Add print functionality to v2 (#2822)

* Add print functionality to v2

* Update changelog

* Update runtime docs

---------

Co-authored-by: Lea Anthony <lea.anthony@gmail.com>

v2/internal/frontend/desktop/darwin/Application.h

@@ -41,6 +41,7 @@ void ShowApplication(void* ctx);
 void SetBackgroundColour(void* ctx, int r, int g, int b, int a);
 void ExecJS(void* ctx, const char*);
 void Quit(void*);
+void WindowPrint(void* ctx);
 
 const char* GetSize(void *ctx);
 const char* GetPosition(void *ctx);

v2/internal/frontend/desktop/darwin/Application.m

@@ -10,6 +10,7 @@
 #import "WailsContext.h"
 #import "Application.h"
 #import "AppDelegate.h"
+#import "WindowDelegate.h"
 #import "WailsMenu.h"
 #import "WailsMenuItem.h"
 
@@ -384,3 +385,36 @@ void ReleaseContext(void *inctx) {
     WailsContext *ctx = (__bridge WailsContext*) inctx;
     [ctx release];
 }
+
+// Credit: https://stackoverflow.com/q/33319295
+void WindowPrint(void *inctx) {
+
+	// Check if macOS 11.0 or newer
+	if (@available(macOS 11.0, *)) {
+        ON_MAIN_THREAD(
+            WailsContext *ctx = (__bridge WailsContext*) inctx;
+            WKWebView* webView = ctx.webview;
+
+            // I think this should be exposed as a config 
+            // It directly affects the printed output/PDF
+            NSPrintInfo *pInfo = [NSPrintInfo sharedPrintInfo];
+            pInfo.horizontalPagination = NSPrintingPaginationModeAutomatic;
+            pInfo.verticalPagination = NSPrintingPaginationModeAutomatic;
+            pInfo.verticallyCentered = YES;
+            pInfo.horizontallyCentered = YES;
+            pInfo.orientation = NSPaperOrientationLandscape;
+            pInfo.leftMargin = 0;
+            pInfo.rightMargin = 0;
+            pInfo.topMargin = 0;
+            pInfo.bottomMargin = 0;
+
+            NSPrintOperation *po = [webView printOperationWithPrintInfo:pInfo];
+            po.showsPrintPanel = YES;
+            po.showsProgressPanel = YES;
+
+            po.view.frame = webView.bounds;
+
+            [po runOperationModalForWindow:ctx.mainWindow delegate:ctx.mainWindow.delegate didRunSelector:nil contextInfo:nil];
+        )
+	}
+}

v2/internal/frontend/desktop/darwin/frontend.go

@@ -286,6 +286,10 @@ func (f *Frontend) Quit() {
 	f.mainWindow.Quit()
 }
 
+func (f *Frontend) WindowPrint() {
+	f.mainWindow.Print()
+}
+
 type EventNotify struct {
 	Name string        `json:"name"`
 	Data []interface{} `json:"data"`

v2/internal/frontend/desktop/darwin/window.go

@@ -263,3 +263,7 @@ func (w *Window) SetApplicationMenu(inMenu *menu.Menu) {
 func (w *Window) UpdateApplicationMenu() {
 	C.UpdateApplicationMenu(w.context)
 }
+
+func (w Window) Print() {
+	C.WindowPrint(w.context)
+}

v2/internal/frontend/desktop/linux/frontend.go

@@ -362,6 +362,10 @@ func (f *Frontend) Quit() {
 	f.mainWindow.Quit()
 }
 
+func (f *Frontend) WindowPrint() {
+	f.ExecJS("window.print();")
+}
+
 type EventNotify struct {
 	Name string        `json:"name"`
 	Data []interface{} `json:"data"`

v2/internal/frontend/desktop/windows/frontend.go

@@ -425,6 +425,10 @@ func (f *Frontend) Quit() {
 	f.mainWindow.Invoke(winc.Exit)
 }
 
+func (f *Frontend) WindowPrint() {
+	f.ExecJS("window.print();")
+}
+
 func (f *Frontend) setupChromium() {
 	chromium := f.chromium
 

v2/internal/frontend/frontend.go

@@ -121,6 +121,7 @@ type Frontend interface {
 	WindowIsNormal() bool
 	WindowIsFullscreen() bool
 	WindowClose()
+	WindowPrint()
 
 	//Screen
 	ScreenGetAll() ([]Screen, error)

v2/pkg/runtime/window.go

@@ -179,3 +179,8 @@ func WindowSetBackgroundColour(ctx context.Context, R, G, B, A uint8) {
 	}
 	appFrontend.WindowSetBackgroundColour(col)
 }
+
+func WindowPrint(ctx context.Context) {
+	appFrontend := getFrontend(ctx)
+	appFrontend.WindowPrint()
+}

website/docs/reference/runtime/window.mdx

@@ -233,6 +233,13 @@ Any value that is not 0 will be considered 255.
 Go: `WindowSetBackgroundColour(ctx context.Context, R, G, B, A uint8)`<br/>
 JS: `WindowSetBackgroundColour(R, G, B, A)`
 
+### WindowPrint
+
+Opens tha native print dialog.
+
+Go: `WindowPrint(ctx context.Context)`<br/>
+JS: `WindowPrint()`
+
 ## TypeScript Object Definitions
 
 ### Position

website/src/pages/changelog.mdx

@@ -40,6 +40,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Added new community template wails-sveltekit-ts. Added by [@haukened](https://github.com/haukened) in [PR](https://github.com/wailsapp/wails/pull/2851)
 - Added support for retrieving the logical and physical screen size in the screen api. Added by @stffabi in [PR](https://github.com/wailsapp/wails/pull/2856)
 - Added new community template wails-sveltekit-tailwind. Added by [@pylotlight](https://github.com/pylotlight) in [PR](https://github.com/wailsapp/wails/pull/2851)
+- Added support for print dialogs. Added by [@aangelisc](https://github.com/aangelisc) in [PR](https://github.com/wailsapp/wails/pull/2822)
 - Added new `wails dev -nogorebuild` flag to prevent restarts on back end file changes. [@haukened](https://github.com/haukened) in [PR #2870](https://github.com/wailsapp/wails/pull/2870)
 
 ### Changed