delphitpagecontrol

How can i change text color of themed TabSheet caption?


Good Day!

I need to change text color of caption of some TabSheet in TPageControl. Something like this on picture

enter image description here

I know how it can be done using OnDrawTab. But if i enabled OwnerDraw, decoration of Windows XP Theme disappears. That's why i try to draw this decoration manually. This is how i tried to do this:

procedure TForm1.PageControl1DrawTab(Control: TCustomTabControl;
  TabIndex: Integer; const Rect: TRect; Active: Boolean);
var
  FRect: TRect;
  Text: string;
begin
  FRect := Control.TabRect(TabIndex);
  if Active then
    ThemeServices.DrawElement(Control.Canvas.Handle, ThemeServices.GetElementDetails(ttTabItemHot), FRect)
  else
    ThemeServices.DrawElement(Control.Canvas.Handle, ThemeServices.GetElementDetails(ttTabItemNormal), FRect);
  Text := PageControl1.Pages[TabIndex].Caption;
  Control.Canvas.Brush.Style := bsClear;
  if not Active then
    FRect.Top := FRect.Top + 4;
  DrawText(Control.Canvas.Handle, PChar(Text), Length(Text), FRect, DT_SINGLELINE or DT_CENTER or DT_VCENTER);
end;

And i got this

enter image description here

(left - OwnerDraw version, right - default draw)

As you can see, TabSheets have some borders that's are not overdrawn. And I can't overdraw this borders.

How can i draw background of tab correctly (like PageControl on the right)?


Solution

  • A possible solution is override the PaintWindow method of the TPageControl instead of use the ownerdraw , in this way you can control every visual aspect of the tabs.

    Check this basic sample.

    type
      TPageControl = class(Vcl.ComCtrls.TPageControl)
      private
        FColorTextTab: TColor;
        procedure  DrawTab(LCanvas: TCanvas; Index: Integer);
        procedure  DoDraw(DC: HDC; DrawTabs: Boolean);
        procedure SetColorTextTab(const Value: TColor);
      protected
        procedure PaintWindow(DC: HDC); override;
      published
        property  ColorTextTab : TColor read FColorTextTab write SetColorTextTab;
    
      end;
    
      TForm1 = class(TForm)
        PageControl1: TPageControl;
        TabSheet1: TTabSheet;
        TabSheet2: TTabSheet;
        CheckBox1: TCheckBox;
        Button2: TButton;
        Button3: TButton;
        Button4: TButton;
        TabSheet3: TTabSheet;
        TabSheet4: TTabSheet;
        TabSheet5: TTabSheet;
        TabSheet6: TTabSheet;
        procedure FormCreate(Sender: TObject);
      private
        { Private declarations }
      public
        { Public declarations }
      end;
    
    var
      Form1: TForm1;
    
    implementation
    
    {$R *.dfm}
    
    uses
     Math,
     Themes,
     Types;
    
    
    type
      TCustomTabControlClass = class(TCustomTabControl);
    
    procedure AngleTextOut2(Canvas: TCanvas; Angle: Integer; X, Y: Integer; const Text: string);
    var
      NewFontHandle, OldFontHandle: hFont;
      LogRec: TLogFont;
    begin
      GetObject(Canvas.Font.Handle, SizeOf(LogRec), Addr(LogRec));
      LogRec.lfEscapement := Angle * 10;
      LogRec.lfOrientation := LogRec.lfEscapement;
      NewFontHandle := CreateFontIndirect(LogRec);
      OldFontHandle := SelectObject(Canvas.Handle, NewFontHandle);
      SetBkMode(Canvas.Handle, TRANSPARENT);
      Canvas.TextOut(X, Y, Text);
      NewFontHandle := SelectObject(Canvas.Handle, OldFontHandle);
      DeleteObject(NewFontHandle);
    end;
    
    
    { TPageControl }
    procedure TPageControl.DrawTab(LCanvas: TCanvas; Index: Integer);
    var
      LDetails    : TThemedElementDetails;
      LImageIndex : Integer;
      LThemedTab  : TThemedTab;
      LIconRect   : TRect;
      R, LayoutR  : TRect;
      LImageW, LImageH, DxImage : Integer;
      LTextX, LTextY: Integer;
      LTextColor    : TColor;
        //draw the text in the tab
        procedure DrawControlText(const S: string; var R: TRect; Flags: Cardinal);
        var
          TextFormat: TTextFormatFlags;
        begin
          LCanvas.Font       := Font;
          TextFormat         := TTextFormatFlags(Flags);
          LCanvas.Font.Color := LTextColor;
          StyleServices.DrawText(LCanvas.Handle, LDetails, S, R, TextFormat, LCanvas.Font.Color);
        end;
    
    begin
      //get the size of tab image (icon)
      if (Images <> nil) and (Index < Images.Count) then
      begin
        LImageW := Images.Width;
        LImageH := Images.Height;
        DxImage := 3;
      end
      else
      begin
        LImageW := 0;
        LImageH := 0;
        DxImage := 0;
      end;
    
      R := TabRect(Index);
    
    
      //check the left position of the tab.
      if R.Left < 0 then Exit;
    
      //adjust the size of the tab to draw
      if TabPosition in [tpTop, tpBottom] then
      begin
        if Index = TabIndex then
          InflateRect(R, 0, 2);
      end
      else
      if Index = TabIndex then
        Dec(R.Left, 2)
      else
        Dec(R.Right, 2);
    
      LCanvas.Font.Assign(Font);
      LayoutR := R;
      LThemedTab := ttTabDontCare;
      //Get the type of the active tab to draw
    
      case TabPosition of
        tpTop:
          begin
            if Index = TabIndex then
              LThemedTab := ttTabItemSelected
            else
            {
            if (Index = HotTabIndex) and MouseInControl then
              LThemedTab := ttTabItemHot
            else
            }
              LThemedTab := ttTabItemNormal;
          end;
        tpLeft:
          begin
            if Index = TabIndex then
              LThemedTab := ttTabItemLeftEdgeSelected
            else
            {
            if (Index = HotTabIndex) and MouseInControl then
              LThemedTab := ttTabItemLeftEdgeHot
            else
            }
              LThemedTab := ttTabItemLeftEdgeNormal;
          end;
        tpBottom:
          begin
            if Index = TabIndex then
              LThemedTab := ttTabItemBothEdgeSelected
            else
            {
            if (Index = HotTabIndex) and MouseInControl then
              LThemedTab := ttTabItemBothEdgeHot
            else
            }
              LThemedTab := ttTabItemBothEdgeNormal;
          end;
        tpRight:
          begin
            if Index = TabIndex then
              LThemedTab := ttTabItemRightEdgeSelected
            else
            {
            if (Index = HotTabIndex) and MouseInControl then
              LThemedTab := ttTabItemRightEdgeHot
            else
            }
              LThemedTab := ttTabItemRightEdgeNormal;
          end;
      end;
    
      //draw the tab
      if StyleServices.Available then
      begin
        LDetails := StyleServices.GetElementDetails(LThemedTab);//necesary for DrawControlText and draw the icon
        StyleServices.DrawElement(LCanvas.Handle, LDetails, R);
      end;
    
      //get the index of the image (icon)
      if Self is TCustomTabControl then
        LImageIndex := TCustomTabControlClass(Self).GetImageIndex(Index)
      else
        LImageIndex := Index;
    
      //draw the image
      if (Images <> nil) and (LImageIndex >= 0) and (LImageIndex < Images.Count) then
      begin
        LIconRect := LayoutR;
        case TabPosition of
          tpTop, tpBottom:
            begin
              LIconRect.Left := LIconRect.Left + DxImage;
              LIconRect.Right := LIconRect.Left + LImageW;
              LayoutR.Left := LIconRect.Right;
              LIconRect.Top := LIconRect.Top + (LIconRect.Bottom - LIconRect.Top) div 2 - LImageH div 2;
              if (TabPosition = tpTop) and (Index = TabIndex) then
                OffsetRect(LIconRect, 0, -1)
              else
              if (TabPosition = tpBottom) and (Index = TabIndex) then
                OffsetRect(LIconRect, 0, 1);
            end;
          tpLeft:
            begin
              LIconRect.Bottom := LIconRect.Bottom - DxImage;
              LIconRect.Top := LIconRect.Bottom - LImageH;
              LayoutR.Bottom := LIconRect.Top;
              LIconRect.Left := LIconRect.Left + (LIconRect.Right - LIconRect.Left) div 2 - LImageW div 2;
            end;
          tpRight:
            begin
              LIconRect.Top := LIconRect.Top + DxImage;
              LIconRect.Bottom := LIconRect.Top + LImageH;
              LayoutR.Top := LIconRect.Bottom;
              LIconRect.Left := LIconRect.Left + (LIconRect.Right - LIconRect.Left) div 2 - LImageW div 2;
            end;
        end;
        if StyleServices.Available then
          StyleServices.DrawIcon(LCanvas.Handle, LDetails, LIconRect, Images.Handle, LImageIndex);
      end;
    
      //draw the text of the tab
      if StyleServices.Available then
      begin
        //StyleServices.GetElementColor(LDetails, ecTextColor, LTextColor);
        LTextColor:=FColorTextTab;
    
        if (TabPosition = tpTop) and (Index = TabIndex) then
          OffsetRect(LayoutR, 0, -1)
        else
        if (TabPosition = tpBottom) and (Index = TabIndex) then
          OffsetRect(LayoutR, 0, 1);
    
        if TabPosition = tpLeft then
        begin
          LTextX := LayoutR.Left + (LayoutR.Right - LayoutR.Left) div 2 - LCanvas.TextHeight(Tabs[Index]) div 2;
          LTextY := LayoutR.Top + (LayoutR.Bottom - LayoutR.Top) div 2 + LCanvas.TextWidth(Tabs[Index]) div 2;
          LCanvas.Font.Color:=LTextColor;
          AngleTextOut2(LCanvas, 90, LTextX, LTextY, Tabs[Index]);
        end
        else
        if TabPosition = tpRight then
        begin
          LTextX := LayoutR.Left + (LayoutR.Right - LayoutR.Left) div 2 + LCanvas.TextHeight(Tabs[Index]) div 2;
          LTextY := LayoutR.Top + (LayoutR.Bottom - LayoutR.Top) div 2 - LCanvas.TextWidth(Tabs[Index]) div 2;
          LCanvas.Font.Color:=LTextColor;
          AngleTextOut2(LCanvas, -90, LTextX, LTextY, Tabs[Index]);
        end
        else
         DrawControlText(Tabs[Index], LayoutR, DT_VCENTER or DT_CENTER or DT_SINGLELINE  or DT_NOCLIP);
      end;
    end;
    
    procedure TPageControl.DoDraw(DC: HDC; DrawTabs: Boolean);
    var
      Details: TThemedElementDetails;
      R: TRect;
      LIndex, SelIndex: Integer;
    begin
      Details := StyleServices.GetElementDetails(ttTabItemNormal);
      SelIndex := TabIndex;
      try
        Canvas.Handle := DC;
        if DrawTabs then
          for LIndex := 0 to Tabs.Count - 1 do
            if LIndex <> SelIndex then
             DrawTab(Canvas, LIndex);
    
        if SelIndex < 0 then
          R := Rect(0, 0, Width, Height)
        else
        begin
          R := TabRect(SelIndex);
          R.Left := 0;
          R.Top := R.Bottom;
          R.Right := Width;
          R.Bottom := Height;
        end;
    
        StyleServices.DrawElement(DC, StyleServices.GetElementDetails(ttPane), R);
    
        if (SelIndex >= 0) and DrawTabs then
          DrawTab(Canvas, SelIndex);
      finally
        Canvas.Handle := 0;
      end;
    end;
    
    procedure TPageControl.PaintWindow(DC: HDC);
    begin
     DoDraw(DC, True);
     //inherited;
    end;
    
    procedure TPageControl.SetColorTextTab(const Value: TColor);
    begin
      FColorTextTab := Value;
    end;
    
    procedure TForm1.FormCreate(Sender: TObject);
    begin
      PageControl1.ColorTextTab:=clGreen;
    end;
    

    And this is the result.

    enter image description here