asked on

Print TForm.Canvas as Bitmap

I am developing a charting application. I use the Canvas of TForm as my drawing area. Is there a way for me to save my drawing as a bitmap file?

My current solution is to use BitBlt, but the problem with this is that when other windows popup over the Form which is being saved; they will also be included in the bitmap. Furthermore, with BitBlt I cannot save the canvas of a Form when the form is minimized. How do I work on this?

ASKER CERTIFIED SOLUTION

hubdog

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hubdog

tform.GetFormImage method can return a tbitmap

good luck
hubdog

aubs

You should try using a bitmap created in memory rather than the form's canvas to draw on. Saving the bitmap is far easier too.

These needs tidying up, but should give you a better idea...

unit Unit1;

interface

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

type
TForm1 = class(TForm)
Button1: TButton;
procedure FormCreate(Sender: TObject);
procedure FormDestroy(Sender: TObject);
procedure FormMouseDown(Sender: TObject; Button: TMouseButton;
Shift: TShiftState; X, Y: Integer);
procedure Button1Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;

var
Form1: TForm1;
Bitmap: TBitmap;
implementation

{$R *.DFM}

procedure TForm1.FormCreate(Sender: TObject);
begin
bitmap:= TBitmap.Create;
bitmap.Width:= Clientwidth;
bitmap.height:= clientheight;
end;

procedure TForm1.FormDestroy(Sender: TObject);
begin
bitmap.Free;
end;

procedure TForm1.FormMouseDown(Sender: TObject; Button: TMouseButton;
Shift: TShiftState; X, Y: Integer);
begin
bitmap.Canvas.LineTo(X,Y);
canvas.Draw(0,0,bitmap);
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
bitmap.SaveToFile('c:\temp\test.bmp');
end;

end.

Aubs

AttarSoftware

Does :

myBmp := tBitmap.Create ;
myBmp.Width := Form1.Width ;
myBmp.Height := Form1.Height ;
Form1.PaintTo( myBmp.Canvas.Handle, 0, 0 ) ;

work?

Good luck,

Tim.

newind

ASKER

Well I say it's a great function. It did solve my problem.

Thanks a lot hubdog!