最近开发的一个系统，需根据用户提交的图片（图片文件以字符流的形式从客户机传到服务器）读出该图片的高和宽，通过下列代码实现了该功能，现在拿出来给大家参考。

……

type

TGIFHeader = packed record

Signature: array[0..2] of Char;

Version: array[0..2] of Char;

ScreenWidth: Word;

ScreenHeight: Word;

PackedFields,

BackgroundColorIndex,

AspectRatio: Byte;

end;

TGIFInfoHeader = TGIFHeader;

……

procedure Ttempphoto.AddMediaRec(out content_no, succed, errno,

errmsg: OleVariant; const PicName, Title, Author, Theme, PublishDate,

KeyWord: WideString; Length: SYSUINT; const Memo: WideString; PicHight,

PicWidth, Color_Pan: SYSUINT; content: OleVariant; PayNo: SYSINT;

const GroupNo: WideString);

file://过程中部分相关的代码

var

p : pwidechar;

bb : string;

tempchar : integer;

mm : SYSUINT;

jpeg: TJPEGImage;

Gif:TGIFInfoHeader;

bmp:TBitmapInfoHeader;

phowidth: integer;

Phoheight: integer;

ss:TStringStream;

fileheader:TBitmapfileheader;

begin

……

p := Tvardata(content).volestr;

setlength(bb,Length);

mm := 1;

while mm<=Length do

begin

tempchar := integer(p[(mm-1) div 2]);

bb[mm]:= chr(tempchar mod 256);

if mm

mm := mm+2;

end;

file://读取图片的高和宽

ss:=tstringstream.Create(bb);

if ((PicName=´jpg´)or(PicName=´jpeg´)) then begin

jpeg:= TJPEGImage.Create;//需uses jpeg

jpeg.LoadFromStream(ss);

phowidth:=jpeg.width;

phoheight:=jpeg.height;

jpeg.free;

end

file://根据自己定义的gif格式图片文件头信息读取图片的高和宽

else if (PicName=´gif´) then begin

ss.Read(gif,sizeof(gif));

phowidth:=gif.ScreenWidth;

phoheight:=gif.ScreenHeight;

end

file://根据windows单元定义的bmp格式图片文件头信息读取图片的高和宽

else if (PicName=´bmp´) then begin

ss.Read(fileheader,sizeof(fileheader));

ss.Read(bmp,sizeof(bmp));

phowidth:=bmp.biWidth;

phoheight:=bmp.biHeight;

end

else begin

end;

ss.Free;

……

end;

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