From 25bcff3656c911e26904e7cf846aefb2a4eaa5b4 Mon Sep 17 00:00:00 2001
From: Len Trigg <lenbok@gmail.com>
Date: Sat, 11 Mar 2017 18:37:17 +1300
Subject: [PATCH] Fix #2861, provide consistent mouse-wheel zoom direction,
 plus a GUI preference to invert (#3749)

* Make mouse-wheel in 2D toolpath zoom in the same direction as it does in 3D and 3D-preview

* Add a GUI preference setting for whether to invert the direction that
mouse-wheel scrolling will zoom in the 2D and 3D panels.
---
 lib/Slic3r/GUI.pm                    | 2 ++
 lib/Slic3r/GUI/3DScene.pm            | 3 +++
 lib/Slic3r/GUI/Plater/2DToolpaths.pm | 5 ++++-
 lib/Slic3r/GUI/Preferences.pm        | 7 +++++++
 4 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/lib/Slic3r/GUI.pm b/lib/Slic3r/GUI.pm
index b3c306850..c4fe92a04 100644
--- a/lib/Slic3r/GUI.pm
+++ b/lib/Slic3r/GUI.pm
@@ -67,6 +67,7 @@ our $Settings = {
         mode => 'simple',
         version_check => 1,
         autocenter => 1,
+        invert_zoom => 0,
         background_processing => 0,
         # If set, the "Controller" tab for the control of the printer over serial line and the serial port settings are hidden.
         # By default, Prusa has the controller hidden.
@@ -124,6 +125,7 @@ sub OnInit {
         $last_version = $Settings->{_}{version};
         $Settings->{_}{mode} ||= 'expert';
         $Settings->{_}{autocenter} //= 1;
+        $Settings->{_}{invert_zoom} //= 0;
         $Settings->{_}{background_processing} //= 1;
         # If set, the "Controller" tab for the control of the printer over serial line and the serial port settings are hidden.
         $Settings->{_}{no_controller} //= 1;
diff --git a/lib/Slic3r/GUI/3DScene.pm b/lib/Slic3r/GUI/3DScene.pm
index 2a37a9b75..56875acc9 100644
--- a/lib/Slic3r/GUI/3DScene.pm
+++ b/lib/Slic3r/GUI/3DScene.pm
@@ -127,6 +127,9 @@ sub new {
         
         # Calculate the zoom delta and apply it to the current zoom factor
         my $zoom = $e->GetWheelRotation() / $e->GetWheelDelta();
+        if ($Slic3r::GUI::Settings->{_}{invert_zoom}) {
+            $zoom *= -1;
+        }
         $zoom = max(min($zoom, 4), -4);
         $zoom /= 10;
         $self->_zoom($self->_zoom / (1-$zoom));
diff --git a/lib/Slic3r/GUI/Plater/2DToolpaths.pm b/lib/Slic3r/GUI/Plater/2DToolpaths.pm
index bc3d4e605..d39c53179 100644
--- a/lib/Slic3r/GUI/Plater/2DToolpaths.pm
+++ b/lib/Slic3r/GUI/Plater/2DToolpaths.pm
@@ -179,7 +179,10 @@ sub new {
         my $old_zoom = $self->_zoom;
         
         # Calculate the zoom delta and apply it to the current zoom factor
-        my $zoom = $e->GetWheelRotation() / $e->GetWheelDelta();
+        my $zoom = -$e->GetWheelRotation() / $e->GetWheelDelta();
+        if ($Slic3r::GUI::Settings->{_}{invert_zoom}) {
+            $zoom *= -1;
+        }
         $zoom = max(min($zoom, 4), -4);
         $zoom /= 10;
         $self->_zoom($self->_zoom / (1-$zoom));
diff --git a/lib/Slic3r/GUI/Preferences.pm b/lib/Slic3r/GUI/Preferences.pm
index 431f642d6..91465fa64 100644
--- a/lib/Slic3r/GUI/Preferences.pm
+++ b/lib/Slic3r/GUI/Preferences.pm
@@ -52,6 +52,13 @@ sub new {
         tooltip     => 'If this is enabled, Slic3r will auto-center objects around the print bed center.',
         default     => $Slic3r::GUI::Settings->{_}{autocenter},
     ));
+    $optgroup->append_single_option_line(Slic3r::GUI::OptionsGroup::Option->new(
+        opt_id      => 'invert_zoom',
+        type        => 'bool',
+        label       => 'Invert zoom in previews',
+        tooltip     => 'If this is enabled, Slic3r will invert the direction of mouse-wheel zoom in preview panes.',
+        default     => $Slic3r::GUI::Settings->{_}{invert_zoom},
+    ));
     $optgroup->append_single_option_line(Slic3r::GUI::OptionsGroup::Option->new(
         opt_id      => 'background_processing',
         type        => 'bool',