Tutorial Algoritma Garis DDA dan Bresenham pada Delphi 7

Assalamualaikum...



full code :
unit Garis;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, ExtCtrls;

type
  TForm1 = class(TForm)
    Label1: TLabel;
    Label2: TLabel;
    editX1: TEdit;
    editX2: TEdit;
    Label3: TLabel;
    Label4: TLabel;
    editY1: TEdit;
    editY2: TEdit;
    ScrollBox1: TScrollBox;
    Image1: TImage;
    btnDDA: TButton;
    btnBrese: TButton;
    btnClear: TButton;
    btnExit: TButton;
    btnEllipse: TButton;
    Label5: TLabel;
    Label6: TLabel;
    EditRx: TEdit;
    EditRy: TEdit;
    Label7: TLabel;
    Label8: TLabel;
    EditA: TEdit;
    EditB: TEdit;
    Label9: TLabel;
    Label10: TLabel;
    Label11: TLabel;
    EditWal: TEdit;
    EditHir: TEdit;
    Label12: TLabel;
    procedure FormShow(Sender: TObject);
    procedure btnClearClick(Sender: TObject);
    procedure btnDDAClick(Sender: TObject);
    procedure btnExitClick(Sender: TObject);
    procedure btnBreseClick(Sender: TObject);
    procedure rgbwarna;
    procedure btnEllipseClick(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;
  x1,x2,y1,y2,i,j : integer;
  x,y : double;
  m,step,stepX,stepY : double;
  dx,dy,p : integer;
  red, green, blue, d : integer;
  c, rx, ry : double;
  sudwal, sudhir : double;
  n, g : integer;

implementation
uses Math;
{$R *.dfm}

procedure TForm1.FormShow(Sender: TObject);
begin
  Image1.Canvas.Pen.Color := clRed;
  Image1.Canvas.Pen.Style := psDash;
  Image1.Canvas.MoveTo(Image1.Width div 2, 0);
  Image1.Canvas.LineTo(Image1.Width div 2,Image1.Height);
  Image1.Canvas.MoveTo(0, Image1.Height div 2);
  Image1.Canvas.LineTo(Image1.Width,Image1.Height div 2);
end;

procedure TForm1.btnClearClick(Sender: TObject);
begin
  Image1.Canvas.Pen.Color := clWhite;
  Image1.Canvas.Brush.Color := clWhite;
  Image1.Canvas.Brush.Style := bsSolid;
  Image1.Canvas.Pen.Style := psSolid;
  Image1.Canvas.Rectangle(0,0,Image1.Width,Image1.Height);
  FormShow(nil);
end;

procedure TForm1.btnDDAClick(Sender: TObject);
begin
  x1 := StrToInt(editX1.Text);
  x2 := StrToInt(editX2.Text);
  y1 := StrToInt(editY1.Text);
  y2 := StrToInt(editY2.Text);

  dx := abs(x2-x1);
  dy := abs(y2-y1);

  //m := abs(dy / dx);

  step := max(abs(dx),abs(dy));
  stepX := (x2 - x1) / step;
  stepY := (y2 - y1) / step;
  x := x1;
  y := y1;
  j := round(step)-1;

  red := 0;
  green := 0;
  blue := 0;

  btnClearClick(sender);
  Image1.Canvas.Pixels[(Image1.Width div 2 + round(x)),(Image1.Height div 2 - round(y))] := RGB(red,green,blue);
  for i := 1 to j do
  begin
    x := x + stepX;
    y := y + stepY;
    rgbwarna();
    Image1.Canvas.Pixels[(Image1.Width div 2 + round(x)),(Image1.Height div 2 - round(y))] := RGB(red,green,blue);
  end;
end;

procedure TForm1.btnExitClick(Sender: TObject);
begin
 close;
end;

procedure TForm1.btnBreseClick(Sender: TObject);
begin
  x1 := StrToInt(editX1.Text);
  x2 := StrToInt(editX2.Text);
  y1 := StrToInt(editY1.Text);
  y2 := StrToInt(editY2.Text);

  //dx dan dy dibulatkan
  dx := abs(x2-x1);
  dy := abs(y2-y1);

  m := abs(dy / dx);

  step := max(abs(dx),abs(dy));
  stepX := (x2 - x1) / dx;
  stepY := (y2 - y1) / dy;
  x := x1;
  y := y1;
  j := round(step)-1;

  red := 0;
  green := 0;
  blue := 0;

  if dx > dy then
  begin
     p := (2 * dy) - dx;
     btnClearClick(sender);
     //rgbwarna();
     Image1.Canvas.Pixels[(Image1.Width div 2 + round(x)),(Image1.Height div 2 - round(y))] := RGB(red,green,blue);
     for i := 1 to j do
     begin
        x := x + stepX;
        if p > 0 then
        begin
            y := y + stepY;
            p := p + ((2 * dy) - (2 * dx));
        end
        else
            p := p + (2 * dy);
            rgbwarna();
        Image1.Canvas.Pixels[(Image1.Width div 2 + round(x)),(Image1.Height div 2 - round(y))] := RGB(red,green,blue);
     end
  end
  else
  begin
     p := (2 * dx) - dy;
     btnClearClick(sender);
     //rgbwarna();
     Image1.Canvas.Pixels[(Image1.Width div 2 + round(x)),(Image1.Height div 2 - round(y))] := RGB(red,green,blue);
     for i := 1 to j do
     begin
        y := y + stepY;
        if p > 0 then
        begin
           x := x + stepX;
           p := p + ((2 * dx) - (2 * dy));
        end
        else
           p := p + (2 * dx);
           rgbwarna();
        Image1.Canvas.Pixels[(Image1.Width div 2 + round(x)),(Image1.Height div 2 - round(y))] := RGB(red,green,blue);
     end
  end
end;

procedure TForm1.rgbwarna;
begin
  red := red + 1;
  green := green + 1;
  blue := blue + 1;
end;

procedure TForm1.btnEllipseClick(Sender: TObject);
var
  sud : double;
begin
  n := StrToInt(EditA.Text);
  g := StrToInt(EditB.Text);

  sudwal := StrToFloat(EditWal.Text);
  sudhir := StrToFloat(EditHir.Text);

  rx := StrToFloat(EditRx.Text);
  ry := StrToFloat(EditRy.Text);

  red := 0;
  green:= 0;
  blue:= 0;

  //ambil C sebagai pencacah dengan nilai R yang terbesar (Rx atau Ry)
  if rx > ry then
    c := 1 / rx
  else
    c := 1 / max(rx,ry);

  //sudwal := 0;
  sud := sudhir / 180 * pi;

  btnClearClick(sender);
  Image1.Canvas.Pixels[(Image1.Width div 2 + round(x)),(Image1.Height div 2 - round(y))] := RGB(red,green,blue);
  (*while (sudwal <= sudhir) do
  begin
      x := n + (rx * cos(sud));
      y := g + (ry * sin(sud));
      Image1.Canvas.Pixels[(Image1.Width div 2 + round(x)),(Image1.Height div 2 - round(y))] := clGreen;
      sudwal := round(sudwal + c);
  end;      *)

end;

end.