EnumEnhMetaFile(
DC: HDC; {目标设备句柄; 如果回调函数不需要回放, 该参数为 0}
Emf: HENHMETAFILE; {图元文件句柄}
EnhMetaFunc: TFNEnhMFEnumProc; {回调函数指针; 回调函数格式见下}
Data: Pointer; {自定义数据指针}
const Rect: TRect {要输出的尺寸; 如果 DC=0 该参数会被忽略}
): BOOL;
//EnumEnhMetaFile 使用的回调函数格式及参数, PlayEnhMetaFileRecord 基本就是使用这些参数:
function EnhMetaFunc(
DisplaySurface: HDC; {目标设备句柄; 如果回调函数不需要回放, 该参数为 0}
var MetafileTable: THandleTable; {句柄表数组指针, 数组包含 HGDIOBJ 对象(画笔、画刷等); 元素1是文件自身句柄}
var MetafileRecord: TEnhMetaRecord; {图元文件记录 TEnhMetaRecord 指针, TEnhMetaRecord 结构见下表}
ObjectCount: Integer; {对象句柄数目, 即句柄表 MetafileTable 中图形对象的数目}
var Data: Longint {自定义数据指针}
): Integer; stdcall;
//TEnhMetaRecord 结构:
tagENHMETARECORD = packed record
iType: DWORD; {类型}
nSize: DWORD; {尺寸}
dParm: array[0..0] of DWORD; {参数数组}
end;
//TEnhMetaRecord.iType 的可能值:
EMR_HEADER = 1;
EMR_POLYBEZIER = 2;
EMR_POLYGON = 3;
EMR_POLYLINE = 4;
EMR_POLYBEZIERTO = 5;
EMR_POLYLINETO = 6;
EMR_POLYPOLYLINE = 7;
EMR_POLYPOLYGON = 8;
EMR_SETWINDOWEXTEX = 9;
EMR_SETWINDOWORGEX = 10;
EMR_SETVIEWPORTEXTEX = 11;
EMR_SETVIEWPORTORGEX = 12;
EMR_SETBRUSHORGEX = 13;
EMR_EOF = 14;
EMR_SETPIXELV = 15;
EMR_SETMAPPERFLAGS = $10;
EMR_SETMAPMODE = 17;
EMR_SETBKMODE = 18;
EMR_SETPOLYFILLMODE = 19;
EMR_SETROP2 = 20;
EMR_SETSTRETCHBLTMODE = 21;
EMR_SETTEXTALIGN = 22;
EMR_SETCOLORADJUSTMENT = 23;
EMR_SETTEXTCOLOR = 24;
EMR_SETBKCOLOR = 25;
EMR_OFFSETCLIPRGN = 26;
EMR_MOVETOEX = 27;
EMR_SETMETARGN = 28;
EMR_EXCLUDECLIPRECT = 29;
EMR_INTERSECTCLIPRECT = 30;
EMR_SCALEVIEWPORTEXTEX = 31;
EMR_SCALEWINDOWEXTEX = 32;
EMR_SAVEDC = 33;
EMR_RESTOREDC = 34;
EMR_SETWORLDTRANSFORM = 35;
EMR_MODIFYWORLDTRANSFORM = 36;
EMR_SELECTOBJECT = 37;
EMR_CREATEPEN = 38;
EMR_CREATEBRUSHINDIRECT = 39;
EMR_DELETEOBJECT = 40;
EMR_ANGLEARC = 41;
EMR_ELLIPSE = 42;
EMR_RECTANGLE = 43;
EMR_ROUNDRECT = 44;
EMR_ARC = 45;
EMR_CHORD = 46;
EMR_PIE = 47;
EMR_SELECTPALETTE = 48;
EMR_CREATEPALETTE = 49;
EMR_SETPALETTEENTRIES = 50;
EMR_RESIZEPALETTE = 51;
EMR_REALIZEPALETTE = 52;
EMR_EXTFLOODFILL = 53;
EMR_LINETO = 54;
EMR_ARCTO = 55;
EMR_POLYDRAW = 56;
EMR_SETARCDIRECTION = 57;
EMR_SETMITERLIMIT = 58;
EMR_BEGINPATH = 59;
EMR_ENDPATH = 60;
EMR_CLOSEFIGURE = 61;
EMR_FILLPATH = 62;
EMR_STROKEANDFILLPATH = 63;
EMR_STROKEPATH = $40;
EMR_FLATTENPATH = 65;
EMR_WIDENPATH = 66;
EMR_SELECTCLIPPATH = 67;
EMR_ABORTPATH = 68;
EMR_GDICOMMENT = 70;
EMR_FILLRGN = 71;
EMR_FRAMERGN = 72;
EMR_INVERTRGN = 73;
EMR_PAINTRGN = 74;
EMR_EXTSELECTCLIPRGN = 75;
EMR_BITBLT = 76;
EMR_STRETCHBLT = 77;
EMR_MASKBLT = 78;
EMR_PLGBLT = 79;
EMR_SETDIBITSTODEVICE = 80;
EMR_STRETCHDIBITS = 81;
EMR_EXTCREATEFONTINDIRECTW = 82;
EMR_EXTTEXTOUTA = 83;
EMR_EXTTEXTOUTW = 84;
EMR_POLYBEZIER16 = 85;
EMR_POLYGON16 = 86;
EMR_POLYLINE16 = 87;
EMR_POLYBEZIERTO16 = 88;
EMR_POLYLINETO16 = 89;
EMR_POLYPOLYLINE16 = 90;
EMR_POLYPOLYGON16 = 91;
EMR_POLYDRAW16 = 92;
EMR_CREATEMONOBRUSH = 93;
EMR_CREATEDIBPATTERNBRUSHPT = 94;
EMR_EXTCREATEPEN = 95;
EMR_POLYTEXTOUTA = 96;
EMR_POLYTEXTOUTW = 97;
EMR_SETICMMODE = 98;
EMR_CREATECOLORSPACE = 99;
EMR_SETCOLORSPACE = 100;
EMR_DELETECOLORSPACE = 101;
EMR_GLSRECORD = 102;
EMR_GLSBOUNDEDRECORD = 103;
EMR_PIXELFORMAT = 104;
EMR_DRAWESCAPE = 105;
EMR_EXTESCAPE = 106;
EMR_STARTDOC = 107;
EMR_SMALLTEXTOUT = 108;
EMR_FORCEUFIMAPPING = 109;
EMR_NAMEDESCAPE = 110;
EMR_COLORCORRECTPALETTE = 111;
EMR_SETICMPROFILEA = 112;
EMR_SETICMPROFILEW = 113;
EMR_ALPHABLEND = 114;
EMR_ALPHADIBBLEND = 115;
EMR_TRANSPARENTBLT = 116;
EMR_TRANSPARENTDIB = 117;
EMR_GRADIENTFILL = 118;
EMR_SETLINKEDUFIS = 119;
EMR_SETTEXTJUSTIFICATION = 120;
在下面的例子中, 先在内存中建立了一个图元文件, 再其中绘制了直线、矩形和两个椭圆; 然后控制显示了图元文件的部分及全部.
运行效果图:
代码文件:
unit Unit1;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls, ExtCtrls;
type
TForm1 = class(TForm)
RadioGroup1: TRadioGroup;
procedure FormCreate(Sender: TObject);
procedure FormDestroy(Sender: TObject);
procedure RadioGroup1Click(Sender: TObject);
end;
var
Form1: TForm1;
implementation
{$R *.dfm}
var
HMetaFile: HENHMETAFILE; {EMF 文件句柄}
RadioGroupItemIndex: Integer = -1;
//EnumEnhMetaFile 的回调函数
function MyEnhMetaFunc(DisplaySurface: HDC; var MetafileTable: THandleTable;
var MetafileRecord: TEnhMetaRecord; ObjectCount: Integer; var Data: Longint
): Integer; stdcall;
var
itype: Integer;
begin
case RadioGroupItemIndex of
1: itype := EMR_RECTANGLE;
2: itype := EMR_ELLIPSE;
end;
if MetafileRecord.iType = itype then
begin
PlayEnhMetaFileRecord(DisplaySurface, MetafileTable, MetafileRecord, ObjectCount);
Result := 1;
end;
end;
procedure TForm1.FormCreate(Sender: TObject);
var
MetaFileDC: HDC;
begin
{文件建立在内存}
MetaFileDC := CreateEnhMetaFile(0, nil, nil, nil);
MoveToEx(MetaFileDC, 0, 0, nil);
LineTo(MetaFileDC, 100, 100);
{矩形}
Rectangle(MetaFileDC, 10, 10, 30, 30);
{椭圆}
Ellipse(MetaFileDC, 30, 30, 50, 50);
Ellipse(MetaFileDC, 45, 45, 65, 65);
HMetaFile := CloseEnhMetaFile(MetaFileDC);
DeleteObject(MetaFileDC);
RadioGroup1.Items.CommaText := '整个图元文件,其中的矩形,其中的椭圆';
end;
procedure TForm1.RadioGroup1Click(Sender: TObject);
begin
Repaint;
RadioGroupItemIndex := RadioGroup1.ItemIndex;
if RadioGroupItemIndex = 0 then
PlayEnhMetaFile(Canvas.Handle, HMetaFile, ClientRect)
else
EnumEnhMetaFile(Canvas.Handle, HMetaFile, @MyEnhMetaFunc, nil, ClientRect);
end;
procedure TForm1.FormDestroy(Sender: TObject);
begin
DeleteEnhMetaFile(HMetaFile);
end;
end.
窗体文件:object Form1: TForm1
Left = 0
Top = 0
Caption = 'Form1'
ClientHeight = 197
ClientWidth = 325
Color = clBtnFace
Font.Charset = DEFAULT_CHARSET
Font.Color = clWindowText
Font.Height = -11
Font.Name = 'Tahoma'
Font.Style = []
OldCreateOrder = False
Position = poDesktopCenter
OnCreate = FormCreate
OnDestroy = FormDestroy
PixelsPerInch = 96
TextHeight = 13
object RadioGroup1: TRadioGroup
Left = 216
Top = 8
Width = 101
Height = 113
Caption = 'RadioGroup1'
TabOrder = 0
OnClick = RadioGroup1Click
end
end
