gifprvw.pas

jvcl driver development envionment

{******************************************************************

                       JEDI-VCL Demo

 Copyright (C) 2002 Project JEDI

 Original author:

 Contributor(s):

 You may retrieve the latest version of this file at the JEDI-JVCL
 home page, located at http://jvcl.sourceforge.net

 The contents of this file are used with permission, subject to
 the Mozilla Public License Version 1.1 (the "License"); you may
 not use this file except in compliance with the License. You may
 obtain a copy of the License at
 http://www.mozilla.org/MPL/MPL-1_1Final.html

 Software distributed under the License is distributed on an
 "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
 implied. See the License for the specific language governing
 rights and limitations under the License.

******************************************************************}

{*******************************************************}
{                                                       }
{     Delphi VCL Extensions (RX) demo program           }
{                                                       }
{     Copyright (c) 1997 Master-Bank                    }
{                                                       }
{*******************************************************}

unit GIFPrvw;

interface

uses
  SysUtils, WinTypes, WinProcs, Messages, Classes, Graphics, Controls,
  Forms, Dialogs, ExtCtrls, StdCtrls, JvSpeedbar, JvGIF, JvGIFCtrl,
  JvxSlider, JvComponent, JvAnimatedImage, JvExControls, JvExExtCtrls;

type
  TPreviewForm = class(TForm)
    JvSpeedbar: TJvSpeedBar ;
    SpeedbarSection1: TjvSpeedbarSection;
    PlayBtn: TjvSpeedItem;
    StopBtn: TjvSpeedItem;
    RewindBtn: TjvSpeedItem;
    BackBtn: TjvSpeedItem;
    NextBtn: TjvSpeedItem;
    ForwardBtn: TjvSpeedItem;
    Label1: TLabel;
    FrameNo: TLabel;
    SliderPanel: TPanel;
    Slider: TJvxSlider ;
    ImagePanel: TPanel;
    Image: TJvGIFAnimator ;
    procedure ImageFrameChanged(Sender: TObject);
    procedure SliderChange(Sender: TObject);
    procedure PlayBtnClick(Sender: TObject);
    procedure StopBtnClick(Sender: TObject);
    procedure RewindBtnClick(Sender: TObject);
    procedure BackBtnClick(Sender: TObject);
    procedure NextBtnClick(Sender: TObject);
    procedure ForwardBtnClick(Sender: TObject);
    procedure ImageChanged(Sender: TObject);
    procedure FormKeyDown(Sender: TObject; var Key: Word;
      Shift: TShiftState);
    procedure FormKeyPress(Sender: TObject; var Key: Char);
    procedure ImageStartStop(Sender: TObject);
  private
    { Private declarations }
    procedure EnableButtons;
    procedure CalculateFormSize;
  public
    { Public declarations }
  end;

procedure PreviewGIF(AImage: TJvGIFImage );

implementation

uses ShellAPI, Math;

{$R *.DFM}

procedure PreviewGIF(AImage: TJvGIFImage );
begin
  with TPreviewForm.Create(Application) do
  try
    Image.Image := AImage;
    Image.Loop := AImage.Looping;
    if not AImage.Empty then Image.Image.FrameIndex := 0;
    if PlayBtn.Enabled then PlayBtnClick(nil);      
    ShowModal;
  finally
    Free;
  end;
end;

{ TPreviewForm }

procedure TPreviewForm.CalculateFormSize;
var
  NewSize: TPoint;
begin
  NewSize.X := Max(Image.Image.ScreenWidth + 4, 270);
  Inc(NewSize.X, (ImagePanel.BorderWidth + ImagePanel.BevelWidth) * 2);
  NewSize.Y := Max(Image.Image.ScreenHeight + 4, 70);
  Inc(NewSize.Y, (ImagePanel.BorderWidth + ImagePanel.BevelWidth) * 2 +
    JvSpeedbar.Height + SliderPanel.Height);
  NewSize.X := Min(NewSize.X, Screen.Width);
  NewSize.Y := Min(NewSize.Y, Screen.Height);
  ClientWidth := NewSize.X;
  ClientHeight := NewSize.Y;
end;

procedure TPreviewForm.EnableButtons;
begin
  PlayBtn.Enabled := not Image.Animate and (Image.Image.Count > 1);
  StopBtn.Enabled := Image.Animate;
  RewindBtn.Enabled := Image.FrameIndex > 0;
  BackBtn.Enabled := ((Image.FrameIndex > 0) or Image.Loop)
    and (Image.Image.Count > 1);
  NextBtn.Enabled := ((Image.FrameIndex < Image.Image.Count - 1) or Image.Loop)
    and (Image.Image.Count > 1);
  ForwardBtn.Enabled := Image.FrameIndex < Image.Image.Count - 1;
end;

procedure TPreviewForm.ImageFrameChanged(Sender: TObject);
begin
  Slider.Value := Image.FrameIndex;
  FrameNo.Caption := IntToStr(Image.FrameIndex + 1);
  EnableButtons;
end;

procedure TPreviewForm.SliderChange(Sender: TObject);
begin
  Image.FrameIndex := Slider.Value;
  Slider.Value := Image.FrameIndex;
end;

procedure TPreviewForm.PlayBtnClick(Sender: TObject);
begin
  Image.Animate := True;
  EnableButtons;
end;

procedure TPreviewForm.StopBtnClick(Sender: TObject);
begin
  Image.Animate := False;
  EnableButtons;
end;

procedure TPreviewForm.RewindBtnClick(Sender: TObject);
begin
  Image.FrameIndex := 0;
end;

procedure TPreviewForm.BackBtnClick(Sender: TObject);
var
  NewIndex: Integer;
begin
  NewIndex := Image.FrameIndex - 1;
  if NewIndex < 0 then begin
    if Image.Loop then NewIndex := Image.Image.Count + NewIndex
    else NewIndex := 0;
  end;
  Image.FrameIndex := NewIndex;
end;

procedure TPreviewForm.NextBtnClick(Sender: TObject);
var
  NewIndex: Integer;
begin
  NewIndex := Image.FrameIndex + 1;
  if NewIndex >= Image.Image.Count then begin
    if Image.Loop then NewIndex := NewIndex - Image.Image.Count
    else NewIndex := Image.Image.Count - 1;
  end;
  Image.FrameIndex := NewIndex;
end;

procedure TPreviewForm.ForwardBtnClick(Sender: TObject);
begin
  Image.FrameIndex := Image.Image.Count - 1;
end;

procedure TPreviewForm.ImageChanged(Sender: TObject);
begin
  Slider.MaxValue := Max(1, Image.Image.Count - 1);
  FrameNo.Caption := IntToStr(Image.FrameIndex + 1);
  EnableButtons;
  Slider.Enabled := Image.Image.Count > 1;
  JvSpeedbar.Enabled := Slider.Enabled;
  CalculateFormSize;
end;

procedure TPreviewForm.FormKeyDown(Sender: TObject; var Key: Word;
  Shift: TShiftState);
begin
  if (Key = VK_F9) and (PlayBtn.Enabled) then begin
    PlayBtnClick(nil);
    Key := 0;
  end;
end;

procedure TPreviewForm.FormKeyPress(Sender: TObject; var Key: Char);
begin
  if Key = #27 then begin
    if Image.Animate then StopBtnClick(nil)
    else ModalResult := mrCancel;
  end
  else if Key = Char(VK_RETURN) then begin
    if not Image.Animate then PlayBtnClick(nil);
  end;
end;

procedure TPreviewForm.ImageStartStop(Sender: TObject);
begin
  EnableButtons;
end;

end.