How to display image transition effects on the table.next event

Problem/Question/Abstract:

How to display image transition effects on the table.next event

Answer:

Here's a rather simple example, using the :DBDEMOS:BIOLIFE table:

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  StdCtrls, Grids, DBGrids, DB, DBTables, ExtCtrls;

type
  TForm1 = class(TForm)
    Table1: TTable;
    DataSource1: TDataSource;
    DBGrid1: TDBGrid;
    Image1: TImage;
    Timer1: TTimer;

    procedure DataSource1DataChange(Sender: TObject; Field: TField);
    procedure Timer1Timer(Sender: TObject);
  private
    { Private declarations }
    Y: integer;
    NewBitmap: TBitmap;
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.DFM}

const
  BIOLifeWidth = 250;
  BIOLifeHeight = 150;

procedure TForm1.DataSource1DataChange(Sender: TObject; Field: TField);
begin
  if Table1.State = dsBrowse then
  begin
    if NewBitmap = nil then
    begin
      NewBitmap := TBitmap.Create;
      Image1.Picture.Graphic := TBitmap.Create;
      with TBitmap(Image1.Picture.Graphic) do
      begin
        Width := BIOLifeWidth;
        Height := BIOLifeHeight;
      end;
    end;
    NewBitmap.Assign(Table1.FieldByName('Graphic'));
    Y := 0;
    Timer1.Enabled := true;
  end;
end;

procedure TForm1.Timer1Timer(Sender: TObject);
var
  R: TRect;
begin
  R := Rect(0, Y, BIOLifeWidth, Y + 4);
  with TBitmap(Image1.Picture.Graphic) do
  begin
    Canvas.CopyRect(R, NewBitmap.Canvas, R);
    Inc(Y, 4);
    if Y >= BIOLifeHeight then
      Timer1.Enabled := false;
  end;
end;

end.