Delphi异形窗口之PNG

//1.单元内容
unit UnitAlienForm;
interface
uses
Windows, Forms, Classes, Graphics;
//从文件加载PNG
procedure AlienForm_PNGFromFile(AForm : TForm; AFileName : String);
//从资源加载PNG
procedure AlienForm_PNGFromResource(AForm : TForm; ResName : String; ResType : PWideChar; Instance : HINST = 0);
//从图像对象加载
procedure AlienForm_PNGFromGraphic(AForm : TForm; AGraphic : TGraphic);
implementation
procedure AlienForm_PNGFromFile(AForm : TForm; AFileName : String);
var
wic : TWICImage;
begin
wic := TWICImage.Create;
wic.LoadFromFile(AFileName);
AlienForm_PNGFromGraphic(AForm, wic);
wic.Free;
end;
procedure AlienForm_PNGFromResource(AForm : TForm; ResName : String;ResType : PWideChar; Instance : HINST);
var
wic : TWICImage;
r : TResourceStream;
begin
if Instance = 0 then
Instance := HInstance;
r := TResourceStream.Create(Instance, ResName, ResType);
wic := TWICImage.Create;
wic.LoadFromStream(r);
AlienForm_PNGFromGraphic(AForm, wic);
wic.Free;
r.Free;
end;
procedure AlienForm_PNGFromGraphic(AForm : TForm; AGraphic : TGraphic);
var
ptDst, ptSrc: TPoint;
Size: TSize;
BlendFunction: TBlendFunction;
bmp : TBitmap;
begin
bmp := TBitmap.Create;
bmp.Assign(AGraphic);
ptDst := Point(AForm.Left, AForm.Top);
ptSrc := Point(0, 0);
Size.cx := AGraphic.Width;
Size.cy := AGraphic.Height;
BlendFunction.BlendOp := AC_SRC_OVER;
BlendFunction.BlendFlags := 0;
BlendFunction.SourceConstantAlpha := $FF; // 透明度
BlendFunction.AlphaFormat := AC_SRC_ALPHA;
SetWindowLong(AForm.Handle, GWL_EXSTYLE, GetWindowLong(AForm.Handle,
GWL_EXSTYLE) or WS_EX_LAYERED);
UpdateLayeredWindow(AForm.Handle,
AForm.Canvas.Handle,
@ptDst,
@Size,
bmp.Canvas.Handle,
@ptSrc,
0,
@BlendFunction,
ULW_ALPHA);
bmp.Free();
end;
end.

//2.调用方法
procedure TForm2.FormCreate(Sender: TObject);
begin
AlienForm_PNGFromFile(Form2, 'E:\未标题.png');
end;