asked on

Determine the dynamic length of the scrollbar

Hello,
in my form is a scrollbox.
Within the scrollbox I have a TImage.

1) The scrollbox should have only a scrollbar if the generated content does not fit on the image. Contents are drawings of rectangles.
2) The scrollbox should only be as high as the generated content, but should be at least X pixels high.
3) When I draw a rectangle out of the view, then the rectangle should be visible, when scrolling.

How can I implement this?
These questions are so important.

unit Unit1;

interface

uses
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.ExtCtrls;

type
  TForm1 = class(TForm)
    ScrollBox1: TScrollBox;
    Image1: TImage;
    procedure FormActivate(Sender: TObject);
  private
    { Private-Deklarationen }
  public
    { Public-Deklarationen }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.FormActivate(Sender: TObject);
begin
  left:=5;
  top:=10;
  form1.Width:=Screen.Width-15;
  form1.Height:=Screen.Height-50;
  ScrollBox1.Align:=alClient;
  image1.Left:=0;
  image1.Top:=0;
  image1.Width:=ScrollBox1.Width;
  image1.Height:=ScrollBox1.Height;
  image1.Canvas.Rectangle(1400,50,2000,100);
end;

end.

Open in new window

Thank you

Geert G

use self !

procedure TForm1.FormActivate(Sender: TObject);
begin
  left:=5;
  top:=10;
  self.Width:

Open in new window

everything drawn outside the TGraphic contained in the TImage is clipped

you should study the differences between a container object and a non container object
what objects have a canvas and how to draw on them
a TPersistent object

the autosize property of Tscrollbox ...

Sinisa Vuk

You have lots of stuff under FormActivate event. Most should be (or better be) defined in design mode (via property toolbox)
Draw your graphic (TBitmap) in back - assign to TImage, set TImage as AutoSize and Scrollbox to autosize too as Geert said.

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