Introduce egui window resizability

Cargo.lock

@@ -1439,7 +1439,7 @@ dependencies = [
  "atomic_float",
  "nih_plug",
  "nih_plug_vizia",
- "open",
+ "open 3.2.0",
  "realfft",
  "semver",
  "triple_buffer",
@@ -1548,7 +1548,7 @@ dependencies = [
 [[package]]
 name = "egui-baseview"
 version = "0.2.0"
-source = "git+https://github.com/BillyDM/egui-baseview.git?rev=68c4d0e8e5c1c702a888a245f4ac50eddfdfcaed#68c4d0e8e5c1c702a888a245f4ac50eddfdfcaed"
+source = "git+https://github.com/BillyDM/egui-baseview.git?rev=87a6cbead6cf89ca27c2f0448e480e901cc2754d#87a6cbead6cf89ca27c2f0448e480e901cc2754d"
 dependencies = [
  "baseview 0.1.0 (git+https://github.com/RustAudio/baseview.git?rev=45465c5f46abed6c6ce370fffde5edc8e4cd5aa3)",
  "copypasta 0.10.1",
@@ -1556,6 +1556,7 @@ dependencies = [
  "egui_glow",
  "keyboard-types",
  "log",
+ "open 5.1.4",
  "raw-window-handle 0.5.2",
 ]
 
@@ -2544,6 +2545,25 @@ dependencies = [
  "windows-sys 0.48.0",
 ]
 
+[[package]]
+name = "is-docker"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "928bae27f42bc99b60d9ac7334e3a21d10ad8f1835a4e12ec3ec0464765ed1b3"
+dependencies = [
+ "once_cell",
+]
+
+[[package]]
+name = "is-wsl"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "173609498df190136aa7dea1a91db051746d339e18476eed5ca40521f02d7aa5"
+dependencies = [
+ "is-docker",
+ "once_cell",
+]
+
 [[package]]
 name = "is_terminal_polyfill"
 version = "1.70.1"
@@ -3420,6 +3440,17 @@ dependencies = [
  "windows-sys 0.42.0",
 ]
 
+[[package]]
+name = "open"
+version = "5.1.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b5ca541f22b1c46d4bb9801014f234758ab4297e7870b904b6a8415b980a7388"
+dependencies = [
+ "is-wsl",
+ "libc",
+ "pathdiff",
+]
+
 [[package]]
 name = "orbclient"
 version = "0.3.47"
@@ -4506,7 +4537,7 @@ dependencies = [
  "crossbeam",
  "nih_plug",
  "nih_plug_vizia",
- "open",
+ "open 3.2.0",
  "realfft",
  "serde",
  "triple_buffer",

nih_plug_egui/Cargo.toml

@@ -20,7 +20,7 @@ nih_plug = { path = "..", default-features = false }
 raw-window-handle = "0.5"
 baseview = { git = "https://github.com/RustAudio/baseview.git", rev = "45465c5f46abed6c6ce370fffde5edc8e4cd5aa3" }
 crossbeam = "0.8"
-egui-baseview = { git = "https://github.com/BillyDM/egui-baseview.git", rev = "68c4d0e8e5c1c702a888a245f4ac50eddfdfcaed", default-features = false }
+egui-baseview = { git = "https://github.com/BillyDM/egui-baseview.git", rev = "87a6cbead6cf89ca27c2f0448e480e901cc2754d", default-features = false }
 parking_lot = "0.12"
 # To make the state persistable
 serde = { version = "1.0", features = ["derive"] }

nih_plug_egui/src/editor.rs

@@ -1,6 +1,10 @@
 //! An [`Editor`] implementation for egui.
 
+use crate::egui::Vec2;
+use crate::egui::ViewportCommand;
+use crate::EguiState;
 use baseview::gl::GlConfig;
+use baseview::PhySize;
 use baseview::{Size, WindowHandle, WindowOpenOptions, WindowScalePolicy};
 use crossbeam::atomic::AtomicCell;
 use egui_baseview::egui::Context;
@@ -11,8 +15,6 @@ use raw_window_handle::{HasRawWindowHandle, RawWindowHandle};
 use std::sync::atomic::Ordering;
 use std::sync::Arc;
 
-use crate::EguiState;
-
 /// An [`Editor`] implementation that calls an egui draw loop.
 pub(crate) struct EguiEditor<T> {
     pub(crate) egui_state: Arc<EguiState>,
@@ -67,6 +69,7 @@ where
         let build = self.build.clone();
         let update = self.update.clone();
         let state = self.user_state.clone();
+        let egui_state = self.egui_state.clone();
 
         let (unscaled_width, unscaled_height) = self.egui_state.size();
         let scaling_factor = self.scaling_factor.load();
@@ -100,9 +103,25 @@ where
             },
             state,
             move |egui_ctx, _queue, state| build(egui_ctx, &mut state.write()),
-            move |egui_ctx, _queue, state| {
+            move |egui_ctx, queue, state| {
                 let setter = ParamSetter::new(context.as_ref());
 
+                // If the window was requested to resize
+                if let Some(new_size) = egui_state.requested_size.swap(None) {
+                    // Ask the plugin host to resize to self.size()
+                    if context.request_resize() {
+                        // Resize the content of egui window
+                        queue.resize(PhySize::new(new_size.0, new_size.1));
+                        egui_ctx.send_viewport_cmd(ViewportCommand::InnerSize(Vec2::new(
+                            new_size.0 as f32,
+                            new_size.1 as f32,
+                        )));
+
+                        // Update the state
+                        egui_state.size.store(new_size);
+                    }
+                }
+
                 // For now, just always redraw. Most plugin GUIs have meters, and those almost always
                 // need a redraw. Later we can try to be a bit more sophisticated about this. Without
                 // this we would also have a blank GUI when it gets first opened because most DAWs open
@@ -119,9 +138,17 @@ where
         })
     }
 
+    /// Size of the editor window
     fn size(&self) -> (u32, u32) {
+        let new_size = self.egui_state.requested_size.load();
+        // This method will be used to ask the host for new size.
+        // If the editor is currently being resized and new size hasn't been consumed and set yet, return new requested size.
+        if let Some(new_size) = new_size {
+            new_size
+        } else {
             self.egui_state.size()
         }
+    }
 
     fn set_scale_factor(&self, factor: f32) -> bool {
         // If the editor is currently open then the host must not change the current HiDPI scale as

nih_plug_egui/src/lib.rs

@@ -21,6 +21,7 @@ compile_error!("There's currently no software rendering support for egui");
 pub use egui_baseview::egui;
 
 mod editor;
+pub mod resizable_window;
 pub mod widgets;
 
 /// Create an [`Editor`] instance using an [`egui`][::egui] GUI. Using the user state parameter is
@@ -66,6 +67,11 @@ pub struct EguiState {
     /// The window's size in logical pixels before applying `scale_factor`.
     #[serde(with = "nih_plug::params::persist::serialize_atomic_cell")]
     size: AtomicCell<(u32, u32)>,
+
+    /// The new size of the window, if it was requested to resize by the GUI.
+    #[serde(skip)]
+    requested_size: AtomicCell<Option<(u32, u32)>>,
+
     /// Whether the editor's window is currently open.
     #[serde(skip)]
     open: AtomicBool,
@@ -90,6 +96,7 @@ impl EguiState {
     pub fn from_size(width: u32, height: u32) -> Arc<EguiState> {
         Arc::new(EguiState {
             size: AtomicCell::new((width, height)),
+            requested_size: Default::default(),
             open: AtomicBool::new(false),
         })
     }
@@ -104,4 +111,9 @@ impl EguiState {
     pub fn is_open(&self) -> bool {
         self.open.load(Ordering::Acquire)
     }
+
+    /// Set the new size that will be used to resize the window if the host allows.
+    fn set_requested_size(&self, new_size: (u32, u32)) {
+        self.requested_size.store(Some(new_size));
+    }
 }

nih_plug_egui/src/resizable_window.rs

@@ -0,0 +1,80 @@
+//! Resizable window wrapper for Egui editor.
+//!
+//!
+
+use crate::egui::{pos2, CentralPanel, Context, Id, Rect, Response, Sense, Ui, Vec2};
+use crate::EguiState;
+use egui_baseview::egui::InnerResponse;
+
+/// Adds a corner to the plugin window that can be dragged in order to resize it.
+/// Resizing happens through plugin API, hence a custom implementation is needed.
+pub struct ResizableWindow {
+    id: Id,
+    min_size: Vec2,
+}
+
+impl ResizableWindow {
+    pub fn new(id_source: impl std::hash::Hash) -> Self {
+        Self {
+            id: Id::new(id_source),
+            min_size: Vec2::splat(16.0),
+        }
+    }
+
+    /// Won't shrink to smaller than this
+    #[inline]
+    pub fn min_size(mut self, min_size: impl Into<Vec2>) -> Self {
+        self.min_size = min_size.into();
+        self
+    }
+
+    pub fn show<R>(
+        self,
+        context: &Context,
+        egui_state: &EguiState,
+        add_contents: impl FnOnce(&mut Ui) -> R,
+    ) -> InnerResponse<R> {
+        CentralPanel::default().show(context, move |ui| {
+            let ui_rect = ui.clip_rect();
+            let mut content_ui = ui.child_ui(ui_rect, *ui.layout());
+
+            let ret = add_contents(&mut content_ui);
+
+            let corner_size = Vec2::splat(ui.visuals().resize_corner_size);
+            let corner_rect = Rect::from_min_size(ui_rect.max - corner_size, corner_size);
+
+            let corner_response = ui.interact(corner_rect, self.id.with("corner"), Sense::drag());
+
+            if let Some(pointer_pos) = corner_response.interact_pointer_pos() {
+                let desired_size = (pointer_pos - ui_rect.min + 0.5 * corner_response.rect.size())
+                    .max(self.min_size);
+
+                if corner_response.dragged() {
+                    egui_state.set_requested_size((
+                        desired_size.x.round() as u32,
+                        desired_size.y.round() as u32,
+                    ));
+                }
+            }
+
+            paint_resize_corner(&content_ui, &corner_response);
+
+            ret
+        })
+    }
+}
+
+pub fn paint_resize_corner(ui: &Ui, response: &Response) {
+    let stroke = ui.style().interact(response).fg_stroke;
+
+    let painter = ui.painter();
+    let rect = response.rect.translate(-Vec2::splat(2.0)); // move away from the corner
+    let cp = painter.round_pos_to_pixels(rect.max);
+
+    let mut w = 2.0;
+
+    while w <= rect.width() && w <= rect.height() {
+        painter.line_segment([pos2(cp.x - w, cp.y), pos2(cp.x, cp.y - w)], stroke);
+        w += 4.0;
+    }
+}

plugins/examples/gain_gui_egui/src/lib.rs

@@ -1,5 +1,10 @@
 use nih_plug::prelude::*;
-use nih_plug_egui::{create_egui_editor, egui, widgets, EguiState};
+use nih_plug_egui::{
+    create_egui_editor,
+    egui::{self, Vec2},
+    resizable_window::ResizableWindow,
+    widgets, EguiState,
+};
 use std::sync::Arc;
 
 /// The time it takes for the peak meter to decay by 12 dB after switching to complete silence.
@@ -102,12 +107,15 @@ impl Plugin for Gain {
     fn editor(&mut self, _async_executor: AsyncExecutor<Self>) -> Option<Box<dyn Editor>> {
         let params = self.params.clone();
         let peak_meter = self.peak_meter.clone();
+        let egui_state = params.editor_state.clone();
         create_egui_editor(
             self.params.editor_state.clone(),
             (),
             |_, _| {},
             move |egui_ctx, setter, _state| {
-                egui::CentralPanel::default().show(egui_ctx, |ui| {
+                ResizableWindow::new("res-wind")
+                    .min_size(Vec2::new(128.0, 128.0))
+                    .show(egui_ctx, egui_state.as_ref(), |ui| {
                         // NOTE: See `plugins/diopser/src/editor.rs` for an example using the generic UI widget
 
                         // This is a fancy widget that can get all the information it needs to properly