From cd683187e07841006959414de4c25fcb30a9b7b4 Mon Sep 17 00:00:00 2001
From: Robbert van der Helm <mail@robbertvanderhelm.nl>
Date: Wed, 9 Feb 2022 11:42:47 +0100
Subject: [PATCH] Allow resetting parameters by double clicking

---
 nih_plug_egui/src/widgets/param_slider.rs | 12 ++++++++++++
 src/context.rs                            | 16 ++++++++++------
 2 files changed, 22 insertions(+), 6 deletions(-)

diff --git a/nih_plug_egui/src/widgets/param_slider.rs b/nih_plug_egui/src/widgets/param_slider.rs
index 570c6f77..9bbbdbd1 100644
--- a/nih_plug_egui/src/widgets/param_slider.rs
+++ b/nih_plug_egui/src/widgets/param_slider.rs
@@ -37,6 +37,13 @@ impl<'a, P: Param> ParamSlider<'a, P> {
         self.setter.set_parameter(self.param, value);
     }
 
+    // This still needs to be part of a drag gestur
+    fn reset_param(&self) {
+        let normalized_default = self.setter.default_normalized_param_value(self.param);
+        self.setter
+            .set_parameter_normalized(self.param, normalized_default);
+    }
+
     fn end_drag(&self) {
         self.setter.end_set_parameter(self.param);
     }
@@ -70,6 +77,7 @@ impl<P: Param> Widget for ParamSlider<'_, P> {
 
         // Handle user input
         // TODO: As mentioned above, handle double click and ctrl+click, maybe also value entry
+        // TODO: Handle shift+drag being more granular
         if response.drag_started() {
             self.begin_drag();
         }
@@ -78,6 +86,10 @@ impl<P: Param> Widget for ParamSlider<'_, P> {
                 egui::emath::remap_clamp(click_pos.x, response.rect.x_range(), 0.0..=1.0) as f64;
             self.set_normalized_value(proportion as f32);
         }
+        // TODO: Also handle ctrl+click
+        if response.double_clicked() {
+            self.reset_param();
+        }
         if response.drag_released() {
             self.end_drag();
         }
diff --git a/src/context.rs b/src/context.rs
index cb8a6d80..2ce65fad 100644
--- a/src/context.rs
+++ b/src/context.rs
@@ -157,14 +157,18 @@ impl<'a> ParamSetter<'a> {
         unsafe { self.context.raw_end_set_parameter(param.as_ptr()) };
     }
 
-    /// Retrieve the default value for a parameter, in case you forgot. This is useful when
-    /// implementing GUIs, and it does not perform a callback.
-    fn raw_default_normalized_param_value<P: Param>(&self, param: &P) -> P::Plain {
-        let normalized = unsafe {
+    /// Retrieve the default value for a parameter, in case you forgot. The value is already
+    /// normalized to `[0, 1]`. This is useful when implementing GUIs, and it does not perform a callback.
+    pub fn default_normalized_param_value<P: Param>(&self, param: &P) -> f32 {
+        unsafe {
             self.context
                 .raw_default_normalized_param_value(param.as_ptr())
-        };
-        param.preview_plain(normalized)
+        }
+    }
+
+    /// The same as [Self::default_normalized_param_value], but without the normalization.
+    pub fn default_param_value<P: Param>(&self, param: &P) -> P::Plain {
+        param.preview_plain(self.default_normalized_param_value(param))
     }
 }