如何把BMP转换成JPG??? TBitmap.Create --> TJPEGImage.Create

Question

如果BMP已经是文件,问题好解决,但现在BMP是TBitmap.Create,已经在内存中,如何与TJPEGImage.Create直接转换.最后保存为jpg文件.请大侠给出Code,共同讨论.

Answer 1

呵呵，通过调用TJPEGImage对象的Assign方法来实现，例如：procedure TForm1.Button1Click(Sender: TObject);
var
  jpeg1:TJPEGImage;
  bmp1:TBitmap;
begin
jpeg1:=TJPEGImage.Create;
bmp1:=TBitmap.Create;
bmp1.Width:=200;
bmp1.Height:=200;
//bmp1.LoadFromFile('c:\123.bmp');
bmp1.Canvas.TextOut(1,1,'测试');
jpeg1.Assign(bmp1);
jpeg1.SaveToFile('c:\abc.jpg');
bmp1.free;
jpeg1.free;
end;

Answer 2

var
  MyJpeg: TJpegImage;
  Image1: TImage;
begin
  Image1:= TImage.Create(self);
  MyJpeg:= TJpegImage.Create;
  Image1.Picture.Bitmap.LoadFromFile('c:\windows\desktop\aa.BMP');  // Load the Bitmap from a file
  MyJpeg.Assign(Image1.Picture.Bitmap);  // Assign the BitMap to MyJpeg object
  MyJpeg.CompressionQuality:=StrToInt('75');
  MyJpeg.Compress;
  MyJpeg.SaveToFile('c:\windows\desktop\test.JPG'); // Save the JPEG to Disk
end;