The center, stretch and tile of the picture in Delphi

Problem Source: http://www.cnblogs.com/del/archive/2008/11/04/1326105.html#1533947

This example effect chart:

Code files:

Unit Unit1;

Interface

Uses
Windows, Messages, sysutils, variants, Classes, Graphics, Controls, Forms,
Dialogs, Stdctrls;

Type
TForm1 = Class (Tform)
Button1:tbutton;
Button2:tbutton;
Button3:tbutton;
Button4:tbutton;
Procedure Formcreate (Sender:tobject);
Procedure Formdestroy (Sender:tobject);
Procedure Button1Click (Sender:tobject);
Procedure Button2click (Sender:tobject);
Procedure Button3click (Sender:tobject);
Procedure Button4click (Sender:tobject);
End

Var
Form1:tform1;

Implementation

{$R *.DFM}

Var
Bit:tbitmap;

Procedure Tform1.button1click (Sender:tobject);
Begin
Repaint;
Bit. LoadFromFile (' C:\Temp\Test.bmp ');
Canvas.draw (0, 0, bit);
End

Procedure Tform1.button2click (Sender:tobject);
Var
X,y:integer;
Begin
Repaint;
x: = (clientwidth-bit. Width) Div 2;
Y: = (clientheight-bit. Height) Div 2;
Canvas.draw (x, y, bit);
End

Procedure Tform1.button3click (Sender:tobject);
Begin
Repaint;
Canvas.stretchdraw (clientrect, bit);
End

Procedure Tform1.button4click (Sender:tobject);
Begin
Self.Brush.Bitmap: = bit;
Repaint;
Self.Brush.Bitmap: = nil;
End

Procedure Tform1.formcreate (Sender:tobject);
Begin
Button1.caption: = ' load ';
Button2.caption: = ' centered ';
Button3.caption: = ' stretching ';
Button4.caption: = ' tile ';

bit: = Tbitmap.create;
Self.Brush.Bitmap: = nil;
End

Procedure Tform1.formdestroy (Sender:tobject);
Begin
Bit. Free;
End

End.