delphi TGPImage - 提取 GIF 动画的每一帧

代码文件:

unit Unit1;
interface
uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;
type
  TForm1 = class(TForm)
    Button1: TButton;
    ListBox1: TListBox;
    OpenDialog1: TOpenDialog;
    procedure FormCreate(Sender: TObject);
    procedure FormDestroy(Sender: TObject);
    procedure Button1Click(Sender: TObject);
    procedure FormPaint(Sender: TObject);
    procedure ListBox1Click(Sender: TObject);
  end;
var
  Form1: TForm1;
implementation
{$R *.dfm}
uses GDIPOBJ, GDIPAPI;
var
  img: TGPImage;
  GifFrame, GifFrameCount: Word;
procedure TForm1.FormCreate(Sender: TObject);
begin
  OpenDialog1.Filter := 'GIF 文件|*.gif';
  img := TGPImage.Create;
end;
procedure TForm1.FormDestroy(Sender: TObject);
begin
  img.Free;
end;
procedure TForm1.Button1Click(Sender: TObject);
var
  DimensionsCount: Integer;
  DimensionsIDs: PGUID;
  i: Integer;
type
  ArrDimensions = array of TGUID;
begin
  if not OpenDialog1.Execute then Exit;
  img.Free;
  img := TGPImage.Create(OpenDialog1.FileName);
  {获取 Gif 总帧数}
  DimensionsCount := img.GetFrameDimensionsCount;
  GetMem(DimensionsIDs, DimensionsCount * SizeOf(TGUID));
  img.GetFrameDimensionsList(DimensionsIDs, DimensionsCount);
  GifFrameCount := img.GetFrameCount(ArrDimensions(DimensionsIDs)[0]);
  FreeMem(DimensionsIDs);
  Text := Format('共有 %d 帧', [GifFrameCount]);
  {显示帧列表}
  ListBox1.Clear;
  for i := 1 to GifFrameCount do
    ListBox1.Items.Add(Format('第 %d 帧', [i]));
  Repaint;
end;
procedure TForm1.FormPaint(Sender: TObject);
var
  g: TGPGraphics;
begin
  g := TGPGraphics.Create(Canvas.Handle);
  g.DrawImage(img, ListBox1.Width + 10, 10, img.GetWidth, img.GetHeight);
  g.Free;
end;
procedure TForm1.ListBox1Click(Sender: TObject);
begin
  GifFrame := ListBox1.ItemIndex;
  img.SelectActiveFrame(FrameDimensionTime, GifFrame);
  Repaint;
end;
end.