From af565c2a20aece2ee3dbd99bdeaf8d4441de3d51 Mon Sep 17 00:00:00 2001
From: Lucas Fernandes Nogueira <lucas@tauri.app>
Date: Thu, 28 Dec 2023 10:03:14 -0300
Subject: [PATCH] fix(macos): allow canceling `data-tauri-drag-region`
 maximization #8312 (#8487)

---
 core/tauri/src/window/plugin.rs       | 20 ++++++--
 core/tauri/src/window/scripts/drag.js | 68 ++++++++++++++++++++++-----
 2 files changed, 74 insertions(+), 14 deletions(-)

diff --git a/core/tauri/src/window/plugin.rs b/core/tauri/src/window/plugin.rs
index 1d295addd..7b6c451e4 100644
--- a/core/tauri/src/window/plugin.rs
+++ b/core/tauri/src/window/plugin.rs
@@ -215,18 +215,32 @@ mod desktop_commands {
 
 /// Initializes the plugin.
 pub fn init<R: Runtime>() -> TauriPlugin<R> {
+  use serialize_to_javascript::{default_template, DefaultTemplate, Template};
+
   let mut init_script = String::new();
   // window.print works on Linux/Windows; need to use the API on macOS
   #[cfg(any(target_os = "macos", target_os = "ios"))]
   {
     init_script.push_str(include_str!("./scripts/print.js"));
   }
-  init_script.push_str(include_str!("./scripts/drag.js"));
+
+  #[derive(Template)]
+  #[default_template("./scripts/drag.js")]
+  struct Drag<'a> {
+    os_name: &'a str,
+  }
+
+  init_script.push_str(
+    &Drag {
+      os_name: std::env::consts::OS,
+    }
+    .render_default(&Default::default())
+    .unwrap()
+    .into_string(),
+  );
 
   #[cfg(any(debug_assertions, feature = "devtools"))]
   {
-    use serialize_to_javascript::{default_template, DefaultTemplate, Template};
-
     #[derive(Template)]
     #[default_template("./scripts/toggle-devtools.js")]
     struct Devtools<'a> {
diff --git a/core/tauri/src/window/scripts/drag.js b/core/tauri/src/window/scripts/drag.js
index 96dd64356..925341bfc 100644
--- a/core/tauri/src/window/scripts/drag.js
+++ b/core/tauri/src/window/scripts/drag.js
@@ -2,16 +2,62 @@
 // SPDX-License-Identifier: Apache-2.0
 // SPDX-License-Identifier: MIT
 
-document.addEventListener('mousedown', (e) => {
-  if (e.target.hasAttribute('data-tauri-drag-region') && e.button === 0) {
-    // prevents text cursor
-    e.preventDefault()
-    // fix #2549: double click on drag region edge causes content to maximize without window sizing change
-    // https://github.com/tauri-apps/tauri/issues/2549#issuecomment-1250036908
-    e.stopImmediatePropagation()
+;(function () {
+  const osName = __TEMPLATE_os_name__
 
-    // start dragging if the element has a `tauri-drag-region` data attribute and maximize on double-clicking it
-    const cmd = e.detail === 2 ? 'internal_toggle_maximize' : 'start_dragging'
-    window.__TAURI_INTERNALS__.invoke('plugin:window|' + cmd)
+  //-----------------------//
+  // drag on mousedown and maximize on double click on Windows and Linux
+  // while macOS macos maximization should be on mouseup and if the mouse
+  // moves after the double click, it should be cancelled (see https://github.com/tauri-apps/tauri/issues/8306)
+  //-----------------------//
+  const TAURI_DRAG_REGION_ATTR = 'data-tauri-drag-region';
+  let x = 0, y = 0;
+  document.addEventListener('mousedown', (e) => {
+    if (
+      // element has the magic data attribute
+      e.target.hasAttribute(TAURI_DRAG_REGION_ATTR) &&
+      // and was left mouse button
+      e.button === 0 &&
+      // and was normal click to drag or double click to maximize
+      (e.detail === 1 || e.detail === 2)
+      ) {
+
+      // macOS maximization happens on `mouseup`,
+      // so we save needed state and early return
+      if (osName === 'macos' && e.detail == 2) {
+        x = e.clientX
+        y = e.clientY
+        return
+      }
+
+      // prevents text cursor
+      e.preventDefault()
+
+      // fix #2549: double click on drag region edge causes content to maximize without window sizing change
+      // https://github.com/tauri-apps/tauri/issues/2549#issuecomment-1250036908
+      e.stopImmediatePropagation()
+
+      // start dragging if the element has a `tauri-drag-region` data attribute and maximize on double-clicking it
+      const cmd = e.detail === 2 ? 'internal_toggle_maximize' : 'start_dragging'
+      window.__TAURI_INTERNALS__.invoke('plugin:window|' + cmd)
+    }
+  })
+  // on macOS we maximze on mouseup instead, to match the system behavior where maximization can be canceled
+  // if the mouse moves outside the data-tauri-drag-region
+  if (osName === "macos") {
+    document.addEventListener('mouseup', (e) => {
+      if (
+        // element has the magic data attribute
+        e.target.hasAttribute(TAURI_DRAG_REGION_ATTR) &&
+        // and was left mouse button
+        e.button === 0 &&
+        // and was double click
+        e.detail === 2 &&
+        // and the cursor hasn't moved from initial mousedown
+        e.clientX === x && e.clientY === y
+      ) {
+        window.__TAURI_INTERNALS__.invoke('plugin:window|internal_toggle_maximize')
+      }
+    })
   }
-})
+})()