Sketcher: Fix: Arc of ellipse when first and second X coordinates are the same (#27327)

src/Mod/Sketcher/Gui/DrawSketchHandlerArcOfEllipse.h

@@ -50,26 +50,23 @@ class DrawSketchHandlerArcOfEllipse: public DrawSketchHandler
 
 public:
     DrawSketchHandlerArcOfEllipse()
-        : Mode(STATUS_SEEK_First)
+        : Mode(SelectMode::First)
         , EditCurve(34)
-        , rx(0)
-        , ry(0)
         , startAngle(0)
         , endAngle(0)
         , arcAngle(0)
-        , arcAngle_t(0)
     {}
 
     ~DrawSketchHandlerArcOfEllipse() override = default;
 
     /// mode table
-    enum SelectMode
+    enum class SelectMode
     {
-        STATUS_SEEK_First,
+        First,
-        STATUS_SEEK_Second,
+        Second,
-        STATUS_SEEK_Third,
+        Third,
-        STATUS_SEEK_Fourth,
+        Fourth,
-        STATUS_Close
+        End
     };
 
     void mouseMove(SnapManager::SnapHandle snapHandle) override
@@ -77,13 +74,13 @@ public:
         using std::numbers::pi;
         Base::Vector2d onSketchPos = snapHandle.compute();
 
-        if (Mode == STATUS_SEEK_First) {
+        if (Mode == SelectMode::First) {
             setPositionText(onSketchPos);
             seekAndRenderAutoConstraint(sugConstr1, onSketchPos, Base::Vector2d(0.f, 0.f));  // TODO:
                                                                                              // ellipse
                                                                                              // prio 1
         }
-        else if (Mode == STATUS_SEEK_Second) {
+        else if (Mode == SelectMode::Second) {
             double rx0 = onSketchPos.x - EditCurve[0].x;
             double ry0 = onSketchPos.y - EditCurve[0].y;
             for (int i = 0; i < 16; i++) {
@@ -113,23 +110,33 @@ public:
                 AutoConstraint::CURVE
             );
         }
-        else if (Mode == STATUS_SEEK_Third) {
+        else if (Mode == SelectMode::Third) {
-            // angle between the major axis of the ellipse and the X axis
+            Base::Vector2d delta12 = axisPoint - centerPoint;
-            double a = (EditCurve[1] - EditCurve[0]).Length();
-            double phi = atan2(EditCurve[1].y - EditCurve[0].y, EditCurve[1].x - EditCurve[0].x);
 
-            // This is the angle at cursor point
+            double a = delta12.Length();
-            double angleatpoint = acos(
+
-                (onSketchPos.x - EditCurve[0].x + (onSketchPos.y - EditCurve[0].y) * tan(phi))
+            Base::Vector2d aDir = delta12.Normalize();
-                / (a * (cos(phi) + tan(phi) * sin(phi)))
+            Base::Vector2d bDir(-aDir.y, aDir.x);
+
+            Base::Vector2d delta13 = onSketchPos - centerPoint;
+            Base::Vector2d delta13Prime(
+                delta13.x * aDir.x + delta13.y * aDir.y,
+                delta13.x * bDir.x + delta13.y * bDir.y
             );
-            double b = (onSketchPos.y - EditCurve[0].y - a * cos(angleatpoint) * sin(phi))
+
-                / (sin(angleatpoint) * cos(phi));
+            double cosT = max(-1.0, min(1.0, delta13Prime.x / a));
+            double sinT = sqrt(max(0.0, 1 - cosT * cosT));
+
+            double b = abs(delta13Prime.y) / sinT;
+            if (sinT == 0.0) {
+                b = 0.0;
+                a = 0.0;
+            }
 
             for (int i = 1; i < 16; i++) {
                 double angle = i * pi / 16.0;
-                double rx1 = a * cos(angle) * cos(phi) - b * sin(angle) * sin(phi);
+                double rx1 = a * cos(angle) * aDir.x + b * sin(angle) * bDir.x;
-                double ry1 = a * cos(angle) * sin(phi) + b * sin(angle) * cos(phi);
+                double ry1 = a * cos(angle) * aDir.y + b * sin(angle) * bDir.y;
                 EditCurve[1 + i] = Base::Vector2d(EditCurve[0].x + rx1, EditCurve[0].y + ry1);
                 EditCurve[17 + i] = Base::Vector2d(EditCurve[0].x - rx1, EditCurve[0].y - ry1);
             }
@@ -148,49 +155,43 @@ public:
             drawEdit(EditCurve);
             seekAndRenderAutoConstraint(sugConstr3, onSketchPos, Base::Vector2d(0.f, 0.f));
         }
-        else if (Mode == STATUS_SEEK_Fourth) {  // here we differ from ellipse creation
+        else if (Mode == SelectMode::Fourth) {  // here we differ from ellipse creation
-            // angle between the major axis of the ellipse and the X axis
+            Base::Vector2d delta12 = axisPoint - centerPoint;
-            double a = (axisPoint - centerPoint).Length();
-            double phi = atan2(axisPoint.y - centerPoint.y, axisPoint.x - centerPoint.x);
 
-            // This is the angle at cursor point
+            double a = delta12.Length();
-            double angleatpoint = acos(
+
-                (startingPoint.x - centerPoint.x + (startingPoint.y - centerPoint.y) * tan(phi))
+            Base::Vector2d aDir = delta12.Normalize();
-                / (a * (cos(phi) + tan(phi) * sin(phi)))
+            Base::Vector2d bDir(-aDir.y, aDir.x);
-            );
+
-            double b = abs(
+            Base::Vector2d delta13 = startingPoint - centerPoint;
-                (startingPoint.y - centerPoint.y - a * cos(angleatpoint) * sin(phi))
+            Base::Vector2d delta13Prime(
-                / (sin(angleatpoint) * cos(phi))
+                delta13.x * aDir.x + delta13.y * aDir.y,
+                delta13.x * bDir.x + delta13.y * bDir.y
             );
 
-            double rxs = startingPoint.x - centerPoint.x;
+            double cosT = max(-1.0, min(1.0, delta13Prime.x / a));
-            double rys = startingPoint.y - centerPoint.y;
+            double sinT = sqrt(max(0.0, 1 - cosT * cosT));
-            startAngle = atan2(
-                a * (rys * cos(phi) - rxs * sin(phi)),
-                b * (rxs * cos(phi) + rys * sin(phi))
-            );  // eccentric anomaly angle
 
-            double angle1 = atan2(
+            double b = abs(delta13Prime.y) / sinT;
-                                a
-                                    * ((onSketchPos.y - centerPoint.y) * cos(phi)
-                                       - (onSketchPos.x - centerPoint.x) * sin(phi)),
-                                b
-                                    * ((onSketchPos.x - centerPoint.x) * cos(phi)
-                                       + (onSketchPos.y - centerPoint.y) * sin(phi))
-                            )
-                - startAngle;
 
+            startAngle = atan2(delta13Prime.y / b, delta13Prime.x / a);
+
+            Base::Vector2d delta14 = onSketchPos - centerPoint;
+            Base::Vector2d delta14Prime(
+                delta14.x * aDir.x + delta14.y * aDir.y,
+                delta14.x * bDir.x + delta14.y * bDir.y
+            );
+            double angle1 = atan2(delta14Prime.y / b, delta14Prime.x / a) - startAngle;
             double angle2 = angle1 + (angle1 < 0. ? 2 : -2) * pi;
+
             arcAngle = abs(angle1 - arcAngle) < abs(angle2 - arcAngle) ? angle1 : angle2;
 
             for (int i = 0; i < 34; i++) {
-                double angle = startAngle + i * arcAngle / 34.0;
+                double angle = startAngle + i * arcAngle / 33.0;
-                double rx1 = a * cos(angle) * cos(phi) - b * sin(angle) * sin(phi);
+                double rx1 = a * cos(angle) * aDir.x + b * sin(angle) * bDir.x;
-                double ry1 = a * cos(angle) * sin(phi) + b * sin(angle) * cos(phi);
+                double ry1 = a * cos(angle) * aDir.y + b * sin(angle) * bDir.y;
                 EditCurve[i] = Base::Vector2d(centerPoint.x + rx1, centerPoint.y + ry1);
             }
-            //             EditCurve[33] = EditCurve[1];
-            //             EditCurve[17] = EditCurve[16];
 
             // Display radii and angle for user
             if (showCursorCoords()) {
@@ -202,35 +203,43 @@ public:
                 setPositionText(onSketchPos, text);
             }
 
+            if (onSketchPos != centerPoint) {
                 drawEdit(EditCurve);
+            }
+            else {
+                drawEdit(std::vector<Base::Vector2d>());
+            }
             seekAndRenderAutoConstraint(sugConstr4, onSketchPos, Base::Vector2d(0.f, 0.f));
         }
     }
 
     bool pressButton(Base::Vector2d onSketchPos) override
     {
-        if (Mode == STATUS_SEEK_First) {
+        using std::numbers::pi;
+
+        if (Mode == SelectMode::First) {
             EditCurve[0] = onSketchPos;
             centerPoint = onSketchPos;
             setAngleSnapping(true, centerPoint);
-            Mode = STATUS_SEEK_Second;
+            Mode = SelectMode::Second;
         }
-        else if (Mode == STATUS_SEEK_Second) {
+        else if (Mode == SelectMode::Second
+                 && (centerPoint - onSketchPos).Length() >= Precision::Confusion()) {
             EditCurve[1] = onSketchPos;
             axisPoint = onSketchPos;
-            Mode = STATUS_SEEK_Third;
+            Mode = SelectMode::Third;
         }
-        else if (Mode == STATUS_SEEK_Third) {
+        else if (Mode == SelectMode::Third && validThirdPoint(onSketchPos)) {
             startingPoint = onSketchPos;
             arcAngle = 0.;
-            arcAngle_t = 0.;
+            Mode = SelectMode::Fourth;
-            Mode = STATUS_SEEK_Fourth;
         }
-        else {  // Fourth
+        else if (Mode == SelectMode::Fourth && centerPoint != onSketchPos && arcAngle != 0
+                 && abs(arcAngle) != 2 * pi) {
             endPoint = onSketchPos;
 
             setAngleSnapping(false);
-            Mode = STATUS_Close;
+            Mode = SelectMode::End;
         }
 
         updateHint();
@@ -243,35 +252,36 @@ public:
 
         using std::numbers::pi;
 
-        if (Mode == STATUS_Close) {
+        if (Mode == SelectMode::End) {
             unsetCursor();
             resetPositionText();
 
-            // angle between the major axis of the ellipse and the X axisEllipse
+            Base::Vector2d delta12 = axisPoint - centerPoint;
-            double a = (axisPoint - centerPoint).Length();
-            double phi = atan2(axisPoint.y - centerPoint.y, axisPoint.x - centerPoint.x);
 
-            // This is the angle at cursor point
+            double a = delta12.Length();
-            double angleatpoint = acos(
+
-                (startingPoint.x - centerPoint.x + (startingPoint.y - centerPoint.y) * tan(phi))
+            Base::Vector2d aDir = delta12.Normalize();
-                / (a * (cos(phi) + tan(phi) * sin(phi)))
+            Base::Vector2d bDir(-aDir.y, aDir.x);
-            );
+
-            double b = abs(
+            Base::Vector2d delta13 = startingPoint - centerPoint;
-                (startingPoint.y - centerPoint.y - a * cos(angleatpoint) * sin(phi))
+            Base::Vector2d delta13Prime(
-                / (sin(angleatpoint) * cos(phi))
+                delta13.x * aDir.x + delta13.y * aDir.y,
+                delta13.x * bDir.x + delta13.y * bDir.y
             );
 
-            double angle1 = atan2(
+            double cosT = max(-1.0, min(1.0, delta13Prime.x / a));
-                                a
+            double sinT = sqrt(max(0.0, 1 - cosT * cosT));
-                                    * ((endPoint.y - centerPoint.y) * cos(phi)
-                                       - (endPoint.x - centerPoint.x) * sin(phi)),
-                                b
-                                    * ((endPoint.x - centerPoint.x) * cos(phi)
-                                       + (endPoint.y - centerPoint.y) * sin(phi))
-                            )
-                - startAngle;
 
+            double b = abs(delta13Prime.y) / sinT;
+
+            Base::Vector2d delta14 = endPoint - centerPoint;
+            Base::Vector2d delta14Prime(
+                delta14.x * aDir.x + delta14.y * aDir.y,
+                delta14.x * bDir.x + delta14.y * bDir.y
+            );
+            double angle1 = atan2(delta14Prime.y / b, delta14Prime.x / a) - startAngle;
             double angle2 = angle1 + (angle1 < 0. ? 2 : -2) * pi;
+
             arcAngle = abs(angle1 - arcAngle) < abs(angle2 - arcAngle) ? angle1 : angle2;
 
             bool isOriginalArcCCW = true;
@@ -391,7 +401,7 @@ public:
             bool continuousMode = hGrp->GetBool("ContinuousCreationMode", true);
             if (continuousMode) {
                 // This code enables the continuous creation mode.
-                Mode = STATUS_SEEK_First;
+                Mode = SelectMode::First;
                 EditCurve.clear();
                 drawEdit(EditCurve);
                 EditCurve.resize(34);
@@ -422,7 +432,7 @@ protected:
     SelectMode Mode;
     std::vector<Base::Vector2d> EditCurve;
     Base::Vector2d centerPoint, axisPoint, startingPoint, endPoint;
-    double rx, ry, startAngle, endAngle, arcAngle, arcAngle_t;
+    double startAngle, endAngle, arcAngle;
     std::vector<AutoConstraint> sugConstr1, sugConstr2, sugConstr3, sugConstr4;
 
 private:
@@ -433,28 +443,47 @@ private:
         return Gui::lookupHints<SelectMode>(
             Mode,
             {
-                {.state = STATUS_SEEK_First,
+                {.state = SelectMode::First,
                  .hints =
                      {
                          {tr("%1 pick ellipse center"), {MouseLeft}},
                      }},
-                {.state = STATUS_SEEK_Second,
+                {.state = SelectMode::Second,
                  .hints =
                      {
                          {tr("%1 pick axis point"), {MouseLeft}},
                      }},
-                {.state = STATUS_SEEK_Third,
+                {.state = SelectMode::Third,
                  .hints =
                      {
                          {tr("%1 pick arc start point"), {MouseLeft}},
                      }},
-                {.state = STATUS_SEEK_Fourth,
+                {.state = SelectMode::Fourth,
                  .hints =
                      {
                          {tr("%1 pick arc end point"), {MouseLeft}},
                      }},
             });
     }
+
+    bool validThirdPoint(Base::Vector2d onSketchPos)
+    {
+        Base::Vector2d delta12 = axisPoint - centerPoint;
+
+        double a = delta12.Length();
+
+        Base::Vector2d aDir = delta12.Normalize();
+        Base::Vector2d bDir(-aDir.y, aDir.x);
+
+        Base::Vector2d delta13 = onSketchPos - centerPoint;
+        Base::Vector2d delta13Prime(
+            delta13.x * aDir.x + delta13.y * aDir.y,
+            delta13.x * bDir.x + delta13.y * bDir.y
+        );
+
+        double cosT = max(-1.0, min(1.0, delta13Prime.x / a));
+        return cosT != -1.0 && cosT != 1.0 && delta13Prime.y != 0;
+    }
 };
 
 }  // namespace SketcherGui