From 70b446fb0709cba7f8aff55a83f328eed4709b9c Mon Sep 17 00:00:00 2001
From: Hanno Braun <hanno@braun-odw.eu>
Date: Tue, 11 Oct 2022 14:07:32 +0200
Subject: [PATCH 1/3] Invert zoom direction

The intent behind the original zoom direction was to provide a
consistent metaphor: You manipulate the model, not an abstract camera.

Unfortunately, it turned out to not be that simple. At least on Gnome,
if you enable "natural scrolling" (which is the same metaphor, applied
to the Gnome UI), you invert all mouse whell input, and so also the zoom
direction in Fornjot.

With this change, the zoom direction in Fornjot follows the "natural
scrolling" configuration in Gnome. Unfortunately I don't have data from
other platforms.
---
 crates/fj-viewer/src/input/zoom.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/crates/fj-viewer/src/input/zoom.rs b/crates/fj-viewer/src/input/zoom.rs
index f4f7a0eb1..9c6e495b7 100644
--- a/crates/fj-viewer/src/input/zoom.rs
+++ b/crates/fj-viewer/src/input/zoom.rs
@@ -14,6 +14,6 @@ impl Zoom {
         let distance = (focus_point.0 - camera.position()).magnitude();
         let displacement = zoom_delta * distance.into_f64();
         camera.translation = camera.translation
-            * Transform::translation(Vector::from([0.0, 0.0, -displacement]));
+            * Transform::translation(Vector::from([0.0, 0.0, displacement]));
     }
 }

From da81720a001feb869213cd2701204e17cf3244bc Mon Sep 17 00:00:00 2001
From: Hanno Braun <hanno@braun-odw.eu>
Date: Tue, 11 Oct 2022 14:13:38 +0200
Subject: [PATCH 2/3] Improve formatting

---
 crates/fj-window/src/run.rs | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/crates/fj-window/src/run.rs b/crates/fj-window/src/run.rs
index b1168dd58..f67df4f41 100644
--- a/crates/fj-window/src/run.rs
+++ b/crates/fj-window/src/run.rs
@@ -264,12 +264,18 @@ fn input_event(
         Event::WindowEvent {
             event: WindowEvent::MouseWheel { delta, .. },
             ..
-        } => Some(input::Event::Zoom(match delta {
-            MouseScrollDelta::LineDelta(_, y) => (*y as f64) * ZOOM_FACTOR_LINE,
-            MouseScrollDelta::PixelDelta(PhysicalPosition { y, .. }) => {
-                y * ZOOM_FACTOR_PIXEL
-            }
-        })),
+        } => {
+            let delta = match delta {
+                MouseScrollDelta::LineDelta(_, y) => {
+                    (*y as f64) * ZOOM_FACTOR_LINE
+                }
+                MouseScrollDelta::PixelDelta(PhysicalPosition {
+                    y, ..
+                }) => y * ZOOM_FACTOR_PIXEL,
+            };
+
+            Some(input::Event::Zoom(delta))
+        }
         _ => None,
     }
 }

From e4c8fcbb424ef6fbd0528ceadfd6d9a109d5ec6b Mon Sep 17 00:00:00 2001
From: Hanno Braun <hanno@braun-odw.eu>
Date: Tue, 11 Oct 2022 14:15:46 +0200
Subject: [PATCH 3/3] Add configuration to invert zoom direction

---
 crates/fj-app/src/config.rs | 1 +
 crates/fj-app/src/main.rs   | 6 ++++--
 crates/fj-window/src/run.rs | 5 +++++
 fj.toml                     | 4 ++++
 4 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/crates/fj-app/src/config.rs b/crates/fj-app/src/config.rs
index 94d6e8967..a2d7ba359 100644
--- a/crates/fj-app/src/config.rs
+++ b/crates/fj-app/src/config.rs
@@ -11,6 +11,7 @@ use serde::Deserialize;
 pub struct Config {
     pub default_path: Option<PathBuf>,
     pub default_model: Option<PathBuf>,
+    pub invert_zoom: Option<bool>,
 }
 
 impl Config {
diff --git a/crates/fj-app/src/main.rs b/crates/fj-app/src/main.rs
index 6513cdc58..3744d32a9 100644
--- a/crates/fj-app/src/main.rs
+++ b/crates/fj-app/src/main.rs
@@ -80,11 +80,13 @@ fn main() -> anyhow::Result<()> {
         return Ok(());
     }
 
+    let invert_zoom = config.invert_zoom.unwrap_or(false);
+
     if let Some(model) = model {
         let watcher = model.load_and_watch(parameters)?;
-        run(Some(watcher), shape_processor, status)?;
+        run(Some(watcher), shape_processor, status, invert_zoom)?;
     } else {
-        run(None, shape_processor, status)?;
+        run(None, shape_processor, status, invert_zoom)?;
     }
 
     Ok(())
diff --git a/crates/fj-window/src/run.rs b/crates/fj-window/src/run.rs
index f67df4f41..cdebae724 100644
--- a/crates/fj-window/src/run.rs
+++ b/crates/fj-window/src/run.rs
@@ -32,6 +32,7 @@ pub fn run(
     watcher: Option<Watcher>,
     shape_processor: ShapeProcessor,
     mut status: StatusReport,
+    invert_zoom: bool,
 ) -> Result<(), Error> {
     let event_loop = EventLoop::new();
     let window = Window::new(&event_loop)?;
@@ -214,6 +215,7 @@ pub fn run(
             &window,
             &held_mouse_button,
             &mut previous_cursor,
+            invert_zoom,
         );
         if let (Some(input_event), Some(fp)) = (input_event, focus_point) {
             input_handler.handle_event(input_event, fp, &mut camera);
@@ -226,6 +228,7 @@ fn input_event(
     window: &Window,
     held_mouse_button: &Option<MouseButton>,
     previous_cursor: &mut Option<NormalizedPosition>,
+    invert_zoom: bool,
 ) -> Option<input::Event> {
     match event {
         Event::WindowEvent {
@@ -274,6 +277,8 @@ fn input_event(
                 }) => y * ZOOM_FACTOR_PIXEL,
             };
 
+            let delta = if invert_zoom { -delta } else { delta };
+
             Some(input::Event::Zoom(delta))
         }
         _ => None,
diff --git a/fj.toml b/fj.toml
index eb26a979f..a7b7a4a93 100644
--- a/fj.toml
+++ b/fj.toml
@@ -5,3 +5,7 @@ default_path = "models"
 # The default models that is loaded, if none is specified. If this is a relative
 # path, it should be relative to `default_path`.
 default_model = "test"
+
+# Indicate whether to invert the zoom direction. Can be used to override the
+# OS-level setting.
+invert_zoom = false