DelphiBasics
Rect
Function
Create a TRect value from 2 points or 4 coordinates Classes unit
1  function Rect ( Left, Top, Right, Bottom : Integer ) : TRect;
2  function Rect ( TopLeft, BottomRight : TPoint ) : TRect;
Description
The Rect function creates a TRect (rectangle) value from either 4 coordinates or 2 points.
 
When creating from two points TopLeft and BottomRight, you can pass two TPoint values, or use the Point function to generate them.
Notes
Important

There are two Rect functions in the Classes and Types units. Only the former supports the second syntax.

If using both of these units in your code, and you specify Types after Classes you must prefix Rect with Classes to use this second syntax.
Related commands
Bounds Create a TRect value from top left and size values
Point Generates a TPoint value from X and Y values
PointsEqual Compares two TPoint values for equality
PtInRect Tests to see if a point lies within a rectangle
TPoint Holds X and Y integer values
TRect Holds rectangle coordinate values
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Example code : Create two rectangles using both syntaxes
// Full Unit code.
// -----------------------------------------------------------
// You must store this code in a unit called Unit1 with a form
// called Form1 that has an OnCreate event called FormCreate.
 
unit Unit1;
 
interface
 
uses
  Classes,   // Unit containing the Rect command
  Types,
  Forms, Dialogs;
 
type
  TForm1 = class(TForm)
    procedure FormCreate(Sender: TObject);
  end;
 
var
  
Form1: TForm1;
 
implementation
{$R *.dfm} // Include form definitions
 
procedure TForm1.FormCreate(Sender: TObject);

var
  rectangle1, rectangle2 : TRect;

begin
  // Set up the first rectangle using syntax 1
  rectangle1 := Rect(20, 40, 60, 80);

  // Set up the second rectangle using the Rect function
  rectangle2 := Classes.Rect(Point(20, 40), Point(60, 80));

  // Display the top left and bottom right coords of each rectangle
  ShowMessageFmt('Rectangle 1 coords = %d,%d,%d,%d',
                 [rectangle1.Left,
                  rectangle1.Top,
                  rectangle1.Right,
                  rectangle1.Bottom]);

  ShowMessageFmt('Rectangle 2 coords = %d,%d,%d,%d',
                 [rectangle2.Left,
                  rectangle2.Top,
                  rectangle2.Right,
                  rectangle2.Bottom]);
end;
 
end.
Hide full unit code
   Rectangle 1 coords = 20,40,60,80
   Rectangle 2 coords = 20,40,60,80
 
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