From 2d22c8f4afa9984b237e0208c6904a6b24e7b18a Mon Sep 17 00:00:00 2001
From: Kacper Donat <kadet1090@gmail.com>
Date: Sat, 26 Aug 2023 20:02:28 +0200
Subject: [PATCH] PD: Keep Length and Offset in sync for LinearPattern

As Length and Offset represents the same concept in different way it is
useful to keep them in sync when it is possible. Update to one of them
will update the other with approperiate value. This behaviour behaviour
works only if both properties are not coming from expression engine -
those will stay not touched.
---
 src/Mod/PartDesign/App/FeatureLinearPattern.cpp      | 12 +++++++++++-
 .../PartDesign/Gui/TaskLinearPatternParameters.cpp   |  3 ++-
 2 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/src/Mod/PartDesign/App/FeatureLinearPattern.cpp b/src/Mod/PartDesign/App/FeatureLinearPattern.cpp
index 7826abf175..2ba1df02a2 100644
--- a/src/Mod/PartDesign/App/FeatureLinearPattern.cpp
+++ b/src/Mod/PartDesign/App/FeatureLinearPattern.cpp
@@ -238,11 +238,21 @@ void LinearPattern::handleChangedPropertyType(Base::XMLReader& reader, const cha
 
 void LinearPattern::onChanged(const App::Property* prop)
 {
+    auto mode = static_cast<LinearPatternMode>(Mode.getValue());
+
     if (prop == &Mode) {
-        auto mode = static_cast<LinearPatternMode>(Mode.getValue());
         setReadWriteStatusForMode(mode);
     }
 
+    // Keep Length in sync with Offset
+    if (mode == LinearPatternMode::offset && prop == &Offset && !Length.testStatus(App::Property::Status::Immutable)) {
+        Length.setValue(Offset.getValue() * (Occurrences.getValue() - 1));
+    }
+
+    if (mode == LinearPatternMode::length && prop == &Length && !Offset.testStatus(App::Property::Status::Immutable)) {
+        Offset.setValue(Length.getValue() / (Occurrences.getValue() - 1));
+    }
+
     Transformed::onChanged(prop);
 }
 
diff --git a/src/Mod/PartDesign/Gui/TaskLinearPatternParameters.cpp b/src/Mod/PartDesign/Gui/TaskLinearPatternParameters.cpp
index 8ed53aac18..b0e6c13d64 100644
--- a/src/Mod/PartDesign/Gui/TaskLinearPatternParameters.cpp
+++ b/src/Mod/PartDesign/Gui/TaskLinearPatternParameters.cpp
@@ -198,7 +198,6 @@ void TaskLinearPatternParameters::setupUI()
     }
 
     adaptVisibilityToMode();
-    updateUI();
     connectSignals();
 }
 
@@ -241,6 +240,8 @@ void TaskLinearPatternParameters::adaptVisibilityToMode()
 
     ui->lengthWrapper->setVisible(mode == PartDesign::LinearPatternMode::length);
     ui->offsetWrapper->setVisible(mode == PartDesign::LinearPatternMode::offset);
+
+    updateUI();
 }
 
 void TaskLinearPatternParameters::onUpdateViewTimer()