fix(macOS): Printing (#235) (#236)

* fix(macOS): Printing

Related to #235

* Add change file

.changes/macos-printing.md

@@ -0,0 +1,5 @@
+---
+"wry": patch
+---
+
+Expose `print()` function to the webview. Work only on macOS for now.

src/webview/linux/mod.rs

@@ -201,6 +201,9 @@ impl InnerWebView {
     Ok(w)
   }
 
+  // not supported yet
+  pub fn print(&self) {}
+
   pub fn eval(&self, js: &str) -> Result<()> {
     let cancellable: Option<&Cancellable> = None;
     self.webview.run_javascript(js, cancellable, |_| ());

src/webview/macos/mod.rs

@@ -35,6 +35,7 @@ mod file_drop;
 
 pub struct InnerWebView {
   webview: Id<Object>,
+  ns_window: id,
   manager: id,
   rpc_handler_ptr: *mut (
     Box<dyn Fn(&Window, RpcRequest) -> Option<RpcResponse>>,
@@ -230,8 +231,12 @@ impl InnerWebView {
         None => set_file_drop_handler(webview, window.clone(), Box::new(|_, _| false)),
       };
 
+      // ns window is required for the print operation
+      let ns_window = window.ns_window() as id;
+
       let w = Self {
         webview: Id::from_ptr(webview),
+        ns_window,
         manager,
         rpc_handler_ptr,
         file_drop_ptr,
@@ -290,7 +295,6 @@ impl InnerWebView {
       // Tell the webview we use layers
       let _: () = msg_send![webview, setWantsLayer: YES];
       // Inject the web view into the window as main content
-      let ns_window = window.ns_window() as id;
       let _: () = msg_send![ns_window, setContentView: webview];
 
       Ok(w)
@@ -333,6 +337,21 @@ impl InnerWebView {
       let () = msg_send![self.webview, loadHTMLString:NSString::new(url) baseURL:empty];
     }
   }
+
+  pub fn print(&self) {
+    // Safety: objc runtime calls are unsafe
+    unsafe {
+      // Create a shared print info
+      let print_info: id = msg_send![class!(NSPrintInfo), sharedPrintInfo];
+      let print_info: id = msg_send![print_info, init];
+      // Create new print operation from the webview content
+      let print_operation: id = msg_send![self.webview, printOperationWithPrintInfo: print_info];
+      // Allow the modal to detach from the current thread and be non-blocker
+      let () = msg_send![print_operation, setCanSpawnSeparateThread: YES];
+      // Launch the modal
+      let () = msg_send![print_operation, runOperationModalForWindow: self.ns_window delegate: null::<*const c_void>() didRunSelector: null::<*const c_void>() contextInfo: null::<*const c_void>()];
+    }
+  }
 }
 
 impl Drop for InnerWebView {

src/webview/mod.rs

@@ -348,6 +348,13 @@ impl WebView {
     Ok(())
   }
 
+  /// Launch print modal for the webview content.
+  /// Works only on macOS for now.
+  pub fn print(&self) -> Result<()> {
+    self.webview.print();
+    Ok(())
+  }
+
   /// Resize the WebView manually. This is required on Windows because its WebView API doesn't
   /// provide a way to resize automatically.
   pub fn resize(&self) -> Result<()> {

src/webview/win32/mod.rs

@@ -217,6 +217,9 @@ impl InnerWebView {
     })
   }
 
+  // not supported yet
+  pub fn print(&self) {}
+
   pub fn eval(&self, js: &str) -> Result<()> {
     if let Some(c) = self.controller.get() {
       let webview = c.get_webview()?;

src/webview/winrt/mod.rs

@@ -239,6 +239,9 @@ impl InnerWebView {
     })
   }
 
+  // not supported yet
+  pub fn print(&self) {}
+
   pub fn eval(&self, js: &str) -> Result<()> {
     if let Some(w) = self.webview.get() {
       let _ = w.ExecuteScriptAsync(js)?;