Buffer panel resize fixes for SimpleOSRBrowser

demos/SimpleOSRBrowser/uSimpleOSRBrowser.dfm

@@ -48,7 +48,8 @@ object Form1: TForm1
         'https://html5demos.com/drag'
         
           'https://www.w3schools.com/tags/tryit.asp?filename=tryhtml5_selec' +
-          't_form')
+          't_form'
+        'https://www.briskbard.com')
     end
     object Panel2: TPanel
       Left = 726
@@ -111,10 +112,10 @@ object Form1: TForm1
     OnEnter = Panel1Enter
     OnExit = Panel1Exit
     OnMouseDown = Panel1MouseDown
-    OnMouseLeave = Panel1MouseLeave
     OnMouseMove = Panel1MouseMove
     OnMouseUp = Panel1MouseUp
     OnResize = Panel1Resize
+    OnMouseLeave = Panel1MouseLeave
   end
   object chrmosr: TChromium
     OnAfterCreated = chrmosrAfterCreated

demos/SimpleOSRBrowser/uSimpleOSRBrowser.pas

@@ -103,15 +103,20 @@ type
     FPopUpBitmap    : TBitmap;
     FPopUpRect      : TRect;
     FShowPopUp      : boolean;
+    FResizing       : boolean;
+    FPendingResize  : boolean;
+    FResizeCS       : TCriticalSection;
 
     function  getModifiers(Shift: TShiftState): TCefEventFlags;
     function  GetButton(Button: TMouseButton): TCefMouseButtonType;
+    procedure DoResize;
 
     procedure WMMove(var aMessage : TWMMove); message WM_MOVE;
     procedure WMMoving(var aMessage : TMessage); message WM_MOVING;
     procedure WMCaptureChanged(var aMessage : TMessage); message WM_CAPTURECHANGED;
     procedure WMCancelMode(var aMessage : TMessage); message WM_CANCELMODE;
     procedure BrowserCreatedMsg(var aMessage : TMessage); message CEF_AFTERCREATED;
+    procedure PendingResizeMsg(var aMessage : TMessage); message CEF_PENDINGRESIZE;
 
   public
     { Public declarations }
@@ -132,6 +137,15 @@ uses
   {$ENDIF}
   uCEFMiscFunctions, uCEFApplication;
 
+// *********************************
+// ********* ATTENTION !!! *********
+// *********************************
+//
+// There is a known bug in the destruction of TChromium in OSR mode.
+// If you destroy the TChromium in OSR mode before the application is closed,
+// add a timer and wait 1-2 seconds after the TChromium's destruction.
+// After that you can close the app. Hide the application in the task bar if necessary.
+
 procedure TForm1.AppEventsMessage(var Msg: tagMSG; var Handled: Boolean);
 var
   TempKeyEvent   : TCefKeyEvent;
@@ -248,6 +262,11 @@ end;
 
 procedure TForm1.GoBtnClick(Sender: TObject);
 begin
+  FResizeCS.Acquire;
+  FResizing      := False;
+  FPendingResize := False;
+  FResizeCS.Release;
+
   chrmosr.LoadURL(ComboBox1.Text);
 end;
 
@@ -351,7 +370,12 @@ var
   n : NativeUInt;
   TempWidth, TempHeight, TempScanlineSize : integer;
   TempBufferBits : Pointer;
+  TempForcedResize : boolean;
 begin
+  try
+    FResizeCS.Acquire;
+    TempForcedResize := False;
+
     if Panel1.BeginBufferDraw then
       begin
         if (kind = PET_POPUP) then
@@ -376,6 +400,7 @@ begin
           end
          else
           begin
+            TempForcedResize := Panel1.UpdateBufferDimensions(Width, Height) or not(Panel1.BufferIsResized(False));
             TempWidth        := Panel1.BufferWidth;
             TempHeight       := Panel1.BufferHeight;
             TempScanlineSize := Panel1.ScanlineSize;
@@ -427,6 +452,17 @@ begin
 
         Panel1.EndBufferDraw;
         Panel1.InvalidatePanel;
+
+        if (kind = PET_VIEW) then
+          begin
+            if TempForcedResize or FPendingResize then PostMessage(Handle, CEF_PENDINGRESIZE, 0, 0);
+
+            FResizing      := False;
+            FPendingResize := False;
+          end;
+      end;
+  finally
+    FResizeCS.Release;
   end;
 end;
 
@@ -535,6 +571,9 @@ begin
   FPopUpBitmap    := nil;
   FPopUpRect      := rect(0, 0, 0, 0);
   FShowPopUp      := False;
+  FResizing       := False;
+  FPendingResize  := False;
+  FResizeCS       := TCriticalSection.Create;
 end;
 
 procedure TForm1.FormDestroy(Sender: TObject);
@@ -635,8 +674,33 @@ end;
 
 procedure TForm1.Panel1Resize(Sender: TObject);
 begin
+  DoResize;
+end;
+
+procedure TForm1.PendingResizeMsg(var aMessage : TMessage);
+begin
+  DoResize;
+end;
+
+procedure TForm1.DoResize;
+begin
+  try
+    FResizeCS.Acquire;
+
+    if FResizing then
+      FPendingResize := True
+     else
+      if Panel1.BufferIsResized then
+        chrmosr.Invalidate(PET_VIEW)
+       else
+        begin
+          FResizing := True;
           chrmosr.WasResized;
         end;
+  finally
+    FResizeCS.Release;
+  end;
+end;
 
 procedure TForm1.Panel1Enter(Sender: TObject);
 begin

source/uBufferPanel.pas

@@ -61,10 +61,9 @@ type
       function  GetBufferWidth : integer;
       function  GetBufferHeight : integer;
 
-      procedure CopyBuffer(aDC : HDC; const aRect : TRect);
+      function  CopyBuffer(aDC : HDC; const aRect : TRect) : boolean;
       function  SaveBufferToFile(const aFilename : string) : boolean;
       procedure DestroyBuffer;
-      procedure Resize; override;
 
       procedure WMPaint(var aMessage: TWMPaint); message WM_PAINT;
       procedure WMEraseBkgnd(var aMessage : TWMEraseBkgnd); message WM_ERASEBKGND;
@@ -78,6 +77,8 @@ type
       function    BeginBufferDraw : boolean;
       procedure   EndBufferDraw;
       procedure   BufferDraw(x, y : integer; const aBitmap : TBitmap);
+      function    UpdateBufferDimensions(aWidth, aHeight : integer) : boolean;
+      function    BufferIsResized(aUseMutex : boolean = True) : boolean;
 
       property Buffer         : TBitmap            read FBuffer;
       property ScanlineSize   : integer            read FScanlineSize;
@@ -173,7 +174,7 @@ type
 implementation
 
 uses
-  uCEFMiscFunctions;
+  uCEFMiscFunctions, uCEFApplication;
 
 constructor TBufferPanel.Create(AOwner: TComponent);
 begin
@@ -254,11 +255,14 @@ begin
   if (FMutex <> 0) then ReleaseMutex(FMutex);
 end;
 
-procedure TBufferPanel.CopyBuffer(aDC : HDC; const aRect : TRect);
+function TBufferPanel.CopyBuffer(aDC : HDC; const aRect : TRect) : boolean;
 begin
+  Result := False;
+
   if BeginBufferDraw then
     begin
-      if (FBuffer <> nil) and (aDC <> 0) then
+      Result := (FBuffer <> nil) and
+                (aDC     <> 0)   and
                 BitBlt(aDC, aRect.Left, aRect.Top, aRect.Right - aRect.Left, aRect.Bottom - aRect.Top,
                        FBuffer.Canvas.Handle, aRect.Left, aRect.Top,
                        SrcCopy);
@@ -285,38 +289,18 @@ begin
         Canvas.Rectangle(0, 0, Width, Height);
       end
      else
-      CopyBuffer(TempDC, TempPaintStruct.rcPaint);
+      if not(CopyBuffer(TempDC, TempPaintStruct.rcPaint)) then
+        begin
+          Canvas.Brush.Color := Color;
+          Canvas.Brush.Style := bsSolid;
+          Canvas.FillRect(rect(0, 0, Width, Height));
+        end;
   finally
     EndPaint(Handle, TempPaintStruct);
     aMessage.Result := 1;
   end;
 end;
 
-procedure TBufferPanel.Resize;
-begin
-  if BeginBufferDraw then
-    begin
-      if ((FBuffer        =  nil)   or
-          (FBuffer.Width  <> Width) or
-          (FBuffer.Height <> Height)) then
-        begin
-          if (FBuffer <> nil) then FreeAndNil(FBuffer);
-
-          FBuffer             := TBitmap.Create;
-          FBuffer.PixelFormat := pf32bit;
-          FBuffer.HandleType  := bmDIB;
-          FBuffer.Width       := Width;
-          FBuffer.Height      := Height;
-
-          FScanlineSize       := FBuffer.Width * SizeOf(TRGBQuad);
-        end;
-
-      EndBufferDraw;
-    end;
-
-  inherited Resize;
-end;
-
 procedure TBufferPanel.WMEraseBkgnd(var aMessage : TWMEraseBkgnd);
 begin
   aMessage.Result := 1;
@@ -351,4 +335,42 @@ begin
   if (FBuffer <> nil) then FBuffer.Canvas.Draw(x, y, aBitmap);
 end;
 
+function TBufferPanel.UpdateBufferDimensions(aWidth, aHeight : integer) : boolean;
+begin
+  if ((FBuffer        =  nil)      or
+      (FBuffer.Width  <> aWidth)   or
+      (FBuffer.Height <> aHeight)) then
+    begin
+      if (FBuffer <> nil) then FreeAndNil(FBuffer);
+
+      FBuffer             := TBitmap.Create;
+      FBuffer.PixelFormat := pf32bit;
+      FBuffer.HandleType  := bmDIB;
+      FBuffer.Width       := aWidth;
+      FBuffer.Height      := aHeight;
+      FScanlineSize       := FBuffer.Width * SizeOf(TRGBQuad);
+      Result              := True;
+    end
+   else
+    Result := False;
+end;
+
+function TBufferPanel.BufferIsResized(aUseMutex : boolean) : boolean;
+begin
+  Result := False;
+
+  if not(aUseMutex) or BeginBufferDraw then
+    begin
+      // CEF and Chromium use 'floor' to round the float values in Device <-> Logical unit conversions
+      // and Delphi uses MulDiv, which uses the bankers rounding, to resize the components in high DPI mode.
+      // This is the cause of slight differences in size between the buffer and the panel in some occasions.
+
+      Result := (FBuffer <> nil) and
+                (FBuffer.Width  = LogicalToDevice(DeviceToLogical(Width,  GlobalCEFApp.DeviceScaleFactor), GlobalCEFApp.DeviceScaleFactor)) and
+                (FBuffer.Height = LogicalToDevice(DeviceToLogical(Height, GlobalCEFApp.DeviceScaleFactor), GlobalCEFApp.DeviceScaleFactor));
+
+      if aUseMutex then EndBufferDraw;
+    end;
+end;
+
 end.

source/uCEFConstants.pas

@@ -360,6 +360,7 @@ const
   CEF_DOONCLOSE          = WM_APP + $A01;
   CEF_STARTDRAGGING      = WM_APP + $A02;
   CEF_AFTERCREATED       = WM_APP + $A03;
+  CEF_PENDINGRESIZE      = WM_APP + $A04;
 
   CEF_USER_TIMER_MINIMUM = $0000000A;
   CEF_USER_TIMER_MAXIMUM = $7FFFFFFF;
@@ -370,3 +371,4 @@ const
 implementation
 
 end.
+