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BadNote/lib/editor/notebook/ink_stroke_adapter.dart
Akiba So 0feca74278
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feat(pen): extensible brush model (4 brushes)
Replace the 2-tool ink system with a data-driven, Krita-style
BrushProfile (lib/editor/engine/brush.dart). Adding a brush is a
const map entry, not render-path branching.

Four presets from the rnote/krita spec:
- fountain pen: quadratic (p^2) pressure, wide dynamic width
- ballpoint:    near-constant width (thinning 0.15)
- highlighter:  flat width, square caps
- pencil:       sqrt(p) pressure, moderate width

Pressure is pre-warped per brush via PressureCurve(gamma) before
perfect_freehand; geometry fields (thinning/streamline/smoothing/
caps) flow through the shared stroke recipe so the PDF overlay and
the note/slide PenCanvas both honor the brush. Brush kind is now
persisted on the stroke model. Picker added to all three toolbars.

Opacity/multiply and pencil grain are carried as data but not yet
composited (TODO brush-opacity / brush-texture); this increment is
width + pressure-curve differentiation. analyze clean, 283 tests.
2026-06-24 11:13:43 +08:00

104 lines
3.9 KiB
Dart

// lib/editor/notebook/ink_stroke_adapter.dart
//
// Bridge between the legacy note/ppt storage model (`InkStroke`, ABSOLUTE pixel
// coordinates, `PenTool`) and the pen-first canvas model (`PenStroke`,
// NORMALIZED [0,1] coordinates, `PenStrokeKind`). The pen-first canvas is the
// single performant inking engine, so notes and slides are rebuilt on top of it
// and persisted back as `InkStroke` via this adapter.
//
// Coordinates are normalized against a logical page rectangle: ink absolute
// (x,y) -> pen (x/pageW, y/pageH) and back. Stroke width is likewise expressed
// as a fraction of the page width on the pen side and as absolute pixels on the
// ink side. Only freehand pen/highlighter strokes round-trip; shape/text
// `PenTool`s have no pen-canvas representation and are dropped (the pen-first
// note is handwriting-first — see the rebuild roadmap).
import 'dart:ui' show Size;
import '../../models/ink_point.dart';
import '../../models/ink_stroke.dart';
import '../../models/pen_tool.dart';
import '../canvas/pen_stroke.dart';
import '../engine/brush.dart';
/// Logical page rectangle a blank note is inked on (portrait, ~A4 √2 ratio).
/// Strokes are normalized against this so they stay pinned under zoom/pan.
const Size kNoteLogicalPage = Size(1000, 1414);
/// True when [tool] is a freehand mark the pen canvas can render
/// (pen/marker/highlighter). Shapes and text are not representable.
bool isFreehandTool(PenTool tool) =>
tool == PenTool.pen ||
tool == PenTool.marker ||
tool == PenTool.highlighter;
/// Maps an ink [PenTool] to the pen-canvas stroke kind.
PenStrokeKind penKindFromTool(PenTool tool) =>
tool == PenTool.highlighter ? PenStrokeKind.highlighter : PenStrokeKind.pen;
/// Maps a pen-canvas stroke kind back to a [PenTool].
PenTool toolFromPenKind(PenStrokeKind kind) =>
kind == PenStrokeKind.highlighter ? PenTool.highlighter : PenTool.pen;
/// Convert a stored [InkStroke] (absolute px on [page]) to a [PenStroke]
/// (normalized). Returns null for non-freehand strokes (shapes/text), which the
/// pen canvas cannot draw.
PenStroke? penStrokeFromInk(InkStroke s, Size page) {
if (!isFreehandTool(s.tool)) return null;
if (s.points.isEmpty) return null;
final w = page.width <= 0 ? 1.0 : page.width;
final h = page.height <= 0 ? 1.0 : page.height;
return PenStroke(
points: [
for (final p in s.points)
PenPoint(p.x / w, p.y / h, p.pressure, tilt: p.tilt),
],
color: s.color,
width: s.strokeWidth / w,
kind: penKindFromTool(s.tool),
// Brush isn't persisted yet (TODO(brush-persist)); derive from the tool so
// a loaded highlighter renders with the flat highlighter brush and pens
// fall back to the fountainPen default.
brush: s.tool == PenTool.highlighter
? BrushKind.highlighter
: BrushKind.fountainPen,
);
}
/// Convert a freshly drawn [PenStroke] (normalized) back to an [InkStroke]
/// (absolute px on [page]) for persistence. [id] and [createdAt] come from the
/// caller (uuid + clock) so this stays pure/deterministic.
InkStroke inkStrokeFromPen(
PenStroke s,
Size page, {
required String id,
required DateTime createdAt,
}) {
final w = page.width <= 0 ? 1.0 : page.width;
final h = page.height <= 0 ? 1.0 : page.height;
return InkStroke(
id: id,
points: [
for (final p in s.points)
InkPoint(
x: p.x * w,
y: p.y * h,
pressure: p.pressure ?? 0.5,
tilt: p.tilt ?? 0.0,
timestamp: 0,
),
],
tool: toolFromPenKind(s.kind),
color: s.color,
strokeWidth: s.width * w,
createdAt: createdAt,
);
}
/// Convert a list of stored ink strokes to pen strokes, dropping the ones the
/// canvas cannot represent (shapes/text). Order is preserved.
List<PenStroke> penStrokesFromInk(Iterable<InkStroke> strokes, Size page) =>
[for (final s in strokes) penStrokeFromInk(s, page)]
.whereType<PenStroke>()
.toList();