Pentagram: Difference between revisions
Added Delphi example
MaiconSoft (talk | contribs) (Added Delphi example) |
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}
</lang>
=={{header|Delphi}}==
{{libheader| Winapi.Windows}}
{{libheader| Vcl.Graphics}}
{{libheader| Vcl.Forms}}
{{libheader| System.Math}}
<lang Delphi>
unit Main;
interface
uses
Winapi.Windows, Vcl.Graphics, Vcl.Forms, System.Math;
type
TForm1 = class(TForm)
procedure FormCreate(Sender: TObject);
procedure FormPaint(Sender: TObject);
private
procedure DrawPentagram(len, x, y: Integer; fill, stoke: TColor);
{ Private declarations }
public
{ Public declarations }
end;
var
Form1: TForm1;
degrees144: double;
degrees72: double;
degrees18: double;
implementation
{$R *.dfm}
procedure TForm1.FormCreate(Sender: TObject);
begin
ClientHeight := 640;
ClientWidth := 640;
degrees144 := DegToRad(144);
degrees72 := DegToRad(72);
degrees18 := DegToRad(18);
end;
procedure CreatePolygon(len, x, y, n: integer; ang: double; var points: TArray<TPoint>);
var
angle: Double;
index, i, x2, y2: Integer;
begin
angle := 0;
index := 0;
SetLength(points, n + 1);
points[index].Create(x, y);
for i := 1 to n do
begin
x2 := x + round(len * cos(angle));
y2 := y + round(len * sin(-angle));
x := x2;
y := y2;
angle := angle - ang;
points[index].Create(x2, y2);
inc(index);
end;
points[index].Create(points[0]);
end;
procedure TForm1.DrawPentagram(len, x, y: Integer; fill, stoke: TColor);
var
points, points_internal: TArray<TPoint>;
L, H: Integer;
begin
// Calc of sides for draw internal pollygon
// 2H+L = len -> 2H = len - L
// L = 2H*sin(36/2) (Pythagorean theorem)
// L = (len-L)sin(18)
// L = len*sin(18)/[1+sin(18)]
L := round(len * sin(degrees18) / (1 + sin(degrees18)));
// H = (len - L)/2
H := (len - L) div 2;
CreatePolygon(L, x + H, y, 5, degrees72, points_internal);
CreatePolygon(len, x, y, 5, degrees144, points);
with Canvas, Canvas.Brush do
begin
with pen do
begin
Color := stoke;
Style := psSolid;
Width := 5;
end;
Color := fill;
Polygon(points_internal);
Polygon(points);
end;
end;
procedure TForm1.FormPaint(Sender: TObject);
begin
with Canvas, Brush do
begin
Style := bsSolid;
Color := clWhite;
// fill background with white
FillRect(ClientRect);
end;
drawPentagram(500, 70, 250, $ED9564, clDkGray);
end;
end.</lang>
form code:
<lang Delphi>
object Form1: TForm1
OnCreate = FormCreate
OnPaint = FormPaint
end
</lang>
=={{header|EasyLang}}==
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