用 GDI 操作 EMF 文件[6]: GetEnhMetaFileHeader - 获取 EMF 的头文件

//增强图元文件的头文件结构 TEnhMetaHeader:
tagENHMETAHEADER = packed recordiType: DWORD;          {记录类型}nSize: DWORD;          {结构大小}rclBounds: TRect;      {外接矩形(单位是像素)}rclFrame: TRect;       {图片矩形(单位是 0.1 毫米)}dSignature: DWORD;     {文件签名}nVersion: DWORD;       {文件版本}nBytes: DWORD;         {文件尺寸}nRecords: DWORD;       {记录数}nHandles: Word;        {句柄数}sReserved: Word;       {保留}nDescription: DWORD;   {说明文本的长度}offDescription: DWORD; {说明文本的偏移量}nPalEntries: DWORD;    {调色板的元素数}szlDevice: TSize;      {分辨率(像素)}szlMillimeters: TSize; {分辨率(毫米)}cbPixelFormat: DWORD;  {}offPixelFormat: DWORD; {}bOpenGL: DWORD;        {}
end;

本例效果图:

---

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 文件头}
procedure TForm1.Button1Click(Sender: TObject);
constn = #13#10;
varMetaHeaderSize: Integer;    {文件头大小}MetaHeader: PEnhMetaHeader; {文件头结构的指针}str: string;buf: array[Word] of Char;
beginMetaHeaderSize := GetEnhMetaFileHeader(HMetaFile, 0, nil);GetMem(MetaHeader, MetaHeaderSize);GetEnhMetaFileHeader(HMetaFile, MetaHeaderSize, MetaHeader);str := 'iType:          %d' + n +'nSize:          %d' + n +'rclBounds:      %d,%d,%d,%d' + n +'rclFrame:       %d,%d,%d,%d' + n +'dSignature:     %d' + n +'nVersion:       %d' + n +'nBytes:         %d' + n +'nRecords:       %d' + n +'nHandles:       %d' + n +//'sReserved:      %d' + n +'nDescription:   %d' + n +'offDescription: %d' + n +'nPalEntries:    %d' + n +'szlDevice:      %d,%d' + n +'szlMillimeters: %d,%d' + n +'cbPixelFormat:  %d' + n +'offPixelFormat: %d' + n +'bOpenGL:        %d';wvsprintf(buf, PChar(str), PChar(MetaHeader));ShowMessage(buf);FreeMem(MetaHeader);
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.