diff --git a/data/pref.xml b/data/pref.xml
index de5b52aaa..d130bacda 100644
--- a/data/pref.xml
+++ b/data/pref.xml
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <!-- Aseprite -->
-<!-- Copyright (C) 2018-2024  Igara Studio S.A. -->
+<!-- Copyright (C) 2018-2025  Igara Studio S.A. -->
 <!-- Copyright (C) 2014-2018  David Capello -->
 <preferences>
 
@@ -522,6 +522,7 @@
       <option id="mode" type="SymmetryMode" default="SymmetryMode::NONE" />
       <option id="x_axis" type="double" default="0" />
       <option id="y_axis" type="double" default="0" />
+      <option id="button_flags" type="int" default="0" />
     </section>
     <section id="grid" canforce="true">
       <option id="snap" type="bool" default="false" />
diff --git a/src/app/ui/context_bar.cpp b/src/app/ui/context_bar.cpp
index 31aa207bd..617f3605c 100644
--- a/src/app/ui/context_bar.cpp
+++ b/src/app/ui/context_bar.cpp
@@ -1,5 +1,5 @@
 // Aseprite
-// Copyright (C) 2018-2024  Igara Studio S.A.
+// Copyright (C) 2018-2025  Igara Studio S.A.
 // Copyright (C) 2001-2018  David Capello
 //
 // This program is distributed under the terms of
@@ -1530,14 +1530,10 @@ public:
 
     DocumentPreferences& docPref = Preferences::instance().document(doc);
 
-    at(0)->setSelected(
-      int(docPref.symmetry.mode()) & int(app::gen::SymmetryMode::HORIZONTAL) ? true : false);
-    at(1)->setSelected(
-      int(docPref.symmetry.mode()) & int(app::gen::SymmetryMode::VERTICAL) ? true : false);
-    at(2)->setSelected(
-      int(docPref.symmetry.mode()) & int(app::gen::SymmetryMode::RIGHT_DIAG) ? true : false);
-    at(3)->setSelected(
-      int(docPref.symmetry.mode()) & int(app::gen::SymmetryMode::LEFT_DIAG) ? true : false);
+    at(0)->setSelected(docPref.symmetry.buttonFlags() & int(app::gen::SymmetryMode::HORIZONTAL));
+    at(1)->setSelected(docPref.symmetry.buttonFlags() & int(app::gen::SymmetryMode::VERTICAL));
+    at(2)->setSelected(docPref.symmetry.buttonFlags() & int(app::gen::SymmetryMode::RIGHT_DIAG));
+    at(3)->setSelected(docPref.symmetry.buttonFlags() & int(app::gen::SymmetryMode::LEFT_DIAG));
   }
 
 private:
@@ -1551,75 +1547,29 @@ private:
 
     DocumentPreferences& docPref = Preferences::instance().document(doc);
 
-    auto oldMode = docPref.symmetry.mode();
-    int mode = 0;
+    int buttonFlags = 0;
     if (at(0)->isSelected())
-      mode |= int(app::gen::SymmetryMode::HORIZONTAL);
+      buttonFlags |= int(app::gen::SymmetryMode::HORIZONTAL);
     if (at(1)->isSelected())
-      mode |= int(app::gen::SymmetryMode::VERTICAL);
+      buttonFlags |= int(app::gen::SymmetryMode::VERTICAL);
     if (at(2)->isSelected())
-      mode |= int(app::gen::SymmetryMode::RIGHT_DIAG);
+      buttonFlags |= int(app::gen::SymmetryMode::RIGHT_DIAG);
     if (at(3)->isSelected())
-      mode |= int(app::gen::SymmetryMode::LEFT_DIAG);
+      buttonFlags |= int(app::gen::SymmetryMode::LEFT_DIAG);
 
-    // Non sense symmetries filter:
-    //  - H + 1Diag
-    //  - V + 1Diag
-    //  - H + V + 1Diag
-    const bool HorV = (mode & int(app::gen::SymmetryMode::HORIZONTAL)) ||
-                      (mode & int(app::gen::SymmetryMode::VERTICAL));
-    const bool HxorV = !(mode & int(app::gen::SymmetryMode::HORIZONTAL)) !=
-                       !(mode & int(app::gen::SymmetryMode::VERTICAL));
-    const bool RDxorLD = !(mode & int(app::gen::SymmetryMode::RIGHT_DIAG)) !=
-                         !(mode & int(app::gen::SymmetryMode::LEFT_DIAG));
-    if (oldMode == gen::SymmetryMode::HORIZONTAL || oldMode == gen::SymmetryMode::VERTICAL ||
-        oldMode == gen::SymmetryMode::BOTH) {
-      if (HorV && RDxorLD) {
-        mode = int(app::gen::SymmetryMode::ALL);
-        at(0)->setSelected(true);
-        at(1)->setSelected(true);
-        at(2)->setSelected(true);
-        at(3)->setSelected(true);
-      }
-    }
-    else if (oldMode == gen::SymmetryMode::ALL) {
-      if (HxorV) {
-        mode = int(app::gen::SymmetryMode::BOTH_DIAG);
-        at(0)->setSelected(false);
-        at(1)->setSelected(false);
-      }
-      else if (RDxorLD) {
-        mode = int(app::gen::SymmetryMode::BOTH);
-        at(2)->setSelected(false);
-        at(3)->setSelected(false);
-      }
-    }
-    else if ((oldMode == gen::SymmetryMode::RIGHT_DIAG || oldMode == gen::SymmetryMode::LEFT_DIAG ||
-              oldMode == gen::SymmetryMode::BOTH_DIAG) &&
-             HorV) {
-      mode = int(app::gen::SymmetryMode::ALL);
-      at(0)->setSelected(true);
-      at(1)->setSelected(true);
-      at(2)->setSelected(true);
-      at(3)->setSelected(true);
-    }
-    // Non sense symmetries filter end
+    const bool forceAllMode = ((buttonFlags & int(app::gen::SymmetryMode::HORIZONTAL)) ||
+                               (buttonFlags & int(app::gen::SymmetryMode::VERTICAL))) &&
+                              ((buttonFlags & int(app::gen::SymmetryMode::RIGHT_DIAG)) ||
+                               (buttonFlags & int(app::gen::SymmetryMode::LEFT_DIAG)));
 
-    if (at(0)->isSelected())
-      mode |= int(app::gen::SymmetryMode::HORIZONTAL);
-    if (at(1)->isSelected())
-      mode |= int(app::gen::SymmetryMode::VERTICAL);
-    if (at(2)->isSelected())
-      mode |= int(app::gen::SymmetryMode::RIGHT_DIAG);
-    if (at(3)->isSelected())
-      mode |= int(app::gen::SymmetryMode::LEFT_DIAG);
-
-    if (app::gen::SymmetryMode(mode) != docPref.symmetry.mode()) {
-      docPref.symmetry.mode(app::gen::SymmetryMode(mode));
-      // Redraw symmetry rules
+    if (buttonFlags != docPref.symmetry.buttonFlags()) {
+      docPref.symmetry.mode(forceAllMode ? app::gen::SymmetryMode::ALL :
+                                           app::gen::SymmetryMode(buttonFlags));
+      docPref.symmetry.buttonFlags(buttonFlags);
       doc->notifyGeneralUpdate();
     }
-    else if (at(4)->isSelected()) {
+
+    if (at(4)->isSelected()) {
       auto* item = at(4);
 
       gfx::Rect bounds = item->bounds();
diff --git a/src/app/ui/editor/editor.cpp b/src/app/ui/editor/editor.cpp
index 0b1088fe0..70c176652 100644
--- a/src/app/ui/editor/editor.cpp
+++ b/src/app/ui/editor/editor.cpp
@@ -1,5 +1,5 @@
 // Aseprite
-// Copyright (C) 2018-2024  Igara Studio S.A.
+// Copyright (C) 2018-2025  Igara Studio S.A.
 // Copyright (C) 2001-2018  David Capello
 //
 // This program is distributed under the terms of
@@ -831,6 +831,85 @@ void Editor::drawOneSpriteUnclippedRect(ui::Graphics* g,
         m_docPref.grid.forceSection();
       }
       m_docPref.show.grid.forceDirtyFlag();
+
+      // Symmetry mode
+      if (isActive() && (m_flags & Editor::kShowSymmetryLine) &&
+          Preferences::instance().symmetryMode.enabled()) {
+        const int mode = int(m_docPref.symmetry.mode());
+        const gfx::Color color = color_utils::color_for_ui(m_docPref.grid.color());
+        const gfx::Color semiTransparentColor =
+          gfx::rgba(rgba_getr(color), rgba_getg(color), rgba_getb(color), rgba_geta(color) / 4);
+        const int symmetryButtonFlags = m_docPref.symmetry.buttonFlags();
+        const double x = int(m_proj.applyX<double>(m_docPref.symmetry.xAxis()));
+        const double y = int(m_proj.applyY<double>(m_docPref.symmetry.yAxis()));
+
+        if (mode & int(app::gen::SymmetryMode::HORIZONTAL) && x > 0) {
+          g->drawVLine(symmetryButtonFlags & int(app::gen::SymmetryMode::HORIZONTAL) ?
+                         color :
+                         semiTransparentColor,
+                       enclosingRect.x + x,
+                       enclosingRect.y,
+                       enclosingRect.h);
+        }
+        if (mode & int(app::gen::SymmetryMode::VERTICAL) && y > 0) {
+          g->drawHLine(symmetryButtonFlags & int(app::gen::SymmetryMode::VERTICAL) ?
+                         color :
+                         semiTransparentColor,
+                       enclosingRect.x,
+                       enclosingRect.y + y,
+                       enclosingRect.w);
+        }
+        if (mode & int(app::gen::SymmetryMode::RIGHT_DIAG)) {
+          // Bottom point intersection:
+          gfx::Point bottomLeft(
+            enclosingRect.x + x + m_proj.turnYinTermsOfX<int>(y - enclosingRect.h),
+            enclosingRect.y2());
+          if (bottomLeft.x < enclosingRect.x) {
+            // Left intersection
+            bottomLeft.y = enclosingRect.y2() +
+                           m_proj.turnXinTermsOfY<int>(bottomLeft.x - enclosingRect.x);
+            bottomLeft.x = enclosingRect.x;
+          }
+          // Top intersection
+          gfx::Point topRight(enclosingRect.x + x + m_proj.turnYinTermsOfX<int>(y),
+                              enclosingRect.y);
+          if (enclosingRect.x2() < topRight.x) {
+            // Right intersection
+            topRight.y = enclosingRect.y +
+                         m_proj.applyY<int>(m_proj.removeX<int>(topRight.x - enclosingRect.x2()));
+            topRight.x = enclosingRect.x2();
+          }
+          g->drawLine(symmetryButtonFlags & int(app::gen::SymmetryMode::RIGHT_DIAG) ?
+                        color :
+                        semiTransparentColor,
+                      bottomLeft,
+                      topRight);
+        }
+        if (mode & int(app::gen::SymmetryMode::LEFT_DIAG)) {
+          // Bottom point intersection:
+          gfx::Point bottomRight(
+            enclosingRect.x + x + m_proj.turnYinTermsOfX<int>(enclosingRect.h - y),
+            enclosingRect.y2());
+          if (enclosingRect.x2() < bottomRight.x) {
+            // Left intersection
+            bottomRight.y = enclosingRect.y2() +
+                            m_proj.turnXinTermsOfY<int>(enclosingRect.x2() - bottomRight.x);
+            bottomRight.x = enclosingRect.x2();
+          }
+          // Top intersection
+          gfx::Point topLeft(enclosingRect.x + x - m_proj.turnYinTermsOfX<int>(y), enclosingRect.y);
+          if (topLeft.x < enclosingRect.x) {
+            // Right intersection
+            topLeft.y = enclosingRect.y + m_proj.turnXinTermsOfY<int>(enclosingRect.x - topLeft.x);
+            topLeft.x = enclosingRect.x;
+          }
+          g->drawLine(symmetryButtonFlags & int(app::gen::SymmetryMode::LEFT_DIAG) ?
+                        color :
+                        semiTransparentColor,
+                      topLeft,
+                      bottomRight);
+        }
+      }
     }
   }
 }
@@ -907,86 +986,6 @@ void Editor::drawSpriteUnclippedRect(ui::Graphics* g, const gfx::Rect& _rc)
   if (m_docPref.show.slices())
     drawSlices(g);
 
-  // Symmetry mode
-  if (isActive() && (m_flags & Editor::kShowSymmetryLine) &&
-      Preferences::instance().symmetryMode.enabled()) {
-    int mode = int(m_docPref.symmetry.mode());
-    if (mode & int(app::gen::SymmetryMode::HORIZONTAL)) {
-      double x = m_docPref.symmetry.xAxis();
-      if (x > 0) {
-        gfx::Color color = color_utils::color_for_ui(m_docPref.grid.color());
-        g->drawVLine(
-          color,
-          spriteRect.x + m_proj.applyX(mainTilePosition().x) + int(m_proj.applyX<double>(x)),
-          enclosingRect.y,
-          enclosingRect.h);
-      }
-    }
-    if (mode & int(app::gen::SymmetryMode::VERTICAL)) {
-      double y = m_docPref.symmetry.yAxis();
-      if (y > 0) {
-        gfx::Color color = color_utils::color_for_ui(m_docPref.grid.color());
-        g->drawHLine(
-          color,
-          enclosingRect.x,
-          spriteRect.y + m_proj.applyY(mainTilePosition().y) + int(m_proj.applyY<double>(y)),
-          enclosingRect.w);
-      }
-    }
-    if (mode & int(app::gen::SymmetryMode::RIGHT_DIAG)) {
-      double y = m_docPref.symmetry.yAxis();
-      double x = m_docPref.symmetry.xAxis();
-      gfx::Color color = color_utils::color_for_ui(m_docPref.grid.color());
-      // Bottom point intersection:
-      gfx::Point bottomLeft(
-        enclosingRect.x + m_proj.applyY(mainTilePosition().x) + int(m_proj.applyX<double>(x)) -
-          (enclosingRect.h - m_proj.applyY(mainTilePosition().y) - int(m_proj.applyY<double>(y))),
-        enclosingRect.y2());
-      if (bottomLeft.x < enclosingRect.x) {
-        // Left intersection
-        bottomLeft.y = enclosingRect.y2() - enclosingRect.x + bottomLeft.x;
-        bottomLeft.x = enclosingRect.x;
-      }
-      // Top intersection
-      gfx::Point topRight(enclosingRect.x + m_proj.applyY(mainTilePosition().x) +
-                            int(m_proj.applyX<double>(x)) + m_proj.applyY(mainTilePosition().y) +
-                            int(m_proj.applyY<double>(y)),
-                          enclosingRect.y);
-      if (enclosingRect.x2() < topRight.x) {
-        // Right intersection
-        topRight.y = enclosingRect.y + topRight.x - enclosingRect.x2();
-        topRight.x = enclosingRect.x2();
-      }
-      g->drawLine(color, bottomLeft, topRight);
-    }
-    if (mode & int(app::gen::SymmetryMode::LEFT_DIAG)) {
-      double y = m_docPref.symmetry.yAxis();
-      double x = m_docPref.symmetry.xAxis();
-      gfx::Color color = color_utils::color_for_ui(m_docPref.grid.color());
-      // Bottom point intersection:
-      gfx::Point bottomRight(
-        enclosingRect.x + m_proj.applyY(mainTilePosition().x) + int(m_proj.applyX<double>(x)) +
-          (enclosingRect.h - m_proj.applyY(mainTilePosition().y) - int(m_proj.applyX<double>(y))),
-        enclosingRect.y2());
-      if (enclosingRect.x2() < bottomRight.x) {
-        // Left intersection
-        bottomRight.y = enclosingRect.y2() - bottomRight.x + enclosingRect.x2();
-        bottomRight.x = enclosingRect.x2();
-      }
-      // Top intersection
-      gfx::Point topLeft(enclosingRect.x + m_proj.applyY(mainTilePosition().x) +
-                           int(m_proj.applyX<double>(x)) - m_proj.applyY(mainTilePosition().y) -
-                           int(m_proj.applyY<double>(y)),
-                         enclosingRect.y);
-      if (topLeft.x < enclosingRect.x) {
-        // Right intersection
-        topLeft.y = enclosingRect.y + enclosingRect.x - topLeft.x;
-        topLeft.x = enclosingRect.x;
-      }
-      g->drawLine(color, topLeft, bottomRight);
-    }
-  }
-
   // Draw active layer/cel edges
   if ((m_docPref.show.layerEdges() || m_showAutoCelGuides) &&
       // Show layer edges and possibly cel guides only on states that
diff --git a/src/render/projection.h b/src/render/projection.h
index 1597ecac0..c1b587bd4 100644
--- a/src/render/projection.h
+++ b/src/render/projection.h
@@ -1,5 +1,5 @@
 // Aseprite Render Library
-// Copyright (c) 2020 Igara Studio S.A.
+// Copyright (c) 2020-2025 Igara Studio S.A.
 // Copyright (c) 2016 David Capello
 //
 // This file is released under the terms of the MIT license.
@@ -70,6 +70,20 @@ public:
     return T(m_zoom.removeCeiling(y)) / T(m_pixelRatio.h);
   }
 
+  // Used in 'editor.cpp' to do some math between x,y values.
+  // Useful for calculating diagonal symmetry axis positions when pixel ratio is other than 1:1
+  template<typename T>
+  T turnXinTermsOfY(T x) const
+  {
+    return x * T(m_pixelRatio.h) / T(m_pixelRatio.w);
+  }
+
+  template<typename T>
+  T turnYinTermsOfX(T y) const
+  {
+    return y * T(m_pixelRatio.w) / T(m_pixelRatio.h);
+  }
+
   gfx::Rect apply(const gfx::Rect& r) const
   {
     int u = applyX(r.x);