From 3c691ac086da3db2de27e9aa8163ddf1b22996c3 Mon Sep 17 00:00:00 2001
From: Arthur <arthur.tang@bambulab.com>
Date: Thu, 7 Sep 2023 14:44:43 +0800
Subject: [PATCH] ENH: improve auto-arranging's aligning to Y axis

Dominant direction is more accurate (solve the problem that cubes are
not arranged neatly).

Jira: STUDIO-4356

Change-Id: I8931f51a97bee96d5d9e75306481eae2e0cdc059
---
 src/libslic3r/Arrange.cpp | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/src/libslic3r/Arrange.cpp b/src/libslic3r/Arrange.cpp
index 8d1b3d12a0..6eb262e652 100644
--- a/src/libslic3r/Arrange.cpp
+++ b/src/libslic3r/Arrange.cpp
@@ -217,8 +217,14 @@ void update_selected_items_axis_align(ArrangePolygons& selected, const DynamicPr
                 double b = m11 / m00 - cx * cy;
                 double c = m02 / m00 - cy * cy;
 
-                angle = std::atan2(2 * b, (a - c)) / 2;
-                validResult = true;
+                //if a and c are close, there is no dominant axis, then do not rotate
+                if (std::abs(a) < 1.5*std::abs(c) && std::abs(c) < 1.5*std::abs(a)) {
+                    validResult = false;
+                }
+                else {
+                    angle = std::atan2(2 * b, (a - c)) / 2;
+                    validResult = true;
+                }
             }
         }
         if (validResult) { ap.rotation += (PI / 2 - angle); }