From 87a68b0a81ec8b6cd4205c96b9ccf6afd4a0c939 Mon Sep 17 00:00:00 2001
From: David Capello <david@igara.com>
Date: Fri, 2 Sep 2022 11:47:09 -0300
Subject: [PATCH] Fix Ctrl+Alt+drag mouse to increase brush size when moving to
 the right (fix #3496)

Regression introduced in 50707117f6856557e6dc77ee7a022d1a3a4fe6c2
---
 src/app/ui/editor/dragging_value_state.cpp    |  3 ++-
 .../ui/editor/state_with_wheel_behavior.cpp   | 24 +++++++++++--------
 src/app/ui/editor/state_with_wheel_behavior.h |  8 ++++++-
 3 files changed, 23 insertions(+), 12 deletions(-)

diff --git a/src/app/ui/editor/dragging_value_state.cpp b/src/app/ui/editor/dragging_value_state.cpp
index 45075b282..1bed93ee8 100644
--- a/src/app/ui/editor/dragging_value_state.cpp
+++ b/src/app/ui/editor/dragging_value_state.cpp
@@ -126,7 +126,8 @@ bool DraggingValueState::onMouseMove(Editor* editor, MouseMessage* msg)
                          delta,
                          dz,
                          ScrollBigSteps::Off,
-                         preciseWheel);
+                         preciseWheel,
+                         FromMouseWheel::Off);
     }
   }
 
diff --git a/src/app/ui/editor/state_with_wheel_behavior.cpp b/src/app/ui/editor/state_with_wheel_behavior.cpp
index 6b2c26505..48648aa6e 100644
--- a/src/app/ui/editor/state_with_wheel_behavior.cpp
+++ b/src/app/ui/editor/state_with_wheel_behavior.cpp
@@ -151,7 +151,8 @@ bool StateWithWheelBehavior::onMouseWheel(Editor* editor, MouseMessage* msg)
                      ScrollBigSteps::Off,
                      (msg->preciseWheel() ?
                       PreciseWheel::On:
-                      PreciseWheel::Off));
+                      PreciseWheel::Off),
+                     FromMouseWheel::On);
   return true;
 }
 
@@ -162,7 +163,8 @@ void StateWithWheelBehavior::processWheelAction(
   gfx::Point delta,
   double dz,
   const ScrollBigSteps scrollBigSteps,
-  const PreciseWheel preciseWheel)
+  const PreciseWheel preciseWheel,
+  const FromMouseWheel fromMouseWheel)
 {
   switch (wheelAction) {
 
@@ -274,17 +276,19 @@ void StateWithWheelBehavior::processWheelAction(
       ToolPreferences::Brush& brush =
         Preferences::instance().tool(tool).brush;
 
+      if (fromMouseWheel == FromMouseWheel::On) {
 #if LAF_WINDOWS || LAF_LINUX
-      // By default on macOS the mouse wheel is correct, up increase
-      // brush size, and down decrease it. But on Windows and Linux
-      // it's inverted.
-      dz = -dz;
+        // By default on macOS the mouse wheel is correct, up increase
+        // brush size, and down decrease it. But on Windows and Linux
+        // it's inverted.
+        dz = -dz;
 #endif
 
-      // We can configure the mouse wheel for brush size to behave as
-      // in previous versions.
-      if (Preferences::instance().editor.invertBrushSizeWheel())
-        dz = -dz;
+        // We can configure the mouse wheel for brush size to behave as
+        // in previous versions.
+        if (Preferences::instance().editor.invertBrushSizeWheel())
+          dz = -dz;
+      }
 
       brush.size(
         std::clamp(
diff --git a/src/app/ui/editor/state_with_wheel_behavior.h b/src/app/ui/editor/state_with_wheel_behavior.h
index bc9568f70..093b47fc4 100644
--- a/src/app/ui/editor/state_with_wheel_behavior.h
+++ b/src/app/ui/editor/state_with_wheel_behavior.h
@@ -33,6 +33,11 @@ namespace app {
     enum class ScrollBigSteps { Off, On };
     enum class PreciseWheel { Off, On };
 
+    // Indicates that the message comes from a real mouse wheel (which
+    // might have special handling inverting the direction of the
+    // wheel action depending on the operating system, etc.)
+    enum class FromMouseWheel { Off, On };
+
     StateWithWheelBehavior();
 
     bool onMouseWheel(Editor* editor, ui::MouseMessage* msg) override;
@@ -46,7 +51,8 @@ namespace app {
                             gfx::Point delta,
                             double dz,
                             const ScrollBigSteps scrollBigSteps,
-                            const PreciseWheel preciseWheel);
+                            const PreciseWheel preciseWheel,
+                            const FromMouseWheel fromMouseWheel);
     const doc::LayerList& browsableLayers(Editor* editor) const;
 
     virtual Color initialFgColor() const;