From 4442fa709e332b7c5ce854da155cdd4b4a07b17f Mon Sep 17 00:00:00 2001
From: PaddleStroke <pierrelouis.boyer@gmail.com>
Date: Thu, 11 Apr 2024 08:26:27 +0200
Subject: [PATCH] Sketcher: Dimension tool : add arc length

---
 src/Mod/Sketcher/Gui/CommandConstraints.cpp | 80 ++++++++++++++-------
 1 file changed, 53 insertions(+), 27 deletions(-)

diff --git a/src/Mod/Sketcher/Gui/CommandConstraints.cpp b/src/Mod/Sketcher/Gui/CommandConstraints.cpp
index 14740c697b..e279cd1502 100644
--- a/src/Mod/Sketcher/Gui/CommandConstraints.cpp
+++ b/src/Mod/Sketcher/Gui/CommandConstraints.cpp
@@ -2018,45 +2018,51 @@ protected:
         int geoId = selCircleArc[0].GeoId;
         bool reverseOrder = isRadiusDoF(geoId);
 
-        if (availableConstraint == AvailableConstraint::FIRST) {
-            if (!reverseOrder) {
+        if (reverseOrder) {
+            if (availableConstraint == AvailableConstraint::FIRST) {
+                restartCommand(QT_TRANSLATE_NOOP("Command", "Add arc angle constraint"));
+                createArcAngleConstrain(geoId, onSketchPos);
+                selAllowed = true;
+            }
+            if (availableConstraint == AvailableConstraint::SECOND) {
+                restartCommand(QT_TRANSLATE_NOOP("Command", "Add arc length constraint"));
+                createArcLengthConstrain(geoId, onSketchPos);
+            }
+            if (availableConstraint == AvailableConstraint::THIRD) {
                 restartCommand(QT_TRANSLATE_NOOP("Command", "Add Radius constraint"));
                 createRadiusDiameterConstrain(geoId, onSketchPos, true);
             }
-            else {
-                restartCommand(QT_TRANSLATE_NOOP("Command", "Add arc angle constraint"));
-                createArcAngleConstrain(geoId, onSketchPos);
-            }
-            selAllowed = true;
-        }
-        if (availableConstraint == AvailableConstraint::SECOND) {
-            restartCommand(QT_TRANSLATE_NOOP("Command", "Add Radius constraint"));
-            createRadiusDiameterConstrain(geoId, onSketchPos, reverseOrder);
-            if (!isArcOfCircle(*Obj->getGeometry(geoId))) {
-                //This way if key is pressed again it goes back to FIRST
+            if (availableConstraint == AvailableConstraint::FOURTH) {
+                restartCommand(QT_TRANSLATE_NOOP("Command", "Add Radius constraint"));
+                createRadiusDiameterConstrain(geoId, onSketchPos, false);
                 availableConstraint = AvailableConstraint::RESET;
             }
         }
-        if (availableConstraint == AvailableConstraint::THIRD) {
-            if (!reverseOrder) {
-                restartCommand(QT_TRANSLATE_NOOP("Command", "Add arc angle constraint"));
-                createArcAngleConstrain(geoId, onSketchPos);
+        else {
+            if (availableConstraint == AvailableConstraint::FIRST) {
+                restartCommand(QT_TRANSLATE_NOOP("Command", "Add Radius constraint"));
+                createRadiusDiameterConstrain(geoId, onSketchPos, true);
+                selAllowed = true;
             }
-            else {
+            if (availableConstraint == AvailableConstraint::SECOND) {
                 restartCommand(QT_TRANSLATE_NOOP("Command", "Add Radius constraint"));
                 createRadiusDiameterConstrain(geoId, onSketchPos, false);
-            }
-            availableConstraint = AvailableConstraint::RESET;
-        }
-        /*
-            bool firstCstr = true;
-            if (availableConstraint != AvailableConstraint::FIRST) {
-                firstCstr = false;
-                if (!isArcOfCircle(*geom)) {
+                if (!isArcOfCircle(*Obj->getGeometry(geoId))) {
                     //This way if key is pressed again it goes back to FIRST
                     availableConstraint = AvailableConstraint::RESET;
                 }
-            }*/
+            }
+            if (availableConstraint == AvailableConstraint::THIRD) {
+                restartCommand(QT_TRANSLATE_NOOP("Command", "Add arc angle constraint"));
+                createArcAngleConstrain(geoId, onSketchPos);
+            }
+            if (availableConstraint == AvailableConstraint::FOURTH) {
+                restartCommand(QT_TRANSLATE_NOOP("Command", "Add arc length constraint"));
+                createArcLengthConstrain(geoId, onSketchPos);
+                availableConstraint = AvailableConstraint::RESET;
+            }
+        }
+
     }
 
     void makeCts_2Circle(bool& selAllowed, Base::Vector2d onSketchPos)
@@ -2429,6 +2435,26 @@ protected:
         moveConstraint(ConStr.size() - 1, onSketchPos);
     }
 
+    void createArcLengthConstrain(int GeoId, Base::Vector2d onSketchPos) {
+        const Part::Geometry* geom = Obj->getGeometry(GeoId);
+        if (isArcOfCircle(*geom)) {
+
+            const auto* arc = static_cast<const Part::GeomArcOfCircle*>(geom);
+            double ActLength = arc->getAngle(false) * arc->getRadius();
+
+            Gui::cmdAppObjectArgs(Obj, "addConstraint(Sketcher.Constraint('Distance',%d,%f))",
+                GeoId, ActLength);
+
+            const std::vector<Sketcher::Constraint*>& ConStr = Obj->Constraints.getValues();
+            if (isPointOrSegmentFixed(Obj, GeoId) || constraintCreationMode == Reference) {
+                // it is a constraint on a external line, make it non-driving
+                Gui::cmdAppObjectArgs(Obj, "setDriving(%i,%s)", ConStr.size() - 1, "False");
+            }
+            numberOfConstraintsCreated++;
+            moveConstraint(ConStr.size() - 1, onSketchPos);
+        }
+    }
+
     void createArcAngleConstrain(int GeoId, Base::Vector2d onSketchPos) {
         const Part::Geometry* geom = Obj->getGeometry(GeoId);
         if (isArcOfCircle(*geom)) {