Merge branch 'invert-mouse-wheel-for-brush-size' into main

* Fixes #2364
* Introduced in PR #2715
* More information about this issue in:
    https://github.com/aseprite/aseprite/issues/2364#issuecomment-832321902
  and
    issue #2896

data/pref.xml

@@ -171,6 +171,7 @@
       <option id="zoom_with_slide" type="bool" default="false" />
       <option id="zoom_from_center_with_wheel" type="bool" default="false" />
       <option id="zoom_from_center_with_keys" type="bool" default="false" />
+      <option id="invert_brush_size_wheel" type="bool" default="false" />
       <option id="show_scrollbars" type="bool" default="true" />
       <option id="auto_scroll" type="bool" default="true" />
       <option id="right_click_mode" type="RightClickMode" default="RightClickMode::PAINT_BGCOLOR" />

data/strings/en.ini

@@ -799,6 +799,7 @@ section_mouse_wheel = Mouse Wheel
 default_wheel_behavior = Default
 custom_wheel_behavior = Custom
 slide_as_wheel = Interpret two fingers slide on Trackpad as mouse wheel
+invert_brush_size_wheel = Invert the mouse wheel direction for increasing the brush size
 ok = &OK
 cancel = &Cancel
 

data/widgets/keyboard_shortcuts.xml

@@ -49,6 +49,8 @@
                    pref="editor.zoom_with_wheel" />
             <check text="@options.slide_zoom" id="slide_zoom"
                    pref="editor.zoom_with_slide" />
+            <check text="@.invert_brush_size_wheel" id="invert_brush_size_scroll"
+                   pref="editor.invert_brush_size_wheel" />
             <view expansive="true">
               <listbox id="wheel_actions" />
             </view>

src/app/ui/editor/state_with_wheel_behavior.cpp

@@ -190,6 +190,18 @@ bool StateWithWheelBehavior::onMouseWheel(Editor* editor, MouseMessage* msg)
       ToolPreferences::Brush& brush =
         Preferences::instance().tool(tool).brush;
 
+#if defined(_WIN32) || defined(__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;
+#endif
+
+      // We can configure the mouse wheel for brush size to behave as
+      // in previous versions.
+      if (Preferences::instance().editor.invertBrushSizeWheel())
+        dz = -dz;
+
       brush.size(
         base::clamp(
           int(brush.size()+dz),