S-VIEW-10: velocity-curve editor UI — draggable spline box beside the Sample hero + in the Zone panel, all math through the pure velocity_curve module

src/vst/velocity_curve.cpp

@@ -216,6 +216,28 @@ bool VelocityCurve::deletePoint(std::size_t index) {
     return true;
 }
 
+VelocityCurve::CurvePixel VelocityCurve::pixelFromPoint(const Box& box, const VelocityPoint& p) {
+    return CurvePixel{velToX(box, p.velocity), ampToY(box, p.amp)};
+}
+
+VelocityPoint VelocityCurve::pointFromPixel(const Box& box, int x, int y) {
+    // The exact inverse of velToX/ampToY (within the one-pixel rounding quantum). Degenerate
+    // dimensions collapse the same way the forward map does: velToX pins to box.left (velocity 0),
+    // ampToY pins to box.top (amp 1).
+    VelocityPoint p;
+    const int w = std::max(0, box.width);
+    const int h = std::max(0, box.height);
+    p.velocity = (w <= 0)
+        ? kVelMin
+        : clampVelocity(kVelMin + static_cast<double>(x - box.left) / static_cast<double>(w) *
+                                      (kVelMax - kVelMin));
+    p.amp = (h <= 1)
+        ? kAmpMax
+        : clampAmp(kAmpMax - static_cast<double>(y - box.top) / static_cast<double>(h - 1) *
+                                 (kAmpMax - kAmpMin));
+    return p;
+}
+
 int VelocityCurve::pointAtPixel(const Box& box, int x, int y) const {
     for (std::size_t i = 0; i < points_.size(); ++i) {
         const int px = velToX(box, points_[i].velocity);