$PBExportHeader$of_getpicturesize_h.srf
global type of_getpicturesize_h from function_object
end type

forward prototypes
global function long of_getpicturesize_h (string as_filename)
end prototypes

global function long of_getpicturesize_h (string as_filename);Integer   li_File,   li_DataRead
Blob   lb_Data
Long   ll_FileLength,ll_PictureWidth,ll_PictureHeight
Long   ll_DataLen,ll_DataPos,ll_FilePos
Boolean   lb_LoopFlag   =   TRUE
Char   lc_Char1,lc_Char2
Long al_PictureWidth,al_PictureHeight
//文件不存在 
IF   NOT   FileExists(as_FileName)   THEN   RETURN   0

//取文件大小 
ll_FileLength   =   FileLength(as_FileName)

//打开文件 
li_File   =   FileOpen(as_FileName,StreamMode!)
IF   li_File  =   -1   THEN   RETURN   0

//读取文件 
li_DataRead   =   FileRead(li_File,lb_Data)
IF   li_DataRead   <=   0  THEN
	FileClose(li_File)
	RETURN  0
END IF

//   GIF目前主要有两种类型 
//   1.   标识为GIF87a,   只是用来存储单幅静止图像 
//   2.   标识为GIF89a,   可以同时存储若干幅静止图像并进而形成连续的动画 
//   文件的前   6   个字节为标识:GIF87a   或   GIF89a,   第   7,8   字节为图像宽度(width),   
//   第   9,10   字节为图像高度(height),   注意两个字节中低位在前 

//   GIF   文件格式判断 
IF   String(BlobMid(lb_Data,1,4)) =  'GIF8' THEN
	ll_PictureWidth   = Asc(String(BlobMid(lb_Data,7,1)))   +  Asc(String(BlobMid(lb_Data,8,1)))   * 256
	ll_PictureHeight   =  Asc(String(BlobMid(lb_Data,9,1)))   +   Asc(String(BlobMid(lb_Data,10,1)))   * 256
	
	IF ll_PictureWidth  > 0 AND  ll_PictureHeight > 0 THEN
		al_PictureWidth   =  ll_PictureWidth
		al_PictureHeight   =  ll_PictureHeight
		FileClose(li_File)
		RETURN  al_PictureHeight  * 4
	ELSE
		FileClose(li_File)
		RETURN   0
	END IF
END IF

//   JPEG文件格式 
//   前   3   个字节为标识:   0xFF,0xD8,0xFF 
IF   String(BlobMid(lb_Data,1,3))   =   Char(255)   +   Char(216)   +   Char(255)   THEN
	ll_DataLen   =   Len(lb_Data)
	ll_DataPos   =   3
	ll_FilePos   =   3
	DO WHILE   lb_LoopFlag
		ll_DataPos   =   ll_DataPos   +   1
		ll_FilePos   =   ll_FilePos   +   1
		lc_Char1   =   String(BlobMid(lb_Data,ll_DataPos,1))
		lc_Char2   =   String(BlobMid(lb_Data,ll_DataPos   +   1,1))
		IF   lc_Char1   =   Char(255)   AND   lc_Char2   <>   Char(255) THEN
			IF   lc_Char2   >=   Char(192)   AND   lc_Char2   <=   Char(195) THEN
				//找到尺寸数据 
				ll_PictureWidth   =   Asc(String(BlobMid(lb_Data,ll_DataPos   +   7,1)))   *   256   +   Asc(String(BlobMid(lb_Data,ll_DataPos   +   8,1)))
				ll_PictureHeight   =   Asc(String(BlobMid(lb_Data,ll_DataPos   +   5,1)))  *   256   +   Asc(String(BlobMid(lb_Data,ll_DataPos   +   6,1)))
				lb_LoopFlag   =   FALSE
			ELSE
				//没有找到尺寸数据,重新读取文件 
				ll_FilePos   =   ll_FilePos   +   Asc(String(BlobMid(lb_Data,ll_DataPos   +  3,1)))   *   256   +   Asc(String(BlobMid(lb_Data,ll_DataPos   +   2,1)))   +   1
				IF   ll_FilePos   >   ll_FileLength THEN
					FileClose(li_File)
					RETURN   0
				ELSE
					FileSeek(li_File,ll_FilePos)
					FileRead(li_File,lb_Data)
					ll_DataLen   =   Len(lb_Data)
					ll_DataPos   =   0
				END IF
			END IF
		END IF
		IF   ll_DataPos   =   ll_DataLen   -   9   AND   lb_LoopFlag   =   TRUE   THEN
			ll_FilePos   =   ll_FilePos   -   9
			FileSeek(li_File,ll_FilePos)
			FileRead(li_File,lb_Data)
			ll_DataLen   =   Len(lb_Data)
			ll_DataPos   =   0
		END IF
		IF   ll_FilePos   >=   ll_FileLength   THEN
			lb_LoopFlag   =   FALSE
		END IF
	LOOP
	IF   ll_PictureWidth   >   0   AND   ll_PictureHeight   >   0   THEN
		al_PictureWidth   =   ll_PictureWidth
		al_PictureHeight   =   ll_PictureHeight
		FileClose(li_File)
		RETURN   al_PictureHeight  * 4
	ELSE
		FileClose(li_File)
		RETURN   0
	END IF
END IF

//   BMP文件格式 
//   前两个字节是标识:标识可能有很多种 
//   第   19,20,21,22   字节为宽度(width),   第   23,24,25,26   字节为高度(height) 
//   四个字节组成dword,   低位在前 
IF   String(BlobMid(lb_Data,1,2))   =   'BM' THEN
	ll_PictureWidth   =   Asc(String(BlobMid(lb_Data,19,1)))   +   Asc(String(BlobMid(lb_Data,20,1)))  *   256   +   Asc(String(BlobMid(lb_Data,21,1)))   *   65536   +   Asc(String(BlobMid(lb_Data,22,1)))   *   16777216
	ll_PictureHeight   =   Asc(String(BlobMid(lb_Data,23,1)))   +   Asc(String(BlobMid(lb_Data,24,1)))  *   256   +   Asc(String(BlobMid(lb_Data,25,1)))   *   65536   +   Asc(String(BlobMid(lb_Data,26,1)))   *   16777216
	IF   ll_PictureWidth   >   0   AND   ll_PictureHeight   >   0   THEN
		al_PictureWidth   =   ll_PictureWidth
		al_PictureHeight   =   ll_PictureHeight
		FileClose(li_File)
		RETURN   al_PictureHeight  * 4
	ELSE
		FileClose(li_File)
		RETURN   0
	END IF
 
	
END IF


return 0










end function