wheel accumulator (smooth wheel support)

notes

@@ -36,7 +36,7 @@ TODO {
         - shift+drag fine tuning
         - alt+drag to move reference point without changing value
         - global switch between horizontal and vertical
-        > scrollwheel support!
+        - scrollwheel support!
     }
     
     ping-pong for delay

xybrid/ui/gadgets/knobgadget.cpp

@@ -119,9 +119,22 @@ void KnobGadget::paint(QPainter* painter, const QStyleOptionGraphicsItem*, QWidg
 
 namespace { // interaction tracking vars
     int acc = 0;
+    int wAcc = 0;
     double trackVal;
 
     inline double stepRound(double v, double s) { return std::round(v / s) * s; }
+
+    int accumulate(int& acc, int step) {
+        int sgn = acc < 0 ? -1 : 1;
+        int rm = std::abs(acc) % step;
+        int diff = (std::abs(acc)-rm)*sgn / step;
+        acc = rm*sgn;
+        return diff;
+    }
+}
+
+void KnobGadget::hoverEnterEvent(QGraphicsSceneHoverEvent*) {
+    wAcc = 0; //reset wheel accumulator on hovering over a new knob
 }
 
 void KnobGadget::mousePressEvent(QGraphicsSceneMouseEvent* e) {
@@ -156,19 +169,15 @@ void KnobGadget::mouseMoveEvent(QGraphicsSceneMouseEvent* e) {
         if (UIConfig::verticalKnobs) acc -= curPos.y() - lastPos.y();
         else acc += curPos.x() - lastPos.x();
 
-        // handle accumulation math
-        int sgn = acc < 0 ? -1 : 1;
-        int rm = std::abs(acc) % stepPx;
-        int diff = (std::abs(acc)-rm)*sgn / stepPx;
-        acc = rm*sgn;
+        auto d = accumulate(acc, stepPx);
 
         auto mod = e->modifiers();
         if (mod.testFlag(Qt::AltModifier)) trackVal = std::clamp(trackVal, min, max); // soft release; just keep track within range
         else if (mod.testFlag(Qt::ShiftModifier) && subStep > 0) {
-            trackVal = stepRound(trackVal + subStep*diff, subStep);
+            trackVal = stepRound(trackVal + subStep*d, subStep);
             fSet(std::clamp(trackVal, min, max));
         } else if (step > 0) {
-            trackVal = stepRound(trackVal + step*diff, step);
+            trackVal = stepRound(trackVal + step*d, step);
             fSet(std::clamp(trackVal, min, max));
         }
     }
@@ -177,7 +186,10 @@ void KnobGadget::mouseMoveEvent(QGraphicsSceneMouseEvent* e) {
 
 void KnobGadget::wheelEvent(QGraphicsSceneWheelEvent* e) {
     if (highlighted) return;
-    auto d = e->delta()/120;
+
+    wAcc += e->delta();
+    auto d = accumulate(wAcc, 120);
+
     auto mod = e->modifiers();
     if (mod.testFlag(Qt::ShiftModifier) && subStep > 0) {
         fSet(std::clamp(stepRound(get()+subStep*d, subStep), min, max));

xybrid/ui/gadgets/knobgadget.h

@@ -49,6 +49,7 @@ namespace Xybrid::UI {
         QPainterPath shape() const override;
         void paint(QPainter*, const QStyleOptionGraphicsItem*, QWidget*) override;
 
+        void hoverEnterEvent(QGraphicsSceneHoverEvent*) override;
         void mousePressEvent(QGraphicsSceneMouseEvent*) override;
         void mouseReleaseEvent(QGraphicsSceneMouseEvent*) override;
         void mouseMoveEvent(QGraphicsSceneMouseEvent*) override;