initial scrollwheel functionality, simplified position tracking slightly

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

@@ -118,12 +118,10 @@ void KnobGadget::paint(QPainter* painter, const QStyleOptionGraphicsItem*, QWidg
 }
 
 namespace { // interaction tracking vars
-    QPoint lastPos;
     int acc = 0;
     double trackVal;
 
     inline double stepRound(double v, double s) { return std::round(v / s) * s; }
-//
 }
 
 void KnobGadget::mousePressEvent(QGraphicsSceneMouseEvent* e) {
@@ -137,7 +135,6 @@ void KnobGadget::mousePressEvent(QGraphicsSceneMouseEvent* e) {
         else if (step > 0.0)
             trackVal = stepRound(trackVal, step);
         fSet(trackVal);
-        lastPos = e->screenPos();
     } else if (e->button() == Qt::RightButton) {
         fSet(defaultVal);
         e->accept();
@@ -154,10 +151,10 @@ void KnobGadget::mouseReleaseEvent(QGraphicsSceneMouseEvent* e) {
 
 void KnobGadget::mouseMoveEvent(QGraphicsSceneMouseEvent* e) {
     if (highlighted) {
-        auto curPos = e->screenPos();
+        auto curPos = e->pos().toPoint();
+        auto lastPos = e->lastPos().toPoint();
         if (UIConfig::verticalKnobs) acc -= curPos.y() - lastPos.y();
         else acc += curPos.x() - lastPos.x();
-        lastPos = curPos;
 
         // handle accumulation math
         int sgn = acc < 0 ? -1 : 1;
@@ -170,7 +167,7 @@ void KnobGadget::mouseMoveEvent(QGraphicsSceneMouseEvent* e) {
         else if (mod.testFlag(Qt::ShiftModifier) && subStep > 0) {
             trackVal = stepRound(trackVal + subStep*diff, subStep);
             fSet(std::clamp(trackVal, min, max));
-        } else {
+        } else if (step > 0) {
             trackVal = stepRound(trackVal + step*diff, step);
             fSet(std::clamp(trackVal, min, max));
         }
@@ -178,6 +175,20 @@ void KnobGadget::mouseMoveEvent(QGraphicsSceneMouseEvent* e) {
     update();
 }
 
+void KnobGadget::wheelEvent(QGraphicsSceneWheelEvent* e) {
+    if (highlighted) return;
+    auto d = e->delta()/120;
+    auto mod = e->modifiers();
+    if (mod.testFlag(Qt::ShiftModifier) && subStep > 0) {
+        fSet(std::clamp(stepRound(get()+subStep*d, subStep), min, max));
+        e->accept();
+    } else if (step > 0) {
+        fSet(std::clamp(stepRound(get()+step*d, step), min, max));
+        e->accept();
+    }
+    update();
+}
+
 void KnobGadget::contextMenuEvent(QGraphicsSceneContextMenuEvent* e) {
     e->accept();
 }

xybrid/ui/gadgets/knobgadget.h

@@ -13,7 +13,6 @@ namespace Xybrid::UI {
         Q_OBJECT
 
         bool highlighted = false;
-        //double startVal;
         double lastVal = 0.0;
         bool dirty = true;
 
@@ -53,6 +52,7 @@ namespace Xybrid::UI {
         void mousePressEvent(QGraphicsSceneMouseEvent*) override;
         void mouseReleaseEvent(QGraphicsSceneMouseEvent*) override;
         void mouseMoveEvent(QGraphicsSceneMouseEvent*) override;
+        void wheelEvent(QGraphicsSceneWheelEvent*) override;
         void contextMenuEvent(QGraphicsSceneContextMenuEvent*) override;
 
         inline KnobGadget* setLabel(const QString& s) { label->setText(s); dirty = true; update(); return this; }