Emscripten: Add Platform::MarkPresentable

So the website knows when to swap the thumbnail with the canvas of the TPT instance

src/PowderToy.cpp

@@ -493,6 +493,7 @@ int Main(int argc, char *argv[])
 			catch (std::exception & e)
 			{
 				new ErrorMessage("Error", ByteString(e.what()).FromUtf8());
+				Platform::MarkPresentable();
 			}
 		}
 

src/PowderToySDLEmscripten.cpp

@@ -49,10 +49,4 @@ void MainLoop()
 {
 	UpdateFpsLimit();
 	MainLoopBody();
-	EM_ASM({
-		let canvas = document.querySelector("canvas.emscripten");
-		if (canvas) {
-			canvas.scrollIntoView(true);
-		}
-	});
 }

src/common/platform/Emscripten.cpp

@@ -74,6 +74,16 @@ int InvokeMain(int argc, char *argv[])
 	return 0;
 }
 
+void MarkPresentable()
+{
+	EM_ASM({
+		try {
+			window.mark_presentable();
+		} catch (e) {
+		}
+	});
+}
+
 void MaybeTriggerSyncFs()
 {
 	if (!syncFsInFlight && shouldSyncFs.exchange(false, std::memory_order_relaxed))

src/common/platform/MainCommon.cpp

@@ -6,4 +6,8 @@ int InvokeMain(int argc, char *argv[])
 {
 	return Main(argc, argv);
 }
+
+void MarkPresentable()
+{
+}
 }

src/common/platform/Platform.h

@@ -66,6 +66,8 @@ namespace Platform
 	ByteString DefaultDdir();
 
 	int InvokeMain(int argc, char *argv[]);
+
+	void MarkPresentable();
 }
 
 extern "C" int Main(int argc, char *argv[]);

src/gui/game/GameController.cpp

@@ -1225,6 +1225,10 @@ void GameController::OpenSaveDone()
 
 void GameController::OpenSavePreview(int saveID, int saveDate, SavePreviewType savePreviewType)
 {
+	if (savePreviewType == savePreviewUrl)
+	{
+		gameView->SkipIntroText();
+	}
 	activePreview = new PreviewController(saveID, saveDate, savePreviewType, [this] { OpenSaveDone(); }, nullptr);
 	ui::Engine::Ref().ShowWindow(activePreview->GetView());
 }

src/gui/game/GameView.cpp

@@ -1659,6 +1659,11 @@ void GameView::OnFileDrop(ByteString filename)
 	c->LoadSaveFile(std::move(saveFile));
 
 	// hide the info text if it's not already hidden
+	SkipIntroText();
+}
+
+void GameView::SkipIntroText()
+{
 	introText = 0;
 }
 

src/gui/game/GameView.h

@@ -225,4 +225,6 @@ public:
 	void DoKeyRelease(int key, int scan, bool repeat, bool shift, bool ctrl, bool alt) override;
 
 	class OptionListener;
+
+	void SkipIntroText();
 };

src/gui/preview/PreviewController.cpp

@@ -52,6 +52,7 @@ void PreviewController::Update()
 	}
 	if (previewModel->GetDoOpen() && previewModel->GetSaveInfo() && previewModel->GetSaveInfo()->GetGameSave())
 	{
+		Platform::MarkPresentable();
 		Exit();
 	}
 }

src/gui/preview/PreviewView.cpp

@@ -25,6 +25,7 @@
 #include "gui/Style.h"
 
 #include "common/tpt-rand.h"
+#include "common/platform/Platform.h"
 #include "Format.h"
 #include "Misc.h"
 
@@ -607,6 +608,7 @@ void PreviewView::SaveLoadingError(String errorMessage)
 {
 	doError = true;
 	doErrorMessage = errorMessage;
+	Platform::MarkPresentable();
 }
 
 void PreviewView::NotifyCommentsPageChanged(PreviewModel * sender)