如何实现IMAGE控件的半透明效果，想用此做界面特效（[阿胡]工作室）

Question

如何实现IMAGE控件的半透明效果，想用此做界面特效（[阿胡]工作室）

Answer 1

http://community.csdn.net/Expert/topic/5014/5014967.xml?temp=.5859796
http://community.csdn.net/Expert/topic/5050/5050346.xml?temp=7.743472E-02

Answer 2

使用GDI+  + 基于alpha 通道的 png 图片  很容易实现。。可以去看看GDI+的使用
http://www.2ccc.com/article.asp?articleid=3131

Answer 3

type
  TForm1 = class(TForm)
    Image1: TImage;
    procedure FormCreate(Sender: TObject);
  private
    { Private declarations }
    OldWndProc: TWndMethod;
    procedure ImageWndProc(var Message: TMessage);
  public
    { Public declarations }
  end;var
  Form1: TForm1;implementationuses GDIPOBJ, GDIPAPI;{$R *.dfm}procedure TForm1.FormCreate(Sender: TObject);
begin
  OldWndProc := Image1.WindowProc;
  Image1.WindowProc := ImageWndProc;
end;procedure TForm1.ImageWndProc(var Message: TMessage);
var
  g: TGpGraphics;
  Image: TGpImage;
  attr: TGpImageAttributes;
  clm: TColorMatrix;
  I: Integer;
begin
  if (Message.Msg = WM_PAINT) and (Message.WParam <> 0) and
     not Image1.Picture.Bitmap.Empty then
  begin
    FillChar(clm, Sizeof(TColorMatrix), 0);
    for I := 0 to 4 do
      clm[I, I] := 1;
    clm[3, 3] := 0.5;
    attr := TGPImageAttributes.Create;
    try
      attr.SetColorMatrix(clm);
      g := TGpGraphics.Create(HDC(Message.WParam));
      try
        with Image1.Picture.Bitmap do
        Image := TGpBitmap.Create(Handle, Palette);
        try
          g.DrawImage(Image, MakeRect(0, 0, Image1.Width, Image1.Height), 0, 0, Image.GetWidth, Image.GetHeight, UnitPixel, attr);
        finally
          Image.Free;
        end;
      finally
        g.Free;
      end;
    finally
      attr.Free;
    end;
    Exit;
  end;
  OldWndProc(Message);
end;

Answer 4

在0-1范围调整下面这句,0.5半透明
clm[3, 3] := 0.5;

Answer 5

上面没考虑TImage设置问题,改进一下:procedure TForm1.ImageWndProc(var Message: TMessage);
var
  g: TGpGraphics;
  Image: TGpImage;
  attr: TGpImageAttributes;
  clm: TColorMatrix;
  I, W, H: Integer;
begin
  if (Message.Msg = WM_PAINT) and (Message.WParam <> 0) and
     not Image1.Picture.Bitmap.Empty then
  begin
    FillChar(clm, Sizeof(TColorMatrix), 0);
    for I := 0 to 4 do
      clm[I, I] := 1;
    clm[3, 3] := 0.5;
    attr := TGPImageAttributes.Create;
    try
      attr.SetColorMatrix(clm);
      g := TGpGraphics.Create(HDC(Message.WParam));
      try
        with Image1.Picture.Bitmap do
        Image := TGpBitmap.Create(Handle, Palette);
        try
          if not Image1.AutoSize and Image1.Stretch then
          begin
            W := Image1.Width;
            H := Image1.Height;
          end else
          begin
            W := Image.Width;
            H := Image.Height;
          end;          
          g.DrawImage(Image, MakeRect(0, 0, W, H), 0, 0, Image.GetWidth, Image.GetHeight, UnitPixel, attr);
        finally
          Image.Free;
        end;
      finally
        g.Free;
      end;
    finally
      attr.Free;
    end;
    Exit;
  end;
  OldWndProc(Message);
end;