Qt5,Qt6: fixed scrollCode messaging. issue #41566

(cherry picked from commit b3c7e1ddd6)

Co-authored-by: zeljan1 <zeljko@holobit.hr>

lcl/interfaces/qt5/qtwidgets.pas

@@ -9344,7 +9344,10 @@ begin
     LMScroll.Msg := LM_VSCROLL;
 
   LMScroll.Pos := p1;
-  LMScroll.ScrollCode := SIF_POS;
+  if getTracking and getSliderDown then
+    LMScroll.ScrollCode := SB_THUMBTRACK
+  else
+    LMScroll.ScrollCode := SB_THUMBPOSITION;
 
   if not InUpdate then
     DeliverMessage(LMScroll);
@@ -9355,8 +9358,14 @@ begin
   begin
     if b and (FChildOfComplexWidget = ccwAbstractScrollArea) and
       not InUpdate and getVisible then
+    begin
+      if p1 = getMin then
+        QAbstractSlider_triggerAction(QAbstractSliderH(Widget),
+          QAbstractSliderSliderToMinimum)
+      else
         QAbstractSlider_triggerAction(QAbstractSliderH(Widget),
           QAbstractSliderSliderToMaximum);
+    end;
   end;
 end;
 
@@ -9395,9 +9404,19 @@ begin
 
   SliderAction := SliderActions[Action];
 
+  if not SliderPressed and not SliderReleased and (SliderAction = QAbstractSliderSliderMove) then
+  begin
+    if LMScroll.Pos = getMin then
+      SliderAction := QAbstractSliderSliderToMinimum
+    else
+    if LMScroll.Pos = getMax then
+      SliderAction := QAbstractSliderSliderToMaximum;
+  end;
+
   case SliderAction of
     QAbstractSliderSliderNoAction:
     begin
+      exit; // issue #41566
       // this is called from mouse release while qt still thinks that
       // slider is pressed, we must update position.issue #14728, #21610
       if getSliderDown then
@@ -9405,6 +9424,7 @@ begin
         LMScroll.ScrollCode := SB_THUMBPOSITION;
         DeliverMessage(LMScroll);
       end;
+
       LMScroll.ScrollCode := SB_ENDSCROLL;
     end;
     QAbstractSliderSliderSingleStepAdd:
@@ -9437,6 +9457,13 @@ begin
       end;
     QAbstractSliderSliderToMinimum:
       begin
+        // send update for SB_THUMBPOSITION
+        if not SliderPressed and not SliderReleased then
+        begin
+          LMScroll.ScrollCode := SB_THUMBPOSITION;
+          DeliverMessage(LMScroll);
+        end;
+
         if LMScroll.Msg = LM_HSCROLL then
           LMScroll.ScrollCode := SB_LEFT
         else
@@ -9447,7 +9474,7 @@ begin
         // issue #21610
         // if we are reaching maximum with eg. mouse wheel
         // and our parent is TScrollingWinControl then update thumbposition.
-        if not getSliderDown then
+        if not SliderPressed and not SliderReleased then
         begin
           LMScroll.ScrollCode := SB_THUMBPOSITION;
           DeliverMessage(LMScroll);
@@ -9460,14 +9487,15 @@ begin
       end;
     QAbstractSliderSliderMove:
       begin
-        if getTracking then
+        if getTracking and getSliderDown then
           LMScroll.ScrollCode := SB_THUMBTRACK
         else
-        if not getSliderDown then
+        if not SliderPressed and not SliderReleased then
-          LMScroll.ScrollCode := SB_THUMBPOSITION;
+          LMScroll.ScrollCode := SB_THUMBPOSITION
+        else
+          exit; //ValueChange will trigger.
       end;
   end;
-
   DeliverMessage(LMScroll);
 end;
 
@@ -9513,8 +9541,10 @@ procedure TQtScrollBar.SlotSliderReleased; cdecl;
 var
   AValue: Integer;
   LMScroll: TLMScroll;
+  SentThumbPosition: boolean;
 begin
   inherited SlotSliderReleased;
+  SentThumbPosition := False;
   if
   {$IFDEF QTSCROLLABLEFORMS}
    ((ChildOfComplexWidget = ccwAbstractScrollArea) and (FOwner <> nil) and
@@ -9545,9 +9575,33 @@ begin
         LMScroll.ScrollCode := SB_THUMBPOSITION
       else
         LMScroll.ScrollCode := SB_THUMBTRACK;
+      SentThumbPosition := LMScroll.ScrollCode = SB_THUMBPOSITION;
       DeliverMessage(LMScroll);
     end;
   end;
+
+  // issue #41566 - must send SB_ENDSCROLL
+  FillChar(LMScroll{%H-}, SizeOf(LMScroll), #0);
+
+  LMScroll.ScrollBar := PtrUInt(Self);
+
+  if QAbstractSlider_orientation(QAbstractSliderH(Widget)) = QtHorizontal then
+    LMScroll.Msg := LM_HSCROLL
+  else
+    LMScroll.Msg := LM_VSCROLL;
+
+  LMScroll.Pos := getSliderPosition;
+
+  if not SentThumbPosition then
+  begin
+    LMScroll.ScrollCode := SB_THUMBPOSITION;
+    DeliverMessage(LMScroll);
+    LMScroll.Result := 0;
+  end;
+  FSliderReleased := False;
+  LMScroll.ScrollCode := SB_ENDSCROLL;
+  DeliverMessage(LMScroll);
+
 end;
 
 function TQtScrollBar.EventFilter(Sender: QObjectH; Event: QEventH): Boolean;

lcl/interfaces/qt6/qtwidgets.pas

@@ -9300,7 +9300,10 @@ begin
     LMScroll.Msg := LM_VSCROLL;
 
   LMScroll.Pos := p1;
-  LMScroll.ScrollCode := SIF_POS;
+  if getTracking and getSliderDown then
+    LMScroll.ScrollCode := SB_THUMBTRACK
+  else
+    LMScroll.ScrollCode := SB_THUMBPOSITION;
 
   if not InUpdate then
     DeliverMessage(LMScroll);
@@ -9311,8 +9314,14 @@ begin
   begin
     if b and (FChildOfComplexWidget = ccwAbstractScrollArea) and
       not InUpdate and getVisible then
+    begin
+      if p1 = getMin then
+        QAbstractSlider_triggerAction(QAbstractSliderH(Widget),
+          QAbstractSliderSliderToMinimum)
+      else
         QAbstractSlider_triggerAction(QAbstractSliderH(Widget),
           QAbstractSliderSliderToMaximum);
+    end;
   end;
 end;
 
@@ -9351,9 +9360,19 @@ begin
 
   SliderAction := SliderActions[Action];
 
+  if not SliderPressed and not SliderReleased and (SliderAction = QAbstractSliderSliderMove) then
+  begin
+    if LMScroll.Pos = getMin then
+      SliderAction := QAbstractSliderSliderToMinimum
+    else
+    if LMScroll.Pos = getMax then
+      SliderAction := QAbstractSliderSliderToMaximum;
+  end;
+
   case SliderAction of
     QAbstractSliderSliderNoAction:
     begin
+      exit; // issue #41566
       // this is called from mouse release while qt still thinks that
       // slider is pressed, we must update position.issue #14728, #21610
       if getSliderDown then
@@ -9361,6 +9380,7 @@ begin
         LMScroll.ScrollCode := SB_THUMBPOSITION;
         DeliverMessage(LMScroll);
       end;
+
       LMScroll.ScrollCode := SB_ENDSCROLL;
     end;
     QAbstractSliderSliderSingleStepAdd:
@@ -9393,6 +9413,13 @@ begin
       end;
     QAbstractSliderSliderToMinimum:
       begin
+        // send update for SB_THUMBPOSITION
+        if not SliderPressed and not SliderReleased then
+        begin
+          LMScroll.ScrollCode := SB_THUMBPOSITION;
+          DeliverMessage(LMScroll);
+        end;
+
         if LMScroll.Msg = LM_HSCROLL then
           LMScroll.ScrollCode := SB_LEFT
         else
@@ -9403,7 +9430,7 @@ begin
         // issue #21610
         // if we are reaching maximum with eg. mouse wheel
         // and our parent is TScrollingWinControl then update thumbposition.
-        if not getSliderDown then
+        if not SliderPressed and not SliderReleased then
         begin
           LMScroll.ScrollCode := SB_THUMBPOSITION;
           DeliverMessage(LMScroll);
@@ -9416,14 +9443,15 @@ begin
       end;
     QAbstractSliderSliderMove:
       begin
-        if getTracking then
+        if getTracking and getSliderDown then
           LMScroll.ScrollCode := SB_THUMBTRACK
         else
-        if not getSliderDown then
+        if not SliderPressed and not SliderReleased then
-          LMScroll.ScrollCode := SB_THUMBPOSITION;
+          LMScroll.ScrollCode := SB_THUMBPOSITION
+        else
+          exit; //ValueChange will trigger.
       end;
   end;
-
   DeliverMessage(LMScroll);
 end;
 
@@ -9469,8 +9497,10 @@ procedure TQtScrollBar.SlotSliderReleased; cdecl;
 var
   AValue: Integer;
   LMScroll: TLMScroll;
+  SentThumbPosition: boolean;
 begin
   inherited SlotSliderReleased;
+  SentThumbPosition := False;
   if
   {$IFDEF QTSCROLLABLEFORMS}
    ((ChildOfComplexWidget = ccwAbstractScrollArea) and (FOwner <> nil) and
@@ -9501,9 +9531,33 @@ begin
         LMScroll.ScrollCode := SB_THUMBPOSITION
       else
         LMScroll.ScrollCode := SB_THUMBTRACK;
+      SentThumbPosition := LMScroll.ScrollCode = SB_THUMBPOSITION;
       DeliverMessage(LMScroll);
     end;
   end;
+
+  // issue #41566 - must send SB_ENDSCROLL
+  FillChar(LMScroll{%H-}, SizeOf(LMScroll), #0);
+
+  LMScroll.ScrollBar := PtrUInt(Self);
+
+  if QAbstractSlider_orientation(QAbstractSliderH(Widget)) = QtHorizontal then
+    LMScroll.Msg := LM_HSCROLL
+  else
+    LMScroll.Msg := LM_VSCROLL;
+
+  LMScroll.Pos := getSliderPosition;
+
+  if not SentThumbPosition then
+  begin
+    LMScroll.ScrollCode := SB_THUMBPOSITION;
+    DeliverMessage(LMScroll);
+    LMScroll.Result := 0;
+  end;
+  FSliderReleased := False;
+  LMScroll.ScrollCode := SB_ENDSCROLL;
+  DeliverMessage(LMScroll);
+
 end;
 
 function TQtScrollBar.EventFilter(Sender: QObjectH; Event: QEventH): Boolean;