From b818be7d5dd426bb6d846ae2c46bc57abc82634e Mon Sep 17 00:00:00 2001
From: Paddle <PaddleStroke@users.noreply.github.com>
Date: Tue, 16 Jan 2024 17:59:38 +0100
Subject: [PATCH] SoDatumLabel : introduce distance arc helpers.

---
 src/Gui/SoDatumLabel.cpp | 40 ++++++++++++++++++++++++++++++++++++++++
 src/Gui/SoDatumLabel.h   |  3 +++
 2 files changed, 43 insertions(+)

diff --git a/src/Gui/SoDatumLabel.cpp b/src/Gui/SoDatumLabel.cpp
index 2e2b44b3c4..52f1823317 100644
--- a/src/Gui/SoDatumLabel.cpp
+++ b/src/Gui/SoDatumLabel.cpp
@@ -93,6 +93,9 @@ SoDatumLabel::SoDatumLabel()
     SO_NODE_ADD_FIELD(param2, (0.f));
     SO_NODE_ADD_FIELD(param4, (0.f));
     SO_NODE_ADD_FIELD(param5, (0.f));
+    SO_NODE_ADD_FIELD(param6, (0.f));
+    SO_NODE_ADD_FIELD(param7, (0.f));
+    SO_NODE_ADD_FIELD(param8, (0.f));
 
     useAntialiasing = true;
 
@@ -989,6 +992,43 @@ void SoDatumLabel::GLRender(SoGLRenderAction * action)
             glVertex2f(ar3[0], ar3[1]);
             glVertex2f(ar4[0], ar4[1]);
         glEnd();
+
+
+        if (this->datumtype.getValue() == DISTANCE) {
+            // Draw arc helpers if needed
+            float range1 = this->param4.getValue();
+            if (range1 != 0.0) {
+                float startangle1 = this->param3.getValue();
+                float radius1 = this->param5.getValue();
+                SbVec3f center = points[2];
+                int countSegments = std::max(6, abs(int(50.0 * range1 / (2 * M_PI))));
+                double segment = range1 / (countSegments - 1);
+
+                glBegin(GL_LINE_STRIP);
+                for (int i = 0; i < countSegments; i++) {
+                    double theta = startangle1 + segment * i;
+                    SbVec3f v1 = center + SbVec3f(radius1 * cos(theta), radius1 * sin(theta), 0);
+                    glVertex2f(v1[0], v1[1]);
+                }
+                glEnd();
+            }
+            float range2 = this->param7.getValue();
+            if (range2 != 0.0) {
+                float startangle2 = this->param6.getValue();
+                float radius2 = this->param8.getValue();
+                SbVec3f center = points[3];
+                int countSegments = std::max(6, abs(int(50.0 * range2 / (2 * M_PI))));
+                double segment = range2 / (countSegments - 1);
+
+                glBegin(GL_LINE_STRIP);
+                for (int i = 0; i < countSegments; i++) {
+                    double theta = startangle2 + segment * i;
+                    SbVec3f v1 = center + SbVec3f(radius2 * cos(theta), radius2 * sin(theta), 0);
+                    glVertex2f(v1[0], v1[1]);
+                }
+                glEnd();
+            }
+        }
     }
     else if (this->datumtype.getValue() == RADIUS || this->datumtype.getValue() == DIAMETER) {
         // Get the Points
diff --git a/src/Gui/SoDatumLabel.h b/src/Gui/SoDatumLabel.h
index 077069236a..2e55ffeb8e 100644
--- a/src/Gui/SoDatumLabel.h
+++ b/src/Gui/SoDatumLabel.h
@@ -77,6 +77,9 @@ public:
     SoSFFloat  param3;
     SoSFFloat  param4;
     SoSFFloat  param5;
+    SoSFFloat  param6;
+    SoSFFloat  param7;
+    SoSFFloat  param8;
     SoMFVec3f  pnts;
     SoSFVec3f  norm;
     SoSFImage  image;