Delphi与DirectX之DelphiX(9) 透明色与是否透明

TDXImageList.Items 中的每个 TPictureCollectionItem 的默认透明色是黑色, 并默认透明.

本例使用的测试图片:

本例效果图:

代码文件:

unit Unit1;
interface
uses
　Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
　Dialogs, DXDraws, StdCtrls, DXClass;
type
　TForm1 = class(TForm)
　　DXDraw1: TDXDraw;
　　DXImageList1: TDXImageList;
　　CheckBox1: TCheckBox;
　　procedure FormCreate(Sender: TObject);
　　procedure CheckBox1Click(Sender: TObject);
　end;
var
　Form1: TForm1;
implementation
{$R *.dfm}
var
　PicItem: TPictureCollectionItem;
procedure TForm1.FormCreate(Sender: TObject);
const
　ImgPath1 = 'C:\Temp\Transparent.bmp';
begin
　DXImageList1.DXDraw := DXDraw1;
　PicItem := TPictureCollectionItem(DXImageList1.Items.Add);
　PicItem.Picture.LoadFromFile(ImgPath1);
　PicItem.TransparentColor := $FFFFFF; {指定透明色; 我测试用的图片是白色背景的}
end;
procedure TForm1.CheckBox1Click(Sender: TObject);
const
　arr: array[Boolean] of string = ('不透明', '透明');
begin
　DXDraw1.Surface.Fill($FF0000);
　PicItem.Restore;
　PicItem.Transparent := CheckBox1.Checked;
　PicItem.Draw(DXDraw1.Surface, 10, 10, 0);
　DXDraw1.Flip;
　CheckBox1.Caption := arr[CheckBox1.Checked];
end;
end.