Raster bars: Difference between revisions

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 {{draft task}}
 Display bars of color, moving up and down across the screen for horizontal raster bars, or left and right across the screen for vertical raster bars, making the raster bars move as stated by swaying side-to-side the respective way if possible. Use multiple colors in succession and carefully make a gradient between the colors if possible to achieve an effect of metallic-looking horizontal bars. Horizontal and/or vertical raster bars are accepted.
+=={{header|Ada}}==
+{{libheader|SDLAda}}
+<lang Ada>with Ada.Numerics.Elementary_Functions;
+with SDL.Video.Windows.Makers;
+with SDL.Video.Renderers.Makers;
+with SDL.Video.Palettes;
+with SDL.Events.Events;
+procedure Raster_Bars is
+   Width   : constant := 1200;
+   Height  : constant := 600;
+   Window   : SDL.Video.Windows.Window;
+   Renderer : SDL.Video.Renderers.Renderer;
+   function Check_Quit return Boolean is
+      use type SDL.Events.Event_Types;
+      Event : SDL.Events.Events.Events;
+   begin
+      while SDL.Events.Events.Poll (Event) loop
+         if Event.Common.Event_Type = SDL.Events.Quit then
+            return True;
+         end if;
+      end loop;
+      return False;
+   end Check_Quit;
+   procedure Draw_Raster_Bar (Y : Integer) is
+      use SDL.Video.Palettes;
+      use SDL.C;
+      Cc : Colour_Component;
+   begin
+      for I in 0 .. 10 loop
+         Cc := Colour_Component (50 + 20 * I);
+         Renderer.Set_Draw_Colour ((Cc, Cc, Cc, 255));
+         Renderer.Draw (Line => ((0,     C.int (Y + I)),
+                                 (Width, C.int (Y + I))));
+      end loop;
+   end Draw_Raster_Bar;
+   procedure Draw_Raster_Bar_V (X : Integer) is
+      use SDL.Video.Palettes;
+      use SDL.C;
+      Cc : Colour_Component;
+   begin
+      for I in 0 .. 10 loop
+         Cc := Colour_Component (250 - 20 * I);
+         Renderer.Set_Draw_Colour ((Cc, Cc, Cc, 255));
+         Renderer.Draw (Line => ((C.int (X + I), 0),
+                                 (C.int (X + I), Height)));
+      end loop;
+   end Draw_Raster_Bar_V;
+   procedure Raster_Bars is
+      use Ada.Numerics.Elementary_Functions;
+      Xc  : constant Integer := 800;
+      Yc  : constant Integer := 200;
+      XA  : constant Float   := 40.0;
+      YA  : constant Float   := 30.0;
+      N : Float := 0.0;
+   begin
+      loop
+         Renderer.Set_Draw_Colour ((0, 0, 0, 255));
+         Renderer.Fill (Rectangle => (0, 0, Width, Height));
+         Draw_Raster_Bar (Yc + Integer (YA * Sin (N + 00.0, 360.0)));
+         Draw_Raster_Bar (Yc + Integer (YA * Sin (N + 25.0, 360.0)));
+         Draw_Raster_Bar (Yc + Integer (YA * Sin (N + 50.0, 360.0)));
+         Draw_Raster_Bar (Yc + Integer (YA * Sin (N + 75.0, 360.0)));
+         Draw_Raster_Bar_V (Xc + Integer (XA * Sin (0.6 * N + 00.0, 360.0)));
+         Draw_Raster_Bar_V (Xc + Integer (XA * Sin (0.6 * N + 90.0, 360.0)));
+         Draw_Raster_Bar_V (Xc + Integer (XA * Sin (0.6 * N + 180.0, 360.0)));
+         Window.Update_Surface;
+         if Check_Quit then
+            exit;
+         end if;
+         delay 0.010;
+         N := N + 4.0;
+      end loop;
+   end Raster_Bars;
+begin
+   if not SDL.Initialise (Flags => SDL.Enable_Screen) then
+      return;
+   end if;
+   SDL.Video.Windows.Makers.Create (Win      => Window,
+                                    Title    => "Raster bar",
+                                    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);
+   Raster_Bars;
+   Window.Finalize;
+   SDL.Finalise;
+end Raster_Bars;</lang>
 =={{header|Go}}==