Add 'Zoom with Scroll' input navigation scheme to preferences (#1021)

* Add use_scroll_as_zoom field to preference handler

* Add {Create,Delete}Mapping variants to message

* Revert "Add {Create,Delete}Mapping variants to message"

This reverts commit 0ba74754c9fb0c78d0b590c96e1d4fe2cfdd13e7.

* Revert "Add use_scroll_as_zoom field to preference handler"

This reverts commit d30f7c9edfa6d6e156939ca07f4db81f288975fd.

* Add basic scroll_as_zoom mapping

* Create overengineered mapping patch abstraction

* Add (for now passthrough) input layout manager

* Actually handle ModifyLayout messages (untested)

* Add backend preferences <-> layout manager comms

* Add scroll-as-zoom to actual preferences UI

* Rename LayoutManager -> KeyMapping

* Add Input section to preferences and title case

* Add scrollAsZoom frontend handling code (untested)

* Handle frontend <-> preferences comms

* (broken) Move scrollAsZoom persistence into state

* Fix scrollAsZoom having no effect on node graph

* Remove debugging helpers

* Fix confusion between horizontal and vertical

* Rename feature

* Move new message handler into folder

---------

Co-authored-by: Keavon Chambers <keavon@keavon.com>

editor/src/messages/input_mapper/key_mapping/key_mapping_message.rs

@@ -0,0 +1,24 @@
+use crate::messages::prelude::*;
+
+use serde::{Deserialize, Serialize};
+
+#[remain::sorted]
+#[impl_message(Message, KeyMapping)]
+#[derive(PartialEq, Eq, Clone, Debug, Hash, Serialize, Deserialize)]
+pub enum KeyMappingMessage {
+	#[child]
+	Lookup(InputMapperMessage),
+	#[child]
+	ModifyMapping(MappingVariant),
+}
+
+#[remain::sorted]
+#[impl_message(Message, KeyMappingMessage, ModifyMapping)]
+#[derive(PartialEq, Eq, Clone, Debug, Default, Hash, Serialize, Deserialize)]
+pub enum MappingVariant {
+	#[remain::unsorted]
+	#[default]
+	Default,
+
+	ZoomWithScroll,
+}

editor/src/messages/input_mapper/key_mapping/key_mapping_message_handler.rs

@@ -0,0 +1,23 @@
+use crate::messages::input_mapper::utility_types::input_keyboard::KeysGroup;
+use crate::messages::prelude::*;
+
+#[derive(Debug, Default)]
+pub struct KeyMappingMessageHandler {
+	mapping_handler: InputMapperMessageHandler,
+}
+
+impl MessageHandler<KeyMappingMessage, (&InputPreprocessorMessageHandler, ActionList)> for KeyMappingMessageHandler {
+	fn process_message(&mut self, message: KeyMappingMessage, responses: &mut VecDeque<Message>, data: (&InputPreprocessorMessageHandler, ActionList)) {
+		match message {
+			KeyMappingMessage::Lookup(input) => self.mapping_handler.process_message(input, responses, data),
+			KeyMappingMessage::ModifyMapping(new_layout) => self.mapping_handler.set_mapping(new_layout.into()),
+		}
+	}
+	advertise_actions!();
+}
+
+impl KeyMappingMessageHandler {
+	pub fn action_input_mapping(&self, action_to_find: &MessageDiscriminant) -> Vec<KeysGroup> {
+		self.mapping_handler.action_input_mapping(action_to_find)
+	}
+}

editor/src/messages/input_mapper/key_mapping/mod.rs

@@ -0,0 +1,7 @@
+mod key_mapping_message;
+mod key_mapping_message_handler;
+
+#[doc(inline)]
+pub use key_mapping_message::{KeyMappingMessage, KeyMappingMessageDiscriminant, MappingVariant, MappingVariantDiscriminant};
+#[doc(inline)]
+pub use key_mapping_message_handler::KeyMappingMessageHandler;