读取一个PNG图形(一个时钟指针形状),并进行旋转！

Question

var
PNG:TPNGObject;  
  
  try
    PNG:=TPNGObject.Create;
    PNG.LoadFromFile('./toolbar/分针.png');
    Image1.Picture.Assign(Png);
  finally
    Png.Free;
  end;怎么对Image1的“分针.PNG”进行旋转，使其指向不同的方向。
在线等待........求救

Answer 1

可以用GDI+处理png图片，还有画布的旋转，参考如下代码：
//....
implementationuses ActiveX;type
  DebugEventLevel = (
    DebugEventLevelFatal,
    DebugEventLevelWarning
  );
  TDebugEventLevel = DebugEventLevel;  DebugEventProc = procedure(level: DebugEventLevel; message: PChar); stdcall;  GdiplusStartupInput = packed record
    GdiplusVersion: Cardinal;
    DebugEventCallback: DebugEventProc;
    SuppressBackgroundThread: BOOL;
    SuppressExternalCodecs: BOOL;
  end;
  TGdiplusStartupInput = GdiplusStartupInput;
  PGdiplusStartupInput = ^TGdiplusStartupInput;  NotificationHookProc = function(out token: ULONG): Integer; stdcall;
  NotificationUnhookProc = procedure(token: ULONG); stdcall;  GdiplusStartupOutput = packed record
    NotificationHook  : NotificationHookProc;
    NotificationUnhook: NotificationUnhookProc;
  end;
  TGdiplusStartupOutput = GdiplusStartupOutput;
  PGdiplusStartupOutput = ^TGdiplusStartupOutput;function GdipCreateBitmapFromFile(filename: PWChar; out bitmap: THandle): Integer;
  stdcall; external 'gdiplus.dll';function GdipDisposeImage(image: THandle): Integer; stdcall;
  stdcall; external 'gdiplus.dll';function GdiplusStartup(out token: ULONG; input: PGdiplusStartupInput;
  output: PGdiplusStartupOutput): Integer; stdcall; external 'gdiplus.dll';procedure GdiplusShutdown(token: ULONG); stdcall; external 'gdiplus.dll';function GdipCreateFromHDC(hdc: HDC;
  out graphics: THandle): Integer; stdcall; external 'gdiplus.dll';function GdipDeleteGraphics(graphics: THandle): Integer; stdcall; external 'gdiplus.dll';function GdipDrawImage(graphics: THandle; image: THandle; x: Single;
  y: Single): Integer; stdcall; external 'gdiplus.dll';function GdipRotateWorldTransform(graphics: THandle; angle: Single;
  order: Integer): Integer; stdcall; external 'gdiplus.dll';function GdipTranslateWorldTransform(graphics: THandle; dx, dy: Single;
  order: Integer): Integer; stdcall; external 'gdiplus.dll';procedure TForm1.Button1Click(Sender: TObject);
var
  vImage: THandle;
  vGraphics: THandle;
begin
  GdipCreateBitmapFromFile('c:\temp\temp.png', vImage); // 载入
  GdipCreateFromHDC(Canvas.Handle, vGraphics);
  GdipRotateWorldTransform(vGraphics, 45, 0);
  //GdipTranslateWorldTransform(vGraphics, x, y, 0); // 根据旋转的中心计算
  GdipDrawImage(vGraphics, vImage, 0, 0); // 绘制
  GdipDeleteGraphics(vGraphics);
  GdipDisposeImage(vImage);
end;var
  vStartupInput: TGDIPlusStartupInput;
  vToken: ULONG;initialization
  vStartupInput.DebugEventCallback := nil;
  vStartupInput.SuppressBackgroundThread := False;
  vStartupInput.SuppressExternalCodecs   := False;
  vStartupInput.GdiplusVersion := 1;
  GdiplusStartup(vToken, @vStartupInput, nil);finalization
  GdiplusShutdown(vToken);end.当然也有相关的gdi+的组件和demo楼主可以自己下来看看。

Answer 2

http://topic.csdn.net/u/20070708/21/eea841ff-647f-47a1-9259-f072331c7b5f.html?seed=534823055