比如有一张BMP大小为1.00MB,1024 x 768象素,我的程序用对话框读入,经过处理,我要将他缩小到200 X 200象素,大小变为0.1MB,达到缩略图的样子,以便更小的存入数据库等,变于读取,请问如何实现,谢谢大大们指点!

請參考下列文章,有很精闢的說明 http://delphi.ktop.com.tw/topic.php?topic_id=49370 http://delphi.ktop.com.tw/topic.php?topic_id=34732 ★ http://delphi.ktop.com.tw/topic.php?topic_id=43205 http://delphi.ktop.com.tw/topic.php?TOPIC_ID=38057 http://delphi.ktop.com.tw/topic.php?TOPIC_ID=38124 ★ 發表人 - chance36 於 2004/05/17 19:03:11

這個問題好像很面熟 class="code"> function StretchImagePercent(FileName : TFileName; Percent, Quality : Integer) : TJpegImage; var bmp, tempbmp : TBitmap; RT : TRect; begin result := TjpegImage.Create; bmp := TBitmap.Create; tempbmp := TBitmap.Create; try if Uppercase(ExtractFileExt(FileName)) = '.JPG' then begin result.LoadFromFile(FileName); bmp.Width := Round(result.Width * Percent / 100); bmp.Height := Round(result.Height * Percent / 100); end else if Uppercase(ExtractFileExt(FileName)) = '.BMP' then begin tempbmp.LoadFromFile(FileName); bmp.Width := Round(tempbmp.Width * Percent / 100); bmp.Height := Round(tempbmp.Height * Percent / 100); end else exit; RT.Left := 0; RT.Top := 0; RT.Right := bmp.Width - 1; RT.Bottom := bmp.Height - 1; if Uppercase(ExtractFileExt(FileName)) = '.JPG' then bmp.Canvas.StretchDraw(RT,result) else bmp.Canvas.StretchDraw(RT,tempbmp); result.CompressionQuality := Quality; result.Assign(bmp); finally tempbmp.Free; bmp.Free; end; end; ~悠遊法國號~

下面是我的方法将图片压缩成了160*120: Function CompressIMG(o_bitmap:Tbitmap):Tbitmap; var MaxPixW: real; MaxPixH: real; imagex: real; imagey: real; proportion:real; tempRect :TRect; n_bitmap:Tbitmap; begin n_bitmap:=TBitmap.create; MaxPixW:=o_bitmap.Width; MaxPixH:=o_bitmap.Height; imagex:=160.0; imagey:=120.0; /////////// 确定n_bitmap的宽高///////////////// proportion:=MaxPixW/MaxPixH; if proportion>=imagex/imagey then begin n_bitmap.Width:=160; n_bitmap.Height:=round(n_bitmap.Width/proportion); end else begin n_bitmap.Height:=120; n_bitmap.Width:=round(n_bitmap.Height*proportion); end; tempRect.Left:=0; tempRect.Right:=n_bitmap.Width; tempRect.Top:=0; tempRect.Bottom:=n_bitmap.Height; n_bitmap.Canvas.StretchDraw(tempRect,o_bitmap); Result:=n_bitmap; end;