Test Blit

gistfile1.txt

   --  Blit_Scaled
   --
   --  Self        : The destination surface to blit onto.
   --  Self_Area   : The coordinates and size of the area to blit into.
   --  Source      : The surface to blit onto Self.
   --  Source_Area : The coordinates and size of the area to blit from.
   procedure Blit_Scaled (Self        : in out Surface;
                          Self_Area   : in out Rectangles.Rectangle;
                          Source      : in Surface;
                          Source_Area : in Rectangles.Rectangle := Rectangles.Null_Rectangle) is
      function SDL_Blit_Scaled (S  : in Internal_Surface_Pointer;
                                SR : access Rectangles.Rectangle;
                                D  : in Internal_Surface_Pointer;
                                DR : access Rectangles.Rectangle) return C.int with
        Import        => True,
        Convention    => C,
        External_Name => "SDL_UpperBlitScaled";  --  SDL_BlitScaled is a macro in SDL_surface.h
      use type Rectangles.Rectangle;

      Result : C.int                        := 0;
      Area   : aliased Rectangles.Rectangle := Self_Area;
   begin
      if Self_Area = Rectangles.Null_Rectangle then
         if Source_Area = Rectangles.Null_Rectangle then
            Result := SDL_Blit_Scaled (Source.Internal, null, Self.Internal, null);
         else
            Result := SDL_Blit_Scaled (Source.Internal, Source_Area'Access, Self.Internal, null);
         end if;
      else
         if Source_Area = Rectangles.Null_Rectangle then
            Result := SDL_Blit_Scaled (Source.Internal, null, Self.Internal, Area'Access);
         else
            Result := SDL_Blit_Scaled (Source.Internal, Source_Area'Access, Self.Internal, Area'Access);
         end if;

         Self_Area := Area;
      end if;

      if Result /= SDL.Success then
         raise Surface_Error with SDL.Error.Get;
      end if;
   end Blit_Scaled;