Task

Create a window and draw a pixel in it, subject to the following:

  the window is 320 x 240
  the color of the pixel must be red (255,0,0)
  the position of the pixel is x = 100, y = 100
with SDL.Video.Windows.Makers;
with SDL.Video.Renderers.Makers;
with SDL.Events.Events;
 
procedure Draw_A_Pixel is
 
   Width   : constant := 320;
   Height  : constant := 200;
 
   Window   : SDL.Video.Windows.Window;
   Renderer : SDL.Video.Renderers.Renderer;
 
   procedure Wait is
      use type SDL.Events.Event_Types;
      Event : SDL.Events.Events.Events;
   begin
      loop
         while SDL.Events.Events.Poll (Event) loop
            if Event.Common.Event_Type = SDL.Events.Quit then
               return;
            end if;
         end loop;
         delay 0.100;
      end loop;
   end Wait;
 
begin
   if not SDL.Initialise (Flags => SDL.Enable_Screen) then
      return;
   end if;
 
   SDL.Video.Windows.Makers.Create (Win      => Window,
                                    Title    => "Draw a pixel",
                                    Position => SDL.Natural_Coordinates'(X => 10, Y => 10),
                                    Size     => SDL.Positive_Sizes'(Width, Height),
                                    Flags    => 0);
   SDL.Video.Renderers.Makers.Create (Renderer, Window.Get_Surface);
   Renderer.Set_Draw_Colour ((0, 0, 0, 255));
   Renderer.Fill (Rectangle => (0, 0, Width, Height));
   Renderer.Set_Draw_Colour ((255, 0, 0, 255));
   Renderer.Draw (Point => (100, 100));
   Window.Update_Surface;
 
   Wait;
   Window.Finalize;
   SDL.Finalise;
end Draw_A_Pixel;