Delphi Basics : Rect command

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

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;

Show full unit code

Rectangle 1 coords = 20,40,60,80
Rectangle 2 coords = 20,40,60,80