Delphi 與 DirectX 之 DelphiX(11): TPictureCollectionItem.DrawAdd、DrawSub

本例:

代碼檔案:

unit Unit1;interfaceuses  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,  Dialogs, DXDraws, StdCtrls, DXClass;type  TForm1 = class(TForm)    DXDraw1: TDXDraw;    DXImageList1: TDXImageList;    Button1: TButton;    Button2: TButton;    procedure FormCreate(Sender: TObject);    procedure Button1Click(Sender: TObject);    procedure Button2Click(Sender: TObject);  end;var  Form1: TForm1;implementation{$R *.dfm}var  pic1,pic2: TPictureCollectionItem;procedure TForm1.FormCreate(Sender: TObject);const  ImgPath1 = 'C:\Temp\Back.jpg';  ImgPath2 = 'C:\Temp\DelphiX.bmp';begin  DXImageList1.DXDraw := DXDraw1;  pic1 := TPictureCollectionItem(DXImageList1.Items.Add);  pic1.Picture.LoadFromFile(ImgPath1);  pic2 := TPictureCollectionItem(DXImageList1.Items.Add);  pic2.Picture.LoadFromFile(ImgPath2);end;procedure TForm1.Button1Click(Sender: TObject);var  r: TRect;begin  r := Bounds((DXDraw1.Width - pic2.Width) div 2,              (DXDraw1.Height - pic2.Height),               pic2.Width,               pic2.Height);  DXDraw1.Surface.Fill(0);  pic1.StretchDraw(DXDraw1.Surface, DXDraw1.ClientRect, 0);  pic2.DrawAdd(DXDraw1.Surface, r, 0);  DXDraw1.Flip;end;procedure TForm1.Button2Click(Sender: TObject);var  r: TRect;begin  r := Bounds((DXDraw1.Width - pic2.Width) div 2,              (DXDraw1.Height - pic2.Height),               pic2.Width,               pic2.Height);  DXDraw1.Surface.Fill(0);  pic1.StretchDraw(DXDraw1.Surface, DXDraw1.ClientRect, 0);  pic2.DrawSub(DXDraw1.Surface, r, 0);  DXDraw1.Flip;end;end.