用 GDI 操作 EMF 文件[5]: GetEnhMetaFileDescription - 获取 EMF 文件的说明文本

再用 CreateEnhMetaFile 函数建立 EMF 文件时可以同时写入描述性说明;

用 GetEnhMetaFileDescription 函数可以读出 EMF 文件的说明文本.

本例给的说明文本非常简单, 不过标准的说明文本的格式应该是: 程序名#0文件标题#0#0

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unit Unit1;interfaceusesWindows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,Dialogs, StdCtrls;typeTForm1 = class(TForm)Button1: TButton;Button2: TButton;procedure FormCreate(Sender: TObject);procedure FormDestroy(Sender: TObject);procedure Button1Click(Sender: TObject);procedure Button2Click(Sender: TObject);end;varForm1: TForm1;implementation{$R *.dfm}varHMetaFile: HENHMETAFILE; {EMF 文件句柄}{建立带说明的 EMF 文件}
procedure TForm1.FormCreate(Sender: TObject);
constPath = 'C:\Temp\MyMeateFile.emf';Description = 'ABCDE'; {当作 EMF 文件的说明}
varMetaFileDC: HDC;
begin{建立并写入说明}MetaFileDC := CreateEnhMetaFile(0, PChar(Path), nil, PChar(Description));{绘图}Rectangle(MetaFileDC, 11, 11, 111, 111);{结束编辑、保存文件, 并返回文件句柄}HMetaFile := CloseEnhMetaFile(MetaFileDC);{删除 DC}DeleteObject(MetaFileDC);
end;{读取 EMF 文件的说明}
procedure TForm1.Button1Click(Sender: TObject);
varDescriptionSize: Integer; {说明段的大小}DescriptionBuf: PChar;    {接受说明的内存指针}
begin{获取大小}DescriptionSize := GetEnhMetaFileDescription(HMetaFile, 0, nil);{分配内存}GetMem(DescriptionBuf, DescriptionSize);{获取说明}GetEnhMetaFileDescription(HMetaFile, DescriptionSize, DescriptionBuf);{显示说明}ShowMessage(DescriptionBuf); {ABCDE}{释放内存}FreeMem(DescriptionBuf);
end;{绘制在窗体}
procedure TForm1.Button2Click(Sender: TObject);
beginPlayEnhMetaFile(Canvas.Handle, HMetaFile, Rect(11,11,111,111));
end;{删除 EMF 文件句柄}
procedure TForm1.FormDestroy(Sender: TObject);
beginDeleteEnhMetaFile(HMetaFile);
end;end.