lcl, win32: use GetTextExtent as suggested in MSDN to get the correct text bounds before use of DrawThemeText() (issue #0021964)

git-svn-id: trunk@41646 -

lcl/forms.pp

@@ -847,6 +847,7 @@ type
     procedure DoShowWindow; override;
     procedure UpdateRegion;
     procedure SetColor(Value: TColor); override;
+    function UseThemes: Boolean;
   public
     constructor Create(AOwner: TComponent); override;
     destructor Destroy; override;

lcl/include/hintwindow.inc

@@ -87,7 +87,7 @@ begin
   if not HandleAllocated then
     Exit;
 
-  if (Color = clInfoBk) or (Color = clDefault) then
+  if UseThemes then
   begin
     Details := ThemeServices.GetElementDetails(tttStandardNormal);
     ARect := ClientRect;
@@ -104,6 +104,11 @@ begin
   UpdateRegion;
 end;
 
+function THintWindow.UseThemes: Boolean;
+begin
+  Result := (Color = clInfoBk) or (Color = clDefault);
+end;
+
 function THintWindow.GetDrawTextFlags: Cardinal;
 var
   EffectiveAlignment: TAlignment;
@@ -150,7 +155,7 @@ var
   Details: TThemedElementDetails;
 begin
   ARect := ClientRect;
-  if (Color = clInfoBk) or (Color = clDefault) then
+  if UseThemes then
   begin
     // draw using themes
     Details := ThemeServices.GetElementDetails(tttStandardNormal);
@@ -240,15 +245,19 @@ end;
 function THintWindow.CalcHintRect(MaxWidth: Integer; const AHint: String;
   AData: Pointer): TRect;
 begin
-  if AHint='' then
+  if AHint = '' then
   begin
-    Result:=Rect(0,0,0,0);
+    Result := Rect(0, 0, 0, 0);
-    exit;
+    Exit;
   end;
   if MaxWidth <= 0 then
     MaxWidth := Screen.Width - 4 * HintBorderWidth;
   Result := Rect(0, 0, MaxWidth, Screen.Height - 4 * HintBorderWidth);
-  DrawText(Canvas.GetUpdatedHandle([csFontValid]), PChar(AHint), Length(AHint),
+  if UseThemes then
+    Result := ThemeServices.GetTextExtent(Canvas.GetUpdatedHandle([csFontValid]),
+      ThemeServices.GetElementDetails(tttStandardNormal), AHint, DT_NOPREFIX or DT_WORDBREAK, @Result)
+  else
+    DrawText(Canvas.GetUpdatedHandle([csFontValid]), PChar(AHint), Length(AHint),
            Result, DT_CALCRECT or DT_NOPREFIX or DT_WORDBREAK);
   inc(Result.Right, 4 * HintBorderWidth);
   inc(Result.Bottom, 4 * HintBorderWidth);

lcl/interfaces/win32/win32themes.pas

@@ -37,6 +37,7 @@ type
     function GetDetailRegion(DC: HDC; Details: TThemedElementDetails; const R: TRect): HRGN; override;
     function GetStockImage(StockID: LongInt; out Image, Mask: HBitmap): Boolean; override;
     function GetOption(AOption: TThemeOption): Integer; override;
+    function GetTextExtent(DC: HDC; Details: TThemedElementDetails; const S: String; Flags: Cardinal; BoundingRect: PRect): TRect; override;
 
     procedure DrawElement(DC: HDC; Details: TThemedElementDetails; const R: TRect;
       ClipRect: PRect = nil); override;
@@ -280,6 +281,22 @@ begin
   end;
 end;
 
+function TWin32ThemeServices.GetTextExtent(DC: HDC; Details: TThemedElementDetails;
+  const S: String; Flags: Cardinal; BoundingRect: PRect): TRect;
+var
+  w: widestring;
+begin
+  if ThemesEnabled then
+    with Details do
+    begin
+      w := UTF8ToUTF16(S);
+      GetThemeTextExtent(Theme[Element], DC, Part, State, PWideChar(W), Length(W),
+        Flags, BoundingRect, Result);
+    end
+  else
+    Result := inherited GetTextExtent(DC, Details, S, Flags, BoundingRect);
+end;
+
 function TWin32ThemeServices.UseThemes: Boolean;
 begin
   Result := UxTheme.UseThemes and (GetFileVersion(comctl32) >= ComCtlVersionIE6);

lcl/themes.pas

@@ -479,6 +479,7 @@ type
     function GetDetailRegion(DC: HDC; Details: TThemedElementDetails; const R: TRect): HRGN; virtual;
     function GetStockImage(StockID: LongInt; out Image, Mask: HBitmap): Boolean; virtual;
     function GetOption(AOption: TThemeOption): Integer; virtual;
+    function GetTextExtent(DC: HDC; Details: TThemedElementDetails; const S: String; Flags: Cardinal; BoundingRect: PRect): TRect; virtual;
 
     function ColorToRGB(Color: LongInt; Details: PThemedElementDetails = nil): COLORREF;
     function ContentRect(DC: HDC; Details: TThemedElementDetails; BoundingRect: TRect): TRect; virtual;
@@ -821,7 +822,8 @@ end;
 
 //----------------------------------------------------------------------------------------------------------------------
 
-function TThemeServices.GetElementDetails(Detail: TThemedListview): TThemedElementDetails;
+function TThemeServices.GetElementDetails(Detail: TThemedListView
+  ): TThemedElementDetails;
 var
   Base: Integer;
 begin
@@ -1911,6 +1913,16 @@ begin
   end;
 end;
 
+function TThemeServices.GetTextExtent(DC: HDC; Details: TThemedElementDetails;
+  const S: String; Flags: Cardinal; BoundingRect: PRect): TRect;
+begin
+  if Assigned(BoundingRect) then
+    Result := BoundingRect^
+  else
+    Result := Rect(0, 0, 0, 0);
+  LCLIntf.DrawText(DC, PChar(S), Length(S), Result, DT_CALCRECT or Flags);
+end;
+
 //----------------------------------------------------------------------------------------------------------------------
 
 function TThemeServices.ColorToRGB(Color: LongInt; Details: PThemedElementDetails = nil): COLORREF;