
//
// `can-undo` and `can-redo` are not set here; `render_now` pushes them on
// every redraw, which is every path that can change them.
{
let weak = window.as_weak();
let session = session.clone();
let redraw = redraw.clone();
let rows = rows.clone();
window.on_undo(move || {
let Some(w) = weak.upgrade() else { return };
let stepped = session.borrow_mut().as_mut().is_some_and(|s| s.undo());
if stepped {
sync_rows(&w, &rows, &session);
redraw(&w);
}
});
}
{
let weak = window.as_weak();
let session = session.clone();
let redraw = redraw.clone();
let rows = rows.clone();
window.on_redo(move || {
let Some(w) = weak.upgrade() else { return };
let stepped = session.borrow_mut().as_mut().is_some_and(|s| s.redo());
if stepped {
sync_rows(&w, &rows, &session);
redraw(&w);
}
});
}
// ---- zoom, pan and crop ---------------------------------------------
//
// Zoom and pan are viewing state and touch no parameter, so unlike the