One taper, one modifier law: extract param_taper, raise the stage ceiling to 10 s, and make the AHDSR schematic axis the taper itself

src/core/instrument/ui/deck_values.h

@@ -11,14 +11,15 @@
 #include "core/instrument/map/play_seconds.h"      // PlaySeconds (the deck's edit target)
 #include "core/instrument/ui/deck_groups.h"        // DeckParam
 #include "core/instrument/ui/envelope_overlay.h"   // kGateStageMaxSeconds
+#include "core/instrument/ui/param_taper.h"        // UnitCategory + the shared tapers
 
 namespace reasampler::instrument::ui {
 
 using map::PlaySeconds;
 
 // Every stage-time knob spans [0, kEnvTimeMaxSeconds] seconds — rate-free, exactly what the
-// parameter set stores. READ from the overlay's schematic scale rather than restated: the AHDSR
-// schematic anchors a maxed knob at the canvas edge, which only holds while the two agree.
+// parameter set stores. An ALIAS of the overlay's schematic domain, which is itself an alias of
+// the taper's; param_taper.h owns why the number has one home.
 inline constexpr double kEnvTimeMaxSeconds = kGateStageMaxSeconds;
 
 // Pitch depth throw: +/-kVelocityPitchRangeSemitones, centred. The one throw the pitch
@@ -28,10 +29,11 @@ inline constexpr double kPitchDepthMaxSemis = kVelocityPitchRangeSemitones;
 // Key-track knob ceiling (0..200%), shared by the pitch and filter key-track controls.
 inline constexpr double kKeyTrackMax = 2.0;
 
-// The normalized [0,1] a control shows: seconds over the ceiling, levels and fractions as-is,
-// signed depths centred at 0.5, curve exponents over their logarithmic travel. Controls backed
-// by per-instance state rather than the parameter set (voice count, master gain, the pitch
-// key-track scalar, preview velocity) are not here — the shell reads those from the processor.
+// The normalized [0,1] a control shows: stage times through the shared time taper, levels and
+// fractions as-is, signed depths through the centre-expanded depth taper, curve exponents over
+// their logarithmic travel. Controls backed by per-instance state rather than the parameter set
+// (voice count, master gain, the pitch key-track scalar, preview velocity) are not here — the
+// shell reads those from the processor.
 double deckParamNorm(DeckParam id, const PlaySeconds& play);
 
 // Applies a committed interaction: a knob's normalized `value`, or a toggle's `segment` (0/1).
@@ -39,13 +41,23 @@ double deckParamNorm(DeckParam id, const PlaySeconds& play);
 void setDeckParam(DeckParam id, PlaySeconds& play, double value, int segment);
 
 // Resets `id` to its default. The default IS what a fresh PlaySeconds carries, so there is no
-// second table of defaults to drift from the real one. It arrives via the norm round trip, so
-// landing EXACTLY on a stage time (0.003 s attack, 0.060 s release) depends on
-// kEnvTimeMaxSeconds being a power of two — x/2^n*2^n is lossless, an arbitrary ceiling is not.
-// Move that ceiling off a power of two and a reset lands a mantissa bit off its own default.
+// second table of defaults to drift from the real one, and the value is COPIED rather than
+// round-tripped through norm -> value. That bypass is MANDATORY: a reset must land on the stored
+// default bit for bit, and no round trip through a log taper over a non-power-of-two ceiling can
+// promise that for every control. Never "simplify" it back into a round trip.
 // For knob-valued controls — a toggle has no reset gesture.
 void resetDeckParam(DeckParam id, PlaySeconds& play);
 
+// THE snap-unit table: which whole unit Shift snaps each control to. Includes the deck's
+// processor-side ids (voice count, master gain), which have no entry in the two functions above
+// because their VALUE lives outside the parameter set — the unit does not.
+UnitCategory deckParamUnit(DeckParam id);
+
+// Applies that snap to a control's normalized value. Snapping happens in the DISPLAYED unit, so
+// this is where each control's full scale enters: 0..100 %, 0..200 % and +/-100 % all snap to a
+// whole displayed percent and therefore take different norm steps.
+double snapDeckParamNorm(DeckParam id, double norm);
+
 // A time constant as MILLISECONDS, e.g. "12 ms". Never switches to seconds: the editor reads in
 // one unit so two stage times are comparable at a glance. Sub-10 ms keeps one decimal so a short
 // attack is not rounded to a bare "0 ms". Writes at most `len` bytes including the terminator.