Make arc default dimenision (radius vs diameter) a configuration option.

src/confscreen.cpp

@@ -70,6 +70,10 @@ void TextWindow::ScreenChangeExportOffset(int link, uint32_t v) {
     SS.TW.edit.meaning = Edit::EXPORT_OFFSET;
 }
 
+void TextWindow::ScreenChangeArcDimDefault(int link, uint32_t v) {
+    SS.arcDimDefaultDiameter = !SS.arcDimDefaultDiameter;
+}
+
 void TextWindow::ScreenChangeFixExportColors(int link, uint32_t v) {
     SS.fixExportColors = !SS.fixExportColors;
 }
@@ -344,6 +348,9 @@ void TextWindow::ShowConfiguration() {
     Printf(false, "  %Fd%f%Ll%s  edit newly added dimensions%E",
         &ScreenChangeImmediatelyEditDimension,
         SS.immediatelyEditDimension ? CHECK_TRUE : CHECK_FALSE);
+    Printf(false, "  %Fd%f%Ll%s  arc default is diameter%E",
+        &ScreenChangeArcDimDefault,
+        SS.arcDimDefaultDiameter ? CHECK_TRUE : CHECK_FALSE);
     Printf(false, "");
     Printf(false, "%Ft autosave interval (in minutes)%E");
     Printf(false, "%Ba   %d %Fl%Ll%f[change]%E",

src/constraint.cpp

@@ -237,7 +237,9 @@ void Constraint::MenuConstrain(Command id) {
                 c.type = Type::DIAMETER;
                 c.entityA = gs.entity[0];
                 Entity* arc = SK.GetEntity(gs.entity[0]);
-                if (arc->type == EntityBase::Type::ARC_OF_CIRCLE) {
+                if ((arc->type == EntityBase::Type::ARC_OF_CIRCLE)
+                    && (!SS.arcDimDefaultDiameter))
+                {
                   c.other = true;
                 }
             } else {

src/solvespace.cpp

@@ -69,6 +69,8 @@ void SolveSpaceUI::Init() {
     exportScale = settings->ThawFloat("ExportScale", 1.0);
     // Export offset (cutter radius comp)
     exportOffset = settings->ThawFloat("ExportOffset", 0.0);
+    // Dimensions on arcs default to diameter vs radius
+    arcDimDefaultDiameter = settings->ThawBool("ArcDimDefaultDiameter", false);
     // Rewrite exported colors close to white into black (assuming white bg)
     fixExportColors = settings->ThawBool("FixExportColors", true);
     // Export background color
@@ -250,6 +252,8 @@ void SolveSpaceUI::Exit() {
     settings->FreezeFloat("ExportScale", exportScale);
     // Export offset (cutter radius comp)
     settings->FreezeFloat("ExportOffset", exportOffset);
+    // Rewrite the default arc dimension setting
+    settings->FreezeBool("ArcDimDefaultDiameter", arcDimDefaultDiameter);
     // Rewrite exported colors close to white into black (assuming white bg)
     settings->FreezeBool("FixExportColors", fixExportColors);
     // Export background color

src/solvespace.h

@@ -573,6 +573,7 @@ public:
     double   gridSpacing;
     double   exportScale;
     double   exportOffset;
+    bool     arcDimDefaultDiameter;
     bool     fixExportColors;
     bool     exportBackgroundColor;
     bool     drawBackFaces;

src/ui.h

@@ -442,6 +442,7 @@ public:
     static void ScreenShowEditView(int link, uint32_t v);
     static void ScreenGoToWebsite(int link, uint32_t v);
 
+    static void ScreenChangeArcDimDefault(int link, uint32_t v);
     static void ScreenChangeFixExportColors(int link, uint32_t v);
     static void ScreenChangeExportBackgroundColor(int link, uint32_t v);
     static void ScreenChangeBackFaces(int link, uint32_t v);