More code improvements

src/engraving/layout/layoutsystem.cpp

@@ -86,8 +86,9 @@ System* LayoutSystem::collectSystem(const LayoutOptions& options, LayoutContext&
     bool curTrailer = ctx.curMeasure->trailer();
     MeasureBase* breakMeasure = nullptr;
 
-    Fraction minTicks = Fraction(4, 1); // Inizialize variable which stores the shortest note of the system
-    Fraction prevMinTicks = Fraction(4, 1);
+    Fraction minTicks = Fraction(10000, 1); // Initializing this variable at a random high value.
+    // In principle, it just needs to be longer than any possible note.
+    Fraction prevMinTicks = Fraction(1, 1);
     bool changeMinSysTicks = false;
     qreal oldStretch = 1;
 
@@ -387,8 +388,12 @@ System* LayoutSystem::collectSystem(const LayoutOptions& options, LayoutContext&
     qreal stretchCoeff = 1;
     qreal prevWidth = 0;
     int iter = 0;
-    while (abs(newRest) > score->spatium() * 0.08 && iter < 200) { // spatium*0.08 is about the width of a note stem
-        stretchCoeff += 1.5 * newRest / curSysWidth;
+    static double epsilon = score->spatium() * 0.08; // For reference: this is approximately as small as the width of a note stem
+    static constexpr int maxIter = 200; // Limits the number of iterations, just for safety. In reality, most systems require less then 10 iterations.
+    static constexpr float multiplier = 1.5; // Empirically optimized value which allows the fastest convergence of the following algorithm.
+
+    while (abs(newRest) > epsilon && iter < maxIter) {
+        stretchCoeff += multiplier * newRest / curSysWidth;
         for (MeasureBase* mb : system->measures()) {
             if (mb->isMeasure()) {
                 Measure* m = toMeasure(mb);

src/engraving/libmscore/measure.cpp

@@ -3149,8 +3149,6 @@ QString Measure::accessibleInfo() const
 
 void Measure::layoutMeasureElements()
 {
-    //bbox().setWidth(targetWidth); // Doesn't seem to be needed but I keep it here just to be safe
-
     //---------------------------------------------------
     //    layout individual elements
     //---------------------------------------------------
@@ -4008,7 +4006,7 @@ static bool hasAccidental(Segment* s)
 }
 
 //---------------------------------------------------------
-//      Stretch formula
+//      durationStretch
 //      Computes the stretch for a given segment depending
 //      on its duration with respect to the shortest one.
 //      Three different options proposed (see documentation).
@@ -4019,7 +4017,7 @@ float Measure::durationStretch(Fraction curTicks, const Fraction minTicks) const
     static constexpr qreal baseSlope = 0.647;
     qreal slope = userSlope * baseSlope;
     // The slope of the spacing formula is determined by the multiplication of user-defined settings and baseSlope.
-    // The value of baseSlope is chosen such that, for the default user settings, the curve matches the Gould.
+    // The value of baseSlope is chosen such that the curve matches the "ideal" one when user settings are at default.
     // See documentation PDF for more detail.
 
     static constexpr int maxMMRestWidth = 20; // At most, MM rests will be spaced "as if" they were 20 bars long.
@@ -4046,7 +4044,7 @@ float Measure::durationStretch(Fraction curTicks, const Fraction minTicks) const
     //qreal str = 1 - 0.112 * slope +  0.112 * slope * qreal(curTicks.ticks()) / qreal(minTicks.ticks());
     // Logarithmic spacing (MS 3.6)
     //qreal str = 1.0 + 0.721 * slope * log(qreal(curTicks.ticks()) / qreal(minTicks.ticks()));
-    // Quadratic spacing (Gould)
+    // Quadratic spacing
     qreal str = 1 - slope + slope * sqrt(qreal(curTicks.ticks()) / qreal(minTicks.ticks()));
 
     if (minTicks > longNoteThreshold) {
@@ -4077,8 +4075,10 @@ void Measure::computeWidth(Segment* s, qreal x, bool isSystemHeader, Fraction mi
     bool first  = isFirstInSystem();
     const Shape ls(first ? RectF(0.0, -1000000.0, 0.0, 2000000.0) : RectF(0.0, 0.0, 0.0, spatium() * 4));
 
-    qreal minNoteSpace = score()->noteHeadWidth() * 1.05;
-    qreal usrStretch = qMax(userStretch() * score()->styleD(Sid::measureSpacing), qreal(0.1)); // The qMax avoids stretch going to zero
+    qreal minNoteSpace = score()->noteHeadWidth() * 1.05; // This used to be minNoteSpace = noteHeadWidth() + minNoteDistance().
+    // I have removed minNoteDistance() because it was causing an unintuitive behaviour in the spacing,
+    // and I've substituted it with a purely empirical factor (*1.05) which obtains a similar default distance.
+    qreal usrStretch = std::max(userStretch() * score()->styleD(Sid::measureSpacing), qreal(0.1)); // The max() avoids stretch going to zero
 
     while (s) {
         s->rxpos() = x;
@@ -4119,7 +4119,7 @@ void Measure::computeWidth(Segment* s, qreal x, bool isSystemHeader, Fraction mi
                     // NOTE: durStretch is the spacing factor purely determined by the duration of the note.
                     // usrStretch is the spacing factor determined by user settings.
                     // stretchCoeff is the spacing factor used to justify the systems, i.e. getting the systems to fill the page.
-                    w = qMax(w, minStretchedWidth);
+                    w = std::max(w, minStretchedWidth);
                 }
             }
             // look back for collisions with previous segments

src/engraving/libmscore/system.cpp

@@ -1832,14 +1832,13 @@ int System::lastVisibleSysStaffOfPart(const Part* part) const
 
 Fraction System::minSysTicks() const
 {
-    Fraction minTicks = Fraction(10, 1); // Initializing the variable at a random high value.
+    Fraction minTicks = Fraction (10000, 1); // Initializing the variable at a random high value.
+    // In principle, it just needs to be longer than any possible note, such that the following loop
+    // always correctly returns the shortest note/rest of the system.
     for (MeasureBase* mb : measures()) {
         if (mb->isMeasure()) {
             Measure* m = toMeasure(mb);
-            Fraction curMinTicks = m->computeTicks();
-            if (curMinTicks < minTicks) {
-                minTicks = curMinTicks;
-            }
+            minTicks = std::min(m->computeTicks(), minTicks);
         }
     }
     return minTicks;