再学 GDI+[98]: TGPImage(18) 获取 GDI+ 图像格式对应的 GUID

和在 Net 中不同的是, 在具体指定图像格式时, 这里常常需要的不是格式名称, 而是格式的 GUID;

知道了格式名称, 用 GetEncoderClsid 函数可以获取格式的 GUID;

GetEncoderClsid 函数来自 GDIPUTIL 单元, 本例并没有用到前面一直不可或缺的 GDIPOBJ、GDIPAPI 单元.

如果要获取 image/bmp、image/jpeg、image/gif、image/tiff、image/png 格式以外的 GUID 不能使用此函数.

另外, 为了把 GUID 转换为字符串显示, 本例用到了 GUIDToString 函数.

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本例效果图:

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代码文件:

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unit Unit1;

interface

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

type
  TForm1 = class(TForm)
    Memo1: TMemo;
    procedure FormCreate(Sender: TObject);
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

uses GDIPUTIL;

procedure TForm1.FormCreate(Sender: TObject);
var
  List: TStringList;
  ImgGUID: TGUID;
  i: Integer;
begin
  List := TStringList.Create;
  List.Add('image/bmp');
  List.Add('image/jpeg');
  List.Add('image/gif');
  List.Add('image/tiff');
  List.Add('image/png');

  Memo1.Clear;
  for i := 0 to List.Count - 1 do
  begin
    GetEncoderClsid(List[i], ImgGUID);
    Memo1.Lines.Add(Format('%s: %s', [GUIDToString(ImgGUID), List[i]]));
  end;

  List.Free;
end;

end.

窗体文件:

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object Form1: TForm1
  Left = 0
  Top = 0
  Caption = 'Form1'
  ClientHeight = 115
  ClientWidth = 329
  Color = clBtnFace
  Font.Charset = DEFAULT_CHARSET
  Font.Color = clWindowText
  Font.Height = -11
  Font.Name = 'Tahoma'
  Font.Style = []
  OldCreateOrder = False
  OnCreate = FormCreate
  PixelsPerInch = 96
  TextHeight = 13
  object Memo1: TMemo
    Left = 0
    Top = 0
    Width = 321
    Height = 115
    Align = alLeft
    Lines.Strings = (
      'Memo1')
    ScrollBars = ssBoth
    TabOrder = 0
    ExplicitHeight = 128
  end
end