Peano curve: Difference between revisions

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 {{out}}
 [https://gitlab.com/amarok8bit/action-rosetta-code/-/raw/master/images/Peano_curve.png Screenshot from Atari 8-bit computer]
+=={{header|Ada}}==
+{{trans|C}}
+{{libheader|APDF}}
+<lang Ada>with PDF_Out;  use PDF_Out;
+procedure Peano_Curve is
+   Filename   : constant String     := "peano-curve.pdf";
+   Order      : constant Positive   := 4;
+   Scale      : constant Real       := 2.1;
+   Line_Width : constant Real       := 2.5;
+   Corner     : constant Point      := (150.0, 50.0);
+   Background : constant Color_Type := (0.827, 0.816, 0.016);
+   Frame      : constant Rectangle  := (10.0, 10.0, 820.0, 575.0);
+   PDF        : PDF_Out_File;
+   type Coord is record
+      X, Y : Natural;
+   end record;
+   function "+" (Left : Coord; Right : Coord) return Coord
+   is ((Left.X + Right.X, Left.Y + Right.Y));
+   function "*" (Left : Natural; Right : Coord) return Coord
+   is ((Left * Right.X, Left * Right.Y));
+   procedure Peano (Pos : Coord; Length : Positive; I1, I2 : Integer) is
+      Len : constant Integer := Length / 3;
+   begin
+      if Length = 1 then
+         PDF.Line (Corner + Scale * (Real (3 * Pos.X), Real (3 * Pos.Y)));
+      else
+         Peano (Pos + Len * (2 * I1,      2 * I1),      Len, I1,     I2);
+         Peano (Pos + Len * (I1 - I2 + 1, I1 + I2),     Len, I1,     1 - I2);
+         Peano (Pos + Len * (1,           1),           Len, I1,     1 - I2);
+         Peano (Pos + Len * (I1 + I2,     I1 - I2 + 1), Len, 1 - I1, 1 - I2);
+         Peano (Pos + Len * (2 * I2,      2 - 2 * I2),  Len, I1,     I2);
+         Peano (Pos + Len * (1 + I2 - I1, 2 - I1 - I2), Len, I1,     I2);
+         Peano (Pos + Len * (2 - 2 * I1,  2 - 2 * I1),  Len, I1,     I2);
+         Peano (Pos + Len * (2 - I1 - I2, 1 + I2 - I1), Len, 1 - I1, I2);
+         Peano (Pos + Len * (2 - 2 * I2,  2 * I2),      Len, 1 - I1, I2);
+      end if;
+   end Peano;
+   procedure Draw_Peano is
+   begin
+      PDF.Stroking_Color (Black);
+      PDF.Line_Width (Line_Width);
+      PDF.Move (Corner);
+      Peano ((0, 0), 3**Order, 0, 0);
+      PDF.Finish_Path (Close_Path => False,
+                       Rendering  => Stroke,
+                       Rule       => Nonzero_Winding_Number);
+   end Draw_Peano;
+begin
+   PDF.Create (Filename);
+   PDF.Page_Setup (A4_Landscape);
+   PDF.Color (Background);
+   PDF.Draw (Frame, Fill);
+   Draw_Peano;
+   PDF.Close;
+end Peano_Curve;</lang>
 =={{header|AutoHotkey}}==