delphi中，如何将位图90°旋转？
如何将位图16X16的单色
在delphi中旋转为
[解决办法]
//基于GDI的方法procedure Rotate90(Bitmap: TBitmap);// 顺时针var aStream: TMemorystream; header: TBITMAPINFO; dc: hDC; P: ^THelpRGB; x, y, b, h: Integer; RowOut: pRGBArray;begin aStream := TMemoryStream.Create; //设置大小，必须是4的倍数 aStream.SetSize(Bitmap.Height * Bitmap.Width * 4); with header.bmiHeader do begin biSize := SizeOf(TBITMAPINFOHEADER); biWidth := Bitmap.Width; biHeight := Bitmap.Height; biPlanes := 1; biBitCount := 32; biCompression := 0; biSizeimage := aStream.Size; biXPelsPerMeter := 1; biYPelsPerMeter := 1; biClrUsed := 0; biClrImportant := 0; end; dc := GetDC(0); P := aStream.Memory; GetDIBits(dc, Bitmap.Handle, 0, Bitmap.Height, P, header, dib_RGB_Colors); ReleaseDC(0, dc); b := bitmap.Height; h := bitmap.Width; bitmap.Width := b; bitmap.height := h; for y := 0 to (h - 1) do begin rowOut := Bitmap.ScanLine[y]; P := aStream.Memory; inc(p, y); for x := 0 to (b - 1) do begin rowout[x] := p^.rgb; inc(p, h); end; end; aStream.Free; end;//调用注意，会改变原来的图像Rotate90(Image.picture.bitmap);基于GDI+的方法:procedure RotalBmp(FAngle: Integer); var Bmp : TGpBitmap; gp : TGpGraphics; M : TGpMatrix;begin Bmp := TGpBitmap.Create('a.JPG'); try Gr := GpRect(0,0,Bmp.Width,Bmp.Height); gp := TGpGraphics.Create(pb1.Canvas.Handle); M := TGpMatrix.Create; Center.X := pb1.Width div 2; Center.Y := pb1.Height div 2; M.RotateAt(FAngle,Center);//FAngle为角度 gp.SetTransform(M); gp.DrawImage(Bmp,Gr); finally gp.Free; Bmp.Free; m.Free; end;end;