Allow configuring the amount of digits displayed after decimal point.

This is useful in niche cases, like making angular measurement tools.

Also, use simpler and more principled code for numeric precision
while editing constraints: don't special-case angles, but use up to
10 digits after the decimal point for everything.

src/confscreen.cpp

@@ -60,10 +60,15 @@ void TextWindow::ScreenChangeGridSpacing(int link, uint32_t v) {
 }
 
 void TextWindow::ScreenChangeDigitsAfterDecimal(int link, uint32_t v) {
-    SS.TW.ShowEditControl(3, ssprintf("%d", SS.UnitDigitsAfterDecimal()));
+    SS.TW.ShowEditControl(14, ssprintf("%d", SS.UnitDigitsAfterDecimal()));
     SS.TW.edit.meaning = Edit::DIGITS_AFTER_DECIMAL;
 }
 
+void TextWindow::ScreenChangeDigitsAfterDecimalDegree(int link, uint32_t v) {
+    SS.TW.ShowEditControl(14, ssprintf("%d", SS.afterDecimalDegree));
+    SS.TW.edit.meaning = Edit::DIGITS_AFTER_DECIMAL_DEGREE;
+}
+
 void TextWindow::ScreenChangeExportScale(int link, uint32_t v) {
     SS.TW.ShowEditControl(5, ssprintf("%.3f", (double)SS.exportScale));
     SS.TW.edit.meaning = Edit::EXPORT_SCALE;
@@ -235,10 +240,14 @@ void TextWindow::ShowConfiguration() {
         SS.MmToString(SS.gridSpacing).c_str(),
         &ScreenChangeGridSpacing, 0);
     Printf(false, "%Ft digits after decimal point to show%E");
-    Printf(false, "%Ba   %d %Fl%Ll%f%D[change]%E (e.g. '%s')",
+    Printf(false, "%Ba%Ft   distances: %Fd%d %Fl%Ll%f%D[change]%E (e.g. '%s')",
         SS.UnitDigitsAfterDecimal(),
         &ScreenChangeDigitsAfterDecimal, 0,
         SS.MmToString(SS.StringToMm("1.23456789")).c_str());
+    Printf(false, "%Ba%Ft   angles:    %Fd%d %Fl%Ll%f%D[change]%E (e.g. '%s')",
+        SS.afterDecimalDegree,
+        &ScreenChangeDigitsAfterDecimalDegree, 0,
+        SS.DegreeToString(1.23456789).c_str());
 
     Printf(false, "");
     Printf(false, "%Ft export scale factor (1:1=mm, 1:25.4=inch)");
@@ -400,13 +409,23 @@ bool TextWindow::EditControlDoneForConfiguration(const std::string &s) {
         case Edit::DIGITS_AFTER_DECIMAL: {
             int v = atoi(s.c_str());
             if(v < 0 || v > 8) {
-                Error(_("Specify between 0 and 8 digits after the decimal."));
+                Error(_("Specify between 0 and %d digits after the decimal."), 8);
             } else {
                 SS.SetUnitDigitsAfterDecimal(v);
                 SS.GW.Invalidate();
             }
             break;
         }
+        case Edit::DIGITS_AFTER_DECIMAL_DEGREE: {
+            int v = atoi(s.c_str());
+            if(v < 0 || v > 4) {
+                Error(_("Specify between 0 and %d digits after the decimal."), 4);
+            } else {
+                SS.afterDecimalDegree = v;
+                SS.GW.Invalidate();
+            }
+            break;
+        }
         case Edit::EXPORT_SCALE: {
             Expr *e = Expr::From(s, /*popUpError=*/true);
             if(e) {

src/drawconstraint.cpp

@@ -11,11 +11,7 @@
 std::string Constraint::Label() const {
     std::string result;
     if(type == Type::ANGLE) {
-        if(valA == floor(valA)) {
+        result = SS.DegreeToString(valA) + "°";
-            result = ssprintf("%.0f°", valA);
-        } else {
-            result = ssprintf("%.2f°", valA);
-        }
     } else if(type == Type::LENGTH_RATIO) {
         result = ssprintf("%.3f:1", valA);
     } else if(type == Type::COMMENT) {

src/mouse.cpp

@@ -1361,36 +1361,30 @@ void GraphicsWindow::MouseLeftDoubleClick(double mx, double my) {
                 editPlaceholder = "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaa";
                 break;
 
-            case Constraint::Type::ANGLE:
-            case Constraint::Type::LENGTH_RATIO:
-                editValue = ssprintf("%.3f", c->valA);
-                editPlaceholder = "0.000";
-                break;
-
             default: {
-                double v = fabs(c->valA);
+                double value = fabs(c->valA);
 
                 // If displayed as radius, also edit as radius.
                 if(c->type == Constraint::Type::DIAMETER && c->other)
-                    v /= 2;
+                    value /= 2;
 
-                std::string def = SS.MmToString(v);
+                // Try showing value with default number of digits after decimal first.
-                double eps = 1e-12;
+                if(c->type == Constraint::Type::LENGTH_RATIO) {
-                if(fabs(SS.StringToMm(def) - v) < eps) {
+                    editValue = ssprintf("%.3f", value);
-                    // Show value with default number of digits after decimal,
+                } else if(c->type == Constraint::Type::ANGLE) {
-                    // which is at least enough to represent it exactly.
+                    editValue = SS.DegreeToString(value);
-                    editValue = def;
                 } else {
-                    // Show value with as many digits after decimal as
+                    editValue = SS.MmToString(value);
-                    // required to represent it exactly, up to 10.
+                    value /= SS.MmPerUnit();
-                    v /= SS.MmPerUnit();
-                    int i;
-                    for(i = 0; i <= 10; i++) {
-                        editValue = ssprintf("%.*f", i, v);
-                        if(fabs(std::stod(editValue) - v) < eps) break;
                 }
+                // If that's not enough to represent it exactly, show the value with as many
+                // digits after decimal as required, up to 10.
+                int digits = 0;
+                while(fabs(std::stod(editValue) - value) > 1e-10) {
+                    editValue = ssprintf("%.*f", digits, value);
+                    digits++;
                 }
-                editPlaceholder = "0.00000";
+                editPlaceholder = "10.000000";
                 break;
             }
         }

src/solvespace.cpp

@@ -56,6 +56,7 @@ void SolveSpaceUI::Init() {
     // Number of digits after the decimal point
     afterDecimalMm = settings->ThawInt("AfterDecimalMm", 2);
     afterDecimalInch = settings->ThawInt("AfterDecimalInch", 3);
+    afterDecimalDegree = settings->ThawInt("AfterDecimalDegree", 2);
     // Camera tangent (determines perspective)
     cameraTangent = settings->ThawFloat("CameraTangent", 0.3f/1e3);
     // Grid spacing
@@ -229,6 +230,7 @@ void SolveSpaceUI::Exit() {
     // Number of digits after the decimal point
     settings->FreezeInt("AfterDecimalMm",   (uint32_t)afterDecimalMm);
     settings->FreezeInt("AfterDecimalInch", (uint32_t)afterDecimalInch);
+    settings->FreezeInt("AfterDecimalDegree", (uint32_t)afterDecimalDegree);
     // Camera tangent (determines perspective)
     settings->FreezeFloat("CameraTangent", (float)cameraTangent);
     // Grid spacing
@@ -320,6 +322,13 @@ std::string SolveSpaceUI::MmToString(double v) {
     }
     return "";
 }
+std::string SolveSpaceUI::DegreeToString(double v) {
+    if(fabs(v - floor(v)) > 1e-10) {
+        return ssprintf("%.*f", afterDecimalDegree, v);
+    } else {
+        return ssprintf("%.0f", v);
+    }
+}
 double SolveSpaceUI::ExprToMm(Expr *e) {
     return (e->Eval()) * MmPerUnit();
 }

src/solvespace.h

@@ -621,9 +621,11 @@ public:
     Unit     viewUnits;
     int      afterDecimalMm;
     int      afterDecimalInch;
+    int      afterDecimalDegree;
     int      autosaveInterval; // in minutes
 
     std::string MmToString(double v);
+    std::string DegreeToString(double v);
     double ExprToMm(Expr *e);
     double StringToMm(const std::string &s);
     const char *UnitName();

src/ui.h

@@ -300,14 +300,15 @@ public:
         CAMERA_TANGENT        = 105,
         GRID_SPACING          = 106,
         DIGITS_AFTER_DECIMAL  = 107,
-        EXPORT_SCALE          = 108,
+        DIGITS_AFTER_DECIMAL_DEGREE = 108,
-        EXPORT_OFFSET         = 109,
+        EXPORT_SCALE          = 109,
-        CANVAS_SIZE           = 110,
+        EXPORT_OFFSET         = 110,
-        G_CODE_DEPTH          = 120,
+        CANVAS_SIZE           = 111,
-        G_CODE_PASSES         = 121,
+        G_CODE_DEPTH          = 112,
-        G_CODE_FEED           = 122,
+        G_CODE_PASSES         = 113,
-        G_CODE_PLUNGE_FEED    = 123,
+        G_CODE_FEED           = 114,
-        AUTOSAVE_INTERVAL     = 124,
+        G_CODE_PLUNGE_FEED    = 115,
+        AUTOSAVE_INTERVAL     = 116,
         // For TTF text
         TTF_TEXT              = 300,
         // For the step dimension screen
@@ -467,6 +468,7 @@ public:
     static void ScreenChangeCameraTangent(int link, uint32_t v);
     static void ScreenChangeGridSpacing(int link, uint32_t v);
     static void ScreenChangeDigitsAfterDecimal(int link, uint32_t v);
+    static void ScreenChangeDigitsAfterDecimalDegree(int link, uint32_t v);
     static void ScreenChangeExportScale(int link, uint32_t v);
     static void ScreenChangeExportOffset(int link, uint32_t v);
     static void ScreenChangeGCodeParameter(int link, uint32_t v);