Fixed an issue copying the bitmap in uCEFBrowserThread

Added more checks to uCEFBrowserThread

demos/Delphi_VCL/ConsoleBrowser2/ConsoleBrowser2_sp.dpr

@@ -53,6 +53,16 @@ begin
   GlobalCEFApp.EnableHighDPISupport       := True;
   GlobalCEFApp.ShowMessageDlg             := False;
   GlobalCEFApp.BlinkSettings              := 'hideScrollbars';
+
+{
+  // In case you use a custom directory for the CEF binaries you have to set these properties
+  // here and in the main process
+  GlobalCEFApp.FrameworkDirPath     := 'c:\cef';
+  GlobalCEFApp.ResourcesDirPath     := 'c:\cef';
+  GlobalCEFApp.LocalesDirPath       := 'c:\cef\locales';
+  GlobalCEFApp.SetCurrentDir        := True;
+}
+
   GlobalCEFApp.StartSubProcess;
   DestroyGlobalCEFApp;
 end.

demos/Delphi_VCL/ConsoleBrowser2/uCEFBrowserThread.pas

@@ -84,16 +84,19 @@ type
       FErrorText             : ustring;
       FFailedUrl             : ustring;
       FPendingUrl            : ustring;
+      FSyncEvents            : boolean;
 
       function  GetErrorCode : integer;
       function  GetErrorText : ustring;
       function  GetFailedUrl : ustring;
       function  GetInitialized : boolean;
 
+      procedure SetErrorText(const aValue : ustring);
+
       procedure Panel_OnResize(Sender: TObject);
 
       procedure Browser_OnAfterCreated(Sender: TObject; const browser: ICefBrowser);
-      procedure Browser_OnPaint(Sender: TObject; const browser: ICefBrowser; kind: TCefPaintElementType; dirtyRectsCount: NativeUInt; const dirtyRects: PCefRectArray; const buffer: Pointer; width, height: Integer);
+      procedure Browser_OnPaint(Sender: TObject; const browser: ICefBrowser; kind: TCefPaintElementType; dirtyRectsCount: NativeUInt; const dirtyRects: PCefRectArray; const buffer: Pointer; aWidth, aHeight: Integer);
       procedure Browser_OnGetViewRect(Sender: TObject; const browser: ICefBrowser; var rect: TCefRect);
       procedure Browser_OnGetScreenPoint(Sender: TObject; const browser: ICefBrowser; viewX, viewY: Integer; var screenX, screenY: Integer; out Result: Boolean);
       procedure Browser_OnGetScreenInfo(Sender: TObject; const browser: ICefBrowser; var screenInfo: TCefScreenInfo; out Result: Boolean);
@@ -104,13 +107,15 @@ type
       procedure Browser_OnLoadError(Sender: TObject; const browser: ICefBrowser; const frame: ICefFrame; errorCode: Integer; const errorText, failedUrl: ustring);
       procedure Browser_OnLoadingStateChange(Sender: TObject; const browser: ICefBrowser; isLoading, canGoBack, canGoForward: Boolean);
 
+      procedure DoOnError;
+      procedure DoOnSnapshotAvailable;
       procedure Resize;
       function  CreateBrowser : boolean;
-      procedure TakeSnapshot;
+      function  TakeSnapshot : boolean;
       procedure CloseBrowser;
-      procedure DoOnError;
       procedure InitError;
       procedure WebpagePostProcessing;
+      procedure WebpageError;
       procedure LoadPendingURL;
       procedure Execute; override;
 
@@ -124,9 +129,11 @@ type
       procedure   LoadUrl(const aURL : ustring);
 
       property ErrorCode             : integer           read GetErrorCode;
-      property ErrorText             : ustring           read GetErrorText;
+      property ErrorText             : ustring           read GetErrorText             write SetErrorText;
       property FailedUrl             : ustring           read GetFailedUrl;
       property Initialized           : boolean           read GetInitialized;
+      property Closing               : boolean           read FClosing;
+      property SyncEvents            : boolean           read FSyncEvents              write FSyncEvents;
 
       property OnSnapshotAvailable   : TNotifyEvent      read FOnSnapshotAvailable     write FOnSnapshotAvailable;
       property OnError               : TNotifyEvent      read FOnError                 write FOnError;
@@ -178,6 +185,7 @@ begin
   FOnSnapshotAvailable   := nil;
   FOnError               := nil;
   FClosing               := False;
+  FSyncEvents            := False;
 end;
 
 destructor TCEFBrowserThread.Destroy;
@@ -234,23 +242,41 @@ end;
 
 function TCEFBrowserThread.GetErrorCode : integer;
 begin
+  if assigned(FBrowserInfoCS) then
+    try
       FBrowserInfoCS.Acquire;
       Result := FErrorCode;
+    finally
       FBrowserInfoCS.Release;
+    end
+   else
+    Result := 0;
 end;
 
 function TCEFBrowserThread.GetErrorText : ustring;
 begin
+  if assigned(FBrowserInfoCS) then
+    try
       FBrowserInfoCS.Acquire;
       Result := FErrorText;
+    finally
       FBrowserInfoCS.Release;
+    end
+   else
+    Result := '';
 end;
 
 function TCEFBrowserThread.GetFailedUrl : ustring;
 begin
+  if assigned(FBrowserInfoCS) then
+    try
       FBrowserInfoCS.Acquire;
       Result := FFailedUrl;
+    finally
       FBrowserInfoCS.Release;
+    end
+   else
+    Result := '';
 end;
 
 function TCEFBrowserThread.GetInitialized : boolean;
@@ -266,12 +292,24 @@ begin
     end;
 end;
 
+procedure TCEFBrowserThread.SetErrorText(const aValue : ustring);
+begin
+  if assigned(FBrowserInfoCS) then
+    try
+      FBrowserInfoCS.Acquire;
+      FErrorText := aValue;
+    finally
+      FBrowserInfoCS.Release;
+    end;
+end;
+
 function TCEFBrowserThread.CopySnapshot(var aSnapshot : TBitmap) : boolean;
 begin
   Result := False;
 
-  if FClosing or Terminated or (FBrowserInfoCS = nil) then exit;
+  if FClosing or Terminated or not(Initialized) then exit;
 
+  if assigned(FBrowserInfoCS) then
     try
       try
         FBrowserInfoCS.Acquire;
@@ -283,11 +321,15 @@ begin
                 aSnapshot             := TBitmap.Create;
                 aSnapshot.PixelFormat := pf32bit;
                 aSnapshot.HandleType  := bmDIB;
-              aSnapshot.Width       := FSnapshot.Width;
-              aSnapshot.Height      := FSnapshot.Height;
               end;
 
-          aSnapshot.Assign(FSnapshot);
+            if (aSnapshot.Width <> FSnapshot.Width) then
+              aSnapshot.Width := FSnapshot.Width;
+
+            if (aSnapshot.Height <> FSnapshot.Height) then
+              aSnapshot.Height := FSnapshot.Height;
+
+            aSnapshot.Canvas.Draw(0, 0, FSnapshot);
             Result := True;
           end;
       except
@@ -303,8 +345,9 @@ function TCEFBrowserThread.SaveSnapshotToFile(const aPath : ustring) : boolean;
 begin
   Result := False;
 
-  if (FBrowserInfoCS = nil) then exit;
+  if FClosing or Terminated or not(Initialized) then exit;
 
+  if assigned(FBrowserInfoCS) and (length(aPath) > 0) then
     try
       try
         FBrowserInfoCS.Acquire;
@@ -325,10 +368,9 @@ end;
 
 procedure TCEFBrowserThread.LoadUrl(const aURL : ustring);
 begin
-  if FClosing or Terminated or (FBrowserInfoCS = nil) then
+  if FClosing or Terminated or not(Initialized) then exit;
-    exit;
 
-  if Initialized then
+  if assigned(FBrowserInfoCS) then
     try
       FBrowserInfoCS.Acquire;
       FPendingUrl := aURL;
@@ -351,12 +393,16 @@ end;
 
 procedure TCEFBrowserThread.Browser_OnAfterCreated(Sender: TObject; const browser: ICefBrowser);
 begin
+  if assigned(FBrowserInfoCS) then
+    try
       FBrowserInfoCS.Acquire;
       FInitialized := True;
+    finally
       FBrowserInfoCS.Release;
     end;
+end;
 
-procedure TCEFBrowserThread.Browser_OnPaint(Sender: TObject; const browser: ICefBrowser; kind: TCefPaintElementType; dirtyRectsCount: NativeUInt; const dirtyRects: PCefRectArray; const buffer: Pointer; width, height: Integer);
+procedure TCEFBrowserThread.Browser_OnPaint(Sender: TObject; const browser: ICefBrowser; kind: TCefPaintElementType; dirtyRectsCount: NativeUInt; const dirtyRects: PCefRectArray; const buffer: Pointer; aWidth, aHeight: Integer);
 var
   src, dst: PByte;
   i, j, TempLineSize, TempSrcOffset, TempDstOffset, SrcStride, DstStride : Integer;
@@ -366,6 +412,7 @@ var
   TempForcedResize : boolean;
   TempSrcRect : TRect;
 begin
+  if assigned(FResizeCS) and assigned(FPanel) then
     try
       FResizeCS.Acquire;
       TempForcedResize := False;
@@ -375,16 +422,16 @@ begin
           if (kind = PET_POPUP) then
             begin
               if (FPopUpBitmap = nil) or
-               (width  <> FPopUpBitmap.Width) or
+                 (aWidth  <> FPopUpBitmap.Width) or
-               (height <> FPopUpBitmap.Height) then
+                 (aHeight <> FPopUpBitmap.Height) then
                 begin
                   if (FPopUpBitmap <> nil) then FPopUpBitmap.Free;
 
                   FPopUpBitmap             := TBitmap.Create;
                   FPopUpBitmap.PixelFormat := pf32bit;
                   FPopUpBitmap.HandleType  := bmDIB;
-                FPopUpBitmap.Width       := width;
+                  FPopUpBitmap.Width       := aWidth;
-                FPopUpBitmap.Height      := height;
+                  FPopUpBitmap.Height      := aHeight;
                 end;
 
               TempWidth        := FPopUpBitmap.Width;
@@ -394,7 +441,7 @@ begin
             end
            else
             begin
-            TempForcedResize := FPanel.UpdateBufferDimensions(Width, Height) or not(FPanel.BufferIsResized(False));
+              TempForcedResize := FPanel.UpdateBufferDimensions(aWidth, aHeight) or not(FPanel.BufferIsResized(False));
               TempWidth        := FPanel.BufferWidth;
               TempHeight       := FPanel.BufferHeight;
               TempScanlineSize := FPanel.ScanlineSize;
@@ -403,7 +450,7 @@ begin
 
           if (TempBufferBits <> nil) then
             begin
-            SrcStride := Width * SizeOf(TRGBQuad);
+              SrcStride := aWidth * SizeOf(TRGBQuad);
               DstStride := - TempScanlineSize;
 
               n := 0;
@@ -416,7 +463,7 @@ begin
 
                       if (TempLineSize > 0) then
                         begin
-                        TempSrcOffset := ((dirtyRects[n].y * Width) + dirtyRects[n].x) * SizeOf(TRGBQuad);
+                          TempSrcOffset := ((dirtyRects[n].y * aWidth) + dirtyRects[n].x) * SizeOf(TRGBQuad);
                           TempDstOffset := ((TempScanlineSize * pred(TempHeight)) - (dirtyRects[n].y * TempScanlineSize)) +
                                            (dirtyRects[n].x * SizeOf(TRGBQuad));
 
@@ -467,12 +514,15 @@ begin
 end;
 
 procedure TCEFBrowserThread.Browser_OnGetViewRect(Sender: TObject; const browser: ICefBrowser; var rect: TCefRect);
+begin
+  if assigned(FPanel) then
     begin
       rect.x      := 0;
       rect.y      := 0;
       rect.width  := DeviceToLogical(FPanel.Width,  FScreenScale);
       rect.height := DeviceToLogical(FPanel.Height, FScreenScale);
     end;
+end;
 
 procedure TCEFBrowserThread.Browser_OnGetScreenPoint(Sender: TObject; const browser: ICefBrowser; viewX, viewY: Integer; var screenX, screenY: Integer; out Result: Boolean);
 begin
@@ -484,6 +534,8 @@ end;
 procedure TCEFBrowserThread.Browser_OnGetScreenInfo(Sender: TObject; const browser: ICefBrowser; var screenInfo: TCefScreenInfo; out Result: Boolean);
 var
   TempRect : TCEFRect;
+begin
+  if assigned(FPanel) then
     begin
       TempRect.x      := 0;
       TempRect.y      := 0;
@@ -499,6 +551,7 @@ begin
 
       Result := True;
     end;
+end;
 
 procedure TCEFBrowserThread.Browser_OnPopupShow(Sender: TObject; const browser: ICefBrowser; show: Boolean);
 begin
@@ -536,7 +589,7 @@ end;
 
 procedure TCEFBrowserThread.Browser_OnLoadError(Sender: TObject; const browser: ICefBrowser; const frame: ICefFrame; errorCode: Integer; const errorText, failedUrl: ustring);
 begin
-  if not(FClosing) and not(Terminated) and (frame <> nil) and frame.IsValid and frame.IsMain then
+  if not(FClosing) and not(Terminated) and (frame <> nil) and frame.IsValid and frame.IsMain and assigned(FBrowserInfoCS) then
     try
       FBrowserInfoCS.Acquire;
 
@@ -558,9 +611,9 @@ end;
 
 procedure TCEFBrowserThread.Resize;
 begin
-  if FClosing or Terminated or (FPanel = nil) or (FResizeCS = nil) or (FBrowser = nil) then
+  if FClosing or Terminated or not(Initialized) then exit;
-    exit;
 
+  if assigned(FResizeCS) and assigned(FPanel) then
     try
       FResizeCS.Acquire;
 
@@ -586,9 +639,9 @@ end;
 
 procedure TCEFBrowserThread.LoadPendingURL;
 begin
-  if FClosing or Terminated or (FBrowser = nil) or (FBrowserInfoCS = nil) then
+  if FClosing or Terminated or not(Initialized) then exit;
-    exit;
 
+  if assigned(FBrowserInfoCS) then
     try
       FBrowserInfoCS.Acquire;
 
@@ -610,31 +663,57 @@ begin
   if (FDelayMs > 0) then
     sleep(FDelayMs);
 
-  TakeSnapshot;
+  if TakeSnapshot and assigned(FOnSnapshotAvailable) then
-
+    begin
-  if assigned(FOnSnapshotAvailable) then FOnSnapshotAvailable(self);
+      if FSyncEvents then
+        Synchronize(DoOnSnapshotAvailable)
+       else
+        DoOnSnapshotAvailable;
+    end;
 end;
 
-procedure TCEFBrowserThread.TakeSnapshot;
+procedure TCEFBrowserThread.WebpageError;
 begin
-  if (FPanel = nil) or (FPanel.Buffer = nil) or (FBrowserInfoCS = nil) then
+  if not(FClosing) and not(Terminated) and assigned(FOnError) then
-    exit;
+    begin
+      if FSyncEvents then
+        Synchronize(DoOnError)
+       else
+        DoOnError;
+    end;
+end;
 
+function TCEFBrowserThread.TakeSnapshot : boolean;
+begin
+  Result := False;
+
+  if FClosing or Terminated or not(Initialized) then exit;
+
+  if assigned(FBrowserInfoCS) and assigned(FPanel) and FPanel.BeginBufferDraw then
     try
       FBrowserInfoCS.Acquire;
 
+      if assigned(FPanel.Buffer) and not(FPanel.Buffer.Empty) then
+        begin
           if (FSnapshot = nil) then
             begin
               FSnapshot             := TBitmap.Create;
               FSnapshot.PixelFormat := pf32bit;
               FSnapshot.HandleType  := bmDIB;
-        FSnapshot.Width       := FPanel.BufferWidth;
-        FSnapshot.Height      := FPanel.BufferHeight;
             end;
 
-    FSnapshot.Assign(FPanel.Buffer);
+          if (FSnapshot.Width <> FPanel.BufferWidth) then
+            FSnapshot.Width := FPanel.BufferWidth;
+
+          if (FSnapshot.Height <> FPanel.BufferHeight) then
+            FSnapshot.Height := FPanel.BufferHeight;
+
+          FSnapshot.Canvas.Draw(0, 0, FPanel.Buffer);
+          Result := True;
+        end;
     finally
       FBrowserInfoCS.Release;
+      FPanel.EndBufferDraw;
     end;
 end;
 
@@ -649,15 +728,21 @@ end;
 
 procedure TCEFBrowserThread.DoOnError;
 begin
-  if assigned(FOnError) then
   FOnError(self);
 end;
 
+procedure TCEFBrowserThread.DoOnSnapshotAvailable;
+begin
+  FOnSnapshotAvailable(self);
+end;
+
 procedure TCEFBrowserThread.InitError;
 begin
-  FBrowserInfoCS.Acquire;
+  ErrorText := 'There was an error initializing the CEF browser.';
-  FErrorText := 'There was an error initializing the CEF browser.';
+
-  FBrowserInfoCS.Release;
+  if FSyncEvents then
+    Synchronize(DoOnError)
+   else
     DoOnError;
 end;
 
@@ -678,7 +763,7 @@ begin
             CEF_CLOSE_BROWSER_MSG    : CloseBrowser;
             CEF_LOAD_PENDING_URL_MSG : LoadPendingURL;
             CEF_WEBPAGE_LOADED_MSG   : WebpagePostProcessing;
-            CEF_WEBPAGE_ERROR_MSG    : DoOnError;
+            CEF_WEBPAGE_ERROR_MSG    : WebpageError;
             WM_QUIT                  : TempCont := False;
           end;
 

demos/Delphi_VCL/ConsoleBrowser2/uEncapsulatedBrowser.pas

@@ -150,6 +150,16 @@ begin
   GlobalCEFApp.BrowserSubprocessPath      := 'ConsoleBrowser2_sp.exe'; // This is the other EXE for the CEF subprocesses. It's on the same directory as this app.
   GlobalCEFApp.BlinkSettings              := 'hideScrollbars';         // This setting removes all scrollbars to capture a cleaner snapshot
   GlobalCEFApp.OnContextInitialized       := GlobalCEFApp_OnContextInitialized;
+
+{
+  // In case you use a custom directory for the CEF binaries you have to set these properties
+  // here and in the subprocess
+  GlobalCEFApp.FrameworkDirPath     := 'c:\cef';
+  GlobalCEFApp.ResourcesDirPath     := 'c:\cef';
+  GlobalCEFApp.LocalesDirPath       := 'c:\cef\locales';
+  GlobalCEFApp.SetCurrentDir        := True;
+}
+
   GlobalCEFApp.StartMainProcess;
 end;
 
@@ -206,6 +216,7 @@ begin
   if (length(FThread.FailedUrl) > 0) then
     FErrorText := FErrorText + ' - ' + FThread.FailedUrl;
 
+  if assigned(MainAppEvent) then
     MainAppEvent.SetEvent;
 end;
 
@@ -213,9 +224,10 @@ procedure TEncapsulatedBrowser.Thread_OnSnapshotAvailable(Sender: TObject);
 begin
   // This code is executed in the TCEFBrowserThread thread context while the main application thread is waiting for MainAppEvent.
 
-  if not(FThread.SaveSnapshotToFile(FSnapshotPath)) then
+  if (FThread = nil) or not(FThread.SaveSnapshotToFile(FSnapshotPath)) then
     FErrorText := 'There was an error copying the snapshot';
 
+  if assigned(MainAppEvent) then
     MainAppEvent.SetEvent;
 end;
 

demos/Delphi_VCL/WebpageSnapshot/uCEFBrowserThread.pas

@@ -84,16 +84,19 @@ type
       FErrorText             : ustring;
       FFailedUrl             : ustring;
       FPendingUrl            : ustring;
+      FSyncEvents            : boolean;
 
       function  GetErrorCode : integer;
       function  GetErrorText : ustring;
       function  GetFailedUrl : ustring;
       function  GetInitialized : boolean;
 
+      procedure SetErrorText(const aValue : ustring);
+
       procedure Panel_OnResize(Sender: TObject);
 
       procedure Browser_OnAfterCreated(Sender: TObject; const browser: ICefBrowser);
-      procedure Browser_OnPaint(Sender: TObject; const browser: ICefBrowser; kind: TCefPaintElementType; dirtyRectsCount: NativeUInt; const dirtyRects: PCefRectArray; const buffer: Pointer; width, height: Integer);
+      procedure Browser_OnPaint(Sender: TObject; const browser: ICefBrowser; kind: TCefPaintElementType; dirtyRectsCount: NativeUInt; const dirtyRects: PCefRectArray; const buffer: Pointer; aWidth, aHeight: Integer);
       procedure Browser_OnGetViewRect(Sender: TObject; const browser: ICefBrowser; var rect: TCefRect);
       procedure Browser_OnGetScreenPoint(Sender: TObject; const browser: ICefBrowser; viewX, viewY: Integer; var screenX, screenY: Integer; out Result: Boolean);
       procedure Browser_OnGetScreenInfo(Sender: TObject; const browser: ICefBrowser; var screenInfo: TCefScreenInfo; out Result: Boolean);
@@ -108,9 +111,11 @@ type
       procedure DoOnSnapshotAvailable;
       procedure Resize;
       function  CreateBrowser : boolean;
-      procedure TakeSnapshot;
+      function  TakeSnapshot : boolean;
       procedure CloseBrowser;
+      procedure InitError;
       procedure WebpagePostProcessing;
+      procedure WebpageError;
       procedure LoadPendingURL;
       procedure Execute; override;
 
@@ -120,12 +125,15 @@ type
       procedure   AfterConstruction; override;
       function    TerminateBrowserThread : boolean;
       function    CopySnapshot(var aSnapshot : TBitmap) : boolean;
+      function    SaveSnapshotToFile(const aPath : ustring) : boolean;
       procedure   LoadUrl(const aURL : ustring);
 
       property ErrorCode             : integer           read GetErrorCode;
-      property ErrorText             : ustring           read GetErrorText;
+      property ErrorText             : ustring           read GetErrorText             write SetErrorText;
       property FailedUrl             : ustring           read GetFailedUrl;
       property Initialized           : boolean           read GetInitialized;
+      property Closing               : boolean           read FClosing;
+      property SyncEvents            : boolean           read FSyncEvents              write FSyncEvents;
 
       property OnSnapshotAvailable   : TNotifyEvent      read FOnSnapshotAvailable     write FOnSnapshotAvailable;
       property OnError               : TNotifyEvent      read FOnError                 write FOnError;
@@ -177,6 +185,7 @@ begin
   FOnSnapshotAvailable   := nil;
   FOnError               := nil;
   FClosing               := False;
+  FSyncEvents            := False;
 end;
 
 destructor TCEFBrowserThread.Destroy;
@@ -233,23 +242,41 @@ end;
 
 function TCEFBrowserThread.GetErrorCode : integer;
 begin
+  if assigned(FBrowserInfoCS) then
+    try
       FBrowserInfoCS.Acquire;
       Result := FErrorCode;
+    finally
       FBrowserInfoCS.Release;
+    end
+   else
+    Result := 0;
 end;
 
 function TCEFBrowserThread.GetErrorText : ustring;
 begin
+  if assigned(FBrowserInfoCS) then
+    try
       FBrowserInfoCS.Acquire;
       Result := FErrorText;
+    finally
       FBrowserInfoCS.Release;
+    end
+   else
+    Result := '';
 end;
 
 function TCEFBrowserThread.GetFailedUrl : ustring;
 begin
+  if assigned(FBrowserInfoCS) then
+    try
       FBrowserInfoCS.Acquire;
       Result := FFailedUrl;
+    finally
       FBrowserInfoCS.Release;
+    end
+   else
+    Result := '';
 end;
 
 function TCEFBrowserThread.GetInitialized : boolean;
@@ -265,12 +292,24 @@ begin
     end;
 end;
 
+procedure TCEFBrowserThread.SetErrorText(const aValue : ustring);
+begin
+  if assigned(FBrowserInfoCS) then
+    try
+      FBrowserInfoCS.Acquire;
+      FErrorText := aValue;
+    finally
+      FBrowserInfoCS.Release;
+    end;
+end;
+
 function TCEFBrowserThread.CopySnapshot(var aSnapshot : TBitmap) : boolean;
 begin
   Result := False;
 
-  if FClosing or Terminated or (FBrowserInfoCS = nil) then exit;
+  if FClosing or Terminated or not(Initialized) then exit;
 
+  if assigned(FBrowserInfoCS) then
     try
       try
         FBrowserInfoCS.Acquire;
@@ -282,11 +321,15 @@ begin
                 aSnapshot             := TBitmap.Create;
                 aSnapshot.PixelFormat := pf32bit;
                 aSnapshot.HandleType  := bmDIB;
-              aSnapshot.Width       := FSnapshot.Width;
-              aSnapshot.Height      := FSnapshot.Height;
               end;
 
-          aSnapshot.Assign(FSnapshot);
+            if (aSnapshot.Width <> FSnapshot.Width) then
+              aSnapshot.Width := FSnapshot.Width;
+
+            if (aSnapshot.Height <> FSnapshot.Height) then
+              aSnapshot.Height := FSnapshot.Height;
+
+            aSnapshot.Canvas.Draw(0, 0, FSnapshot);
             Result := True;
           end;
       except
@@ -298,12 +341,36 @@ begin
     end;
 end;
 
+function TCEFBrowserThread.SaveSnapshotToFile(const aPath : ustring) : boolean;
+begin
+  Result := False;
+
+  if FClosing or Terminated or not(Initialized) then exit;
+
+  if assigned(FBrowserInfoCS) and (length(aPath) > 0) then
+    try
+      try
+        FBrowserInfoCS.Acquire;
+
+        if assigned(FSnapshot) and not(FSnapshot.Empty) then
+          begin
+            FSnapshot.SaveToFile(aPath);
+            Result := True;
+          end;
+      except
+        on e : exception do
+          if CustomExceptionHandler('TCEFBrowserThread.SaveSnapshotToFile', e) then raise;
+      end;
+    finally
+      FBrowserInfoCS.Release;
+    end;
+end;
+
 procedure TCEFBrowserThread.LoadUrl(const aURL : ustring);
 begin
-  if FClosing or Terminated or (FBrowserInfoCS = nil) then
+  if FClosing or Terminated or not(Initialized) then exit;
-    exit;
 
-  if Initialized then
+  if assigned(FBrowserInfoCS) then
     try
       FBrowserInfoCS.Acquire;
       FPendingUrl := aURL;
@@ -326,12 +393,16 @@ end;
 
 procedure TCEFBrowserThread.Browser_OnAfterCreated(Sender: TObject; const browser: ICefBrowser);
 begin
+  if assigned(FBrowserInfoCS) then
+    try
       FBrowserInfoCS.Acquire;
       FInitialized := True;
+    finally
       FBrowserInfoCS.Release;
     end;
+end;
 
-procedure TCEFBrowserThread.Browser_OnPaint(Sender: TObject; const browser: ICefBrowser; kind: TCefPaintElementType; dirtyRectsCount: NativeUInt; const dirtyRects: PCefRectArray; const buffer: Pointer; width, height: Integer);
+procedure TCEFBrowserThread.Browser_OnPaint(Sender: TObject; const browser: ICefBrowser; kind: TCefPaintElementType; dirtyRectsCount: NativeUInt; const dirtyRects: PCefRectArray; const buffer: Pointer; aWidth, aHeight: Integer);
 var
   src, dst: PByte;
   i, j, TempLineSize, TempSrcOffset, TempDstOffset, SrcStride, DstStride : Integer;
@@ -341,6 +412,7 @@ var
   TempForcedResize : boolean;
   TempSrcRect : TRect;
 begin
+  if assigned(FResizeCS) and assigned(FPanel) then
     try
       FResizeCS.Acquire;
       TempForcedResize := False;
@@ -350,16 +422,16 @@ begin
           if (kind = PET_POPUP) then
             begin
               if (FPopUpBitmap = nil) or
-               (width  <> FPopUpBitmap.Width) or
+                 (aWidth  <> FPopUpBitmap.Width) or
-               (height <> FPopUpBitmap.Height) then
+                 (aHeight <> FPopUpBitmap.Height) then
                 begin
                   if (FPopUpBitmap <> nil) then FPopUpBitmap.Free;
 
                   FPopUpBitmap             := TBitmap.Create;
                   FPopUpBitmap.PixelFormat := pf32bit;
                   FPopUpBitmap.HandleType  := bmDIB;
-                FPopUpBitmap.Width       := width;
+                  FPopUpBitmap.Width       := aWidth;
-                FPopUpBitmap.Height      := height;
+                  FPopUpBitmap.Height      := aHeight;
                 end;
 
               TempWidth        := FPopUpBitmap.Width;
@@ -369,7 +441,7 @@ begin
             end
            else
             begin
-            TempForcedResize := FPanel.UpdateBufferDimensions(Width, Height) or not(FPanel.BufferIsResized(False));
+              TempForcedResize := FPanel.UpdateBufferDimensions(aWidth, aHeight) or not(FPanel.BufferIsResized(False));
               TempWidth        := FPanel.BufferWidth;
               TempHeight       := FPanel.BufferHeight;
               TempScanlineSize := FPanel.ScanlineSize;
@@ -378,7 +450,7 @@ begin
 
           if (TempBufferBits <> nil) then
             begin
-            SrcStride := Width * SizeOf(TRGBQuad);
+              SrcStride := aWidth * SizeOf(TRGBQuad);
               DstStride := - TempScanlineSize;
 
               n := 0;
@@ -391,7 +463,7 @@ begin
 
                       if (TempLineSize > 0) then
                         begin
-                        TempSrcOffset := ((dirtyRects[n].y * Width) + dirtyRects[n].x) * SizeOf(TRGBQuad);
+                          TempSrcOffset := ((dirtyRects[n].y * aWidth) + dirtyRects[n].x) * SizeOf(TRGBQuad);
                           TempDstOffset := ((TempScanlineSize * pred(TempHeight)) - (dirtyRects[n].y * TempScanlineSize)) +
                                            (dirtyRects[n].x * SizeOf(TRGBQuad));
 
@@ -426,11 +498,11 @@ begin
             end;
 
           FPanel.EndBufferDraw;
-        FPanel.InvalidatePanel;
 
           if (kind = PET_VIEW) then
             begin
-            if TempForcedResize or FPendingResize then PostThreadMessage(ThreadID, CEF_PENDINGRESIZE, 0, 0);
+              if TempForcedResize or FPendingResize then
+                PostThreadMessage(ThreadID, CEF_PENDINGRESIZE, 0, 0);
 
               FResizing      := False;
               FPendingResize := False;
@@ -442,12 +514,15 @@ begin
 end;
 
 procedure TCEFBrowserThread.Browser_OnGetViewRect(Sender: TObject; const browser: ICefBrowser; var rect: TCefRect);
+begin
+  if assigned(FPanel) then
     begin
       rect.x      := 0;
       rect.y      := 0;
       rect.width  := DeviceToLogical(FPanel.Width,  FScreenScale);
       rect.height := DeviceToLogical(FPanel.Height, FScreenScale);
     end;
+end;
 
 procedure TCEFBrowserThread.Browser_OnGetScreenPoint(Sender: TObject; const browser: ICefBrowser; viewX, viewY: Integer; var screenX, screenY: Integer; out Result: Boolean);
 begin
@@ -459,6 +534,8 @@ end;
 procedure TCEFBrowserThread.Browser_OnGetScreenInfo(Sender: TObject; const browser: ICefBrowser; var screenInfo: TCefScreenInfo; out Result: Boolean);
 var
   TempRect : TCEFRect;
+begin
+  if assigned(FPanel) then
     begin
       TempRect.x      := 0;
       TempRect.y      := 0;
@@ -474,6 +551,7 @@ begin
 
       Result := True;
     end;
+end;
 
 procedure TCEFBrowserThread.Browser_OnPopupShow(Sender: TObject; const browser: ICefBrowser; show: Boolean);
 begin
@@ -511,7 +589,7 @@ end;
 
 procedure TCEFBrowserThread.Browser_OnLoadError(Sender: TObject; const browser: ICefBrowser; const frame: ICefFrame; errorCode: Integer; const errorText, failedUrl: ustring);
 begin
-  if not(FClosing) and not(Terminated) and (frame <> nil) and frame.IsValid and frame.IsMain then
+  if not(FClosing) and not(Terminated) and (frame <> nil) and frame.IsValid and frame.IsMain and assigned(FBrowserInfoCS) then
     try
       FBrowserInfoCS.Acquire;
 
@@ -531,21 +609,11 @@ begin
     PostThreadMessage(ThreadID, CEF_WEBPAGE_LOADED_MSG, 0, 0);
 end;
 
-procedure TCEFBrowserThread.DoOnError;
-begin
-  FOnError(self);
-end;
-
-procedure TCEFBrowserThread.DoOnSnapshotAvailable;
-begin
-  FOnSnapshotAvailable(self);
-end;
-
 procedure TCEFBrowserThread.Resize;
 begin
-  if FClosing or Terminated or (FPanel = nil) or (FResizeCS = nil) or (FBrowser = nil) then
+  if FClosing or Terminated or not(Initialized) then exit;
-    exit;
 
+  if assigned(FResizeCS) and assigned(FPanel) then
     try
       FResizeCS.Acquire;
 
@@ -571,9 +639,9 @@ end;
 
 procedure TCEFBrowserThread.LoadPendingURL;
 begin
-  if FClosing or Terminated or (FBrowser = nil) or (FBrowserInfoCS = nil) then
+  if FClosing or Terminated or not(Initialized) then exit;
-    exit;
 
+  if assigned(FBrowserInfoCS) then
     try
       FBrowserInfoCS.Acquire;
 
@@ -595,32 +663,57 @@ begin
   if (FDelayMs > 0) then
     sleep(FDelayMs);
 
-  TakeSnapshot;
+  if TakeSnapshot and assigned(FOnSnapshotAvailable) then
-
+    begin
-  if assigned(FOnSnapshotAvailable) then
+      if FSyncEvents then
-    Synchronize(DoOnSnapshotAvailable);
+        Synchronize(DoOnSnapshotAvailable)
+       else
+        DoOnSnapshotAvailable;
+    end;
 end;
 
-procedure TCEFBrowserThread.TakeSnapshot;
+procedure TCEFBrowserThread.WebpageError;
 begin
-  if (FPanel = nil) or (FPanel.Buffer = nil) or (FBrowserInfoCS = nil) then
+  if not(FClosing) and not(Terminated) and assigned(FOnError) then
-    exit;
+    begin
+      if FSyncEvents then
+        Synchronize(DoOnError)
+       else
+        DoOnError;
+    end;
+end;
 
+function TCEFBrowserThread.TakeSnapshot : boolean;
+begin
+  Result := False;
+
+  if FClosing or Terminated or not(Initialized) then exit;
+
+  if assigned(FBrowserInfoCS) and assigned(FPanel) and FPanel.BeginBufferDraw then
     try
       FBrowserInfoCS.Acquire;
 
+      if assigned(FPanel.Buffer) and not(FPanel.Buffer.Empty) then
+        begin
           if (FSnapshot = nil) then
             begin
               FSnapshot             := TBitmap.Create;
               FSnapshot.PixelFormat := pf32bit;
               FSnapshot.HandleType  := bmDIB;
-        FSnapshot.Width       := FPanel.BufferWidth;
-        FSnapshot.Height      := FPanel.BufferHeight;
             end;
 
-    FSnapshot.Assign(FPanel.Buffer);
+          if (FSnapshot.Width <> FPanel.BufferWidth) then
+            FSnapshot.Width := FPanel.BufferWidth;
+
+          if (FSnapshot.Height <> FPanel.BufferHeight) then
+            FSnapshot.Height := FPanel.BufferHeight;
+
+          FSnapshot.Canvas.Draw(0, 0, FPanel.Buffer);
+          Result := True;
+        end;
     finally
       FBrowserInfoCS.Release;
+      FPanel.EndBufferDraw;
     end;
 end;
 
@@ -633,6 +726,26 @@ begin
     end;
 end;
 
+procedure TCEFBrowserThread.DoOnError;
+begin
+  FOnError(self);
+end;
+
+procedure TCEFBrowserThread.DoOnSnapshotAvailable;
+begin
+  FOnSnapshotAvailable(self);
+end;
+
+procedure TCEFBrowserThread.InitError;
+begin
+  ErrorText := 'There was an error initializing the CEF browser.';
+
+  if FSyncEvents then
+    Synchronize(DoOnError)
+   else
+    DoOnError;
+end;
+
 procedure TCEFBrowserThread.Execute;
 var
   TempCont : boolean;
@@ -646,17 +759,19 @@ begin
       while TempCont and GetMessage(TempMsg, 0, 0, 0) and not(Terminated) do
         begin
           case TempMsg.Message of
-            WM_QUIT                  : TempCont := False;
             CEF_PENDINGRESIZE        : Resize;
             CEF_CLOSE_BROWSER_MSG    : CloseBrowser;
             CEF_LOAD_PENDING_URL_MSG : LoadPendingURL;
             CEF_WEBPAGE_LOADED_MSG   : WebpagePostProcessing;
-            CEF_WEBPAGE_ERROR_MSG    : if assigned(FOnError) then Synchronize(DoOnError);
+            CEF_WEBPAGE_ERROR_MSG    : WebpageError;
+            WM_QUIT                  : TempCont := False;
           end;
 
           DispatchMessage(TempMsg);
         end;
-    end;
+    end
+   else
+    InitError;
 end;
 
 end.

demos/Delphi_VCL/WebpageSnapshot/uWebpageSnapshot.pas

@@ -115,6 +115,7 @@ begin
       FThread                     := TCEFBrowserThread.Create(AddressEdt.Text, 1024, 768);
       FThread.OnError             := Thread_OnError;
       FThread.OnSnapshotAvailable := Thread_OnSnapshotAvailable;
+      FThread.SyncEvents          := True;
       FThread.Start;
     end
    else

demos/Lazarus_Windows/ConsoleBrowser2/ConsoleBrowser2.lps

@@ -8,9 +8,8 @@
       <Unit0>
         <Filename Value="ConsoleBrowser2.lpr"/>
         <IsPartOfProject Value="True"/>
-        <IsVisibleTab Value="True"/>
+        <TopLine Value="83"/>
-        <TopLine Value="37"/>
+        <CursorPos X="45" Y="84"/>
-        <CursorPos X="101" Y="71"/>
         <UsageCount Value="20"/>
         <Loaded Value="True"/>
         <DefaultSyntaxHighlighter Value="Delphi"/>
@@ -18,10 +17,12 @@
       <Unit1>
         <Filename Value="uEncapsulatedBrowser.pas"/>
         <IsPartOfProject Value="True"/>
-        <EditorIndex Value="-1"/>
+        <IsVisibleTab Value="True"/>
-        <TopLine Value="203"/>
+        <EditorIndex Value="1"/>
-        <CursorPos X="31" Y="225"/>
+        <TopLine Value="141"/>
+        <CursorPos X="3" Y="222"/>
         <UsageCount Value="20"/>
+        <Loaded Value="True"/>
         <DefaultSyntaxHighlighter Value="Delphi"/>
       </Unit1>
       <Unit2>

demos/Lazarus_Windows/ConsoleBrowser2/uCEFBrowserThread.pas

@@ -10,7 +10,7 @@
 // For more information about CEF4Delphi visit :
 //         https://www.briskbard.com/index.php?lang=en&pageid=cef
 //
-//        Copyright © 2020 Salvador Diaz Fau. All rights reserved.
+//        Copyright � 2020 Salvador Diaz Fau. All rights reserved.
 //
 // ************************************************************************
 // ************ vvvv Original license and comments below vvvv *************
@@ -86,12 +86,15 @@ type
       FErrorText             : ustring;
       FFailedUrl             : ustring;
       FPendingUrl            : ustring;
+      FSyncEvents            : boolean;
 
       function  GetErrorCode : integer;
       function  GetErrorText : ustring;
       function  GetFailedUrl : ustring;
       function  GetInitialized : boolean;
 
+      procedure SetErrorText(const aValue : ustring);
+
       procedure Panel_OnResize(Sender: TObject);
 
       procedure Browser_OnAfterCreated(Sender: TObject; const browser: ICefBrowser);
@@ -106,13 +109,15 @@ type
       procedure Browser_OnLoadError(Sender: TObject; const browser: ICefBrowser; const frame: ICefFrame; errorCode: Integer; const errorText, failedUrl: ustring);
       procedure Browser_OnLoadingStateChange(Sender: TObject; const browser: ICefBrowser; isLoading, canGoBack, canGoForward: Boolean);
 
+      procedure DoOnError;
+      procedure DoOnSnapshotAvailable;
       procedure Resize;
       function  CreateBrowser : boolean;
-      procedure TakeSnapshot;
+      function  TakeSnapshot : boolean;
       procedure CloseBrowser;
-      procedure DoOnError;
       procedure InitError;
       procedure WebpagePostProcessing;
+      procedure WebpageError;
       procedure LoadPendingURL;
       procedure Execute; override;
 
@@ -126,9 +131,11 @@ type
       procedure   LoadUrl(const aURL : ustring);
 
       property ErrorCode             : integer           read GetErrorCode;
-      property ErrorText             : ustring           read GetErrorText;
+      property ErrorText             : ustring           read GetErrorText             write SetErrorText;
       property FailedUrl             : ustring           read GetFailedUrl;
       property Initialized           : boolean           read GetInitialized;
+      property Closing               : boolean           read FClosing;
+      property SyncEvents            : boolean           read FSyncEvents              write FSyncEvents;
 
       property OnSnapshotAvailable   : TNotifyEvent      read FOnSnapshotAvailable     write FOnSnapshotAvailable;
       property OnError               : TNotifyEvent      read FOnError                 write FOnError;
@@ -180,6 +187,7 @@ begin
   FOnSnapshotAvailable   := nil;
   FOnError               := nil;
   FClosing               := False;
+  FSyncEvents            := False;
 end;
 
 destructor TCEFBrowserThread.Destroy;
@@ -236,23 +244,41 @@ end;
 
 function TCEFBrowserThread.GetErrorCode : integer;
 begin
+  if assigned(FBrowserInfoCS) then
+    try
       FBrowserInfoCS.Acquire;
       Result := FErrorCode;
+    finally
       FBrowserInfoCS.Release;
+    end
+   else
+    Result := 0;
 end;
 
 function TCEFBrowserThread.GetErrorText : ustring;
 begin
+  if assigned(FBrowserInfoCS) then
+    try
       FBrowserInfoCS.Acquire;
       Result := FErrorText;
+    finally
       FBrowserInfoCS.Release;
+    end
+   else
+    Result := '';
 end;
 
 function TCEFBrowserThread.GetFailedUrl : ustring;
 begin
+  if assigned(FBrowserInfoCS) then
+    try
       FBrowserInfoCS.Acquire;
       Result := FFailedUrl;
+    finally
       FBrowserInfoCS.Release;
+    end
+   else
+    Result := '';
 end;
 
 function TCEFBrowserThread.GetInitialized : boolean;
@@ -268,12 +294,24 @@ begin
     end;
 end;
 
+procedure TCEFBrowserThread.SetErrorText(const aValue : ustring);
+begin
+  if assigned(FBrowserInfoCS) then
+    try
+      FBrowserInfoCS.Acquire;
+      FErrorText := aValue;
+    finally
+      FBrowserInfoCS.Release;
+    end;
+end;
+
 function TCEFBrowserThread.CopySnapshot(var aSnapshot : TBitmap) : boolean;
 begin
   Result := False;
 
-  if FClosing or Terminated or (FBrowserInfoCS = nil) then exit;
+  if FClosing or Terminated or not(Initialized) then exit;
 
+  if assigned(FBrowserInfoCS) then
     try
       try
         FBrowserInfoCS.Acquire;
@@ -285,11 +323,15 @@ begin
                 aSnapshot             := TBitmap.Create;
                 aSnapshot.PixelFormat := pf32bit;
                 aSnapshot.HandleType  := bmDIB;
-              aSnapshot.Width       := FSnapshot.Width;
-              aSnapshot.Height      := FSnapshot.Height;
               end;
 
-          aSnapshot.Assign(FSnapshot);
+            if (aSnapshot.Width <> FSnapshot.Width) then
+              aSnapshot.Width := FSnapshot.Width;
+
+            if (aSnapshot.Height <> FSnapshot.Height) then
+              aSnapshot.Height := FSnapshot.Height;
+
+            aSnapshot.Canvas.Draw(0, 0, FSnapshot);
             Result := True;
           end;
       except
@@ -305,8 +347,9 @@ function TCEFBrowserThread.SaveSnapshotToFile(const aPath : ustring) : boolean;
 begin
   Result := False;
 
-  if (FBrowserInfoCS = nil) then exit;
+  if FClosing or Terminated or not(Initialized) then exit;
 
+  if assigned(FBrowserInfoCS) and (length(aPath) > 0) then
     try
       try
         FBrowserInfoCS.Acquire;
@@ -327,10 +370,9 @@ end;
 
 procedure TCEFBrowserThread.LoadUrl(const aURL : ustring);
 begin
-  if FClosing or Terminated or (FBrowserInfoCS = nil) then
+  if FClosing or Terminated or not(Initialized) then exit;
-    exit;
 
-  if Initialized then
+  if assigned(FBrowserInfoCS) then
     try
       FBrowserInfoCS.Acquire;
       FPendingUrl := aURL;
@@ -353,10 +395,14 @@ end;
 
 procedure TCEFBrowserThread.Browser_OnAfterCreated(Sender: TObject; const browser: ICefBrowser);
 begin
+  if assigned(FBrowserInfoCS) then
+    try
       FBrowserInfoCS.Acquire;
       FInitialized := True;
+    finally
       FBrowserInfoCS.Release;
     end;
+end;
 
 procedure TCEFBrowserThread.Browser_OnPaint(Sender: TObject; const browser: ICefBrowser; kind: TCefPaintElementType; dirtyRectsCount: NativeUInt; const dirtyRects: PCefRectArray; const buffer: Pointer; aWidth, aHeight: Integer);
 var
@@ -369,6 +415,7 @@ var
   TempBitmap : TBitmap;
   TempSrcRect : TRect;
 begin
+  if assigned(FResizeCS) and assigned(FPanel) then
     try
       FResizeCS.Acquire;
       TempForcedResize := False;
@@ -470,12 +517,15 @@ begin
 end;
 
 procedure TCEFBrowserThread.Browser_OnGetViewRect(Sender: TObject; const browser: ICefBrowser; var rect: TCefRect);
+begin
+  if assigned(FPanel) then
     begin
       rect.x      := 0;
       rect.y      := 0;
       rect.width  := DeviceToLogical(FPanel.Width,  FScreenScale);
       rect.height := DeviceToLogical(FPanel.Height, FScreenScale);
     end;
+end;
 
 procedure TCEFBrowserThread.Browser_OnGetScreenPoint(Sender: TObject; const browser: ICefBrowser; viewX, viewY: Integer; var screenX, screenY: Integer; out Result: Boolean);
 begin
@@ -487,6 +537,8 @@ end;
 procedure TCEFBrowserThread.Browser_OnGetScreenInfo(Sender: TObject; const browser: ICefBrowser; var screenInfo: TCefScreenInfo; out Result: Boolean);
 var
   TempRect : TCEFRect;
+begin
+  if assigned(FPanel) then
     begin
       TempRect.x      := 0;
       TempRect.y      := 0;
@@ -502,6 +554,7 @@ begin
 
       Result := True;
     end;
+end;
 
 procedure TCEFBrowserThread.Browser_OnPopupShow(Sender: TObject; const browser: ICefBrowser; show: Boolean);
 begin
@@ -539,7 +592,7 @@ end;
 
 procedure TCEFBrowserThread.Browser_OnLoadError(Sender: TObject; const browser: ICefBrowser; const frame: ICefFrame; errorCode: Integer; const errorText, failedUrl: ustring);
 begin
-  if not(FClosing) and not(Terminated) and (frame <> nil) and frame.IsValid and frame.IsMain then
+  if not(FClosing) and not(Terminated) and (frame <> nil) and frame.IsValid and frame.IsMain and assigned(FBrowserInfoCS) then
     try
       FBrowserInfoCS.Acquire;
 
@@ -561,9 +614,9 @@ end;
 
 procedure TCEFBrowserThread.Resize;
 begin
-  if FClosing or Terminated or (FPanel = nil) or (FResizeCS = nil) or (FBrowser = nil) then
+  if FClosing or Terminated or not(Initialized) then exit;
-    exit;
 
+  if assigned(FResizeCS) and assigned(FPanel) then
     try
       FResizeCS.Acquire;
 
@@ -589,9 +642,9 @@ end;
 
 procedure TCEFBrowserThread.LoadPendingURL;
 begin
-  if FClosing or Terminated or (FBrowser = nil) or (FBrowserInfoCS = nil) then
+  if FClosing or Terminated or not(Initialized) then exit;
-    exit;
 
+  if assigned(FBrowserInfoCS) then
     try
       FBrowserInfoCS.Acquire;
 
@@ -613,31 +666,57 @@ begin
   if (FDelayMs > 0) then
     sleep(FDelayMs);
 
-  TakeSnapshot;
+  if TakeSnapshot and assigned(FOnSnapshotAvailable) then
-
+    begin
-  if assigned(FOnSnapshotAvailable) then FOnSnapshotAvailable(self);
+      if FSyncEvents then
+        Synchronize(DoOnSnapshotAvailable)
+       else
+        DoOnSnapshotAvailable;
+    end;
 end;
 
-procedure TCEFBrowserThread.TakeSnapshot;
+procedure TCEFBrowserThread.WebpageError;
 begin
-  if (FPanel = nil) or (FPanel.Buffer = nil) or (FBrowserInfoCS = nil) then
+  if not(FClosing) and not(Terminated) and assigned(FOnError) then
-    exit;
+    begin
+      if FSyncEvents then
+        Synchronize(DoOnError)
+       else
+        DoOnError;
+    end;
+end;
 
+function TCEFBrowserThread.TakeSnapshot : boolean;
+begin
+  Result := False;
+
+  if FClosing or Terminated or not(Initialized) then exit;
+
+  if assigned(FBrowserInfoCS) and assigned(FPanel) and FPanel.BeginBufferDraw then
     try
       FBrowserInfoCS.Acquire;
 
+      if assigned(FPanel.Buffer) and not(FPanel.Buffer.Empty) then
+        begin
           if (FSnapshot = nil) then
             begin
               FSnapshot             := TBitmap.Create;
               FSnapshot.PixelFormat := pf32bit;
               FSnapshot.HandleType  := bmDIB;
-        FSnapshot.Width       := FPanel.BufferWidth;
-        FSnapshot.Height      := FPanel.BufferHeight;
             end;
 
-    FSnapshot.Assign(FPanel.Buffer);
+          if (FSnapshot.Width <> FPanel.BufferWidth) then
+            FSnapshot.Width := FPanel.BufferWidth;
+
+          if (FSnapshot.Height <> FPanel.BufferHeight) then
+            FSnapshot.Height := FPanel.BufferHeight;
+
+          FSnapshot.Canvas.Draw(0, 0, FPanel.Buffer);
+          Result := True;
+        end;
     finally
       FBrowserInfoCS.Release;
+      FPanel.EndBufferDraw;
     end;
 end;
 
@@ -652,15 +731,21 @@ end;
 
 procedure TCEFBrowserThread.DoOnError;
 begin
-  if assigned(FOnError) then
   FOnError(self);
 end;
 
+procedure TCEFBrowserThread.DoOnSnapshotAvailable;
+begin
+  FOnSnapshotAvailable(self);
+end;
+
 procedure TCEFBrowserThread.InitError;
 begin
-  FBrowserInfoCS.Acquire;
+  ErrorText := 'There was an error initializing the CEF browser.';
-  FErrorText := 'There was an error initializing the CEF browser.';
+
-  FBrowserInfoCS.Release;
+  if FSyncEvents then
+    Synchronize(DoOnError)
+   else
     DoOnError;
 end;
 
@@ -681,7 +766,7 @@ begin
             CEF_CLOSE_BROWSER_MSG    : CloseBrowser;
             CEF_LOAD_PENDING_URL_MSG : LoadPendingURL;
             CEF_WEBPAGE_LOADED_MSG   : WebpagePostProcessing;
-            CEF_WEBPAGE_ERROR_MSG    : DoOnError;
+            CEF_WEBPAGE_ERROR_MSG    : WebpageError;
             WM_QUIT                  : TempCont := False;
           end;
 

demos/Lazarus_Windows/ConsoleBrowser2/uEncapsulatedBrowser.pas

@@ -152,6 +152,16 @@ begin
   GlobalCEFApp.BrowserSubprocessPath      := 'ConsoleBrowser2_sp.exe'; // This is the other EXE for the CEF subprocesses. It's on the same directory as this app.
   GlobalCEFApp.BlinkSettings              := 'hideScrollbars';         // This setting removes all scrollbars to capture a cleaner snapshot
   GlobalCEFApp.OnContextInitialized       := GlobalCEFApp_OnContextInitialized;
+
+  {
+    // In case you use a custom directory for the CEF binaries you have to set these properties
+    // here and in the subprocess
+    GlobalCEFApp.FrameworkDirPath     := 'c:\cef';
+    GlobalCEFApp.ResourcesDirPath     := 'c:\cef';
+    GlobalCEFApp.LocalesDirPath       := 'c:\cef\locales';
+    GlobalCEFApp.SetCurrentDir        := True;
+  }
+
   GlobalCEFApp.StartMainProcess;
 end;
 
@@ -208,6 +218,7 @@ begin
   if (length(FThread.FailedUrl) > 0) then
     FErrorText := FErrorText + ' - ' + FThread.FailedUrl;
 
+  if assigned(MainAppEvent) then
     MainAppEvent.SetEvent;
 end;
 
@@ -215,9 +226,10 @@ procedure TEncapsulatedBrowser.Thread_OnSnapshotAvailable(Sender: TObject);
 begin
   // This code is executed in the TCEFBrowserThread thread context while the main application thread is waiting for MainAppEvent.
 
-  if not(FThread.SaveSnapshotToFile(FSnapshotPath)) then
+  if (FThread = nil) or not(FThread.SaveSnapshotToFile(FSnapshotPath)) then
     FErrorText := 'There was an error copying the snapshot';
 
+  if assigned(MainAppEvent) then
     MainAppEvent.SetEvent;
 end;
 

demos/Lazarus_Windows/WebpageSnapshot/WebpageSnapshot.lpi

@@ -47,7 +47,9 @@
       <Unit2>
         <Filename Value="uWebpageSnapshot.pas"/>
         <IsPartOfProject Value="True"/>
+        <ComponentName Value="WebpageSnapshotFrm"/>
         <HasResources Value="True"/>
+        <ResourceBaseClass Value="Form"/>
       </Unit2>
     </Units>
   </ProjectOptions>

demos/Lazarus_Windows/WebpageSnapshot/WebpageSnapshot.lps

@@ -4,12 +4,12 @@
     <PathDelim Value="\"/>
     <Version Value="11"/>
     <BuildModes Active="Default"/>
-    <Units Count="6">
+    <Units Count="8">
       <Unit0>
         <Filename Value="WebpageSnapshot.lpr"/>
         <IsPartOfProject Value="True"/>
         <TopLine Value="45"/>
-        <CursorPos X="37" Y="58"/>
+        <CursorPos Y="73"/>
         <UsageCount Value="23"/>
         <Loaded Value="True"/>
         <DefaultSyntaxHighlighter Value="Delphi"/>
@@ -18,9 +18,9 @@
         <Filename Value="uCEFBrowserThread.pas"/>
         <IsPartOfProject Value="True"/>
         <IsVisibleTab Value="True"/>
-        <EditorIndex Value="1"/>
+        <EditorIndex Value="2"/>
-        <TopLine Value="637"/>
+        <TopLine Value="471"/>
-        <CursorPos X="70" Y="657"/>
+        <CursorPos X="66" Y="483"/>
         <UsageCount Value="23"/>
         <Loaded Value="True"/>
         <DefaultSyntaxHighlighter Value="Delphi"/>
@@ -28,11 +28,14 @@
       <Unit2>
         <Filename Value="uWebpageSnapshot.pas"/>
         <IsPartOfProject Value="True"/>
+        <ComponentName Value="WebpageSnapshotFrm"/>
         <HasResources Value="True"/>
-        <EditorIndex Value="-1"/>
+        <ResourceBaseClass Value="Form"/>
-        <TopLine Value="139"/>
+        <EditorIndex Value="1"/>
-        <CursorPos X="74" Y="162"/>
+        <TopLine Value="98"/>
+        <CursorPos X="71" Y="163"/>
         <UsageCount Value="23"/>
+        <Loaded Value="True"/>
         <DefaultSyntaxHighlighter Value="Delphi"/>
       </Unit2>
       <Unit3>
@@ -52,112 +55,89 @@
       <Unit5>
         <Filename Value="..\..\..\source\uCEFBufferPanel.pas"/>
         <EditorIndex Value="-1"/>
-        <TopLine Value="628"/>
+        <TopLine Value="636"/>
-        <CursorPos Y="644"/>
+        <CursorPos Y="652"/>
         <UsageCount Value="10"/>
       </Unit5>
+      <Unit6>
+        <Filename Value="..\ConsoleBrowser2\uCEFBrowserThread.pas"/>
+        <EditorIndex Value="-1"/>
+        <TopLine Value="31"/>
+        <CursorPos X="17" Y="40"/>
+        <UsageCount Value="10"/>
+        <DefaultSyntaxHighlighter Value="Delphi"/>
+      </Unit6>
+      <Unit7>
+        <Filename Value="uCEFBrowserThread_v.pas"/>
+        <UnitName Value="uCEFBrowserThread"/>
+        <EditorIndex Value="-1"/>
+        <TopLine Value="321"/>
+        <CursorPos Y="338"/>
+        <UsageCount Value="10"/>
+        <DefaultSyntaxHighlighter Value="Delphi"/>
+      </Unit7>
     </Units>
-    <JumpHistory Count="25" HistoryIndex="24">
+    <JumpHistory Count="15" HistoryIndex="14">
       <Position1>
         <Filename Value="uCEFBrowserThread.pas"/>
-        <Caret Line="381" TopLine="361"/>
+        <Caret Line="348" TopLine="334"/>
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+        <Caret Line="382" TopLine="363"/>
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         <Filename Value="uCEFBrowserThread.pas"/>
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         <Filename Value="uCEFBrowserThread.pas"/>
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+        <Caret Line="515" Column="28" TopLine="397"/>
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         <Filename Value="uCEFBrowserThread.pas"/>
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+        <Caret Line="416" Column="50" TopLine="403"/>
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demos/Lazarus_Windows/WebpageSnapshot/uCEFBrowserThread.pas

@@ -10,7 +10,7 @@
 // For more information about CEF4Delphi visit :
 //         https://www.briskbard.com/index.php?lang=en&pageid=cef
 //
-//        Copyright © 2020 Salvador Diaz Fau. All rights reserved.
+//        Copyright � 2020 Salvador Diaz Fau. All rights reserved.
 //
 // ************************************************************************
 // ************ vvvv Original license and comments below vvvv *************
@@ -47,7 +47,7 @@ uses
   {$IFDEF DELPHI16_UP}
   Winapi.Windows, Winapi.Messages, System.SysUtils, System.Classes, Vcl.Graphics, System.SyncObjs, System.Math,
   {$ELSE}
-  LCLIntf, LCLType, LMessages, Windows, Messages, SysUtils, Classes, Graphics, SyncObjs, Math,
+  Windows, Messages, SysUtils, Classes, Graphics, SyncObjs, Math,
   {$ENDIF}
   uCEFChromium, uCEFTypes, uCEFInterfaces, uCEFConstants, uCEFBufferPanel, uCEFChromiumCore, uCEFMiscFunctions;
 
@@ -86,12 +86,15 @@ type
       FErrorText             : ustring;
       FFailedUrl             : ustring;
       FPendingUrl            : ustring;
+      FSyncEvents            : boolean;
 
       function  GetErrorCode : integer;
       function  GetErrorText : ustring;
       function  GetFailedUrl : ustring;
       function  GetInitialized : boolean;
 
+      procedure SetErrorText(const aValue : ustring);
+
       procedure Panel_OnResize(Sender: TObject);
 
       procedure Browser_OnAfterCreated(Sender: TObject; const browser: ICefBrowser);
@@ -110,9 +113,11 @@ type
       procedure DoOnSnapshotAvailable;
       procedure Resize;
       function  CreateBrowser : boolean;
-      procedure TakeSnapshot;
+      function  TakeSnapshot : boolean;
       procedure CloseBrowser;
+      procedure InitError;
       procedure WebpagePostProcessing;
+      procedure WebpageError;
       procedure LoadPendingURL;
       procedure Execute; override;
 
@@ -122,12 +127,15 @@ type
       procedure   AfterConstruction; override;
       function    TerminateBrowserThread : boolean;
       function    CopySnapshot(var aSnapshot : TBitmap) : boolean;
+      function    SaveSnapshotToFile(const aPath : ustring) : boolean;
       procedure   LoadUrl(const aURL : ustring);
 
       property ErrorCode             : integer           read GetErrorCode;
-      property ErrorText             : ustring           read GetErrorText;
+      property ErrorText             : ustring           read GetErrorText             write SetErrorText;
       property FailedUrl             : ustring           read GetFailedUrl;
       property Initialized           : boolean           read GetInitialized;
+      property Closing               : boolean           read FClosing;
+      property SyncEvents            : boolean           read FSyncEvents              write FSyncEvents;
 
       property OnSnapshotAvailable   : TNotifyEvent      read FOnSnapshotAvailable     write FOnSnapshotAvailable;
       property OnError               : TNotifyEvent      read FOnError                 write FOnError;
@@ -179,6 +187,7 @@ begin
   FOnSnapshotAvailable   := nil;
   FOnError               := nil;
   FClosing               := False;
+  FSyncEvents            := False;
 end;
 
 destructor TCEFBrowserThread.Destroy;
@@ -235,23 +244,41 @@ end;
 
 function TCEFBrowserThread.GetErrorCode : integer;
 begin
+  if assigned(FBrowserInfoCS) then
+    try
       FBrowserInfoCS.Acquire;
       Result := FErrorCode;
+    finally
       FBrowserInfoCS.Release;
+    end
+   else
+    Result := 0;
 end;
 
 function TCEFBrowserThread.GetErrorText : ustring;
 begin
+  if assigned(FBrowserInfoCS) then
+    try
       FBrowserInfoCS.Acquire;
       Result := FErrorText;
+    finally
       FBrowserInfoCS.Release;
+    end
+   else
+    Result := '';
 end;
 
 function TCEFBrowserThread.GetFailedUrl : ustring;
 begin
+  if assigned(FBrowserInfoCS) then
+    try
       FBrowserInfoCS.Acquire;
       Result := FFailedUrl;
+    finally
       FBrowserInfoCS.Release;
+    end
+   else
+    Result := '';
 end;
 
 function TCEFBrowserThread.GetInitialized : boolean;
@@ -267,12 +294,24 @@ begin
     end;
 end;
 
+procedure TCEFBrowserThread.SetErrorText(const aValue : ustring);
+begin
+  if assigned(FBrowserInfoCS) then
+    try
+      FBrowserInfoCS.Acquire;
+      FErrorText := aValue;
+    finally
+      FBrowserInfoCS.Release;
+    end;
+end;
+
 function TCEFBrowserThread.CopySnapshot(var aSnapshot : TBitmap) : boolean;
 begin
   Result := False;
 
-  if FClosing or Terminated or (FBrowserInfoCS = nil) then exit;
+  if FClosing or Terminated or not(Initialized) then exit;
 
+  if assigned(FBrowserInfoCS) then
     try
       try
         FBrowserInfoCS.Acquire;
@@ -284,11 +323,15 @@ begin
                 aSnapshot             := TBitmap.Create;
                 aSnapshot.PixelFormat := pf32bit;
                 aSnapshot.HandleType  := bmDIB;
-              aSnapshot.Width       := FSnapshot.Width;
-              aSnapshot.Height      := FSnapshot.Height;
               end;
 
-          aSnapshot.Assign(FSnapshot);
+            if (aSnapshot.Width <> FSnapshot.Width) then
+              aSnapshot.Width := FSnapshot.Width;
+
+            if (aSnapshot.Height <> FSnapshot.Height) then
+              aSnapshot.Height := FSnapshot.Height;
+
+            aSnapshot.Canvas.Draw(0, 0, FSnapshot);
             Result := True;
           end;
       except
@@ -300,12 +343,36 @@ begin
     end;
 end;
 
+function TCEFBrowserThread.SaveSnapshotToFile(const aPath : ustring) : boolean;
+begin
+  Result := False;
+
+  if FClosing or Terminated or not(Initialized) then exit;
+
+  if assigned(FBrowserInfoCS) and (length(aPath) > 0) then
+    try
+      try
+        FBrowserInfoCS.Acquire;
+
+        if assigned(FSnapshot) and not(FSnapshot.Empty) then
+          begin
+            FSnapshot.SaveToFile(aPath);
+            Result := True;
+          end;
+      except
+        on e : exception do
+          if CustomExceptionHandler('TCEFBrowserThread.SaveSnapshotToFile', e) then raise;
+      end;
+    finally
+      FBrowserInfoCS.Release;
+    end;
+end;
+
 procedure TCEFBrowserThread.LoadUrl(const aURL : ustring);
 begin
-  if FClosing or Terminated or (FBrowserInfoCS = nil) then
+  if FClosing or Terminated or not(Initialized) then exit;
-    exit;
 
-  if Initialized then
+  if assigned(FBrowserInfoCS) then
     try
       FBrowserInfoCS.Acquire;
       FPendingUrl := aURL;
@@ -328,10 +395,14 @@ end;
 
 procedure TCEFBrowserThread.Browser_OnAfterCreated(Sender: TObject; const browser: ICefBrowser);
 begin
+  if assigned(FBrowserInfoCS) then
+    try
       FBrowserInfoCS.Acquire;
       FInitialized := True;
+    finally
       FBrowserInfoCS.Release;
     end;
+end;
 
 procedure TCEFBrowserThread.Browser_OnPaint(Sender: TObject; const browser: ICefBrowser; kind: TCefPaintElementType; dirtyRectsCount: NativeUInt; const dirtyRects: PCefRectArray; const buffer: Pointer; aWidth, aHeight: Integer);
 var
@@ -344,6 +415,7 @@ var
   TempBitmap : TBitmap;
   TempSrcRect : TRect;
 begin
+  if assigned(FResizeCS) and assigned(FPanel) then
     try
       FResizeCS.Acquire;
       TempForcedResize := False;
@@ -445,12 +517,15 @@ begin
 end;
 
 procedure TCEFBrowserThread.Browser_OnGetViewRect(Sender: TObject; const browser: ICefBrowser; var rect: TCefRect);
+begin
+  if assigned(FPanel) then
     begin
       rect.x      := 0;
       rect.y      := 0;
       rect.width  := DeviceToLogical(FPanel.Width,  FScreenScale);
       rect.height := DeviceToLogical(FPanel.Height, FScreenScale);
     end;
+end;
 
 procedure TCEFBrowserThread.Browser_OnGetScreenPoint(Sender: TObject; const browser: ICefBrowser; viewX, viewY: Integer; var screenX, screenY: Integer; out Result: Boolean);
 begin
@@ -462,6 +537,8 @@ end;
 procedure TCEFBrowserThread.Browser_OnGetScreenInfo(Sender: TObject; const browser: ICefBrowser; var screenInfo: TCefScreenInfo; out Result: Boolean);
 var
   TempRect : TCEFRect;
+begin
+  if assigned(FPanel) then
     begin
       TempRect.x      := 0;
       TempRect.y      := 0;
@@ -477,6 +554,7 @@ begin
 
       Result := True;
     end;
+end;
 
 procedure TCEFBrowserThread.Browser_OnPopupShow(Sender: TObject; const browser: ICefBrowser; show: Boolean);
 begin
@@ -514,7 +592,7 @@ end;
 
 procedure TCEFBrowserThread.Browser_OnLoadError(Sender: TObject; const browser: ICefBrowser; const frame: ICefFrame; errorCode: Integer; const errorText, failedUrl: ustring);
 begin
-  if not(FClosing) and not(Terminated) and (frame <> nil) and frame.IsValid and frame.IsMain then
+  if not(FClosing) and not(Terminated) and (frame <> nil) and frame.IsValid and frame.IsMain and assigned(FBrowserInfoCS) then
     try
       FBrowserInfoCS.Acquire;
 
@@ -534,21 +612,11 @@ begin
     PostThreadMessage(ThreadID, CEF_WEBPAGE_LOADED_MSG, 0, 0);
 end;
 
-procedure TCEFBrowserThread.DoOnError;
-begin
-  FOnError(self);
-end;
-
-procedure TCEFBrowserThread.DoOnSnapshotAvailable;
-begin
-  FOnSnapshotAvailable(self);
-end;
-
 procedure TCEFBrowserThread.Resize;
 begin
-  if FClosing or Terminated or (FPanel = nil) or (FResizeCS = nil) or (FBrowser = nil) then
+  if FClosing or Terminated or not(Initialized) then exit;
-    exit;
 
+  if assigned(FResizeCS) and assigned(FPanel) then
     try
       FResizeCS.Acquire;
 
@@ -574,9 +642,9 @@ end;
 
 procedure TCEFBrowserThread.LoadPendingURL;
 begin
-  if FClosing or Terminated or (FBrowser = nil) or (FBrowserInfoCS = nil) then
+  if FClosing or Terminated or not(Initialized) then exit;
-    exit;
 
+  if assigned(FBrowserInfoCS) then
     try
       FBrowserInfoCS.Acquire;
 
@@ -598,32 +666,57 @@ begin
   if (FDelayMs > 0) then
     sleep(FDelayMs);
 
-  TakeSnapshot;
+  if TakeSnapshot and assigned(FOnSnapshotAvailable) then
-
+    begin
-  if assigned(FOnSnapshotAvailable) then
+      if FSyncEvents then
-    Synchronize(DoOnSnapshotAvailable);
+        Synchronize(DoOnSnapshotAvailable)
+       else
+        DoOnSnapshotAvailable;
+    end;
 end;
 
-procedure TCEFBrowserThread.TakeSnapshot;
+procedure TCEFBrowserThread.WebpageError;
 begin
-  if (FPanel = nil) or (FPanel.Buffer = nil) or (FBrowserInfoCS = nil) then
+  if not(FClosing) and not(Terminated) and assigned(FOnError) then
-    exit;
+    begin
+      if FSyncEvents then
+        Synchronize(DoOnError)
+       else
+        DoOnError;
+    end;
+end;
 
+function TCEFBrowserThread.TakeSnapshot : boolean;
+begin
+  Result := False;
+
+  if FClosing or Terminated or not(Initialized) then exit;
+
+  if assigned(FBrowserInfoCS) and assigned(FPanel) and FPanel.BeginBufferDraw then
     try
       FBrowserInfoCS.Acquire;
 
+      if assigned(FPanel.Buffer) and not(FPanel.Buffer.Empty) then
+        begin
           if (FSnapshot = nil) then
             begin
               FSnapshot             := TBitmap.Create;
               FSnapshot.PixelFormat := pf32bit;
               FSnapshot.HandleType  := bmDIB;
-        FSnapshot.Width       := FPanel.BufferWidth;
-        FSnapshot.Height      := FPanel.BufferHeight;
             end;
 
-    FSnapshot.Assign(FPanel.Buffer);
+          if (FSnapshot.Width <> FPanel.BufferWidth) then
+            FSnapshot.Width := FPanel.BufferWidth;
+
+          if (FSnapshot.Height <> FPanel.BufferHeight) then
+            FSnapshot.Height := FPanel.BufferHeight;
+
+          FSnapshot.Canvas.Draw(0, 0, FPanel.Buffer);
+          Result := True;
+        end;
     finally
       FBrowserInfoCS.Release;
+      FPanel.EndBufferDraw;
     end;
 end;
 
@@ -636,6 +729,26 @@ begin
     end;
 end;
 
+procedure TCEFBrowserThread.DoOnError;
+begin
+  FOnError(self);
+end;
+
+procedure TCEFBrowserThread.DoOnSnapshotAvailable;
+begin
+  FOnSnapshotAvailable(self);
+end;
+
+procedure TCEFBrowserThread.InitError;
+begin
+  ErrorText := 'There was an error initializing the CEF browser.';
+
+  if FSyncEvents then
+    Synchronize(DoOnError)
+   else
+    DoOnError;
+end;
+
 procedure TCEFBrowserThread.Execute;
 var
   TempCont : boolean;
@@ -649,17 +762,19 @@ begin
       while TempCont and GetMessage(TempMsg, 0, 0, 0) and not(Terminated) do
         begin
           case TempMsg.Message of
-            WM_QUIT                  : TempCont := False;
             CEF_PENDINGRESIZE        : Resize;
             CEF_CLOSE_BROWSER_MSG    : CloseBrowser;
             CEF_LOAD_PENDING_URL_MSG : LoadPendingURL;
             CEF_WEBPAGE_LOADED_MSG   : WebpagePostProcessing;
-            CEF_WEBPAGE_ERROR_MSG    : if assigned(FOnError) then Synchronize(DoOnError);
+            CEF_WEBPAGE_ERROR_MSG    : WebpageError;
+            WM_QUIT                  : TempCont := False;
           end;
 
           DispatchMessage(TempMsg);
         end;
-    end;
+    end
+   else
+    InitError;
 end;
 
 end.

demos/Lazarus_Windows/WebpageSnapshot/uWebpageSnapshot.lfm

@@ -1,24 +1,24 @@
 object WebpageSnapshotFrm: TWebpageSnapshotFrm
   Left = 0
+  Height = 486
   Top = 0
+  Width = 711
   Caption = 'Web page snapshot'
   ClientHeight = 486
   ClientWidth = 711
   Color = clBtnFace
-  Font.Charset = DEFAULT_CHARSET
   Font.Color = clWindowText
   Font.Height = -11
   Font.Name = 'Tahoma'
-  Font.Style = []
-  Position = poScreenCenter
   OnCloseQuery = FormCloseQuery
   OnCreate = FormCreate
-  PixelsPerInch = 96
+  Position = poScreenCenter
+  LCLVersion = '2.0.10.0'
   object Image1: TImage
     Left = 0
+    Height = 438
     Top = 25
     Width = 711
-    Height = 442
     Align = alClient
     AutoSize = True
     Center = True
@@ -26,9 +26,9 @@ object WebpageSnapshotFrm: TWebpageSnapshotFrm
   end
   object StatusBar1: TStatusBar
     Left = 0
-    Top = 467
+    Height = 23
+    Top = 463
     Width = 711
-    Height = 19
     Panels = <    
       item
         Width = 1000
@@ -37,27 +37,29 @@ object WebpageSnapshotFrm: TWebpageSnapshotFrm
   end
   object NavigationPnl: TPanel
     Left = 0
+    Height = 25
     Top = 0
     Width = 711
-    Height = 25
     Align = alTop
     BevelOuter = bvNone
+    ClientHeight = 25
+    ClientWidth = 711
     TabOrder = 1
     object GoBtn: TButton
-      Left = 632
+      Left = 636
+      Height = 25
       Top = 0
       Width = 75
-      Height = 21
       Align = alRight
       Caption = 'Go'
-      TabOrder = 0
       OnClick = GoBtnClick
+      TabOrder = 0
     end
     object AddressEdt: TEdit
       Left = 0
+      Height = 25
       Top = 0
-      Width = 632
+      Width = 636
-      Height = 21
       Align = alClient
       TabOrder = 1
       Text = 'https://www.google.com'

demos/Lazarus_Windows/WebpageSnapshot/uWebpageSnapshot.pas

@@ -117,6 +117,7 @@ begin
       FThread                     := TCEFBrowserThread.Create(AddressEdt.Text, 1024, 768);
       FThread.OnError             := Thread_OnError;
       FThread.OnSnapshotAvailable := Thread_OnSnapshotAvailable;
+      FThread.SyncEvents          := True;
       FThread.Start;
     end
    else

update_CEF4Delphi.json

@@ -2,7 +2,7 @@
   "UpdateLazPackages" : [
     {
       "ForceNotify" : true,
-      "InternalVersion" : 207,
+      "InternalVersion" : 208,
       "Name" : "cef4delphi_lazarus.lpk",
       "Version" : "87.1.12.0"
     }