Crop Image with Drag the Mouse

Author: admin | Category: Graphic, Tips and Tricks

//This is how we can crop image by dragging mouse over the image
//This example needs Image (TImage) and Button (TButton)
//Drag your mouse over Image1 then click Button1
 
unit Unit1;
 
interface
 
uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, ExtCtrls, StdCtrls;
 
type
  TForm1 = class(TForm)
    Button1: TButton;
    Image1: TImage;
    procedure Image1MouseDown(Sender: TObject; Button: TMouseButton;
      Shift: TShiftState; X, Y: Integer);
    procedure Image1MouseMove(Sender: TObject; Shift: TShiftState; X,
      Y: Integer);
    procedure Image1MouseUp(Sender: TObject; Button: TMouseButton;
      Shift: TShiftState; X, Y: Integer);
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;
 
var
  Form1: TForm1;
 
implementation
 
{$R *.dfm}
 
var
  PDown             : TPoint;
  PActually         : TPoint;
  MouseIsDown       : Boolean;
 
procedure TForm1.Image1MouseDown(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
begin
  PDown := Point(x, y);
  PActually := Point(x, y);
  MouseIsDown := TRUE;
  Image1.Canvas.DrawFocusRect(Rect(x, y, x, y));
end;
 
procedure TForm1.Image1MouseMove(Sender: TObject; Shift: TShiftState; X,
  Y: Integer);
begin
  if MouseIsDown then
  begin
    Image1.Canvas.DrawFocusRect(Rect(PDown.x, PDown.y, PActually.x,PActually.y));
    PActually := Point(x, y);
    Image1.Canvas.DrawFocusRect(Rect(PDown.x, PDown.y, x, y));
  end;
end;
 
procedure TForm1.Image1MouseUp(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
begin
  Image1.Canvas.DrawFocusRect(Rect(PDown.x, PDown.y, PActually.x, PActually.y));
  Image1.Canvas.DrawFocusRect(Rect(PDown.x, PDown.y, x, y));
  PActually := Point(x, y);
  MouseIsDown := FALSE;
end;
 
procedure TForm1.Button1Click(Sender: TObject);
var
  TmpBmp            : TBitmap;
begin
  Image1.Canvas.DrawFocusRect(Rect(PDown.x, PDown.y, PActually.x, PActually.y));
  TmpBmp := TBitmap.Create;
  with TmpBmp do
  try
    Width := Round(abs(PActually.x - PDown.x));
    Height := Round(abs(PActually.y - PDown.y));
    BitBlt(Canvas.Handle, 0, 0, Width, Height, Image1.Canvas.Handle, PDown.x,
      PDown.y, SRCCOPY);
    Image1.AutoSize := TRUE;
    Image1.Picture.Bitmap.Assign(TmpBmp);
  finally
    Free;
  end;
end;
 
end.

Tags: Bitmap, Graphic, Image