LCL/CheckListbox: Add new properties HeaderBackgroundColor and HeaderColor and implement them for win32 WS. Issue #39874, patch by Don Siders.

lcl/checklst.pas

@@ -36,6 +36,8 @@ type
   TCustomCheckListBox = class(TCustomListBox)
   private
     FAllowGrayed: Boolean;
+    FHeaderBackgroundColor: TColor;
+    FHeaderColor: TColor;
     FItemDataOffset: Integer;
     FOnClickCheck : TNotifyEvent;
     FOnItemClick: TCheckListClicked;
@@ -49,6 +51,8 @@ type
     procedure SendItemHeader(const AIndex: Integer; const AHeader: Boolean);
     procedure DoChange(var Msg: TLMessage); message LM_CHANGED;
     procedure SetHeader(AIndex: Integer; const AValue: Boolean);
+    procedure SetHeaderBackgroundColor(AValue: TColor);
+    procedure SetHeaderColor(AValue: TColor);
     procedure SetItemEnabled(AIndex: Integer; const AValue: Boolean);
     procedure SetState(AIndex: Integer; const AValue: TCheckBoxState);
   protected
@@ -75,6 +79,8 @@ type
     property AllowGrayed: Boolean read FAllowGrayed write FAllowGrayed default False;
     property Checked[AIndex: Integer]: Boolean read GetChecked write SetChecked;
     property Header[AIndex: Integer]: Boolean read GetHeader write SetHeader;
+    property HeaderBackgroundColor: TColor read FHeaderBackgroundColor write SetHeaderBackgroundColor default clInfoBk;
+    property HeaderColor: TColor read FHeaderColor write SetHeaderColor default clInfoText;
     property ItemEnabled[AIndex: Integer]: Boolean read GetItemEnabled write SetItemEnabled;
     property State[AIndex: Integer]: TCheckBoxState read GetState write SetState;
     property OnClickCheck: TNotifyEvent read FOnClickCheck write FOnClickCheck;
@@ -100,6 +106,8 @@ type
     property ExtendedSelect;
     property Enabled;
     property Font;
+    property HeaderBackgroundColor;
+    property HeaderColor;
     property IntegralHeight;
     property Items;
     property ItemHeight;
@@ -208,6 +216,8 @@ begin
   inherited Create(AOwner);
   FCompStyle := csCheckListBox;
   FItemDataOffset := inherited GetCachedDataSize;
+  FHeaderBackgroundColor := clInfoBk;
+  FHeaderColor := clInfoText;
 end;
 
 function TCustomCheckListBox.CalculateStandardItemHeight: Integer;
@@ -367,6 +377,20 @@ begin
     PCachedItemData(GetCachedData(AIndex) + FItemDataOffset)^.Header := AValue;
 end;
 
+procedure TCustomCheckListBox.SetHeaderBackgroundColor(AValue: TColor);
+begin
+  if FHeaderBackgroundColor = AValue then Exit;
+  FHeaderBackgroundColor := AValue;
+  Invalidate;
+end;
+
+procedure TCustomCheckListBox.SetHeaderColor(AValue: TColor);
+begin
+  if FHeaderColor = AValue then Exit;
+  FHeaderColor := AValue;
+  Invalidate;
+end;
+
 class procedure TCustomCheckListBox.WSRegisterClass;
 begin
   inherited WSRegisterClass;

lcl/interfaces/win32/win32wschecklst.pp

@@ -192,15 +192,25 @@ class procedure TWin32WSCustomCheckListBox.DefaultWndHandler(
     OldBkMode: Integer;
     sz: TSize;
     WideBuffer: widestring;
+    HdrBg, HdrTxt: TColor;
+    BgBrush: Windows.HBRUSH;
   begin
     Selected := (Data^.itemState and ODS_SELECTED) > 0;
     Enabled := CheckListBox.Enabled and CheckListBox.ItemEnabled[Data^.itemID];
     Header := CheckListBox.Header[Data^.itemID];
 
+    if Header then
+    begin
+      HdrBg := CheckListBox.HeaderBackgroundColor;
+      if HdrBg = clDefault then HdrBg := clInfoBk;
+      HdrTxt := CheckListBox.HeaderColor;
+      if HdrTxt = clDefault then HdrTxt := clInfoText;
+    end;
+
     ARect := Data^.rcItem;
     TextRect := ARect;
 
-    // adjust text rectangle for check box items
+    // adjust text rectangle for check box and padding
     if not Header then
     begin
       if CheckListBox.UseRightToLeftAlignment then
@@ -209,9 +219,13 @@ class procedure TWin32WSCustomCheckListBox.DefaultWndHandler(
         TextRect.Left := TextRect.Left + TextRect.Bottom - TextRect.Top + 4;
     end;
 
+    // fill the background
     if Header then
-      // TODO: use TCheckListBox.HeaderBackground when implemented
+    begin
-      Windows.FillRect(Data^._HDC, ARect, GetSysColorBrush(SysColorToSysColorIndex(clInfoBk)))
+      BgBrush := Windows.CreateSolidBrush(ColorToRGB(HdrBg));
+      Windows.FillRect(Data^._HDC, ARect, BgBrush);
+      Windows.DeleteObject(BgBrush);
+    end
     else if Selected then
     begin
       Windows.FillRect(Data^._HDC, Rect(ARect.Left, ARect.Top, TextRect.Left, ARect.Bottom), CheckListBox.Brush.Reference.Handle);
@@ -249,13 +263,11 @@ class procedure TWin32WSCustomCheckListBox.DefaultWndHandler(
       TextFlags := DT_SINGLELINE or DT_VCENTER or DT_NOPREFIX;
     end;
     OldBkMode := Windows.SetBkMode(Data^._HDC, TRANSPARENT);
-    if Header then
+    if not Enabled then
-      // TODO: use TCheckListBox.HeaderColor when implemented
-      OldColor := Windows.SetTextColor(Data^._HDC, Windows.GetSysColor(SysColorToSysColorIndex(clInfoText)))
-    else if not Enabled then
       OldColor := Windows.SetTextColor(Data^._HDC, Windows.GetSysColor(COLOR_GRAYTEXT))
-    else
+    else if Header then
-    if Selected then
+      OldColor := Windows.SetTextColor(Data^._HDC, ColorToRGB(HdrTxt))
+    else if Selected then
       OldColor := Windows.SetTextColor(Data^._HDC, Windows.GetSysColor(COLOR_HIGHLIGHTTEXT))
     else
     begin