Show/Hide Window Programmatically

CHANGELOG.md

@@ -10,6 +10,7 @@ You can find its changes [documented below](#082---2023-01-27).
 ### Added
 
 - `foreground`, `set_foreground`, and `clear_foreground` methods to `Container` and `WidgetExt::foreground` method for convenience. ([#2346] by [@giannissc])
+- `WindowHandle::hide` method to hide a window. ([#2191] by [@newcomb-luke])
 
 ### Changed
 
@@ -768,6 +769,7 @@ Last release without a changelog :(
 [@lzhoucs]: https://github.com/lzhoucs
 [@ratmice]: https://github.com/ratmice
 [@giannissc]: https://github.com/giannissc
+[@newcomb-luke]: https://github.com/newcomb-luke
 
 [#599]: https://github.com/linebender/druid/pull/599
 [#611]: https://github.com/linebender/druid/pull/611
@@ -1164,6 +1166,7 @@ Last release without a changelog :(
 [#2157]: https://github.com/linebender/druid/pull/2157
 [#2158]: https://github.com/linebender/druid/pull/2158
 [#2172]: https://github.com/linebender/druid/pull/2172
+[#2191]: https://github.com/linebender/druid/pull/2191
 [#2195]: https://github.com/linebender/druid/pull/2195
 [#2196]: https://github.com/linebender/druid/pull/2196
 [#2203]: https://github.com/linebender/druid/pull/2203

druid-shell/src/backend/gtk/window.rs

@@ -1105,6 +1105,13 @@ impl WindowHandle {
         }
     }
 
+    /// Hide the window
+    pub fn hide(&self) {
+        if let Some(state) = self.state.upgrade() {
+            state.window.hide();
+        }
+    }
+
     /// Bring this window to the front of the window stack and give it focus.
     pub fn bring_to_front_and_focus(&self) {
         if let Some(state) = self.state.upgrade() {

druid-shell/src/backend/mac/window.rs

@@ -1038,6 +1038,14 @@ impl WindowHandle {
         }
     }
 
+    /// Hide the window.
+    pub fn hide(&self) {
+        unsafe {
+            let window: id = msg_send![*self.nsview.load(), window];
+            let () = msg_send![window, orderOut: self];
+        }
+    }
+
     /// Bring this window to the front of the window stack and give it focus.
     pub fn bring_to_front_and_focus(&self) {
         unsafe {

druid-shell/src/backend/wayland/window.rs

@@ -161,9 +161,14 @@ impl WindowHandle {
         }
     }
 
+    /// Hide the window.
+    pub fn hide(&self) {
+        tracing::warn!("hide is unimplemented on wayland");
+    }
+
     /// Bring this window to the front of the window stack and give it focus.
     pub fn bring_to_front_and_focus(&self) {
-        tracing::warn!("unimplemented bring_to_front_and_focus initiated");
+        tracing::warn!("bring_to_front_and_focus is unimplemented on wayland");
     }
 
     /// Request a new paint, but without invalidating anything.

druid-shell/src/backend/web/window.rs

@@ -545,6 +545,10 @@ impl WindowHandle {
         // TODO
     }
 
+    pub fn hide(&self) {
+        warn!("hide unimplemented for web");
+    }
+
     pub fn bring_to_front_and_focus(&self) {
         warn!("bring_to_frontand_focus unimplemented for web");
     }

druid-shell/src/backend/windows/window.rs

@@ -161,6 +161,7 @@ enum DeferredOp {
     SetSize(Size),
     SetResizable(bool),
     SetWindowState(window::WindowState),
+    ShowWindow(bool),
     ReleaseMouseCapture,
 }
 
@@ -618,6 +619,17 @@ impl MyWndProc {
                         ShowWindow(hwnd, show);
                     }
                 }
+                DeferredOp::ShowWindow(should_show) => {
+                    let show = if should_show { SW_SHOW } else { SW_HIDE };
+
+                    unsafe {
+                        ShowWindow(hwnd, show);
+
+                        if should_show {
+                            SetForegroundWindow(hwnd);
+                        }
+                    }
+                }
                 DeferredOp::SaveAs(options, token) => {
                     let info = unsafe {
                         get_file_dialog_path(hwnd, FileDialogType::Save, options)
@@ -758,6 +770,9 @@ impl WndProc for MyWndProc {
                 Some(0)
             }
             WM_ACTIVATE => {
+                // Check if the low-order word is not 0
+                // If it were 0, then that means we are being deactivated, in which case we do nothing.
+                // If it is != 0, then we have been activated.
                 if LOWORD(wparam as u32) as u32 != 0 {
                     unsafe {
                         if !self.has_titlebar() && !self.is_transparent() {
@@ -1850,6 +1865,7 @@ impl WindowHandle {
         }
     }
 
+    /// Closes the window.
     pub fn close(&self) {
         if let Some(w) = self.state.upgrade() {
             let hwnd = w.hwnd.get();
@@ -1859,10 +1875,14 @@ impl WindowHandle {
         }
     }
 
+    /// Hides the window.
+    pub fn hide(&self) {
+        self.defer(DeferredOp::ShowWindow(false));
+    }
+
     /// Bring this window to the front of the window stack and give it focus.
     pub fn bring_to_front_and_focus(&self) {
-        //FIXME: implementation goes here
-        warn!("bring_to_front_and_focus not yet implemented on windows");
+        self.defer(DeferredOp::ShowWindow(true));
     }
 
     pub fn request_anim_frame(&self) {

druid-shell/src/backend/x11/window.rs

@@ -853,6 +853,12 @@ impl Window {
         }
     }
 
+    fn hide(&self) {
+        if !self.destroyed() {
+            log_x11!(self.app.connection().unmap_window(self.id));
+        }
+    }
+
     fn close(&self) {
         self.destroy();
     }
@@ -922,12 +928,17 @@ impl Window {
             return;
         }
 
-        // TODO(x11/misc): Unsure if this does exactly what the doc comment says; need a test case.
         let conn = self.app.connection();
+
+        // This has no effect if we are already "mapped" but it shows the application if it was previously hidden
+        log_x11!(conn.map_window(self.id));
+
+        // Ask nicely to have our window to be at the top of the window stack
         log_x11!(conn.configure_window(
             self.id,
             &xproto::ConfigureWindowAux::new().stack_mode(xproto::StackMode::ABOVE),
         ));
+
         log_x11!(conn.set_input_focus(
             xproto::InputFocus::POINTER_ROOT,
             self.id,
@@ -1609,6 +1620,14 @@ impl WindowHandle {
         }
     }
 
+    pub fn hide(&self) {
+        if let Some(w) = self.window.upgrade() {
+            w.hide();
+        } else {
+            error!("Window {} has already been dropped", self.id);
+        }
+    }
+
     pub fn close(&self) {
         if let Some(w) = self.window.upgrade() {
             w.close();

druid-shell/src/window.rs

@@ -174,9 +174,6 @@ pub struct WindowHandle(pub(crate) backend::WindowHandle);
 
 impl WindowHandle {
     /// Make this window visible.
-    ///
-    /// This is part of the initialization process; it should only be called
-    /// once, when a window is first created.
     pub fn show(&self) {
         self.0.show()
     }
@@ -186,6 +183,11 @@ impl WindowHandle {
         self.0.close()
     }
 
+    /// Hide the window
+    pub fn hide(&self) {
+        self.0.hide()
+    }
+
     /// Set whether the window should be resizable
     pub fn resizable(&self, resizable: bool) {
         self.0.resizable(resizable)

druid/src/command.rs

@@ -211,6 +211,13 @@ pub mod sys {
     /// will automatically target the window containing the widget.
     pub const SHOW_WINDOW: Selector = Selector::new("druid-builtin.show-window");
 
+    /// The selector for a command to hide a specific window
+    ///
+    /// The command must target a specific window.
+    /// When calling `submit_command` on a `Widget`s context, passing `None` as target
+    /// will automatically target the window containing the widget.
+    pub const HIDE_WINDOW: Selector = Selector::new("druid-builtin.hide-window");
+
     /// Apply the configuration payload to an existing window. The target should be a WindowId.
     pub const CONFIGURE_WINDOW: Selector<WindowConfig> =
         Selector::new("druid-builtin.configure-window");

druid/src/win_handler.rs

@@ -324,6 +324,12 @@ impl<T: Data> InnerAppState<T> {
         }
     }
 
+    fn hide_window(&mut self, id: WindowId) {
+        if let Some(win) = self.windows.get_mut(id) {
+            win.handle.hide();
+        }
+    }
+
     fn configure_window(&mut self, config: &WindowConfig, id: WindowId) {
         if let Some(win) = self.windows.get_mut(id) {
             config.apply_to_handle(&mut win.handle);
@@ -689,13 +695,17 @@ impl<T: Data> AppState<T> {
                 }
             }
             T::Window(id) if cmd.is(sys_cmd::SHOW_WINDOW) => self.show_window(id),
+            T::Window(id) if cmd.is(sys_cmd::HIDE_WINDOW) => self.hide_window(id),
             T::Window(id) if cmd.is(sys_cmd::PASTE) => self.do_paste(id),
             _ if cmd.is(sys_cmd::CLOSE_WINDOW) => {
                 tracing::warn!("CLOSE_WINDOW command must target a window.")
             }
             _ if cmd.is(sys_cmd::SHOW_WINDOW) => {
                 tracing::warn!("SHOW_WINDOW command must target a window.")
             }
+            _ if cmd.is(sys_cmd::HIDE_WINDOW) => {
+                tracing::warn!("HIDE_WINDOW command must target a window.")
+            }
             _ if cmd.is(sys_cmd::SHOW_OPEN_PANEL) => {
                 tracing::warn!("SHOW_OPEN_PANEL command must target a window.")
             }
@@ -848,6 +858,10 @@ impl<T: Data> AppState<T> {
         self.inner.borrow_mut().show_window(id);
     }
 
+    fn hide_window(&mut self, id: WindowId) {
+        self.inner.borrow_mut().hide_window(id);
+    }
+
     fn configure_window(&mut self, cmd: Command, id: WindowId) {
         if let Some(config) = cmd.get(sys_cmd::CONFIGURE_WINDOW) {
             self.inner.borrow_mut().configure_window(config, id);