Question about Themes.pas and TWinControl.Canvas

[Avishai]

Maybe someone that is familiar with Themes.pas can explain to me what this code does.  The reason I ask is because when I mirror TWinControl for RightToLeftLayout, TWinControl.Canvas is corrupted and can not be used.

Code: [Select]

procedure TThemeServices.UpdateThemes;
begin
  if FUseThemes then
    UnloadThemeData;
  FUseThemes := UseThemes;
  if FUseThemes then
    FThemedControlsEnabled := ThemedControlsEnabled
  else
    FThemedControlsEnabled := False;
end;

If I change the code as follows, everything seems to work correctly and the Canvas is fine, but I'm not sure about any side effects.  It may have effects that I don't know about.

Code: [Select]

procedure TThemeServices.UpdateThemes;
begin
  if FUseThemes then
    UnloadThemeData;
  FUseThemes := UseThemes;

  //if FUseThemes then
  //  FThemedControlsEnabled := ThemedControlsEnabled
  //else
    FThemedControlsEnabled := False;
end;

Edit:  I found one of the side effects.  Some TGraphicControls are drawn differently with my changes.  I.E. TSpeedButton has square corners.  But for me, this is a very small price to pay to be able to produce RightToLeft Forms.

[Bart]

Well, basically you are disabling themes...

Bart

[Avishai]

Well I sure hope so.  At least that is my intent.  What I don't understand is this. 

If I disable Themes by un-checking "Use manifest file to enable themes" in Project Options, it affects the drawing on almost all controls. 

If I disable Themes in "procedure TThemeServices.UpdateThemes;" it looks like only TGraphicControls are drawn differently.

[Avishai]

What I'm really looking for is a way to fix Themes so that it doesn't corrupt TCanvas when RightToLeftLayout is used.